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Sample records for earth magnetosphere

  1. LANL Studies Earth's Magnetosphere

    ScienceCinema

    Daughton, Bill

    2018-02-13

    A new 3-D supercomputer model presents a new theory of how magnetic reconnection works in high-temperature plasmas. This Los Alamos National Laboratory research supports an upcoming NASA mission to study Earth's magnetosphere in greater detail than ever.

  2. Plasma entry into the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Frank, L. A.

    1972-01-01

    Both high- and low-altitude measurements are used to establish the salient features of the three regions presently thought to be the best candidates for the entry of magnetosheath plasma into the magnetosphere, and hence the primal sources of charged particles for the plasma sheet and its earthward termination in the ring current. These three regions are (1) the polar cusps and their extensions into the nighttime magnetosphere, (2) the downstream flanks of the magnetosphere at geocentric radial distances approximately equal to 10 to 50 earth radii along the plasma sheet-magnetosheath interface, and (3) the distant magnetotail at radial distances greater than or approximately equal to 50 earth radii. Present observational knowledge of each of these regions is discussed critically as to evidences for charged particle entry into the magnetosphere from the magnetosheath. The possibility that all three of these magnetospheric domains share an intimate topological relationship is also examined.

  3. The Earth's magnetosphere modeling and ISO standard

    NASA Astrophysics Data System (ADS)

    Alexeev, I.

    The empirical model developed by Tsyganenko T96 is constructed by minimizing the rms deviation from the large magnetospheric data base Fairfield et al 1994 which contains Earth s magnetospheric magnetic field measurements accumulated during many years The applicability of the T96 model is limited mainly by quiet conditions in the solar wind along the Earth orbit But contrary to the internal planet s field the external magnetospheric magnetic field sources are much more time-dependent A reliable representation of the magnetic field is crucial in the framework of radiation belt modelling especially for disturbed conditions The last version of the Tsyganenko model has been constructed for a geomagnetic storm time interval This version based on the more accurate and physically consistent approach in which each source of the magnetic field would have its own relaxation timescale and a driving function based on an individual best fit combination of the solar wind and IMF parameters The same method has been used previously for paraboloid model construction This method is based on a priori information about the global magnetospheric current systems structure Each current system is included as a separate block module in the magnetospheric model As it was shown by the spacecraft magnetometer data there are three current systems which are the main contributors to the external magnetospheric magnetic field magnetopause currents ring current and tail current sheet Paraboloid model is based on an analytical solution of the Laplace

  4. Juno Magnetometer Observations in the Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Connerney, J. E.; Oliversen, R. J.; Espley, J. R.; MacDowall, R. J.; Schnurr, R.; Sheppard, D.; Odom, J.; Lawton, P.; Murphy, S.; Joergensen, J. L.; Joergensen, P. S.; Merayo, J. M.; Denver, T.; Bloxham, J.; Smith, E. J.; Murphy, N.

    2013-12-01

    The Juno spacecraft enjoyed a close encounter with Earth on October 9, 2013, en route to Jupiter Orbit Insertion (JOI) on July 5, 2016. The Earth Flyby (EFB) provided a unique opportunity for the Juno particles and fields instruments to sample mission relevant environments and exercise operations anticipated for orbital operations at Jupiter, particularly the period of intense activity around perijove. The magnetic field investigation onboard Juno is equipped with two magnetometer sensor suites, located at 10 and 12 m from the spacecraft body at the end of one of the three solar panel wings. Each contains a vector fluxgate magnetometer (FGM) sensor and a pair of co-located non-magnetic star tracker camera heads which provide accurate attitude determination for the FGM sensors. This very capable magnetic observatory sampled the Earth's magnetic field at 64 vector samples/second throughout passage through the Earth's magnetosphere. We present observations of the Earth's magnetic field and magnetosphere obtained throughout the encounter and compare these observations with those of other Earth-orbiting assets, as available, and with particles and fields observations acquired by other Juno instruments operated during EFB.

  5. Dynamics of the Earth's Radiation Belts and Inner Magnetosphere

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-12-01

    Trapped by Earth's magnetic field far above the planet's surface, the energetic particles that fill the radiation belts are a sign of the Sun's influence and a threat to our technological future. In the AGU monograph Dynamics of the Earth's Radiation Belts and Inner Magnetosphere, editors Danny Summers, Ian R. Mann, Daniel N. Baker, and Michael Schulz explore the inner workings of the magnetosphere. The book reviews current knowledge of the magnetosphere and recent research results and sets the stage for the work currently being done by NASA's Van Allen Probes (formerly known as the Radiation Belt Storm Probes). In this interview, Eos talks to Summers about magnetospheric research, whistler mode waves, solar storms, and the effects of the radiation belts on Earth.

  6. Radiation shelter effectiveness beyond the earth magnetosphere

    NASA Astrophysics Data System (ADS)

    Shurshakov, V. A.; Benghin, V. V.; Kolomensky, A. V.; Petrov, V. M.

    Solar energetic particles (SEP) and galactic cosmic rays are known to be the sources of radiation hazard for missions beyond the Earth magnetosphere. An additionally shielded compartment of the mission spacecraft, called usually the radiation shelter, is considered as an important part of the radiation safety system. The shielding of the radiation shelter must be at least a few times higher than that of the remaining compartments. The mission crewmembers are supposed to stay in the radiation shelter for relatively short time of less than a day or two during SEP events only. A job-oriented radiation monitoring system (RMS) should be used on board the Martian mission spacecraft to provide the crew with necessary prediction information concerning the onset of a large SEP event. The information should be obtained independently of the ground-based support services and, hence, should be derived from online measurements of the dynamics of soft X-rays and charged energetic particles using the RMS sensors. As a result, the signal for the spacecrew members to go to the shelter gets somewhat delayed with respect to the SEP event onset, so that they appear to stay outside the shelter for some time during the event. The dependence of the crew-received dose on the SEP event prediction lag has been analyzed in terms of the standard SEP dynamics model for a typical 500-day Martian mission scenario. The Martian mission dose simulations have demonstrated a high efficiency of the radiation shelter despite the unavoidable lag of the RMS prediction signal.

  7. Quasi-static MHD processes in earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Voigt, Gerd-Hannes

    1988-01-01

    An attempt is made to use the MHD equilibrium theory to describe the global magnetic field configuration of earth's magnetosphere and its time evolution under the influence of magnetospheric convection. To circumvent the difficulties inherent in today's MHD codes, use is made of a restriction to slowly time-dependent convection processes with convective velocities well below the typical Alfven speed. This restriction leads to a quasi-static MHD theory. The two-dimensional theory is outlined, and it is shown how sequences of two-dimensional equilibria evolve into a steady state configuration that is likely to become tearing mode unstable. It is then concluded that magnetospheric substorms occur periodically in earth's magnetosphere, thus being an integral part of the entire convection cycle.

  8. Is Jupiter's magnetosphere like a pulsar's or earth's?

    NASA Technical Reports Server (NTRS)

    Kennel, C. F.; Coroniti, F. V.

    1974-01-01

    The application of pulsar physics to determine the magnetic structure in the planet Jupiter outer magnetosphere is discussed. A variety of theoretical models are developed to illuminate broad areas of consistency and conflict between theory and experiment. Two possible models of Jupiter's magnetosphere, a pulsar-like radial outflow model and an earth-like convection model, are examined. A compilation of the simple order of magnitude estimates derivable from the various models is provided.

  9. The outer magnetosphere. [composition and comparison with earth

    NASA Technical Reports Server (NTRS)

    Schardt, A. W.; Behannon, K. W.; Lepping, R. P.; Carbary, J. F.; Eviatar, A.; Siscoe, G. L.

    1984-01-01

    Similarities between the Saturnian and terrestrial outer magnetosphere are examined. Saturn, like earth, has a fully developed magnetic tail, 80 to 100 RS in diameter. One major difference between the two outer magnetospheres is the hydrogen and nitrogen torus produced by Titan. This plasma is, in general, convected in the corotation direction at nearly the rigid corotation speed. Energies of magnetospheric particles extend to above 500 keV. In contrast, interplanetary protons and ions above 2 MeV have free access to the outer magnetosphere to distances well below the Stormer cutoff. This access presumably occurs through the magnetotail. In addition to the H+, H2+, and H3+ ions primarily of local origin, energetic He, C, N, and O ions are found with solar composition. Their flux can be substantially enhanced over that of interplanetary ions at energies of 0.2 to 0.4 MeV/nuc.

  10. Magnetosphere-Regolith/Exosphere Coupling: Differences and Similarities to the Earth Magnetosphere-Ionosphere Coupling

    NASA Technical Reports Server (NTRS)

    Gjerleov, J. W.; Slavin, J. A.

    2001-01-01

    Of the three Mercury passes made by Mariner 10, the first and third went through the Mercury magnetosphere. The third encounter which occurred during northward IMF (interplanetary magnetic field) showed quiet time magnetic fields. In contrast the third encounter observed clear substorm signatures including dipolarization, field-aligned currents (FACs) and injection of energetic electrons at geosynchronous orbit. However, the determined cross-tail potential drop and the assumed height integrated conductance indicate that the FAC should be 2-50 times weaker than observed. We address this inconsistency and the fundamental problem of FAC closure whether this takes place in the regolith or in the exosphere. The current state of knowledge of the magnetosphere-exosphere/regolith coupling is addressed and similarities and differences to the Earth magnetosphere-ionosphere coupling are discussed.

  11. Buoyancy Waves in Earth's Magnetosphere: Calculations for a 2-D Wedge Magnetosphere

    NASA Astrophysics Data System (ADS)

    Wolf, R. A.; Toffoletto, F. R.; Schutza, A. M.; Yang, J.

    2018-05-01

    To improve theoretical understanding of the braking oscillations observed in Earth's inner plasma sheet, we have derived a theoretical model that describes k∥ = 0 magnetohydrodynamic waves in an idealized magnetospheric configuration that consists of a 2-D wedge with circular-arc field lines. The low-frequency, short-perpendicular-wavelength mode obeys a differential equation that is often used to describe buoyancy oscillations in a neutral atmosphere, so we call those waves "buoyancy waves," though the magnetospheric buoyancy force results from magnetic tension rather than gravity. Propagation of the wave is governed mainly by a position-dependent frequency ωb, the "buoyancy frequency," which is a fundamental property of the magnetosphere. The waves propagate if ωb > ω but otherwise evanesce. In the wedge magnetosphere, ωb turns out to be exactly the fundamental oscillation frequency for poloidal oscillations of a thin magnetic filament, and we assume that the same is true for the real magnetosphere. Observable properties of buoyancy oscillations are discussed, but propagation characteristics vary considerably with the state of the magnetosphere. For a given event, the buoyancy frequency and propagation characteristics can be determined from pressure and density profiles and a magnetic field model, and these characteristics have been worked out for one typical configuration. A localized disturbance that initially resembles a dipolarizing flux bundle spreads east-west and also penetrates into the plasmasphere to some extent. The calculated amplitude near the center of the original wave packet decays in a few oscillation periods, even though our calculation includes no dissipation.

  12. Density Variations in the Earth's Magnetospheric Cusps

    NASA Technical Reports Server (NTRS)

    Walsh, B. M.; Niehof, J.; Collier, M. R.; Welling, D. T.; Sibeck, D. G.; Mozer, F. S.; Fritz, T. A.; Kuntz, K. D.

    2016-01-01

    Seven years of measurements from the Polar spacecraft are surveyed to monitor the variations of plasma density within the magnetospheric cusps. The spacecraft's orbital precession from 1998 through 2005 allows for coverage of both the northern and southern cusps from low altitude out to the magnetopause. In the mid- and high- altitude cusps, plasma density scales well with the solar wind density (n(sub cusp)/n(sub sw) approximately 0.8). This trend is fairly steady for radial distances greater then 4 R(sub E). At low altitudes (r less than 4R(sub E)) the density increases with decreasing altitude and even exceeds the solar wind density due to contributions from the ionosphere. The density of high charge state oxygen (O(greater +2) also displays a positive trend with solar wind density within the cusp. A multifluid simulation with the Block-Adaptive-Tree Solar Wind Roe-Type Upwind Scheme MHD model was run to monitor the relative contributions of the ionosphere and solar wind plasma within the cusp. The simulation provides similar results to the statistical measurements from Polar and confirms the presence of ionospheric plasma at low altitudes.

  13. VLF-HISS from electrons in the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Maeda, K.

    1973-01-01

    Intensities of auroral and magnetospheric hiss generated by the Cherenkov radiation process of electrons in the lower magnetosphere were calculated with respect to a realistic model of the earth's magnetosphere. In this calculation, the magnetic field was expressed by the Mead-Fairfield Model, and a static model of the iono-magnetospheric plasma distribution was constructed by accumulated data obtained by recent satellite observations. The energy range of hiss producing electrons and the frequency range of produced VLF in the computation are 100 eV to 200 keV, and 2 to 200 kHz, respectively. The maximum hiss intensity produced by soft electrons is more than one order higher than that of hard electron produced hiss. Higher rate of hiss occurrence in the daytime side, particularly in the soft electron precipitation zone in the morning sector, and less association of auroral hiss in nighttime sectors must be, therefore, due to the local time dependence of the energy spectra of precipitating electrons rather than the difference in the geomagnetic field and in the geoplasma distributions.

  14. Discovery of Suprathermal Fe+ in and near Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Christon, S. P.; Hamilton, D. C.; Plane, J. M. C.; Mitchell, D. G.; Grebowsky, J. M.; Spjeldvik, W. N.; Nylund, S. R.

    2017-12-01

    Suprathermal (87-212 keV/e) singly charged iron, Fe+, has been observed in and near Earth's equatorial magnetosphere using long-term ( 21 years) Geotail/STICS ion composition data. Fe+ is rare compared to dominant suprathermal solar wind and ionospheric origin heavy ions. Earth's suprathermal Fe+ appears to be positively associated with both geomagnetic and solar activity. Three candidate lower-energy sources are examined for relevance: ionospheric outflow of Fe+ escaped from ion layers altitude, charge exchange of nominal solar wind Fe+≥7, and/or solar wind transported inner source pickup Fe+ (likely formed by solar wind Fe+≥7 interaction with near sun interplanetary dust particles, IDPs). Semi-permanent ionospheric Fe+ layers form near 100 km altitude from the tons of IDPs entering Earth's atmosphere daily. Fe+ scattered from these layers is observed up to 1000 km altitude, likely escaping in strong ionospheric outflows. Using 26% of STICS's magnetosphere-dominated data at low-to-moderate geomagnetic activity levels, we demonstrate that solar wind Fe charge exchange secondaries are not an obvious Fe+ source then. Earth flyby and cruise data from Cassini/CHEMS, a nearly identical instrument, show that inner source pickup Fe+ is likely not important at suprathermal energies. Therefore, lacking any other candidate sources, it appears that ionospheric Fe+ constitutes at least an important portion of Earth's suprathermal Fe+, comparable to observations at Saturn where ionospheric origin suprathermal Fe+ has also been observed.

  15. Energy coupling in the magnetospheres of earth and Mercury

    NASA Technical Reports Server (NTRS)

    Baker, D. N.

    1990-01-01

    The mechanisms involved in the dissipation of solar-wind energy during magnetospheric substorms are considered theoretically, comparing models for earth and Mercury. In the model for terrestrial substorms, IMF lines interconnect with terrestrial field lines near the front of the magnetosphere and are dragged back, carrying plasma and energy, to form tail lobes; a magnetic neutral region is then formed by reconnection of the open lines as the plasma sheet thins, and reconnective heating and acceleration of tail plasma lead to plasma inflow at the poles and formation of a plasmoid flowing down the tail at high velocity. Analogous phenomena on Mercury could produce precipitation of particles carrying 10-1000 GW of power into 'auroral zones' on the dark side of the planet. The feasibility of remote or in situ observations to detect such processes is discussed.

  16. On the paleo-magnetospheres of Earth and Mars

    NASA Astrophysics Data System (ADS)

    Scherf, Manuel; Khodachenko, Maxim; Alexeev, Igor; Belenkaya, Elena; Blokhina, Marina; Johnstone, Colin; Tarduno, John; Lammer, Helmut; Tu, Lin; Guedel, Manuel

    2017-04-01

    The intrinsic magnetic field of a terrestrial planet is considered to be an important factor for the evolution of terrestrial atmospheres. This is in particular relevant for early stages of the solar system, in which the solar wind as well as the EUV flux from the young Sun were significantly stronger than at present-day. We therefore will present simulations of the paleo-magnetospheres of ancient Earth and Mars, which were performed for ˜4.1 billion years ago, i.e. the Earth's late Hadean eon and Mars' early Noachian. These simulations were performed with specifically adapted versions of the Paraboloid Magnetospheric Model (PMM) of the Skobeltsyn Institute of Nuclear Physics of the Moscow State University, which serves as ISO-standard for the Earth's magnetic field (see e.g. Alexeev et al., 2003). One of the input parameters into our model is the ancient solar wind pressure. This is derived from a newly developed solar/stellar wind evolution model, which is strongly dependent on the initial rotation rate of the early Sun (Johnstone et al., 2015). Another input parameter is the ancient magnetic dipole field. In case of Earth this is derived from measurements of the paleomagnetic field strength by Tarduno et al., 2015. These data from zircons are varying between 0.12 and 1.0 of today's magnetic field strength. For Mars the ancient magnetic field is derived from the remanent magnetization in the Martian crust as measured by the Mars Global Surveyor MAG/ER experiment. These data together with dynamo theory are indicating an ancient Martian dipole field strength in the range of 0.1 to 1.0 of the present-day terrestrial dipole field. For the Earth our simulations show that the paleo-magnetosphere during the late Hadean eon was significantly smaller than today, with a standoff-distance rs ranging from ˜3.4 to 8 Re, depending on the input parameters. These results also have implications for the early terrestrial atmosphere. Due to the significantly higher EUV flux, the

  17. Auroral Phenomenology and Magnetospheric Processes: Earth and Other Planets

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-07-01

    The dancing glow of the aurorae, the long tendrils of light that seem to reach up into space, has mesmerized scientists for centuries. More than a beautiful display, the aurorae tell us about the Earth—about its atmosphere, its magnetic field, and its relationship with the Sun. As technology developed, researchers looking beyond Earth's borders discovered an array of auroral processes on planets throughout the solar system. In the AGU monograph Auroral Phenomenology and Magnetospheric Processes: Earth and Other Planets, editors Andreas Keiling, Eric Donovan, Fran Bagenal, and Tomas Karlsson explore the many open questions that permeate the science of auroral physics and the relatively recent field of extraterrestrial aurorae. In this interview, Eos talks to Karlsson about extraterrestrial aurorae, Alfvén waves, and the sounds of the northern lights.

  18. The Earth's magnetosphere as a sample of the plasma universe

    NASA Technical Reports Server (NTRS)

    Faelthammar, Carl-Gunne

    1986-01-01

    Plasma processes in the Earth's neighborhood determine the environmental conditions under which space-based equipment for science or technology must operate. These processes are peculiar to a state of matter that is rare on Earth but dominates the universe as whole. The physical, and especially the electrodynamic, properties of this state of matter is still far from well understood. By fortunate circumstances, the magnetosphere-ionosphere system of the Earth provides a rich sample of widely different plasma populations, and, even more importantly, it is the site of a remarkable variety of plasma processes. In different combinations such processes must be important throughout the universe, which is overwhelmingly dominated by matter in the plasma state. Therefore, observations and experiments in the near-Earth plasma serve a multitude of purposes. They will not only (1) clarify the dynamics of the space environment but also (2) widen the understanding of matter, (3) form a basis for interpretating remote observations of astrophysical objects, thereby even (4) help to reconstruct events that led to the evolution of the solar system. Last but not least they will (5) provide know-how required for adapting space-based technology to the plasma environment. Such observations and experiments will require a close mutual interplay between science and technology.

  19. The Transport of Solar Ions Through the Earth's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Lennartsson, O. W.

    1999-01-01

    This report covers the initial phase of an investigation that was originally selected by NASA Headquarters for funding by a grant but was later transferred to NASA GSFC for continued funding under a new and separate contract. The principal objective of the investigation, led by Dr. O.W. Lennartsson, is to extract information about the solar origin plasma in Earth's magnetosphere, specifically about the entry and transport of this plasma, using energetic (10 eV/e to 18 keV/e) ion composition data from the Lockheed Plasma Composition Experiment on the NASA/ESA International Sun-Earth Explorer One (ISEE 1) satellite. These data were acquired many years ago, from November 1977 through March of 1982, but, because of subsequent failures of similar experiments on several other spacecraft, they are still the only substantial ion composition data available from Earth's magnetotail, beyond 10 R(sub E), in the critically important sub-kev to keV energy range. All of the Lockheed data now exist in a compacted scientific format, suitable for large-scale statistical investigations, which has been archived both at Lockheed Martin in Palo Alto and at the National Space Science Data Center (NSSDC) in Greenbelt. The completion of the archiving, by processing the remaining half of the data, was made possible by separate funding through a temporary NASA program for data restoration and was given priority over the data analysis by a no-cost extension of the subject grant. By chance, the period of performance coincided with an international study of source and loss processes of magnetospheric plasma, sponsored by the International Space Science Institute (ISSI) in Bern, Switzerland, for which Dr. Lennartsson was invited to serve as one of 12 co-chairs. This study meshed well with the continued analysis of the NASA/Lockheed ISEE ion composition data and provided a natural forum for a broader discussion of the results from this unique experiment. What follows is arranged, for the most

  20. Transport and acceleration of plasma in the magnetospheres of Earth and Jupiter and expectations for Saturn

    NASA Astrophysics Data System (ADS)

    Kivelson, M. G.

    The first comparative magnetospheres conference was held in Frascati, Italy thirty years ago this summer, less than half a year after the first spacecraft encounter with Jupiter's magnetosphere (Formisano, V. (Ed.), The Magnetospheres of the Earth and Jupiter, Proceedings of the Neil Brice Memorial Symposium held in Frascati, Italy, May 28-June 1, 1974. D. Reidel Publishing Co., Boston, USA, 1975). Disputes highlighted various issues still being investigated, such as how plasma transport at Jupiter deviates from the prototypical form of transport at Earth and the role of substorms in Jupiter's dynamics. Today there is a wealth of data on which to base the analysis, data gathered by seven missions that culminated with Galileo's 8-year orbital tour. We are still debating how magnetic flux is returned to the inner magnetosphere following its outward transport by iogenic plasma. We are still uncertain about the nature of sporadic dynamical disturbances at Jupiter and their relation to terrestrial substorms. At Saturn, the centrifugal stresses are not effective in distorting the magnetic field, so in some ways the magnetosphere appears Earthlike. Yet the presence of plasma sources in the close-in equatorial magnetosphere parallels conditions at Jupiter. This suggests that we need to study both Jupiter and Earth when thinking about what to anticipate from Cassini's exploration of Saturn's magnetosphere. This paper addresses issues relevant to plasma transport and acceleration in all three magnetospheres.

  1. Study of effects of space power satellites on life support functions of the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Douglas, M.; Laquey, R.; Deforest, S. E.; Lindsey, C.; Warshaw, H.

    1977-01-01

    The effects of the Satellite Solar Power System (SSPS) on the life support functions of the earth's magnetosphere were investigated. Topics considered include: (1) thruster effluent effects on the magnetosphere; (2) biological consequences of SSPS reflected light; (3) impact on earth bound astronomy; (4) catastrophic failure and debris; (5) satellite induced processes; and (6) microwave power transmission. Several impacts are identified and recommendations for further studies are provided.

  2. Dynamics of the Earth's Inner Magnetosphere and its Connection to the Ionosphere: Current Understanding and Challenges

    NASA Technical Reports Server (NTRS)

    Zheng, Yihua

    2010-01-01

    The Earth's inner magnetosphere, a vast volume in space spanning from 1.5 Re (Earth radii) to 10 Re, is a host to a variety of plasma populations (with energy from 1 eV to few MeV) and physical processes where most of which involve plasma and field coupling. As a gigantic particle accelerator, the inner magnetosphere includes three overlapping regions: the plasmasphere, the ring current, and the Van Allen radiation belt. The complex structures and dynamics of these regions are externally driven by solar activities and internally modulated by intricate interactions and coupling. As a major constituent of Space Weather, the inner magnetosphere is both scientifically intriguing and practically important to our society. In this presentation, I will discuss our recent results from the Comprehensive Ring Current Model, in the context of our current understanding of the inner magnetosphere in general and challenges ahead in making further progresses.

  3. Dynamics of the Earth's Inner Magnetosphere and Its Connection to the Ionosphere: Current Understanding and Challenges

    NASA Technical Reports Server (NTRS)

    Zheng, Yihua

    2011-01-01

    The Earth's inner magnetosphere, a vast volume in space spanning from 1.5 Re (Earth radii) to 10 Re, is a host to a variety of plasma populations (with energy from 1 eV to few MeV) and physical processes where most of which involve plasma and field coupling. As a gigantic particle accelerator, the inner magnetosphere includes three overlapping regions: the plasmasphere, the ring current, and the Van Allen radiation belt. The complex structures and dynamics of these regions are externally driven by solar activities and internally modulated by intricate interactions and coupling. As a major constituent of Space Weather, the inner magnetosphere is both scientifically intriguing and practically important to our society. In this presentation, I will discuss our recent results from the Comprehensive Ring Current Model, in the context of our current understanding of the inner magnetosphere in general and challenges ahead in making further progresses.

  4. Mass loading of the Earth's magnetosphere by micron size lunar ejecta. 2: Ejecta dynamics and enhanced lifetimes in the Earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Alexander, W. M.; Tanner, W. G.; Anz, P. D.; Chen, A. L.

    1986-01-01

    Extensive studies were conducted concerning the indivdual mass, temporal and positional distribution of micron and submicron lunar ejecta existing in the Earth-Moon gravitational sphere of influence. Initial results show a direct correlation between the position of the Moon, relative to the Earth, and the percentage of lunar ejecta leaving the Moon and intercepting the magnetosphere of the Earth at the magnetopause surface. It is seen that the Lorentz Force dominates all other forces, thus suggesting that submicron dust particles might possibly be magnetically trapped in the well known radiation zones.

  5. First report of resonant interactions between whistler mode waves in the Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Gao, Xinliang; Lu, Quanming; Wang, Shui

    2017-06-01

    Nonlinear physics related to whistler mode waves in the Earth's magnetosphere are now becoming a hot topic. In this letter, based on Time History of Events and Macroscale Interactions during Substorms waveform data, we report several interesting whistler mode wave events, where the upper band whistler mode waves are believed to be generated through the nonlinear wave-wave coupling between two lower band waves. This is the first report on resonant interactions between whistler mode waves in the Earth's magnetosphere. In these events, the two lower band whistler mode waves are observed to have oppositely propagating directions, while the generated upper band wave has the same propagating direction as the lower band wave with the relatively higher frequency. Moreover, the wave normal angle of the excited upper band wave is usually larger than those of two lower band whistler mode waves. Our results reveal the large diversity of the evolution of whistler mode waves in the Earth's magnetosphere.

  6. Global Evolution of the Earth's Magnetosphere in Response to a Sudden Ring Current Injection

    NASA Astrophysics Data System (ADS)

    No, Jincheol; Choe, Gwangson; Park, Geunseok

    2014-05-01

    The dynamical evolution of the Earth's magnetosphere loaded with a transiently enhanced ring current is investigated by global magnetohydrodynamic simulations. Two cases with different values of the primitive ring current are considered. In one case, the initial ring current is strong enough to create a magnetic island in the magnetosphere. The magnetic island readily reconnects with the earth-connected ambient field and is destroyed as the system approaches a steady equilibrium. In the other case, the initial ring current is not so strong, and the initial magnetic field configuration bears no magnetic island, but features a wake of bent field lines, which is smoothed out through the relaxing evolution of the magnetosphere. The relaxation time of the magnetosphere is found to be about five to six minutes, over which the ring current is reduced to about a quarter of its initial value. Before reaching a steady state, the magnetosphere is found to undergo an overshooting expansion and a subsequent contraction. Fast and slow magnetosonic waves are identified to play an important role in the relaxation toward equilibrium. Our study suggests that a sudden injection of the ring current can generate an appreciable global pulsation of the magnetosphere.

  7. Particle-in-cell simulations of Earth-like magnetosphere during a magnetic field reversal

    NASA Astrophysics Data System (ADS)

    Barbosa, M. V. G.; Alves, M. V.; Vieira, L. E. A.; Schmitz, R. G.

    2017-12-01

    The geologic record shows that hundreds of pole reversals have occurred throughout Earth's history. The mean interval between the poles reversals is roughly 200 to 300 thousand years and the last reversal occurred around 780 thousand years ago. Pole reversal is a slow process, during which the strength of the magnetic field decreases, become more complex, with the appearance of more than two poles for some time and then the field strength increases, changing polarity. Along the process, the magnetic field configuration changes, leaving the Earth-like planet vulnerable to the harmful effects of the Sun. Understanding what happens with the magnetosphere during these pole reversals is an open topic of investigation. Only recently PIC codes are used to modeling magnetospheres. Here we use the particle code iPIC3D [Markidis et al, Mathematics and Computers in Simulation, 2010] to simulate an Earth-like magnetosphere at three different times along the pole reversal process. The code was modified, so the Earth-like magnetic field is generated using an expansion in spherical harmonics with the Gauss coefficients given by a MHD simulation of the Earth's core [Glatzmaier et al, Nature, 1995; 1999; private communication to L.E.A.V.]. Simulations show the qualitative behavior of the magnetosphere, such as the current structures. Only the planet magnetic field was changed in the runs. The solar wind is the same for all runs. Preliminary results show the formation of the Chapman-Ferraro current in the front of the magnetosphere in all the cases. Run for the middle of the reversal process, the low intensity magnetic field and its asymmetrical configuration the current structure changes and the presence of multiple poles can be observed. In all simulations, a structure similar to the radiation belts was found. Simulations of more severe solar wind conditions are necessary to determine the real impact of the reversal in the magnetosphere.

  8. Ion Composition and Energization in the Earth's Inner Magnetosphere and the Effects on Ring Current Buildup

    NASA Astrophysics Data System (ADS)

    Keika, K.; Kistler, L. M.; Brandt, P. C.

    2014-12-01

    In-situ observations and modeling work have confirmed that singly-charged oxygen ions, O+, which are of Earth's ionospheric origin, are heated/accelerated up to >100 keV in the magnetosphere. The energetic O+ population makes a significant contribution to the plasma pressure in the Earth's inner magnetosphere during magnetic storms, although under quiet conditions H+ dominates the plasma pressure. The pressure enhancements, which we term energization, are caused by adiabatic heating through earthward transport of source population in the plasma sheet, local acceleration in the inner magnetosphere and near-Earth plasma sheet, and enhanced ion supply from the topside ionosphere. The key issues regarding stronger O+ energization than H+ are non-adiabatic local acceleration, responsible for increase in O+ temperature, and more significant O+ supply than H+, responsible for increase in O+ density. Although several acceleration mechanisms and O+ supply processes have been proposed, it remains an open question what mechanism(s)/process(es) play the dominant role in stronger O+ energization. In this paper we summarize important spacecraft observations including those from Van Allen Probes, introduces the proposed mechanisms/processes that generate O+-rich energetic plasma population, and outlines possible scenarios of O+ pressure abundance in the Earth's inner magnetosphere.

  9. Real-time global MHD simulation of the solar wind interaction with the earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Shimazu, H.; Tanaka, T.; Fujita, S.; Nakamura, M.; Obara, T.

    We have developed a real-time global MHD simulation of the solar wind interaction with the earth s magnetosphere By adopting the real-time solar wind parameters including the IMF observed routinely by the ACE spacecraft responses of the magnetosphere are calculated with the MHD code We adopted the modified spherical coordinates and the mesh point numbers for this simulation are 56 58 and 40 for the r theta and phi direction respectively The simulation is carried out routinely on the super computer system NEC SX-6 at National Institute of Information and Communications Technology Japan The visualized images of the magnetic field lines around the earth pressure distribution on the meridian plane and the conductivity of the polar ionosphere can be referred to on the Web site http www nict go jp dk c232 realtime The results show that various magnetospheric activities are almost reproduced qualitatively They also give us information how geomagnetic disturbances develop in the magnetosphere in relation with the ionosphere From the viewpoint of space weather the real-time simulation helps us to understand the whole image in the current condition of the magnetosphere To evaluate the simulation results we compare the AE index derived from the simulation and observations In the case of isolated substorms the indices almost agreed well in both timing and intensities In other cases the simulation can predict general activities although the exact timing of the onset of substorms and intensities did not always agree By analyzing

  10. Statistical Behavior of Quasi-Steady Balanced Reconnection in Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Kissinger, Jennifer Eileen

    Magnetic reconnection between Earth's magnetosphere and the solar wind results in several modes of response, including the impulsive substorm and the quasi-steady mode known as steady magnetospheric convection (SMC). SMC events are theorized to result from balancing the dayside and nightside reconnection rates. The reasons the magnetosphere responds with different modes are not fully known. This dissertation comprises statistical data analysis of the SMC mode to investigate the solar wind conditions and magnetospheric properties during these events. A comprehensive list of SMC events is selected from 1997-2011. In the first of three studies, an association between SMCs and solar wind stream interfaces (SI) is identified in the declining phase of Solar Cycle 23. SMC occurrence peaks 12-24 hours after an SI if the solar wind is geoeffective. The subset of SI-associated SMCs occurs during fast solar wind velocity, in contrast to previous results, but the driving electric field imposed on the magnetosphere (Ey) is the same for SI-associated and unassociated SMC events. Therefore the magnitude and steadiness of E y is the most important solar wind parameter for an SMC to occur. The second study shows that magnetotail convection is significantly different for SMC events, compared to quiet intervals and isolated substorms. Fast flows transporting enhanced magnetic flux are deflected toward the dawn and dusk flanks during SMC. Flow diversion is due to a broad high pressure region in the inner magnetosphere. The interval preceding SMC events is found to set up the magnetotail conditions that assist balanced reconnection. In particular inner magnetosphere pressure before SMCs is enhanced from substorm levels but not as high as SMC levels. The final study shows that nearly all SMCs are preceded by a substorm expansion. In rare cases when an SMC occurs without a preceding substorm, we hypothesize that the distant x-line is able to balance a weak solar wind driver. These

  11. Transport of solar wind into Earth's magnetosphere through rolled-up Kelvin-Helmholtz vortices.

    PubMed

    Hasegawa, H; Fujimoto, M; Phan, T-D; Rème, H; Balogh, A; Dunlop, M W; Hashimoto, C; Tandokoro, R

    2004-08-12

    Establishing the mechanisms by which the solar wind enters Earth's magnetosphere is one of the biggest goals of magnetospheric physics, as it forms the basis of space weather phenomena such as magnetic storms and aurorae. It is generally believed that magnetic reconnection is the dominant process, especially during southward solar-wind magnetic field conditions when the solar-wind and geomagnetic fields are antiparallel at the low-latitude magnetopause. But the plasma content in the outer magnetosphere increases during northward solar-wind magnetic field conditions, contrary to expectation if reconnection is dominant. Here we show that during northward solar-wind magnetic field conditions-in the absence of active reconnection at low latitudes-there is a solar-wind transport mechanism associated with the nonlinear phase of the Kelvin-Helmholtz instability. This can supply plasma sources for various space weather phenomena.

  12. Penetration boundary of solar cosmic rays into the earth's magnetosphere during magnetically quiet times

    SciTech Connect

    Biryukov, A.S.; Ivanova, T.A.; Kovrygina, L.M.

    1984-05-01

    Data is used from the satellites Interkosmos-17 and Kosmos-900 to determine penetration boundaries at high latitudes in the earth's magnetosphere. Considered are the results of observations of the penetration boundary of solar cosmic ray (SCR) protons and electrons during an SCR increase on November 22-25, 1977. The position of the SCR penetration boundary during a single increase at practically all values of MLT in quiet conditions is examined. Magnetospheric structure is determined in the region of closed drift shells where the magnetic field is asymmetric. The authors can estimate how the solar wind pressure affects the magnetosphere by using datamore » on the penetration boundaries of solar protons obtained during quiet geomagnetic conditions.« less

  13. Acceleration mechanisms for energetic particles in the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Schiferl, S.; Fan, C. Y.; Hsieh, K. C.; Erickson, K. N.; Gloeckler, G.

    1982-01-01

    By analyzing data on energetic particle fluxes measured simultaneously with detector systems on several earth satellites, signatures of different acceleration mechanisms for these particles were searched for. One of the samples is an event observed on ATS-6 and IMP-7. IMP-7 was in the dusk quarter at 38 earth radii while ATS-6 was located at local midnight at a distance of 6.6 earth radii. Although the flux variations as observed on the two spacecraft both showed 1.5 min periodicity, there was a 40-second time lag with IMP-7 behind. The results indicate that the particles are accelerated by magnetic field line annihilation, with the x-point located at about 10 earth radii.

  14. The Earth's magnetosphere is 165 R(sub E) long: Self-consistent currents, convection, magnetospheric structure, and processes for northward interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Fedder, J. A.; Lyon, J. G.

    1995-01-01

    The subject of this paper is a self-consistent, magnetohydrodynamic numerical realization for the Earth's magnetosphere which is in a quasi-steady dynamic equilibrium for a due northward interplanetary magnetic field (IMF). Although a few hours of steady northward IMF are required for this asymptotic state to be set up, it should still be of considerable theoretical interest because it constitutes a 'ground state' for the solar wind-magnetosphere interaction. Moreover, particular features of this ground state magnetosphere should be observable even under less extreme solar wind conditions. Certain characteristics of this magnetosphere, namely, NBZ Birkeland currents, four-cell ionospheric convection, a relatively weak cross-polar potential, and a prominent flow boundary layer, are widely expected. Other characteristics, such as no open tail lobes, no Earth-connected magnetic flux beyond 155 R(sub E) downstream, magnetic merging in a closed topology at the cusps, and a 'tadpole' shaped magnetospheric boundary, might not be expected. In this paper, we will present the evidence for this unusual but interesting magnetospheric equilibrium. We will also discuss our present understanding of this singular state.

  15. Earth's magnetosphere and outer radiation belt under sub-Alfvénic solar wind.

    PubMed

    Lugaz, Noé; Farrugia, Charles J; Huang, Chia-Lin; Winslow, Reka M; Spence, Harlan E; Schwadron, Nathan A

    2016-10-03

    The interaction between Earth's magnetic field and the solar wind results in the formation of a collisionless bow shock 60,000-100,000 km upstream of our planet, as long as the solar wind fast magnetosonic Mach (hereafter Mach) number exceeds unity. Here, we present one of those extremely rare instances, when the solar wind Mach number reached steady values <1 for several hours on 17 January 2013. Simultaneous measurements by more than ten spacecraft in the near-Earth environment reveal the evanescence of the bow shock, the sunward motion of the magnetopause and the extremely rapid and intense loss of electrons in the outer radiation belt. This study allows us to directly observe the state of the inner magnetosphere, including the radiation belts during a type of solar wind-magnetosphere coupling which is unusual for planets in our solar system but may be common for close-in extrasolar planets.

  16. Earth's magnetosphere and outer radiation belt under sub-Alfvénic solar wind

    PubMed Central

    Lugaz, Noé; Farrugia, Charles J.; Huang, Chia-Lin; Winslow, Reka M.; Spence, Harlan E.; Schwadron, Nathan A.

    2016-01-01

    The interaction between Earth's magnetic field and the solar wind results in the formation of a collisionless bow shock 60,000–100,000 km upstream of our planet, as long as the solar wind fast magnetosonic Mach (hereafter Mach) number exceeds unity. Here, we present one of those extremely rare instances, when the solar wind Mach number reached steady values <1 for several hours on 17 January 2013. Simultaneous measurements by more than ten spacecraft in the near-Earth environment reveal the evanescence of the bow shock, the sunward motion of the magnetopause and the extremely rapid and intense loss of electrons in the outer radiation belt. This study allows us to directly observe the state of the inner magnetosphere, including the radiation belts during a type of solar wind-magnetosphere coupling which is unusual for planets in our solar system but may be common for close-in extrasolar planets. PMID:27694887

  17. Double-reconnected magnetic structures driven by Kelvin-Helmholtz vortices at the Earth's magnetosphere

    SciTech Connect

    Borgogno, D.; Califano, F.; Pegoraro, F.

    2015-03-15

    In an almost collisionless magnetohydrodynamic plasma in a relatively strong magnetic field, stresses can be conveyed far from the region where they are exerted, e.g., through the propagation of Alfvèn waves. The forced dynamics of line-tied magnetic structures in solar and stellar coronae (see, e.g., A. F. Rappazzo and E. N. Parker, Astrophys. J. 773, L2 (2013) and references therein) is a paradigmatic case. Here, we investigate how this action at a distance develops from the equatorial region of the Kelvin-Helmholtz unstable flanks of the Earth's magnetosphere leading to the onset, at mid latitude in both hemispheres, of correlated doublemore » magnetic field line reconnection events that can allow the solar wind plasma to enter the Earth's magnetosphere.« less

  18. Double-reconnected magnetic structures driven by Kelvin-Helmholtz vortices at the Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Faganello, Matteo; Borgogno, Dario; Califano, Francesco; Pegoraro, Francesco

    2015-11-01

    In an almost collisionless MagnetoHydrodynamic plasma in a relatively strong magnetic field, stresses can be conveyed far from the region where they are exerted e.g., through the propagation of Alfvèn waves. The forced dynamics of line-tied magnetic structures in solar and stellar coronae is a paradigmatic case. We investigate how this action at a distance develops from the equatorial region of the Kelvin-Helmholtz unstable flanks of the Earth's magnetosphere leading to the onset, at mid latitude in both hemispheres, of correlated double magnetic field line reconnection events that can allow the solar wind plasma to enter the Earth's magnetosphere. This mid-latitude double reconnection process, first investigated in, has been confirmed here by following a large set of individual field lines using a method similar to a Poincarè map.

  19. Global electric field determination in the Earth's outer magnetosphere using energetic charged particles

    NASA Technical Reports Server (NTRS)

    Eastman, Timothy E.; Sheldon, R.; Hamilton, D.

    1995-01-01

    Although many properties of the Earth's magnetosphere have been measured and quantified in the past 30 years since it was discovered, one fundamental measurement (for zeroth order MHD equilibrium) has been made infrequently and with poor spatial coverage - the global electric field. This oversight is due in part to the neglect of theorists. However, there is renewed interest in the convection electric field because it is now realized to be central to many magnetospheric processes, including the global MHD equilibrium, reconnection rates, Region 2 Birkeland currents, magnetosphere ionosphere coupling, ring current and radiation belt transport, substorm injections, and several acceleration mechanisms. Unfortunately the standard experimental methods have not been able to synthesize a global field (excepting the pioneering work of McIlwain's geostationary models) and we are left with an overly simplistic theoretical field, the Volland-Stern electric field model. Single point measurements of the plasmapause were used to infer the appropriate amplitudes of this model, parameterized by K(sub p). Although this result was never intended to be the definitive electric field model, it has gone nearly unchanged for 20 years. The analysis of current data sets requires a great deal more accuracy than can be provided by the Volland-Stern model. The variability of electric field shielding has not been properly addressed although effects of penetrating magnetospheric electric fields has been seen in mid-and low-latitude ionospheric data sets. The growing interest in substorm dynamics also requires a much better assessment of the electric fields responsible for particle injections. Thus we proposed and developed algorithms for extracting electric fields from particle data taken in the Earth's magnetosphere. As a test of the effectiveness of these new techniques, we analyzed data taken by the AMPTE/CCE spacecraft in equatorial orbit from 1984 to 1989.

  20. First Observations of a Foreshock Bubble at Earth: Implications for Magnetospheric Activity and Energetic Particle Acceleration

    NASA Technical Reports Server (NTRS)

    Turner, D. L.; Omidi, N.; Sibeck, D. G.; Angelopoulos, V.

    2011-01-01

    Earth?s foreshock, which is the quasi-parallel region upstream of the bow shock, is a unique plasma region capable of generating several kinds of large-scale phenomena, each of which can impact the magnetosphere resulting in global effects. Interestingly, such phenomena have also been observed at planetary foreshocks throughout our solar system. Recently, a new type of foreshock phenomena has been predicted: foreshock bubbles, which are large-scale disruptions of both the foreshock and incident solar wind plasmas that can result in global magnetospheric disturbances. Here we present unprecedented, multi-point observations of foreshock bubbles at Earth using a combination of spacecraft and ground observations primarily from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission, and we include detailed analysis of the events? global effects on the magnetosphere and the energetic ions and electrons accelerated by them, potentially by a combination of first and second order Fermi and shock drift acceleration processes. This new phenomena should play a role in energetic particle acceleration at collisionless, quasi-parallel shocks throughout the Universe.

  1. The UAH Spinning Terrella Experiment: A Laboratory Analog for the Earth's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Sheldon, R. B.; Gallagher, D. L.; Craven, P. D.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The UAH Spinning Terrella Experiment has been modified to include the effect of a second magnet. This is a simple laboratory demonstration of the well-known double-dipole approximation to the Earth's magnetosphere. In addition, the magnet has been biassed $\\sim$-400V which generates a DC glow discharge and traps it in a ring current around the magnet. This ring current is easily imaged with a digital camera and illustrates several significant topological properties of a dipole field. In particular, when the two dipoles are aligned, and therefore repel, they emulate a northward IMF Bz magnetosphere. Such a geometry traps plasma in the high latitude cusps as can be clearly seen in the movies. Likewise, when the two magnets are anti-aligned, they emulate a southward IMF Bz magnetosphere with direct feeding of plasma through the x-line. We present evidence for trapping and heating of the plasma, comparing the dipole-trapped ring current to the cusp-trapped population. We also present a peculiar asymmetric ring current produced in by the plasma at low plasma densities. We discuss the similarities and dissimilarities of the laboratory analog to the collisionless Earth plasma, and implications for the interpretation of IMAGE data.

  2. Magnetospheric Multiscale Mission Observations of Magnetic Flux Ropes in the Earth's Plasma Sheet

    NASA Astrophysics Data System (ADS)

    Slavin, J. A.; Akhavan-Tafti, M.; Poh, G.; Le, G.; Russell, C. T.; Nakamura, R.; Baumjohann, W.; Torbert, R. B.; Gershman, D. J.; Pollock, C. J.; Giles, B. L.; Moore, T. E.; Burch, J. L.

    2017-12-01

    A major discovery by the Cluster mission and the previous generation of science missions is the presence of earthward and tailward moving magnetic flux ropes in the Earth's plasma sheet. However, the lack of high-time resolution plasma measurements severely limited progress concerning the formation and evolution of these reconnection generated structures. We use high-time resolution magnetic and electric field and plasma measurements from the Magnetospheric Multiscale mission's first tail season to investigate: 1) the distribution of flux rope diameters relative to the local ion and electron inertial lengths; 2) the internal force balance sustaining these structures; and 3) the magnetic connectivity of the flux ropes to the Earth and/or the interplanetary medium; 4) the specific entropy of earthward moving flux ropes and the possible effect of "buoyancy" on how deep they penetrate into the inner magnetosphere; and 5) evidence for coalescence of adjacent flux ropes and/or the division of existing flux ropes through the formation of secondary X-lines. The results of these initial analyses will be discussed in terms of their implications for reconnection-driven magnetospheric dynamics and substorms.

  3. Near-Earth Magnetic Field Effects of Large-Scale Magnetospheric Currents

    NASA Astrophysics Data System (ADS)

    Lühr, Hermann; Xiong, Chao; Olsen, Nils; Le, Guan

    2017-03-01

    Magnetospheric currents play an important role in the electrodynamics of near-Earth space. This has been the topic of many space science studies. Here we focus on the magnetic fields they cause close to Earth. Their contribution to the geomagnetic field is the second largest after the core field. Significant progress in interpreting the magnetic fields from the different sources has been achieved thanks to magnetic satellite missions like Ørsted, CHAMP and now Swarm. Of particular interest for this article is a proper representation of the magnetospheric ring current effect. Uncertainties in modelling its effect still produce the largest residuals between observations and present-day geomagnetic field models. A lot of progress has been achieved so far, but there are still open issues like the characteristics of the partial ring current. Other currents discussed are those flowing in the magnetospheric tail. Also their magnetic contribution at LEO orbits is non-negligible. Treating them as an independent source is a more recent development, which has cured some of the problems in geomagnetic field modelling. Unfortunately there is no index available for characterising the tail current intensity. Here we propose an approach that may help to properly quantify the magnetic contribution from the tail current for geomagnetic field modelling. Some open questions that require further investigation are mentioned at the end.

  4. Near-Earth Magnetic Field Effects of Large-Scale Magnetospheric Currents

    NASA Technical Reports Server (NTRS)

    Luehr, Hermann; Xiong, Chao; Olsen, Nils; Le, Guan

    2016-01-01

    Magnetospheric currents play an important role in the electrodynamics of near- Earth space. This has been the topic of many space science studies. Here we focus on the magnetic fields they cause close to Earth. Their contribution to the geomagnetic field is the second largest after the core field. Significant progress in interpreting the magnetic fields from the different sources has been achieved thanks to magnetic satellite missions like Ørsted, CHAMP and now Swarm. Of particular interest for this article is a proper representation of the magnetospheric ring current effect. Uncertainties in modelling its effect still produce the largest residuals between observations and present-day geomagnetic field models. A lot of progress has been achieved so far, but there are still open issues like the characteristics of the partial ring current. Other currents discussed are those flowing in the magnetospheric tail. Also their magnetic contribution at LEO orbits is non-negligible. Treating them as an independent source is a more recent development, which has cured some of the problems in geomagnetic field modelling. Unfortunately there is no index available for characterizing the tail current intensity. Here we propose an approach that may help to properly quantify the magnetic contribution from the tail current for geomagnetic field modelling. Some open questions that require further investigation are mentioned at the end.

  5. Significance of the Eccentricity of the Earth's Magnetic Field for the Magnetosphere and Ionospheric Modification

    NASA Astrophysics Data System (ADS)

    Koochak, Z.; Fraser-Smith, A. C.

    2016-12-01

    This paper is an extension of an earlier study of the centered and eccentric dipole models of the Earth's magnetic field [Fraser-Smith, 1987]. We have used the 1980-2015 International Geomagnetic Reference Field (IGRF) Gauss coefficients to recalculate the magnetic dipole moments and magnetic pole positions for both the centered and eccentric dipoles for an additional 35 years, thus bringing them up to date. These magnetic field models play an important role in ionosphere modification, since they influence the properties of the ionosphere. However it is not widely known that the nominal origin of the Earth's magnetic field is offset from the center of the Earth by nearly 10% of the Earth's radius, which must similarly lead to an offset of some of the larger-scale modifying effects such as those associated with the magnetosphere. We describe this offset magnetic field here to help identify its effects in ionospheric modification experiments.

  6. The role of distinct parameters of interplanetary shocks in their propagation into and within the Earth's dayside magnetosphere, and their impact on magnetospheric particle populations

    NASA Astrophysics Data System (ADS)

    Colpitts, C. A.; Cattell, C. A.

    2016-12-01

    Interplanetary (IP) shocks are abrupt changes in the solar wind velocity and/or magnetic field. When an IP shock impacts the Earth's magnetosphere, it can trigger a number of responses including geomagnetic storms and substorms that affect radiation to satellites and aircraft, and ground currents that disrupt the power grid. There are a wide variety of IP shocks, and they interact with the magnetosphere in different ways depending on their orientation, speed and other factors. The distinct individual characteristics of IP shocks can have a dramatic effect on their impact on the near-earth environment. While some research has been done on the impact of shock parameters on their geo-effectiveness, these studies primarily utilized ground magnetometer derived indices such as Dst, AE and SME or signals at geosynchronous satellites. The current unprecedented satellite coverage of the magnetosphere, particularly on the dayside, presents an opportunity to directly measure how different shocks propagate into and within the magnetosphere, and how they affect the various particle populations therein. Initial case studies reveal that smaller shocks can have unexpected impacts in the dayside magnetosphere, including unusual particle and electric field signatures, depending on shock parameters. We have recently compiled a database of sudden impulses from 2012-2016, and the location of satellites in the dayside magnetosphere at the impulse times. We are currently combining and comparing this with existing databases compiled at UNH, Harvard and others, as well as solar wind data from ACE, Wind and other solar wind monitors, to generate a complete and accurate list of IP shocks, cataloguing parameters such as the type of shock (CME, CIR etc.), strength (Mach number, solar wind velocity etc.) and shock normal angle. We are investigating the magnetospheric response to these shocks using GOES, ARTEMIS and Cluster data, augmented with RBSP and MMS data where available, to determine

  7. Characterizing the Meso-scale Plasma Flows in Earth's Coupled Magnetosphere-Ionosphere-Thermosphere System

    NASA Astrophysics Data System (ADS)

    Gabrielse, C.; Nishimura, T.; Lyons, L. R.; Gallardo-Lacourt, B.; Deng, Y.; McWilliams, K. A.; Ruohoniemi, J. M.

    2017-12-01

    NASA's Heliophysics Decadal Survey put forth several imperative, Key Science Goals. The second goal communicates the urgent need to "Determine the dynamics and coupling of Earth's magnetosphere, ionosphere, and atmosphere and their response to solar and terrestrial inputs...over a range of spatial and temporal scales." Sun-Earth connections (called Space Weather) have strong societal impacts because extreme events can disturb radio communications and satellite operations. The field's current modeling capabilities of such Space Weather phenomena include large-scale, global responses of the Earth's upper atmosphere to various inputs from the Sun, but the meso-scale ( 50-500 km) structures that are much more dynamic and powerful in the coupled system remain uncharacterized. Their influences are thus far poorly understood. We aim to quantify such structures, particularly auroral flows and streamers, in order to create an empirical model of their size, location, speed, and orientation based on activity level (AL index), season, solar cycle (F10.7), interplanetary magnetic field (IMF) inputs, etc. We present a statistical study of meso-scale flow channels in the nightside auroral oval and polar cap using SuperDARN. These results are used to inform global models such as the Global Ionosphere Thermosphere Model (GITM) in order to evaluate the role of meso-scale disturbances on the fully coupled magnetosphere-ionosphere-thermosphere system. Measuring the ionospheric footpoint of magnetospheric fast flows, our analysis technique from the ground also provides a 2D picture of flows and their characteristics during different activity levels that spacecraft alone cannot.

  8. Magnetosphere-ionosphere interactions: Near Earth manifestations of the plasma universe

    NASA Technical Reports Server (NTRS)

    Faelthammar, Carl-Gunne

    1986-01-01

    As the universe consists almost entirely of plasma, the understanding of astrophysical phenomena must depend critically on the understanding of how matter behaves in the plasma state. In situ observations in the near Earth cosmical plasma offer an excellent opportunity of gaining such understanding. The near Earth cosmical plasma not only covers vast ranges of density and temperature, but is the site of a rich variety of complex plasma physical processes which are activated as a results of the interactions between the magnetosphere and the ionosphere. The geomagnetic field connects the ionosphere, tied by friction to the Earth, and the magnetosphere, dynamically coupled to the solar wind. This causes an exchange of energy an momentum between the two regions. The exchange is executed by magnetic-field-aligned electric currents, the so-called Birkeland currents. Both directly and indirectly (through instabilities and particle acceleration) these also lead to an exchange of plasma, which is selective and therefore causes chemical separation. Another essential aspect of the coupling is the role of electric fields, especially magnetic field aligned (parallel) electric fields, which have important consequences both for the dynamics of the coupling and, especially, for energization of charged particles.

  9. Discovery of Suprathermal Ionospheric Origin Fe+ in and Near Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Christon, S. P.; Hamilton, D. C.; Plane, J. M. C.; Mitchell, D. G.; Grebowsky, J. M.; Spjeldvik, W. N.; Nylund, S. R.

    2017-11-01

    Suprathermal (87-212 keV/e) singly charged iron, Fe+, has been discovered in and near Earth's 9-30 RE equatorial magnetosphere using 21 years of Geotail STICS (suprathermal ion composition spectrometer) data. Its detection is enhanced during higher geomagnetic and solar activity levels. Fe+, rare compared to dominant suprathermal solar wind and ionospheric origin heavy ions, might derive from one or all three candidate lower-energy sources: (a) ionospheric outflow of Fe+ escaped from ion layers near 100 km altitude, (b) charge exchange of nominal solar wind iron, Fe+≥7, in Earth's exosphere, or (c) inner source pickup Fe+ carried by the solar wind, likely formed by solar wind Fe interaction with near-Sun interplanetary dust particles. Earth's semipermanent ionospheric Fe+ layers derive from tons of interplanetary dust particles entering Earth's atmosphere daily, and Fe+ scattered from these layers is observed up to 1000 km altitude, likely escaping in strong ionospheric outflows. Using 26% of STICS's magnetosphere-dominated data when possible Fe+2 ions are not masked by other ions, we demonstrate that solar wind Fe charge exchange secondaries are not an obvious Fe+ source. Contemporaneous Earth flyby and cruise data from charge-energy-mass spectrometer on the Cassini spacecraft, a functionally identical instrument, show that inner source pickup Fe+ is likely not important at suprathermal energies. Consequently, we suggest that ionospheric Fe+ constitutes at least a significant portion of Earth's suprathermal Fe+, comparable to the situation at Saturn where suprathermal Fe+ is also likely of ionospheric origin.

  10. An experiment to study energetic particle fluxes in and beyond the earth's outer magnetosphere

    NASA Technical Reports Server (NTRS)

    Anderson, K. A.; Lin, R. P.; Paoli, R. J.; Parks, G. K.; Lin, C. S.; Reme, H.; Bosqued, J. M.; Martel, F.; Cotin, F.; Cros, A.

    1978-01-01

    This experiment is designed to take advantage of the ISEE Mother/Daughter dual spacecraft system to study energetic particle phenomena in the earth's outer magnetosphere and beyond. Large geometric factor fixed voltage electrostatic analyzers and passively cooled semiconductor detector telescopes provide high time resolution coverage of the energy range from 1.5 to 300 keV for both ions and electrons. Essentially identical instrumentation is placed on the two spacecraft to separate temporal from spatial effects in the observed particle phenomena.

  11. Conditions for double layers in the earth's magnetosphere and perhaps in other astrophysical objects

    NASA Technical Reports Server (NTRS)

    Lyons, L. R.

    1987-01-01

    It is suggested that the features which govern the formation of the double layers are: (1) the divergence of the magnetospheric electric field, (2) the ionospheric conductivity, and (3) the current-voltage characteristics of auroral magnetic field lines. Also considered are conditions in other astrophysical objects that could lead to the formation of DLs in a manner analogous to what occurs in the earth's auroral zones. It is noted that two processes can drive divergent Pedersen currents within a collisional conducting layer: (1) sheared plasma flow applied anywhere along the magnetic field lines connected to the conducting layer and (2) a neutral flow with shear within the conducting layer.

  12. Observations and analysis of Alfvén wave phase mixing in the Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Sarris, T. E.; Wright, A. N.; Li, X.

    2009-03-01

    Signatures of Alfvén wave phase mixing in the Earth's magnetosphere, observed as polarization rotation of a transverse, Pc5 magnetospheric pulsation, are presented and compared to theory. The polarization rotation occurred during a rare event of a dayside narrowband ULF magnetospheric pulsation that lasted for 5 consecutive days, from 24 to 30 November 1997; details of this event were reported by Sarris et al. (2009) through observations at geosynchronous orbit and on the ground. In this paper we investigate the polarization signatures of the pulsation by performing a detailed analysis of its transverse components as observed through hodogram plots. Density measurements from one of the Los Alamos National Laboratory (LANL) spacecraft which had its L shells closest to GOES-8 are used to calculate field line resonance frequencies at geosynchronous orbit; these frequency calculations show good agreement with the observed pulsations but also have a local time offset. For an instance of an observed polarization rotation we estimate the observed poloidal lifetime of the pulsation by the time taken for the poloidal and toroidal amplitudes to become equal, which we compare with the theoretical approximation to the poloidal lifetime, as calculated in a box model magnetosphere by Mann and Wright (1995). Density measurements from different LANL spacecraft at geosynchronous orbit and their varying L shells as derived from their varying local times are used to estimate a local gradient in the local Alfvén speed, which is then used in the calculation of the predicted poloidal lifetime. This is the first time that such polarization rotations are directly observed and compared with theoretical predictions.

  13. Source of seed fluctuations for electromagnetic ion cyclotron waves in Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Gamayunov, K. V.; Engebretson, M. J.; Zhang, M.; Rassoul, H. K.

    2015-06-01

    We consider a nonlinear wave energy cascade from the low frequency range into the higher frequency domain of electromagnetic ion cyclotron (EMIC) wave generation as a possible source of seed fluctuations for EMIC wave growth due to the ion cyclotron instability in Earth's magnetosphere. The presented theoretical analysis shows that energy cascade from the Pc 4-5 frequency range (2-22 mHz) into the range of Pc 1-2 pulsations (0.1-5 Hz), i.e. into the frequency range of EMIC waves, is able to supply the needed level of seed fluctuations that guarantees growth of EMIC waves up to the observable level during one pass through the near equatorial region where the ion cyclotron instability takes place. We also analyze the magnetic field data from the Polar and Van Allen Probes spacecraft to test the suggested nonlinear mechanism. In this initial study we restrict our analysis to magnetic fluctuation spectra only. We do not analyze the third-order structure function, but judge whether a nonlinear energy cascade is present or whether it is not by only analyzing the appearance of power-law distributions in the low-frequency part of the magnetic field spectra. While the power-law spectrum alone does not guarantee that a nonlinear cascade is present, the power-law distribution is a strong indication of the possible development of a nonlinear cascade. Our analysis shows that a nonlinear energy cascade is indeed observed in both the outer and inner magnetosphere data, and EMIC waves are growing from this nonthermal background. All the analyzed data are in good agreement with the theoretical model presented in this study. Overall, the results of this study support a nonlinear energy cascade in Earth's magnetosphere as a mechanism which is responsible for supplying seed fluctuating energy in the higher frequency domain where EMIC waves grow due to the ion cyclotron instability.

  14. Features of the impact of the solar wind diamagnetic structure on Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Parhomov, Vladimir; Borodkova, Natalia; Eselevich, Viktor; Eselevich, Maxim; Dmitriev, Aleksey; Chilikin, Vitaliy

    2017-12-01

    At Earth's orbit on June 28, 1999, there was a diamagnetic structure (DS) representing a filament with a uniquely high speed (about 900 km/s). We show that the filament is a part of the specific sporadic solar wind (SW) stream, which is characterized as a small interplanetary transient. We report the results of studies on the interaction between such a fast filament (DS) and Earth's magnetosphere. Around noon hours at daytime cusp latitudes, we recorded a powerful aurora in the UV band (shock aurora), which rapidly spread to the west and east. Ground-based observations of geo-magnetic field variations, auroral absorption, and auroras on the midnight meridian have shown the development of a powerful substorm-like disturbance (SLD) (AE∼1000 nT), whose origin is associated with the impact of the SW diamagnetic structure on the magnetosphere. The geostationary satellite GOES-8, which was in the midnight sector of the outer quasi capture region during SLD, recorded variations of the Bz and Bx geomagnetic components corresponding to the dipolization process.

  15. The dependence of magnetosphere-ionosphere system on the Earth's magnetic dipole moment

    NASA Astrophysics Data System (ADS)

    Ngwira, C. M.; Pulkkinen, A. A.; Sibeck, D. G.; Rastaetter, L.

    2017-12-01

    Space weather is increasingly recognized as an international problem affecting several different man-made technologies. The ability to understand, monitor and forecast Earth-directed space weather is of paramount importance for our highly technology-dependent society and for the current rapid developments in awareness and exploration within the heliosphere. It is well known that the strength of the Earth's magnetic field changes over long time scales. We use physics-based simulations with the University of Michigan Space Weather Modeling Framework (SWMF) to examine how the magnetosphere, ionosphere, and ground geomagnetic field perturbations respond as the geomagnetic dipole moment changes. We discuss the implication of these results for our community and the end-users of space weather information.

  16. Biogenic oxygen from Earth transported to the Moon by a wind of magnetospheric ions

    NASA Astrophysics Data System (ADS)

    Terada, Kentaro; Yokota, Shoichiro; Saito, Yoshifumi; Kitamura, Naritoshi; Asamura, Kazushi; Nishino, Masaki N.

    2017-01-01

    For five days of each lunar orbit, the Moon is shielded from solar wind bombardment by the Earth's magnetosphere, which is filled with terrestrial ions. Although the possibility of the presence of terrestrial nitrogen and noble gases in lunar soil has been discussed based on their isotopic composition 1 , complicated oxygen isotope fractionation in lunar metal 2,3 (particularly the provenance of a 16O-poor component) re­mains an enigma 4,5 . Here, we report observations from the Japanese spacecraft Kaguya of significant numbers of 1-10 keV O+ ions, seen only when the Moon was in the Earth's plasma sheet. Considering the penetration depth into metal of O+ ions with such energy, and the 16O-poor mass-independent fractionation of the Earth's upper atmosphere 6 , we conclude that biogenic terrestrial oxygen has been transported to the Moon by the Earth wind (at least 2.6 × 104 ions cm-2 s-1) and implanted into the surface of the lunar regolith, at around tens of nanometres in depth 3,4 . We suggest the possibility that the Earth's atmosphere of billions of years ago may be preserved on the present-day lunar surface.

  17. Planetary magnetospheres

    NASA Technical Reports Server (NTRS)

    Stern, D. P.; Ness, N. F.

    1981-01-01

    A concise overview is presented of our understanding of planetary magnetospheres (and in particular, of that of the Earth), as of the end of 1981. Emphasis is placed on processes of astrophysical interest, e.g., on particle acceleration, collision-free shocks, particle motion, parallel electric fields, magnetic merging, substorms, and large scale plasma flows. The general morphology and topology of the Earth's magnetosphere are discussed, and important results are given about the magnetospheres of Jupiter, Saturn and Mercury, including those derived from the Voyager 1 and 2 missions and those related to Jupiter's satellite Io. About 160 references are cited, including many reviews from which additional details can be obtained.

  18. Kinetic models for space plasmas: Recent progress for the solar wind and the Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Pierrard, V.; Moschou, S. P.; Lazar, M.; Borremans, K.; Rosson, G. Lopez

    2016-11-01

    Recent models for the solar wind and the inner magnetosphere have been developed using the kinetic approach. The solution of the evolution equation is used to determine the velocity distribution function of the particles and their moments. The solutions depend on the approximations and assumptions made in the development of the models. Effects of suprathermal particles often observed in space plasmas are taken into account to show their influence on the characteristics of the plasma, with specific applications for coronal heating and solar wind acceleration. We describe in particular the results obtained with the collisionless exospheric approximation based on the Lorentzian velocity distribution function for the electrons and its recent progress in three dimensions. The effects of Coulomb collisions obtained by using a Fokker-Planck term in the evolution equation were also investigated, as well as effects of the whistler wave turbulence at electron scale and the kinetic Alfven waves at the proton scale. For solar wind especially, modelling efforts with both magnetohydrodynamic and kinetic treatments have been compared and combined in order to improve the predictions in the vicinity of the Earth. Photospheric magnetograms serve as observational input in semi-empirical coronal models used for estimating the plasma characteristics up to coronal heliocentric distances taken as boundary conditions in solar wind models. The solar wind fluctuations may influence the dynamics of the space environment of the Earth and generate geomagnetic storms. In the magnetosphere of the Earth, the trajectories of the particles are simulated to study the plasmasphere, the extension of the ionosphere along closed magnetic field lines and to better understand the physical mechanisms involved in the radiation belts dynamics.

  19. Mini-Magnetospheres at the Moon in the Solar Wind and the Earth's Plasma Sheet

    NASA Astrophysics Data System (ADS)

    Harada, Y.; Futaana, Y.; Barabash, S. V.; Wieser, M.; Wurz, P.; Bhardwaj, A.; Asamura, K.; Saito, Y.; Yokota, S.; Tsunakawa, H.; Machida, S.

    2014-12-01

    Lunar mini-magnetospheres are formed as a consequence of solar-wind interaction with remanent crustal magnetization on the Moon. A variety of plasma and field perturbations have been observed in a vicinity of the lunar magnetic anomalies, including electron energization, ion reflection/deflection, magnetic field enhancements, electrostatic and electromagnetic wave activities, and low-altitude ion deceleration and electron acceleration. Recent Chandrayaan-1 observations of the backscattered energetic neutral atoms (ENAs) from the Moon in the solar wind revealed upward ENA flux depletion (and thus depletion of the proton flux impinging on the lunar surface) in association with strongly magnetized regions. These ENA observations demonstrate that the lunar surface is shielded from the solar wind protons by the crustal magnetic fields. On the other hand, when the Moon was located in the Earth's plasma sheet, no significant depletion of the backscattered ENA flux was observed above the large and strong magnetic anomaly. It suggests less effective magnetic shielding of the surface from the plasma sheet protons than from the solar wind protons. We conduct test-particle simulations showing that protons with a broad velocity distribution are more likely to reach a strongly magnetized surface than those with a beam-like velocity distribution. The ENA observations together with the simulation results suggest that the lunar crustal magnetic fields are no longer capable of standing off the ambient plasma when the Moon is immersed in the hot magnetospheric plasma.

  20. Magnetohydrodynamic Oscillations in the Solar Corona and Earth's Magnetosphere: Towards Consolidated Understanding

    NASA Astrophysics Data System (ADS)

    Nakariakov, V. M.; Pilipenko, V.; Heilig, B.; Jelínek, P.; Karlický, M.; Klimushkin, D. Y.; Kolotkov, D. Y.; Lee, D.-H.; Nisticò, G.; Van Doorsselaere, T.; Verth, G.; Zimovets, I. V.

    2016-04-01

    Magnetohydrodynamic (MHD) oscillatory processes in different plasma systems, such as the corona of the Sun and the Earth's magnetosphere, show interesting similarities and differences, which so far received little attention and remain under-exploited. The successful commissioning within the past ten years of THEMIS, Hinode, STEREO and SDO spacecraft, in combination with matured analysis of data from earlier spacecraft (Wind, SOHO, ACE, Cluster, TRACE and RHESSI) makes it very timely to survey the breadth of observations giving evidence for MHD oscillatory processes in solar and space plasmas, and state-of-the-art theoretical modelling. The paper reviews several important topics, such as Alfvénic resonances and mode conversion; MHD waveguides, such as the magnetotail, coronal loops, coronal streamers; mechanisms for periodicities produced in energy releases during substorms and solar flares, possibility of Alfvénic resonators along open field lines; possible drivers of MHD waves; diagnostics of plasmas with MHD waves; interaction of MHD waves with partly-ionised boundaries (ionosphere and chromosphere). The review is mainly oriented to specialists in magnetospheric physics and solar physics, but not familiar with specifics of the adjacent research fields.

  1. Generation of multiband chorus by lower band cascade in the Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Gao, Xinliang; Lu, Quanming; Bortnik, Jacob; Li, Wen; Chen, Lunjin; Wang, Shui

    2016-03-01

    Chorus waves are intense electromagnetic whistler mode emissions in the magnetosphere, typically falling into two distinct frequency bands: a lower band (0.1-0.5fce) and an upper band (0.5-0.8fce) with a power gap at about 0.5fce. In this letter, with the Time History of Events and Macroscale Interactions during Substorms satellite, we observed two special chorus events, which are called as multiband chorus because upper band chorus is located at harmonics of lower band chorus. We propose a new potential generation mechanism for multiband chorus, which is called as lower band cascade. In this scenario, a density mode with a frequency equal to that of lower band chorus is generated by the ponderomotive effect (inhomogeneity of the electric amplitude) along the wave vector, and then upper band chorus with the frequency twice that of lower band chorus is generated through wave-wave couplings between lower band chorus and the density mode. The mechanism provides a new insight into the evolution of whistler mode chorus in the Earth's magnetosphere.

  2. Generation of Multi-band Chorus by Lower Band Cascade in the Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Gao, X.; Lu, Q.; Chen, L.; Bortnik, J.; Li, W.; Wang, S.

    2016-12-01

    Chorus waves are intense electromagnetic whistler-mode emissions in the magnetosphere, typically falling into two distinct frequency bands: a lower band (0.1-0.5fce) and an upper band (0.5-0.8fce) with a power gap at about 0.5fce. In this letter, with the THEMIS satellite, we observed two special chorus events, which are called as multi-band chorus because upper band chorus is located at harmonics of lower band chorus. We propose a new potential generation mechanism for multi-band chorus, which is called as lower band cascade. In this scenario, a density mode with a frequency equal to that of lower band chorus is caused by the ponderomotive effect (inhomogeneity of the electric amplitude) along the wave vector, and then upper band chorus with the frequency twice that of lower band chorus is generated through wave-wave couplings between lower band chorus and the density mode. The mechanism provides a new insight into the evolution of whistler-mode chorus in the Earth's magnetosphere.

  3. Geomagnetic response of interplanetary coronal mass ejections in the Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Badruddin; Mustajab, F.; Derouich, M.

    2018-05-01

    A coronal mass ejections (CME) is the huge mass of plasma with embedded magnetic field ejected abruptly from the Sun. These CMEs propagate into interplanetary space with different speed. Some of them hit the Earth's magnetosphere and create many types of disturbances; one of them is the disturbance in the geomagnetic field. Individual geomagnetic disturbances differ not only in their magnitudes, but the nature of disturbance is also different. It is, therefore, desirable to understand these differences not only to understand the physics of geomagnetic disturbances but also to understand the properties of solar/interplanetary structures producing these disturbances of different magnitude and nature. In this work, we use the spacecraft measurements of CMEs with distinct magnetic properties propagating in the interplanetary space and generating disturbances of different levels and nature. We utilize their distinct plasma and field properties to search for the interplanetary parameter(s) playing important role in influencing the geomagnetic response of different coronal mass ejections.

  4. Ion Acceleration at Earth, Saturn and Jupiter and its Global Impact on Magnetospheric Structure

    NASA Astrophysics Data System (ADS)

    Brandt, Pontus

    2016-07-01

    The ion plasma pressures at Earth, Saturn and Jupiter are significant players in the electrodynamic force-balance that governs the structure and dynamics of these magnetospheres. There are many similarities between the physical mechanisms that are thought to heat the ion plasma to temperatures that even exceed those of the solar corona. In this presentation we compare the ion acceleration mechanisms at the three planetary magnetospheres and discuss their global impacts on magnetopsheric structure. At Earth, bursty-bulk flows, or "bubbles", have been shown to accelerate protons and O+ to high energies by the earthward moving magnetic dipolarization fronts. O+ ions display a more non-adiabatic energization in response to these fronts than protons do as they are energized and transported in to the ring-current region where they reach energies of several 100's keV. We present both in-situ measurements from the NASA Van Allen Probes Mission and global Energetic Neutral (ENA) images from the High-Energy Neutral Atom (HENA) Camera on board the IMAGE Mission, that illustrate these processes. The global impact on the magnetospheric structure is explored by comparing the empirical magnetic field model TS07d for given driving conditions with global plasma pressure distributions derived from the HENA images. At Saturn, quasi-periodic energization events, or large-scale injections, occur beyond about 9 RS around the post-midnight sector, clearly shown by the Ion and Neutral Atom Camera (INCA) on board the Cassini mission. In contrast to Earth, the corotational drift dominates even the energetic ion distributions. The large-scale injections display similar dipolarization front features can be found and there are indications that like at Earth the O+ responds more non-adiabatically than protons do. However, at Saturn there are also differences in that there appears to be energization events deep in the inner magnetosphere (6-9 RS) preferentially occurring in the pre

  5. Toward a System-Based Approach to Electromagnetic Ion Cyclotron Waves in Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Gamayunov, K. V.; Engebretson, M. J.; Rassoul, H.

    2015-12-01

    We consider a nonlinear wave energy cascade from the low frequency range into the higher frequency domain of electromagnetic ion cyclotron (EMIC) wave generation as a possible source of seed fluctuations for EMIC wave growth due to the ion cyclotron instability in Earth's magnetosphere. The theoretical analysis shows that energy cascade from the Pc 4-5 frequency range (2-22 mHz) into the range of Pc 1-2 pulsations (0.1-5 Hz) is able to supply the level of seed fluctuations that guarantees growth of EMIC waves up to an observable level during one pass through the near equatorial region where the ion cyclotron instability takes place. We also analyze magnetic field data from the Polar and Van Allen Probes spacecraft to test this nonlinear mechanism. We restrict our analysis to magnetic spectra only. We do not analyze the third-order moment for total energy of the magnetic and velocity fluctuations, but judge whether a nonlinear energy cascade is present or whether it is not by only analyzing the appearance of power-law distributions in the low frequency part of the magnetic field spectra. While the power-law spectrum alone does not guarantee that a nonlinear cascade is present, the power-law distribution is a strong indication of the possible development of a nonlinear cascade. Our data analysis shows that a nonlinear energy cascade is indeed observed in both the outer and inner magnetosphere, and EMIC waves are growing from this nonthermal background. All the analyzed data are in good agreement with the theoretical model presented in this study. Overall, the results of this study support a nonlinear energy cascade in Earth's magnetosphere as a mechanism which is responsible for supplying seed fluctuating energy in the higher frequency domain where EMIC waves grow due to the ion cyclotron instability. Keywords: nonlinear energy cascade, ultra low frequency waves, electromagnetic ion cyclotron waves, seed fluctuationsAcknowledgments: This paper is based upon work

  6. The interaction of ultra-low-frequency pc3-5 waves with charged particles in Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Zong, Qiugang; Rankin, Robert; Zhou, Xuzhi

    2017-12-01

    One of the most important issues in space physics is to identify the dominant processes that transfer energy from the solar wind to energetic particle populations in Earth's inner magnetosphere. Ultra-low-frequency (ULF) waves are an important consideration as they propagate electromagnetic energy over vast distances with little dissipation and interact with charged particles via drift resonance and drift-bounce resonance. ULF waves also take part in magnetosphere-ionosphere coupling and thus play an essential role in regulating energy flow throughout the entire system. This review summarizes recent advances in the characterization of ULF Pc3-5 waves in different regions of the magnetosphere, including ion and electron acceleration associated with these waves.

  7. Simultaneous observation of Pc 3-4 pulsations in the solar wind and in the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Engebretson, M. J.; Zanetti, L. J.; Potemra, T. A.; Baumjohann, W.; Luehr, H.; Acuna, M. H.

    1987-01-01

    The equatorially orbiting Active Magnetospheric Particle Tracer Explorers CCE and IRM satellites have made numerous observations of Pc 3-4 magnetic field pulsations (10-s to 100-s period) simultaneously at locations upstream of the earth's bow shock and inside the magnetosphere. These observations show solar wind/IMF control of two categories of dayside magnetospheric pulsations. Harmonically structured, azimuthally polarized pulsations are commonly observed from L = 4 to 9 in association with upstream waves. More monochromatic compressional pulsations are clearly evident on occasion, with periods identical to those observed simultaneously in the solar wind. The observations reported here are consistent with a high-latitude (cusp) entry mechanism for wave energy related to harmonically structured pulsations.

  8. First simultaneous detection of terrestrial ionospheric molecular ions in the Earth's inner magnetosphere and at the Moon

    NASA Astrophysics Data System (ADS)

    Dandouras, Iannis; Poppe, Andrew R.; Fillingim, Matt O.; Kistler, Lynn M.; Mouikis, Christopher G.; Rème, Henri

    2017-04-01

    Heavy molecular ions escaping from a planetary atmosphere can contribute to the long-term evolution of its composition. The ARTEMIS (Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's Interaction with the Sun) spacecraft has recently observed outflowing molecular ions at lunar distances in the terrestrial magnetotail (Poppe et al., 2016). Backward particle tracing indicated that these ions should originate from the terrestrial inner magnetosphere. Here we have examined Cluster data acquired by the CIS-CODIF (Cluster Ion Spectrometry-Composition Distribution Function) ion mass spectrometer, obtained in the terrestrial magnetosphere. An event was selected where the orbital conditions were favourable and the Cluster spacecraft were in the high-latitude inner magnetosphere a few hours before the ARTEMIS molecular ion detection. Analysis shows that the CIS-CODIF instrument detected a series of energetic ion species, including not only O+ but also a group of molecular ions around 30 amu. Given the 5-7 m/Δm mass resolution of the instrument, these could include N2+, NO+, or O2+. These ions were detected by Cluster about 14 hours before the ARTEMIS observation in the lunar environment, a time which is compatible with the transfer to lunar distances. The event was during an active period followed by a northward rotation of the IMF. Although energetic heavy molecular ions have been detected in the storm time magnetosphere in the past (e.g. Klecker et al., 1986; Christon et al., 1994), this event constitutes the first coordinated observation in the Earth's inner magnetosphere and at the Moon. Additional events of coordinated outflowing molecular ion observations are currently under analysis. Future missions, as the proposed ESCAPE mission, should investigate in detail the mechanisms of molecular ion acceleration and escape, their link to the solar and magnetospheric activity, and their role in the magnetospheric dynamics and in the long-term evolution

  9. ULF Waves in the Earth's Inner Magnetosphere: Role in Radiation Belt and Ring Current Dynamics

    NASA Astrophysics Data System (ADS)

    Mann, I. R.; Murphy, K. R.; Rae, J.; Claudepierre, S. G.; Fennell, J. F.; Baker, D. N.; Reeves, G. D.; Spence, H. E.; Ozeke, L.; Milling, D. K.

    2013-05-01

    Ultra-low frequency (ULF) waves in the Pc4-5 band can be excited in the magnetosphere by the solar wind. Much recent work has shown how ULF wave power is strongly correlated with solar wind speed. However, little attention has been paid the dynamics of ULF wave power penetration onto low L-shells in the inner magnetosphere. We use more than a solar cycle of ULF wave data, derived from ground-based magnetometer networks, to examine this ULF wave power penetration and its dependence on solar wind and geomagnetic activity indices. In time domain data, we show very clearly that dayside ULF wave power, spanning more than 4 orders of magnitude, follows solar wind speed variations throughout the whole solar cycle - during periods of sporadic solar maximum ICMEs, during declining phase fast solar wind streams, and at solar minimum, alike. We also show that time domain ULF wave power increases during magnetic storms activations, and significantly demonstrate that a deeper ULF wave power penetration into the inner magnetosphere occurs during larger negative excursions in Dst. We discuss potential explanations for this low-L ULF wave power penetration, including the role of plasma mass density (such as during plasmaspheric erosion), or ring current ion instabilities during near-Earth ring current penetration. Interestingly, we also show that both ULF wave power and SAMPEX MeV electron flux show a remarkable similarity in their penetration to low-L, which suggests that ULF wave power penetration may be important for understanding and explaining radiation belt dynamics. Moreover, the correlation of ULF wave power with Dst, which peaks at one day lag, suggests the ULF waves might also be important for the inward transport of ions into the ring current. Current ring current models, which exclude long period ULF wave transport, under-estimate the ring current during fast solar wind streams which is consistent with a potential role for ULF waves in ring current energisation

  10. The Role of Ionospheric Conductivity in the Response of the Magnetosphere and Ionosphere to Changes in the Earth's Magnetic Field

    NASA Astrophysics Data System (ADS)

    Cnossen, I.; Wiltberger, M. J.; Richmond, A. D.; Ouellette, J.

    2014-12-01

    The strength and orientation of the Earth's magnetic field play an important role in the magnetosphere-ionosphere-thermosphere system. This is demonstrated in a set of idealized experiments with the Coupled Magnetosphere-Ionosphere-Thermosphere model using a dipolar magnetic field. A decrease of the dipole moment (M) causes an increase in ionospheric conductance. This increase in conductance results in enhanced field-aligned currents (FACs), which change the shape of the magnetosphere, and causes a deviation from theoretical scaling relations of the stand-off distance, the size of the polar cap, and the cross-polar cap potential with M. The orientation of the Earth's magnetic field determines how the angle μ between the geomagnetic dipole axis and the geocentric solar magnetospheric (GSM) z-axis varies with season and universal time (UT). The angle μ can affect solar wind-magnetosphere-ionosphere coupling in two distinct ways: via variations in ionospheric conductivity over the polar caps or via a change in the coupling efficiency between the solar wind and magnetosphere as a result of changes in geometry. Simulations in which the ionospheric conductivity was either kept fixed or allowed to vary realistically demonstrated that variations in ionospheric conductance are responsible for ~10-30% of the variations in the cross-polar cap potential associated with variations in μ for southward interplanetary magnetic field (IMF). The remainder was mostly due to variations in the magnetic reconnection rate, which were associated with variations in the length of the section of the separator line along which relatively strong reconnection occurs.

  11. The effects of magnetospheric processes on relativistic electron dynamics in the Earth's outer radiation belt

    SciTech Connect

    Tang, C. L.; Wang, Y. X.; Ni, B.

    Using the electron phase space density (PSD) data measured by Van Allen Probe A from January 2013 to April 2015, we investigate the effects of magnetospheric processes on relativistic electron dynamics in the Earth's outer radiation belt during 50 geomagnetic storms. A statistical study shows that the maximum electron PSDs for various μ (μ = 630, 1096, 2290, and 3311 MeV/G) at L*~4.0 after the storm peak have good correlations with storm intensity (cc~0.70). This suggests that the occurrence and magnitude of geomagnetic storms are necessary for relativistic electron enhancements at the inner edge of the outer radiation belt (L*more » = 4.0). For moderate or weak storm events (SYM–H min > ~–100 nT) with weak substorm activity (AE max < 800 nT) and strong storm events (SYM–H min ≤ ~–100 nT) with intense substorms (AE max ≥ 800 nT) during the recovery phase, the maximum electron PSDs for various μ at different L* values (L* = 4.0, 4.5, and 5.0) are well correlated with storm intensity (cc > 0.77). For storm events with intense substorms after the storm peak, relativistic electron enhancements at L* = 4.5 and 5.0 are observed. This shows that intense substorms during the storm recovery phase are crucial to relativistic electron enhancements in the heart of the outer radiation belt. In conclusion, our statistics study suggests that magnetospheric processes during geomagnetic storms have a significant effect on relativistic electron dynamics.« less

  12. The effects of magnetospheric processes on relativistic electron dynamics in the Earth's outer radiation belt

    DOE PAGES

    Tang, C. L.; Wang, Y. X.; Ni, B.; ...

    2017-08-11

    Using the electron phase space density (PSD) data measured by Van Allen Probe A from January 2013 to April 2015, we investigate the effects of magnetospheric processes on relativistic electron dynamics in the Earth's outer radiation belt during 50 geomagnetic storms. A statistical study shows that the maximum electron PSDs for various μ (μ = 630, 1096, 2290, and 3311 MeV/G) at L*~4.0 after the storm peak have good correlations with storm intensity (cc~0.70). This suggests that the occurrence and magnitude of geomagnetic storms are necessary for relativistic electron enhancements at the inner edge of the outer radiation belt (L*more » = 4.0). For moderate or weak storm events (SYM–H min > ~–100 nT) with weak substorm activity (AE max < 800 nT) and strong storm events (SYM–H min ≤ ~–100 nT) with intense substorms (AE max ≥ 800 nT) during the recovery phase, the maximum electron PSDs for various μ at different L* values (L* = 4.0, 4.5, and 5.0) are well correlated with storm intensity (cc > 0.77). For storm events with intense substorms after the storm peak, relativistic electron enhancements at L* = 4.5 and 5.0 are observed. This shows that intense substorms during the storm recovery phase are crucial to relativistic electron enhancements in the heart of the outer radiation belt. In conclusion, our statistics study suggests that magnetospheric processes during geomagnetic storms have a significant effect on relativistic electron dynamics.« less

  13. Methodology and Data Sources for Assessing Extreme Charging Events within the Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Parker, L. N.; Minow, J. I.; Talaat, E. R.

    2016-12-01

    Spacecraft surface and internal charging is a potential threat to space technologies because electrostatic discharges on, or within, charged spacecraft materials can result in a number of adverse impacts to spacecraft systems. The Space Weather Action Plan (SWAP) ionizing radiation benchmark team recognized that spacecraft charging will need to be considered to complete the ionizing radiation benchmarks in order to evaluate the threat of charging to critical space infrastructure operating within the near-Earth ionizing radiation environments. However, the team chose to defer work on the lower energy charging environments and focus the initial benchmark efforts on the higher energy galactic cosmic ray, solar energetic particle, and trapped radiation belt particle environments of concern for radiation dose and single event effects in humans and hardware. Therefore, an initial set of 1 in 100 year spacecraft charging environment benchmarks remains to be defined to meet the SWAP goals. This presentation will discuss the available data sources and a methodology to assess the 1 in 100 year extreme space weather events that drive surface and internal charging threats to spacecraft. Environments to be considered are the hot plasmas in the outer magnetosphere during geomagnetic storms, relativistic electrons in the outer radiation belt, and energetic auroral electrons in low Earth orbit at high latitudes.

  14. Saturn and Earth polar oval position forecast by IMPEx InfrastructureWeb Services based on the Paraboloid magnetospheric model

    NASA Astrophysics Data System (ADS)

    Blokhina, M. S.; Alexeev, I. I.; Belenkaya, E. S.; Kalegaev, V. V.; Barinova, V. O.; Khodachenko, M. L.; Topf, F.

    2012-09-01

    The Saturn and Earth auroral emissions have different generation mechanisms, however, both mechanisms are not understood very well till now (see [1]). Both of these phenomena have a long history of observations. For Saturn these are Hubble images and big onground telescope images, as well as the Cassini ones in recent time. For Earth these are the satellite visible and UV camera images and onground observations. In course of the EU-FP7 Project "Integrated Medium for Planetary Exploration" the Web services based on the paraboloid magnetospheric models were constructed . The model field lines tracing gives us a possibility to distinguish the closed and open field line bundles. Additionally, we can find a boundary between the dipole type field lines and determine a region of the tail-like field lines crossing the equatorial plane tailward from the inner edge of the tail current sheet. Projections of this boundary and of the boundary between open and closed field lines at the ionospheric level mark the terrestrial auroral oval boundaries. The final result depends on the solar wind parameters and the magnetospheric state. In the Earth's case we have the ACE solar wind monitoring data which should be used to determine the magnetospheric state (http://smdc.sinp.msu.ru/index.py? nav=paraboloid/index [Interactive Earth]). For Saturn we use the three levels of the solar wind dynamic pressure (http://smdc.sinp. msu.ru/index.py?nav=paraboloid/index [Interactive Saturn]).

  15. Investigation of the Transport of Solar Ions Through the Earth's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Lennartsson, O. W.; Evans, David (Technical Monitor)

    2000-01-01

    The objective of this study has been to infer, by statistical means, the most probable mode of entry of solar wind plasma into Earth's magnetotail, using a particular set of archived data from the Lockheed Plasma Composition Experiment on the International Sun-Earth Explorer One (ISEE-1) satellite, jointly sponsored by the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA) in the 1970's and 80's. Despite their considerable age, the Lockheed ISEE-1 data are still, at the time of this report, the only substantial ion composition data in the sub-keV to keV energy range available from the magnetotail beyond 9 R(sub E), because of various technical problems with ion mass spectrometers on later missions, and are therefore a unique source of information about the mixing of solar and terrestrial origin plasmas in the tail, within the ISEE-1 apogee of almost 23 R(sub E). The entire set of archived data used in this study, covering the 4.5 years of operation of the instrument and comprising not only tail measurements but also data from the inner magnetosphere as well as data from outside the magnetopause, is now available to the public via the WorldWideWeb at the address: http://cis.spasci.com/ISEE_ions The fundamental assumption of this and other studies of magnetosphere ion composition is that He++ and O+ ions are virtually certain "tags" of solar and terrestrial origins, respectively. This is an assumption with strong theoretical basis and it is corroborated by observational evidence, including the often substantial differences between the velocity distribution functions of those two species. The H+ ions can have a dual origin, in principle, but the close resemblance in the ISEE-1 data between the dynamics of H+ and He++ ions indicates a predominantly solar origin of the H+ ions in the tail, at least. By the same token, the usually minor He+ ions are probably almost entirely of terrestrial origin, because of their similarity to the O

  16. Observations of the mean ionization states of energetic particles in the vicinity of the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Ma Sung, L. S.; Gloeckler, G.; Fan, C. Y.; Hovestadt, D.

    1980-01-01

    The mean ionization states of 44-260 keV per charge ions observed as bursts in and near the earth's magnetosphere have been determined by using the particle data collected by the University of Maryland experiment on Imp 8. We find that during the period from October 1973 to December 1976 (1) the abundance ratio of heavy ions (Z greater than 2) to alphas ranges from 0.04 to 0.10, with a mean value of 0.08 plus or minus 0.02; (2) the energy spectra of alphas and Z greater than 2 ions in these bursts are adequately represented as exponentials in energy per charge with e-folding energies of 30-50 keV/Q; (3) the e-folding energies of both alpha particles and heavier ions are generally harder upstream from the bow shock than in the magnetotail and magnetosheath; and (4) the elemental abundances and ionization state distribution of the heavy ions are consistent with those of the corona at an equilibrium coronal temperature of 1-2 x 10 to the 6th K, which tends to support a solar wind origin for these particles.

  17. Charged Particle Environments in Earth's Magnetosphere and their Effects on Space System

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.

    2009-01-01

    This slide presentation reviews information on space radiation environments important to magnetospheric missions including trapped radiation, solar particle events, cosmic rays, and solar winds. It also includes information about ion penetration of the magnetosphere, galactic cosmic rays, solar particle environments, CRRES internal discharge monitor, surface charging and radiation effects.

  18. First simultaneous detection of terrestrial ionospheric molecular ions in the Earth's inner magnetosphere and at the Moon

    NASA Astrophysics Data System (ADS)

    Dandouras, I.; Poppe, A. R.; Fillingim, M. O.; Kistler, L. M.; Mouikis, C. G.; Rème, H.

    2017-09-01

    First coordinated observation of escaping heavy molecular ions in the Earth's inner magnetosphere and at the Moon. Quantifying the underlying escape mechanisms is important in order to understand the long-term (billion years scale) evolution of the atmospheric composition, and in particular the evolution of the N/O ratio, which is essential for habitability. Terrestrial heavy ions, transported to the Moon, suggest also that the Earth's atmosphere of billions of years ago may be preserved on the present-day lunar regolith.

  19. Global Effects of Transmitted Shock Wave Propagation Through the Earth's Inner Magnetosphere: First Results from 3-D Hybrid Kinetic Modeling

    NASA Technical Reports Server (NTRS)

    Lipatov, A. S.; Sibeck, D. G.

    2016-01-01

    We use a new hybrid kinetic model to simulate the response of ring current, outer radiation belt, and plasmaspheric particle populations to impulsive interplanetary shocks. Since particle distributions attending the interplanetary shock waves and in the ring current and radiation belts are non-Maxwellian, waveparticle interactions play a crucial role in energy transport within the inner magnetosphere. Finite gyroradius effects become important in mass loading the shock waves with the background plasma in the presence of higher energy ring current and radiation belt ions and electrons. Initial results show that shocks cause strong deformations in the global structure of the ring current, radiation belt, and plasmasphere. The ion velocity distribution functions at the shock front, in the ring current, and in the radiation belt help us determine energy transport through the Earth's inner magnetosphere.

  20. Simulating the interplay between plasma transport, electric field, and magnetic field in the near-earth nightside magnetosphere

    NASA Astrophysics Data System (ADS)

    Gkioulidou, Malamati

    The convection electric field resulting from the coupling of the Earth's magnetosphere with the solar wind and interplanetary magnetic field (IMF) drives plasma in the tail plasma sheet earthward. This transport and the resulting energy storage in the near Earth plasma sheet are important for setting up the conditions that lead to major space weather disturbances, such as storms and substorms. Penetration of plasma sheet particles into the near-Earth magnetosphere in response to enhanced convection is crucial to the development of the Region 2 field-aligned current system and large-scale magnetosphere-ionosphere (M-I) coupling, which results in the shielding of the convection electric field. In addition to the electric field, plasma transport is also strongly affected by the magnetic field, which is distinctly different from dipole field in the inner plasma sheet and changes with plasma pressure in maintaining force balance. The goal of this dissertation is to investigate how the plasma transport into the inner magnetosphere is affected by the interplay between plasma, electric field and magnetic field. For this purpose, we conduct simulations using the Rice Convection Model (RCM), which self-consistently calculates the electric field resulting from M-I coupling. In order to quantitatively evaluate the interplay, we improved the RCM simulations by establishing realistic plasma sheet particle sources, by incorporating it with a modified Dungey force balance magnetic field solver (RCM-Dungey runs), and by adopting more realistic electron loss rates. We found that plasma sheet particle sources strongly affect the shielding of the convection electric field, with a hotter and more tenuous plasma sheet resulting in less shielding than a colder and denser one and thus in more earthward penetration of the plasma sheet. The Harang reversal, which is closely associated with the shielding of the convection electric field and the earthward penetration of low-energy protons, is

  1. The Effect of Background Plasma Temperature on Growth and Damping of Whistler Mode Wave Power in the Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Maxworth, A. S.; Golkowski, M.; Malaspina, D.; Jaynes, A. N.

    2017-12-01

    Whistler mode waves play a dominant role in the energy dynamics of the Earth's magnetosphere. Trajectory of whistler mode waves can be predicted by raytracing. Raytracing is a numerical method which solves the Haselgrove's equations at each time step taking the background plasma parameters in to account. The majority of previous raytracing work was conducted assuming a cold (0 K) background magnetospheric plasma. Here we perform raytracing in a finite temperature plasma with background electron and ion temperatures of a few eV. When encountered with a high energy (>10 keV) electron distribution, whistler mode waves can undergo a power attenuation and/or growth, depending on resonance conditions which are a function of wave frequency, wave normal angle and particle energy. In this work we present the wave power attenuation and growth analysis of whistler mode waves, during the interaction with a high energy electron distribution. We have numerically modelled the high energy electron distribution as an isotropic velocity distribution, as well as an anisotropic bi-Maxwellian distribution. Both cases were analyzed with and without the temperature effects for the background magnetospheric plasma. Finally we compare our results with the whistler mode energy distribution obtained by the EMFISIS instrument hosted at the Van Allen Probe spacecraft.

  2. Modeling the Earth's magnetospheric magnetic field confined within a realistic magnetopause

    NASA Technical Reports Server (NTRS)

    Tsyganenko, N. A.

    1995-01-01

    Empirical data-based models of the magnetosphereic magnetic field have been widely used during recent years. However, the existing models (Tsyganenko, 1987, 1989a) have three serious deficiencies: (1) an unstable de facto magnetopause, (2) a crude parametrization by the K(sub p) index, and (3) inaccuracies in the equatorial magnetotail B(sub z) values. This paper describes a new approach to the problem; the essential new features are (1) a realistic shape and size of the magnetopause, based on fits to a large number of observed crossing (allowing a parametrization by the solar wind pressure), (2) fully controlled shielding of the magnetic field produced by all magnetospheric current systems, (3) new flexible representations for the tail and ring currents, and (4) a new directional criterion for fitting the model field to spacecraft data, providing improved accuracy for field line mapping. Results are presented from initial efforts to create models assembled from these modules and calibrated against spacecraft data sets.

  3. Role of the magnetosheath in the interaction of magnetic clouds with the Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Fontaine, Dominique; Turc, Lucile; Savoini, Philippe; Modolo, Ronan

    2016-04-01

    Magnetic clouds are among the most geoeffective solar events capable to trigger strong magnetic storms in the terrestrial magnetosphere. However, their characteristics and those of the surrounding media are not always capable to explain their high level of geoeffectivity. From observations and simulations, we investigate here the role of the bow shock and of the magnetosheath. Conjugated observations upstream (ACE) and downstream (CLUSTER) of the bow shock show that the magnetic clouds' magnetic structure in the magnetosheath can strongly depart from their pristine structure upstream of the bow shock. This modification depends on the shock configuration (quasi-perpendicular, quasi-parallel). We also discuss this question from hybrid simulations of the interaction of magnetic clouds with the bow shock. We show that this interaction may produce unexpected characteristics in the magnetosheath, such as asymmetric distributions of magnetic field, density, temperature, velocity. They thus lead to interactions with the magnetosphere which were not expected from the pristine characteristics of the magnetic clouds in the solar wind upstream of bow shock. We here discuss the effects of such an asymmetric magnetosheath on key parameters for the interaction with the magnetopause (reconnection, instabilities), responsible in turn for the development of geomagnetic activity inside the magnetosphere.

  4. Mercury's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Slavin, J. A.

    1999-01-01

    Among the major discoveries made by the Mariner 10 mission to the inner planets was the existence of an intrinsic magnetic field at Mercury with a dipole moment of approx. 300 nT R(sup 3, sub M). This magnetic field is sufficient to stand off the solar wind at an altitude of about 1 R(sub M) (i.e. approx. 2439 km). Hence, Mercury possesses a 'magnetosphere' from which the so]ar wind plasma is largely excluded and within which the motion of charged particles is controlled by the planetary magnetic field. Despite its small size relative to the magnetospheres of the other planets, a Mercury orbiter mission is a high priority for the space physics community. The primary reason for this great interest is that Mercury unlike all the other planets visited thus far, lacks a significant atmosphere; only a vestigial exosphere is present. This results in a unique situation where the magnetosphere interacts directly with the outer layer of the planetary crust (i.e. the regolith). At all of the other planets the topmost regions of their atmospheres become ionized by solar radiation to form ionospheres. These planetary ionospheres then couple to electrodynamically to their magnetospheres or, in the case of the weakly magnetized Venus and Mars, directly to the solar wind. This magnetosphere-ionosphere coupling is mediated largely through field-aligned currents (FACs) flowing along the magnetic field lines linking the magnetosphere and the high-latitude ionosphere. Mercury is unique in that it is expected that FACS will be very short lived due to the low electrical conductivity of the regolith. Furthermore, at the earth it has been shown that the outflow of neutral atmospheric species to great altitudes is an important source of magnetospheric plasma (following ionization) whose composition may influence subsequent magnetotail dynamics. However, the dominant source of plasma for most of the terrestrial magnetosphere is the 'leakage'of solar wind across the magnetopause and more

  5. Penetration of Solar Wind Driven ULF Waves into the Earth's Inner Magnetosphere: Role in Radiation Belt and Ring Current Dynamics

    NASA Astrophysics Data System (ADS)

    Mann, Ian; Murphy, Kyle; Rae, Jonathan; Ozeke, Louis; Milling, David

    2013-04-01

    Ultra-low frequency (ULF) waves in the Pc4-5 band can be excited in the magnetosphere by the solar wind. Much recent work has shown how ULF wave power is strongly correlated with solar wind speed. However, little attention has been paid the dynamics of ULF wave power penetration onto low L-shells in the inner magnetosphere. We use more than a solar cycle of ULF wave data, derived from ground-based magnetometer networks, to examine this ULF wave power penetration and its dependence on solar wind and geomagnetic activity indices. In time domain data, we show very clearly that dayside ULF wave power, spanning more than 4 orders of magnitude, follows solar wind speed variations throughout the whole solar cycle - during periods of sporadic solar maximum ICMEs, during declining phase fast solar wind streams, and at solar minimum, alike. We also show that time domain ULF wave power increases during magnetic storms activations, and significantly demonstrate that a deeper ULF wave power penetration into the inner magnetosphere occurs during larger negative excursions in Dst. We discuss potential explanations for this low-L ULF wave power penetration, including the role of plasma mass density (such as during plasmaspheric erosion), or ring current ion instabilities during near-Earth ring current penetration. Interestingly, we also show that both ULF wave power and SAMPEX MeV electron flux show a remarkable similarity in their penetration to low-L, which suggests that ULF wave power penetration may be important for understanding and explaining radiation belt dynamics. Moreover, the correlation of ULF wave power with Dst, which peaks at one day lag, suggests the ULF waves might also be important for the inward transport of ions into the ring current. Current ring current models, which exclude long period ULF wave transport, under-estimate the ring current during fast solar wind streams which is consistent with a potential role for ULF waves in ring current energisation. The

  6. Shape of the terrestrial plasma sheet in the near-Earth magnetospheric tail as imaged by the Interstellar Boundary Explorer

    DOE PAGES

    Dayeh, M. A.; Fuselier, S. A.; Funsten, H. O.; ...

    2015-04-11

    We present remote, continuous observations from the Interstellar Boundary Explorer of the terrestrial plasma sheet location back to -16 Earth radii (R E) in the magnetospheric tail using energetic neutral atom emissions. The time period studied includes two orbits near the winter and summer solstices, thus associated with large negative and positive dipole tilt, respectively. Continuous side-view images reveal a complex shape that is dominated mainly by large-scale warping due to the diurnal motion of the dipole axis. Superposed on the global warped geometry are short-time fluctuations in plasma sheet location that appear to be consistent with plasma sheet flappingmore » and possibly twisting due to changes in the interplanetary conditions. We conclude that the plasma sheet warping due to the diurnal motion dominates the average shape of the plasma sheet. Over short times, the position of the plasma sheet can be dominated by twisting and flapping.« less

  7. A study of an expanding interplanatary magnetic cloud and its interaction with the earth's magnetosphere - The interplanetary aspect

    NASA Technical Reports Server (NTRS)

    Farrugia, C. J.; Burlaga, L. F.; Osherovich, V. A.; Richardson, I. G.; Freeman, M. P.; Lepping, R. P.; Lazarus, A. J.

    1993-01-01

    High time resolution interplanetary magnetic field and plasma measurements of an interplanetary magnetic cloud and its interaction with the earth's magnetosphere on January 14/15, 1988 are interpreted and discussed. It is argued that the data are consistent with the theoretical model of magnetic clouds as flux ropes of local straight cylindrical geometry. The data also suggest that this cloud is aligned with its axis in the ecliptic plane and pointing in the east-west direction. Evidence consisting of the intensity and directional distribution of energetic particle in the magnetic cloud argues in favor of the connectedness of the magnetic field lines to the sun's surface. The intensities of about 0.5 MeV ions is rapidly enhanced and the particles stream in a collimated beam along the magnetic field preferentially from the west of the sun. The particles travel form a flare site along the cloud magnetic field lines, which are thus presumably still attached to the sun.

  8. Simulation of electromagnetic ion cyclotron triggered emissions in the Earth's inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Shoji, Masafumi; Omura, Yoshiharu

    2011-05-01

    In a recent observation by the Cluster spacecraft, emissions triggered by electromagnetic ion cyclotron (EMIC) waves were discovered in the inner magnetosphere. We perform hybrid simulations to reproduce the EMIC triggered emissions. We develop a self-consistent one-dimensional hybrid code with a cylindrical geometry of the background magnetic field. We assume a parabolic magnetic field to model the dipole magnetic field in the equatorial region of the inner magnetosphere. Triggering EMIC waves are driven by a left-handed polarized external current assumed at the magnetic equator in the simulation model. Cold proton, helium, and oxygen ions, which form branches of the dispersion relation of the EMIC waves, are uniformly distributed in the simulation space. Energetic protons with a loss cone distribution function are also assumed as resonant particles. We reproduce rising tone emissions in the simulation space, finding a good agreement with the nonlinear wave growth theory. In the energetic proton velocity distribution we find formation of a proton hole, which is assumed in the nonlinear wave growth theory. A substantial amount of the energetic protons are scattered into the loss cone, while some of the resonant protons are accelerated to higher pitch angles, forming a pancake velocity distribution.

  9. Spectral properties and associated plasma energization by magnetosonic waves in the Earth's magnetosphere: Particle-in-cell simulations

    NASA Astrophysics Data System (ADS)

    Sun, Jicheng; Gao, Xinliang; Lu, Quanming; Chen, Lunjin; Liu, Xu; Wang, Xueyi; Tao, Xin; Wang, Shui

    2017-05-01

    In this paper, we perform a 1-D particle-in-cell (PIC) simulation model consisting of three species, cold electrons, cold ions, and energetic ion ring, to investigate spectral structures of magnetosonic waves excited by ring distribution protons in the Earth's magnetosphere, and dynamics of charged particles during the excitation of magnetosonic waves. As the wave normal angle decreases, the spectral range of excited magnetosonic waves becomes broader with upper frequency limit extending beyond the lower hybrid resonant frequency, and the discrete spectra tends to merge into a continuous one. This dependence on wave normal angle is consistent with the linear theory. The effects of magnetosonic waves on the background cold plasma populations also vary with wave normal angle. For exactly perpendicular magnetosonic waves (parallel wave number k|| = 0), there is no energization in the parallel direction for both background cold protons and electrons due to the negligible fluctuating electric field component in the parallel direction. In contrast, the perpendicular energization of background plasmas is rather significant, where cold protons follow unmagnetized motion while cold electrons follow drift motion due to wave electric fields. For magnetosonic waves with a finite k||, there exists a nonnegligible parallel fluctuating electric field, leading to a significant and rapid energization in the parallel direction for cold electrons. These cold electrons can also be efficiently energized in the perpendicular direction due to the interaction with the magnetosonic wave fields in the perpendicular direction. However, cold protons can be only heated in the perpendicular direction, which is likely caused by the higher-order resonances with magnetosonic waves. The potential impacts of magnetosonic waves on the energization of the background cold plasmas in the Earth's inner magnetosphere are also discussed in this paper.

  10. Instrument technology for magnetosphere plasma imaging from high Earth orbit. Design of a radio plasma sounder

    NASA Technical Reports Server (NTRS)

    Haines, D. Mark; Reinisch, Bodo W.

    1995-01-01

    The use of radio sounding techniques for the study of the ionospheric plasma dates back to G. Briet and M. A. Tuve in 1926. Ground based swept frequency sounders can monitor the electron number density (N(sub e)) as a function of height (the N(sub e) profile). These early instruments evolved into a global network that produced high-resolution displays of echo time delay vs frequency on 35-mm film. These instruments provided the foundation for the success of the International Geophysical Year (1958). The Alouette and International Satellites for Ionospheric Studies (ISIS) programs pioneered the used of spaceborne, swept frequency sounders to obtain N(sub e) profiles of the topside of the ionosphere, from a position above the electron density maximum. Repeated measurements during the orbit produced an orbital plane contour which routinely provided density measurements to within 10%. The Alouette/ISIS experience also showed that even with a high powered transmitter (compared to the low power sounder possible today) a radio sounder can be compatible with other imaging instruments on the same satellite. Digital technology was used on later spacecraft developed by the Japanese (the EXOS C and D) and the Soviets (Intercosmos 19 and Cosmos 1809). However, a full coherent pulse compression and spectral integrating capability, such as exist today for ground-based sounders (Reinisch et al., 1992), has never been put into space. NASA's 1990 Space Physics Strategy Implementation Study "The NASA Space Physics Program from 1995 to 2010" suggested using radio sounders to study the plasmasphere and the magnetopause and its boundary layers (Green and Fung, 1993). Both the magnetopause and plasmasphere, as well as the cusp and boundary layers, can be observed by a radio sounder in a high-inclination polar orbit with an apogee greater than 6 R(sub e) (Reiff et al., 1994; Calvert et al., 1995). Magnetospheric radio sounding from space will provide remote density measurements of

  11. Cetacean beachings correlate with geomagnetic disturbances in Earth's magnetosphere: an example of how astronomical changes impact the future of life

    NASA Astrophysics Data System (ADS)

    Ferrari, Thomas E.

    2017-04-01

    The beaching and stranding of whales and dolphins around the world has been mystifying scientists for centuries. Although many theories have been proposed, few are substantiated by unequivocal statistical evidence. Advances in the field of animal magnetoreception have established that many organisms, including cetaceans, have an internal `compass,' which they use for orientation when traveling long distances. Astrobiology involves not only the origin and distribution of life in the universe, but also the scientific study of how extraterrestrial conditions affect evolution of life on planet Earth. The focus of this study is how cetacean life is influenced by disturbances in its environment that originate from an astrological phenomenon - in the present study that involves solar flares and cetacean beachings. Solar storms are caused by major coronal eruptions on the Sun. Upon reaching Earth, they cause disturbances in Earth's normally stable magnetosphere. Unable to follow an accurate magnetic bearing under such circumstances, cetaceans lose their compass reading while travelling and, depending on their juxtaposition and nearness to land, eventually beach themselves. (1) This hypothesis was supported by six separate, independent surveys of beachings: (A) in the Mediterranean Sea, (B) the northern Gulf of Mexico, (C) the east and (D) west coasts of the USA and two surveys (E and F) from around the world. When the six surveys were pooled (1614 strandings), a highly significant correlation (R 2 = 0.981) of when strandings occurred with when major geomagnetic disturbances in Earth's magnetosphere occurred was consistent with this hypothesis. (2) Whale and dolphin strandings in the northern Gulf of Mexico and the east coast of the USA were correlated (R 2 = 0.919, R 2 = 0.924) with the number of days before and after a geomagnetic storm. (3) Yearly strandings were correlated with annual geomagnetic storm days. (4) Annual beachings of cetaceans from 1998 to 2012 were

  12. Satellite and Ground Signatures of Kinetic and Inertial Scale ULF Alfven Waves Propagating in Warm Plasma in Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Rankin, R.; Sydorenko, D.

    2015-12-01

    Results from a 3D global numerical model of Alfven wave propagation in a warm multi-species plasma in Earth's magnetosphere are presented. The model uses spherical coordinates, accounts for a non-dipole magnetic field, vertical structure of the ionosphere, and an air gap below the ionosphere. A realistic density model is used. Below the exobase altitude (2000 km) the densities and the temperatures of electrons, ions, and neutrals are obtained from the IRI and MSIS models. Above the exobase, ballistic (originating from the ionosphere and returning to ionosphere) and trapped (bouncing between two reflection points above the ionosphere) electron populations are considered similar to [Pierrard and Stegen (2008), JGR, v.113, A10209]. Plasma parameters at the exobase provided by the IRI are the boundary conditions for the ballistic electrons while the [Carpenter and Anderson (1992), JGR, v.97, p.1097] model of equatorial electron density defines parameters of the trapped electron population. In the simulations that are presented, Alfven waves with frequencies from 1 Hz to 0.01 Hz and finite azimuthal wavenumbers are excited in the magnetosphere and compared with Van Allen Probes data and ground-based observations from the CARISMA array of ground magnetometers. When short perpendicular scale waves reflect form the ionosphere, compressional Alfven waves are observed to propagate across the geomagnetic field in the ionospheric waveguide [e.g., Lysak (1999), JGR, v.104, p.10017]. Signals produced by the waves on the ground are discussed. The wave model is also applied to interpret recent Van Allen Probes observations of kinetic scale ULF waves that are associated with radiation belt electron dynamics and energetic particle injections.

  13. Characteristics of VLF wave propagation in the Earth's magnetosphere in the presence of an artificial density duct

    NASA Astrophysics Data System (ADS)

    Pasmanik, Dmitry; Demekhov, Andrei

    We study the propagation of VLF waves in the Earth's ionosphere and magnetosphere in the presence of large-scale artificial plasma inhomogeneities which can be created by HF heating facilities like HAARP and ``Sura''. A region with enhanced cold plasma density can be formed due to the action of HF heating. This region is extended along geomagnetic field (up to altitudes of several thousand km) and has rather small size across magnetic field (about 1 degree). The geometric-optical approximation is used to study wave propagation. The plasma density and ion composition are calculated with the use of SAMI2 model, which was modified to take the effect of HF heating into account. We calculate ray trajectories of waves with different initial frequency and wave-normal angles and originating at altitudes of about 100 km in the region near the heating area. The source of such waves could be the lightning discharges, modulated HF heating of the ionosphere, or VLF transmitters. Variation of the wave amplitude along the ray trajectories due to refraction is considered and spatial distribution of wave intensity in the magnetosphere is analyzed. We show that the presence of such a density disturbances can lead to significant changes of wave propagation trajectories, in particular, to efficient guiding of VLF waves in this region. This can result in a drastic increase of the VLF-wave intensity in the density duct. The dependence of wave propagation properties on parameters of heating facility operation regime is considered. We study the variation of the spatial distribution of VLF wave intensity related to the slow evolution of the artificial inhomogeneity during the heating.

  14. The magnetospheric disturbance ring current as a source for probing the deep earth electrical conductivity

    USGS Publications Warehouse

    Campbell, W.H.

    1990-01-01

    Two current rings have been observed in the equatorial plane of the earth at times of high geomagnetic activity. An eastward current exists between about 2 and 3.5 earth radii (Re) distant, and a larger, more variable companion current exists between about 4 and 9 Re. These current regions are loaded during geomagnetic substorms. They decay, almost exponentially, after the cessation of the particle influx that attends the solar wind disturbance. This review focuses upon characteristics needed for intelligent use of the ring current as a source for induction probing of the earth's mantle. Considerable difficulties are found with the assumption that Dst is a ring-current index. ?? 1990 Birkha??user Verlag.

  15. Plasma Turbulence in Earth's Magnetotail Observed by the Magnetospheric Multiscale Mission

    NASA Astrophysics Data System (ADS)

    Mackler, D. A.; Avanov, L. A.; Boardsen, S. A.; Pollock, C. J.

    2017-12-01

    Magnetic reconnection, a process in which the magnetic topology undergoes multi-scale changes, is a significant mechanism for particle energization as well as energy dissipation. Reconnection is observed to occur in thin current sheets generated between two regions of magnetized plasma merging with a non-zero shear angle. Within a thinning current sheet, the dominant scale size approaches first the ion and then electron kinetic scale. The plasma becomes demagnetized, field lines transform, then once again the plasma becomes frozen-in. The reconnection process accelerates particles, leading to heated jets of plasma. Turbulence is another fundamental process in collision less plasmas. Despite decades of turbulence studies, an essential science question remains as to how turbulent energy dissipates at small scales by heating and accelerating particles. Turbulence in both plasmas and fluids has a fundamental property in that it follows an energy cascade into smaller scales. Energy introduced into a fluid or plasma can cause large scale motion, introducing vorticity, which merge and interact to make increasingly smaller eddies. It has been hypothesized that turbulent energy in magnetized plasmas may be dissipated by magnetic reconnection, just as viscosity dissipates energy in neutral fluid turbulence. The focus of this study is to use the new high temporal resolution suite of instruments on board the Magnetospheric MultiScale (MMS) mission to explore this hypothesis. An observable feature of the energy cascade in a turbulent magnetized plasma is its similarity to classical hydrodynamics in that the Power Spectral Density (PSD) of turbulent fluctuations follows a Kolmogorov-like power law (Image-5/3). We use highly accurate (0.1 nT) Flux Gate Magnetometer (FGM) data to derive the PSD as a function of frequency in the magnetic fluctuations. Given that we are able to confirm the turbulent nature of the flow field; we apply the method of Partial Variance of Increments (PVI

  16. Magnetospheric Multiscale observations of Poynting flux associated with magnetic reconnection in the Earth's magnetotail from 10 to 25 RE

    NASA Astrophysics Data System (ADS)

    Stawarz, J. E.; Eastwood, J. P.; Ergun, R.; Shay, M. A.; Phan, T.; Nakamura, R.; Varsani, A.; Burch, J. L.; Fuselier, S. A.; Gershman, D. J.; Giles, B. L.; Goodrich, K.; Khotyaintsev, Y. V.; Lindqvist, P. A.; Russell, C. T.; Strangeway, R. J.; Torbert, R. B.

    2017-12-01

    Magnetic reconnection plays an important role in energy conversion and transport in space plasmas. In the Earth's magnetotail, fast Earthward, as well as tailward, flows known as bursty bulk flows (BBFs) are thought to be jets caused by reconnection. Alfvénic Poynting flux associated with these reconnection events is thought to transport energy that results in auroral activity. It has been proposed that the reconnection event itself can generate a kinetic Alfvén wave signature along the separatrix. Furthermore, the process of BBF braking as the reconnection jet impinges on the dipolar near-Earth magnetic field can excite turbulence and wave activity, which can propagate along the field to the auroral region. Recently, Poynting flux at 10 RE in the tail near the plasma sheet boundary has been examined using observations from the Magnetospheric Multiscale (MMS) mission. The 3D structure of the fluctuations was investigated and it was demonstrated that they are consistent with kinetic Alfvén waves with non-plane-wave structure. However, at this location in the tail, the observed Poynting flux may be linked to either the reconnection separatrix or waves excited by BBF braking. Some evidence for two classes of Poynting flux events that may be consistent with these two source mechanisms has been found at 10 RE distances. In this presentation, these results will be discussed and compared with new MMS observations nearer to the reconnection site at 25 RE. At this location, BBF braking is likely not contributing to the Poynting flux, which helps to further elucidate the importance of the various sources of reconnection related Alfvénic Poynting flux in the magnetotail.

  17. Behold Saturn's Magnetosphere!

    NASA Image and Video Library

    2004-07-01

    Saturn's magnetosphere is seen for the first time in this image taken by the Cassini spacecraft on June 21, 2004. A magnetosphere is a magnetic envelope of charged particles that surrounds some planets, including Earth. It is invisible to the human eye, but Cassini's Magnetospheric Imaging Instrument was able to detect the hydrogen atoms (represented in red) that escape it. The emission from these hydrogen atoms comes primarily from regions far from Saturn, well outside the planet's rings, and perhaps beyond the orbit of the largest moon Titan. The image represents the first direct look at the shape of Saturn's magnetosphere. Previously, NASA's Voyager mission had inferred what Saturn's magnetosphere would look like in the same way that a blind person might feel the shape of an elephant. With Cassini, the "elephant" has been revealed in a picture. This picture was taken by the ion and neutral camera, one of three sensors that comprise the magnetosphereic imaging instrument, from a distance of about 3.7 million miles (about 6 million kilometers) from Saturn. The magnetospheric imaging instrument will continue to study Saturn's magnetosphere throughout the mission's four-year lifetime. http://photojournal.jpl.nasa.gov/catalog/PIA06345

  18. The influence of the Earth's magnetosphere on the high-energy solar protons

    NASA Technical Reports Server (NTRS)

    Bazilevskaya, G. A.; Makhmutov, V. S.; Charakhchyan, T. N.

    1985-01-01

    In the Earth's polar regions the intensity of the solar protons with the energy above the critical energy of geomagnetic cutoff is the same as in the interplanetary space. The penumbra in the polar regions is small and the East-West effect is also small. However the geomagnetic cutoff rigidity R sub c in polar regions is difficult to calculate because it is not sufficient to include only the internal sources of the geomagnetic field. During the magneto-quiescent periods the real value of R sub c can be less by 0.1 GV than the calculated value because of the external sources. During the geomagnetic storms the real value of R sub c is still lower.

  19. Electron hybrid simulations of whistler-mode chorus generation with real parameters in the Earth's inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Katoh, Y.; Omura, Y.

    2016-12-01

    Whistler-mode chorus emissions play curial roles in the evolution of radiation belt electrons. Chorus emissions are narrow band emissions observed in the typical frequency range of 0.2 to 0.8 fce0 with a gap at half the fce0, where fce0 represents the electron gyrofrequency at the magnetic equator. The generation process of chorus has been explained by the nonlinear wave growth theory [see review by Omura et al., in AGU Monograph "Dynamics of the Earth's Radiation Belts and Inner Magnetosphere, 2012] and has been reproduced by self-consistent numerical experiments [e.g., Katoh and Omura, GRL 2007, JGR 2011, 2013]. In the present study, we show the result of electron hybrid simulation of the generation process of whistler-mode chorus emissions under realistic initial conditions. We refer in-situ observations by Cluster [Santolik et al., 2003] for the initial parameters of energetic electrons and the spatial inhomogeneity of the background magnetic field. In the simulation results we observe chorus emissions with rising tones whose the spectral characteristics are consistent with the observation. We also find that the simulation results are consistently explained by the theoretically estimated threshold and optimum wave amplitudes of chorus elements based on the nonlinear wave growth theory. A series of simulations reveal properties of the chorus generation depending on the velocity distribution of energetic electrons [Katoh and Omura, JGR 2011] and the background magnetic field inhomogeneity [Katoh and Omura, JGR 2013]. These properties should be evaluated by comparison with in-situ and ground-based observations.

  20. Turbulence in a Global Magnetohydrodynamic Simulation of the Earth's Magnetosphere during Northward and Southward Interplanetary Magnetic Field

    NASA Technical Reports Server (NTRS)

    El-Alaoui, M.; Richard, R. L.; Ashour-Abdalla, M.; Walker, R. J.; Goldstein, M. L.

    2012-01-01

    We report the results of MHD simulations of Earth's magnetosphere for idealized steady solar wind plasma and interplanetary magnetic field (IMF) conditions. The simulations feature purely northward and southward magnetic fields and were designed to study turbulence in the magnetotail plasma sheet. We found that the power spectral densities (PSDs) for both northward and southward IMF had the characteristics of turbulent flow. In both cases, the PSDs showed the three scale ranges expected from theory: the energy-containing scale, the inertial range, and the dissipative range. The results were generally consistent with in-situ observations and theoretical predictions. While the two cases studied, northward and southward IMF, had some similar characteristics, there were significant differences as well. For southward IMF, localized reconnection was the main energy source for the turbulence. For northward IMF, remnant reconnection contributed to driving the turbulence. Boundary waves may also have contributed. In both cases, the PSD slopes had spatial distributions in the dissipative range that reflected the pattern of resistive dissipation. For southward IMF there was a trend toward steeper slopes in the dissipative range with distance down the tail. For northward IMF there was a marked dusk-dawn asymmetry with steeper slopes on the dusk side of the tail. The inertial scale PSDs had a dusk-dawn symmetry during the northward IMF interval with steeper slopes on the dawn side. This asymmetry was not found in the distribution of inertial range slopes for southward IMF. The inertial range PSD slopes were clustered around values close to the theoretical expectation for both northward and southward IMF. In the dissipative range, however, the slopes were broadly distributed and the median values were significantly different, consistent with a different distribution of resistivity.

  1. Soft X-ray study of solar wind charge exchange from the Earth's magnetosphere : Suzaku observations and a future X-ray imaging mission concept

    NASA Astrophysics Data System (ADS)

    Ezoe, Y.; Ishisaki, Y.; Ohashi, T.; Ishikawa, K.; Miyoshi, Y.; Fujimoto, R.; Terada, N.; Kasahara, S.; Fujimoto, M.; Mitsuda, K.; Nishijo, K.; Noda, A.

    2013-12-01

    Soft X-ray observations of solar wind charge exchange (SWCX) emission from the Earth's magnetosphere using the Japanese X-ray astronomy satellite Suzaku are shown, together with our X-ray imaging mission concept to characterize the solar wind interaction with the magnetosphere. In recent years, the SWCX emission from the Earth's magnetosphere, originally discovered as unexplained noise during the soft X-ray all sky survey (Snowden et al. 1994), is receiving increased attention on studying geospace. The SWCX is a reaction between neutrals in exosphere and highly charged ions in the magnetosphere originated from solar wind. Robertson et al. (2005) modeled the SWCX emission as seen from an observation point 50 Re from Earth. In the resulting X-ray intensities, the magnetopause, bow shock and cusp were clearly visible. High sensitivity soft X-ray observation with CCDs onboard recent X-ray astronomy satellites enables us to resolve SWCX emission lines and investigate time correlation with solar wind as observed with ACE and WIND more accurately. Suzaku is the 5th Japanese X-ray astronomy satellite launched in 2005. The line of sight direction through cusp is observable, while constraints on Earth limb avoidance angle of other satellites often limits observable regions. Suzaku firstly detected the SWCX emission while pointing in the direction of the north ecliptic pole (Fujimoto et al. 2007). Using the Tsyganenko 1996 magnetic field model, the distance to the nearest SWCX region was estimated as 2-8 Re, implying that the line of sight direction can be through magnetospheric cusp. Ezoe et al. (2010) reported SWCX events toward the sub-solar side of the magnetosheath. These cusp and sub-solar side magnetosheath regions are predicted to show high SWCX fluxes by Robertson et al. (2005). On the other hand, Ishikawa et al. (2013) discovered a similarly strong SWCX event when the line of sight direction did not transverse these two regions. Motivated by these detections

  2. Theoretical analysis on lower band cascade as a mechanism for multiband chorus in the Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Gao, Xinliang; Lu, Quanming; Wang, Shaojie; Wang, Shui

    2018-05-01

    Whistler-mode waves play a crucial role in controlling electron dynamics in the Earth's Van Allen radiation belt, which is increasingly important for spacecraft safety. Using THEMIS waveform data, Gao et al. [X. L. Gao, Q. Lu, J. Bortnik, W. Li, L. Chen, and S. Wang, Geophys. Res. Lett., 43, 2343-2350, 2016] have reported two multiband chorus events, wherein upper-band chorus appears at harmonics of lower-band chorus. They proposed that upper-band harmonic waves are excited through the nonlinear coupling between the electromagnetic and electrostatic components of lower-band chorus, a second-order effect called "lower band cascade". However, the theoretical explanation of lower band cascade was not thoroughly explained in the earlier work. In this paper, based on a cold plasma assumption, we have obtained the explicit nonlinear driven force of lower band cascade through a full nonlinear theoretical analysis, which includes both the ponderomotive force and coupling between electrostatic and electromagnetic components of the pump whistler wave. Moreover, we discover the existence of an efficient energy-transfer (E-t) channel from lower-band to upper-band whistler-mode waves during lower band cascade for the first time, which is also confirmed by PIC simulations. For lower-band whistler-mode waves with a small wave normal angle (WNA), the E-t channel is detected when the driven upper-band wave nearly satisfies the linear dispersion relation of whistler mode. While, for lower-band waves with a large WNA, the E-t channel is found when the lower-band wave is close to its resonant frequency, and the driven upper-band wave becomes quasi-electrostatic. Through this efficient channel, the harmonic upper band of whistler waves is generated through energy cascade from the lower band, and the two-band spectral structure of whistler waves is then formed. Both two types of banded whistler-mode spectrum have also been successfully reproduced by PIC simulations.

  3. Magnetospheric plasma interactions

    NASA Astrophysics Data System (ADS)

    Faelthammar, Carl-Gunne

    1994-04-01

    The Earth's magnetosphere (including the ionosphere) is our nearest cosmical plasma system and the only one accessible to mankind for extensive empirical study by in situ measurements. As virtually all matter in the universe is in the plasma state, the magnetosphere provides an invaluable sample of cosmical plasma from which we can learn to better understand the behavior of matter in this state, which is so much more complex than that of unionized matter. It is therefore fortunate that the magnetosphere contains a wide range of different plasma populations, which vary in density over more than six powers of ten and even more in equivalent temperature. Still more important is the fact that its dual interaction with the solar wind above and the atmosphere below make the magnetopshere the site of a large number of plasma phenomena that are of fundamental interest in plasma physics as well as in astrophysics and cosmology. The interaction of the rapidly streaming solar wind plasma with the magnetosphere feeds energy and momentum, as well as matter, into the magnetosphere. Injection from the solar wind is a source of plasma populations in the outer magnetosphere, although much less dominating than previously thought. We now know that the Earth's own atmosphere is the ultimate source of much of the plasma in large regions of the magnetosphere. The input of energy and momentum drives large scale convection of magnetospheric plasma and establishes a magnetospheric electric field and large scale electric current systems that car ry millions of ampere between the ionosphere and outer space. These electric fields and currents play a crucial role in generating one of the the most spectacular among natural phenomena, the aurora, as well as magnetic storms that can disturb man-made systems on ground and in orbit. The remarkable capability of accelerating charged particles, which is so typical of cosmical plasmas, is well represented in the magnetosphere, where mechanisms of such

  4. Saturn's outer magnetosphere

    NASA Technical Reports Server (NTRS)

    Schardt, A. W.; Behannon, K. W.; Carbary, J. F.; Eviatar, A.; Lepping, R. P.; Siscoe, G. L.

    1983-01-01

    Similarities between the Saturnian and terrestrial outer magnetosphere are examined. Saturn, like Earth, has a fully developed magnetic tail, 80 to 100 RS in diameter. One major difference between the two outer magnetospheres is the hydrogen and nitrogen torus produced by Titan. This plasma is, in general, convected in the corotation direction at nearly the rigid corotation speed. Energies of magnetospheric particles extend to above 500 keV. In contrast, interplanetary protons and ions above 2 MeV have free access to the outer magnetosphere to distances well below the Stormer cutoff. This access presumably occurs through the magnetotail. In addition to the H+, H2+, and H3+ ions primarily of local origin, energetic He, C, N, and O ions are found with solar composition. Their flux can be substantially enhanced over that of interplanetary ions at energies of 0.2 to 0.4 MeV/nuc.

  5. Concepts of magnetospheric convection

    NASA Technical Reports Server (NTRS)

    Vasyliunas, V. M.

    1975-01-01

    The paper describes the basic theoretical notions of convection applicable to magnetospheres in general and discusses the relative importance of convective and corrotational motions, with particular reference to the comparison of the earth and Jupiter. The basic equations relating the E, B, and J fields and the bulk plasma velocity are given for the three principal regions in magnetosphere dynamics, namely, the central object and its magnetic field, the space surrounding the central object, and the external medium outside the magnetosphere. The notion of driving currents of magnetospheric convection and their closure is explained, while consideration of the added effects of the rotation of the central body completes the basic theoretical picture. Flow topology is examined for the two cases where convection dominates over corotation and vice versa.

  6. Plasma motions in planetary magnetospheres

    NASA Technical Reports Server (NTRS)

    Hill, T. W.; Dessler, A. J.

    1991-01-01

    Interplanetary space is pervaded by a supersonic 'solar wind' plasma; five planets, in addition to the earth, have magnetic fields of sufficient strength to form the cometlike cavities called 'magnetospheres'. Comparative studies of these structures have indicated the specific environmental factor that can result in dramatic differences in the behavior of any pair of magnetospheres. Although planetary magnetospheres are large enough to serve as laboratories for in situ study of cosmic plasma and magnetic field behavior effects on particle acceleration and EM emission, much work remains to be done toward relating magnetospheric physics results to the study of remote astrophysical plasmas.

  7. A novel approach to the dynamical complexity of the Earth's magnetosphere at geomagnetic storm time-scales based on recurrences

    NASA Astrophysics Data System (ADS)

    Donner, Reik; Balasis, Georgios; Stolbova, Veronika; Wiedermann, Marc; Georgiou, Marina; Kurths, Jürgen

    2016-04-01

    Magnetic storms are the most prominent global manifestations of out-of-equilibrium magnetospheric dynamics. Investigating the dynamical complexity exhibited by geomagnetic observables can provide valuable insights into relevant physical processes as well as temporal scales associated with this phenomenon. In this work, we introduce several innovative data analysis techniques enabling a quantitative analysis of the Dst index non-stationary behavior. Using recurrence quantification analysis (RQA) and recurrence network analysis (RNA), we obtain a variety of complexity measures serving as markers of quiet- and storm-time magnetospheric dynamics. We additionally apply these techniques to the main driver of Dst index variations, the V BSouth coupling function and interplanetary medium parameters Bz and Pdyn in order to discriminate internal processes from the magnetosphere's response directly induced by the external forcing by the solar wind. The derived recurrence-based measures allow us to improve the accuracy with which magnetospheric storms can be classified based on ground-based observations. The new methodology presented here could be of significant interest for the space weather research community working on time series analysis for magnetic storm forecasts.

  8. Sun-to-Earth simulations of geo-effective Coronal Mass Ejections with EUHFORIA: a heliospheric-magnetospheric model chain approach

    NASA Astrophysics Data System (ADS)

    Scolini, C.; Verbeke, C.; Gopalswamy, N.; Wijsen, N.; Poedts, S.; Mierla, M.; Rodriguez, L.; Pomoell, J.; Cramer, W. D.; Raeder, J.

    2017-12-01

    Coronal Mass Ejections (CMEs) and their interplanetary counterparts are considered to be the major space weather drivers. An accurate modelling of their onset and propagation up to 1 AU represents a key issue for more reliable space weather forecasts, and predictions about their actual geo-effectiveness can only be performed by coupling global heliospheric models to 3D models describing the terrestrial environment, e.g. magnetospheric and ionospheric codes in the first place. In this work we perform a Sun-to-Earth comprehensive analysis of the July 12, 2012 CME with the aim of testing the space weather predictive capabilities of the newly developed EUHFORIA heliospheric model integrated with the Gibson-Low (GL) flux rope model. In order to achieve this goal, we make use of a model chain approach by using EUHFORIA outputs at Earth as input parameters for the OpenGGCM magnetospheric model. We first reconstruct the CME kinematic parameters by means of single- and multi- spacecraft reconstruction methods based on coronagraphic and heliospheric CME observations. The magnetic field-related parameters of the flux rope are estimated based on imaging observations of the photospheric and low coronal source regions of the eruption. We then simulate the event with EUHFORIA, testing the effect of the different CME kinematic input parameters on simulation results at L1. We compare simulation outputs with in-situ measurements of the Interplanetary CME and we use them as input for the OpenGGCM model, so to investigate the magnetospheric response to solar perturbations. From simulation outputs we extract some global geomagnetic activity indexes and compare them with actual data records and with results obtained by the use of empirical relations. Finally, we discuss the forecasting capabilities of such kind of approach and its future improvements.

  9. The effects of seasonal and diurnal variations in the Earth's magnetic dipole orientation on solar wind-magnetosphere-ionosphere coupling

    NASA Astrophysics Data System (ADS)

    Cnossen, Ingrid; Wiltberger, Michael; Ouellette, Jeremy E.

    2012-11-01

    The angle μ between the geomagnetic dipole axis and the geocentric solar magnetospheric (GSM) z axis, sometimes called the “dipole tilt,” varies as a function of UT and season. Observations have shown that the cross-polar cap potential tends to maximize near the equinoxes, when on average μ = 0, with smaller values observed near the solstices. This is similar to the well-known semiannual variation in geomagnetic activity. We use numerical model simulations to investigate the role of two possible mechanisms that may be responsible for the influence of μ on the magnetosphere-ionosphere system: variations in the coupling efficiency between the solar wind and the magnetosphere and variations in the ionospheric conductance over the polar caps. Under southward interplanetary magnetic field (IMF) conditions, variations in ionospheric conductance at high magnetic latitudes are responsible for 10-30% of the variations in the cross-polar cap potential associated with μ, but variations in solar wind-magnetosphere coupling are more important and responsible for 70-90%. Variations in viscous processes contribute slightly to this, but variations in the reconnection rate with μ are the dominant cause. The variation in the reconnection rate is primarily the result of a variation in the length of the section of the separator line along which relatively strong reconnection occurs. Changes in solar wind-magnetosphere coupling also affect the field-aligned currents, but these are influenced as well by variations in the conductance associated with variations in μ, more so than the cross-polar cap potential. This may be the case for geomagnetic activity too.

  10. Planetary magnetospheres

    NASA Technical Reports Server (NTRS)

    Hill, T. W.; Michel, F. C.

    1975-01-01

    Space-probe observations of planetary magnetospheres are discussed. Three different categories of planetary magnetospheres are identified (intrinsic slowly rotating, intrinsic rapidly rotating, and induced), and the characteristics of each type are outlined. The structure and physical processes of the magnetospheres of Mercury, Mars, and Jupiter are described, and possible configurations are presented for the Martian and Jovian ones. Expected magnetic moments are derived for Saturn, Uranus, and Neptune. Models are constructed for possible induced magnetospheres of the moon, Mercury, Venus, Mars, and Io.

  11. Magnetospheric Multiscale (MMS) [video

    NASA Image and Video Library

    2014-05-09

    MMS Spacecraft Animation The Magnetospheric Multiscale (MMS) mission is a Solar Terrestrial Probes mission comprising four identically instrumented spacecraft that will use Earth's magnetosphere as a laboratory to study the microphysics of three fundamental plasma processes: magnetic reconnection, energetic particle acceleration, and turbulence. These processes occur in all astrophysical plasma systems but can be studied in situ only in our solar system and most efficiently only in Earth's magnetosphere, where they control the dynamics of the geospace environment and play an important role in the processes known as "space weather." Learn more about MMS at www.nasa.gov/mms Learn more about MMS at www.nasa.gov/mms Credit NASA/Goddard The Magnetospheric Multiscale, or MMS, will study how the sun and the Earth's magnetic fields connect and disconnect, an explosive process that can accelerate particles through space to nearly the speed of light. This process is called magnetic reconnection and can occur throughout all space. NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  12. Magnetospheric Multiscale (MMS)

    NASA Image and Video Library

    2017-12-08

    MMS Spacecraft Animation The Magnetospheric Multiscale (MMS) mission is a Solar Terrestrial Probes mission comprising four identically instrumented spacecraft that will use Earth's magnetosphere as a laboratory to study the microphysics of three fundamental plasma processes: magnetic reconnection, energetic particle acceleration, and turbulence. These processes occur in all astrophysical plasma systems but can be studied in situ only in our solar system and most efficiently only in Earth's magnetosphere, where they control the dynamics of the geospace environment and play an important role in the processes known as "space weather." Learn more about MMS at www.nasa.gov/mms Learn more about MMS at www.nasa.gov/mms Credit NASA/Chris Gunn The Magnetospheric Multiscale, or MMS, will study how the sun and the Earth's magnetic fields connect and disconnect, an explosive process that can accelerate particles through space to nearly the speed of light. This process is called magnetic reconnection and can occur throughout all space. NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  13. Comparison of various multifractal approaches to analyze the intermittent magnetic fluctuations observed in the Earth's magnetospheric cusp

    NASA Astrophysics Data System (ADS)

    Lamy, Hervé; Echim, Marius; Chang, Tom

    2014-05-01

    Several approaches exist to compute the multifractal characteristics of an intermittent set of fluctuations. First, the classical method based on the computation of the partition function uses the full set of fluctuations . Since it is dominated by the more numerous fluctuations of small amplitudes, this method can mask the fractal characteristics of minor fluctuations of much larger amplitude. To solve this issue, a new method was developed by Chang & Wu (2008) : the Rank-Ordered Multifractal Analysis (ROMA) The ROMA method offers a natural connection between the one-parameter monofractal scaling idea and the multifractal phenomenon of intermittency. The key-element in ROMA is to find s(Y), the spectrum of the scaling exponents, and Ps(Y), the scaled Probability Distribution Function (PDFs), from the raw PDFs of the variable X at various scales tau , P(X,tau), with the following scaling: P(X,tau) tau ^s(Y)=Ps(Y) with Y= X/tau ^s(Y) The first (direct) method is to use range-limited structure functions in a sufficiently small range of the scaled variable Y and search for the value of monofroctal exponent s(Y). A drawback of this approach is that the range of Y must be large enough to ensure that the statistics is meaningful. As a consequence, some cross-over behavior between fluctuations with different monofractal exponents can lead to an ambiguity with several solutions s(Y) for some ranges of Y. Also the multifractal spectrum produced is step-wise discontinuous. To overcome these difficulties, Wu & Chang (2011) have suggested a refined method where a value of the parameter s is assumed and the corresponding value of Y ensuring a collapse of the raw PDFs is searched for. The advantage of this latter approach is that s(Y) and Ps(Y) can be obtained for single values of Y. The two ROMA methods and the partition function method are used on a set of intermittent magnetic field fluctuations observed by the Cluster spacecraft in the Earth's magnetospheric cusp. Results

  14. Dominance of high-energy (>150 keV) heavy ion intensities in Earth's middle to outer magnetosphere

    NASA Astrophysics Data System (ADS)

    Cohen, Ian J.; Mitchell, Donald G.; Kistler, Lynn M.; Mauk, Barry H.; Anderson, Brian J.; Westlake, Joseph H.; Ohtani, Shinichi; Hamilton, Douglas C.; Turner, Drew L.; Blake, J. Bernard; Fennell, Joseph F.; Jaynes, Allison N.; Leonard, Trevor W.; Gerrard, Andrew J.; Lanzerotti, Louis J.; Allen, Robert C.; Burch, James L.

    2017-09-01

    Previous observations have driven the prevailing assumption in the field that energetic ions measured by an instrument using a bare solid state detector (SSD) are predominantly protons. However, new near-equatorial energetic particle observations obtained between 7 and 12 RE during Phase 1 of the Magnetospheric Multiscale mission challenge the validity of this assumption. In particular, measurements by the Energetic Ion Spectrometer (EIS) instruments have revealed that the intensities of heavy ion species (specifically oxygen and helium) dominate those of protons at energies ≳150-220 keV in the middle to outer (>7 RE) magnetosphere. Given that relative composition measurements can drift as sensors degrade in gain, quality cross-calibration agreement between EIS observations and those from the SSD-based Fly's Eye Energetic Particle Spectrometer (FEEPS) sensors provides critical support to the veracity of the measurement. Similar observations from the Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) instruments aboard the Van Allen Probes spacecraft extend the ion composition measurements into the middle magnetosphere and reveal a strongly proton-dominated environment at L≲6 but decreasing proton intensities at L≳6. It is concluded that the intensity dominance of the heavy ions at higher energies (>150 keV) arises from the existence of significant populations of multiply-charged heavy ions, presumably of solar wind origin.

  15. The Sun, Its Extended Corona, the Interplanetary Space, the Earth's Magnetosphere, Ionosphere, Middle and Low Atmosphere, are All Parts of a Complex System - the Heliosphere

    NASA Technical Reports Server (NTRS)

    Gopalswamy, Natchimuthuk

    2011-01-01

    Various manifestations of solar activity cause disturbances known as space weather effects in the interplanetary space, near-Earth environment, and all the Earth's "spheres. Longterm variations in the frequency, intensity and relative importance of the manifestations of solar activity are due to the slow changes in the output of the solar dynamo, and they define space climate. Space climate governs long-term variations in geomagnetic activity and is the primary natural driver of terrestrial climate. To understand how the variable solar activity affects the Earth's environment, geomagnetic activity and climate on both short and long time scales, we need to understand the origins of solar activity itself and its different manifestations, as well as the sequence of coupling processes linking various parts of the system. This session provides a forum to discuss the chain of processes and relations from the Sun to the Earth's surface: the origin and long-term and short-term evolution of solar activity, initiation and temporal variations in solar flares, CMEs, coronal holes, the solar wind and its interaction with the terrestrial magnetosphere, the ionosphere and its connection to the neutral dominated regions below and the plasma dominated regions above, the stratosphere, its variations due to the changing solar activity and its interactions with the underlying troposphere, and the mechanisms of solar influences on the lower atmosphere on different time-scales. Particularly welcome are papers highlighting the coupling processes between the different domains in this complex system.

  16. Generation of EMIC Waves Observed by Van Allen Probes at Low L-shells of Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Gamayunov, K. V.; Zhang, J.; Saikin, A.; Rassoul, H.

    2017-12-01

    In a multi-ion magnetospheric plasma, where the major species are H+, He+, and O+, the He-band of electromagnetic ion cyclotron (EMIC) waves is the dominant band observed in the inner magnetosphere, and waves are generally quasi-field-aligned inside the geostationary orbit. Almost all the satellite-based studies of EMIC waves before Van Allen Probes, however, have not reported waves below L 3.5. There is probably only one exception from the Akebono satellite where both the H-band and He-band EMIC waves were observed at L 2. The situation has changed dramatically after two Van Allen Probes spacecraft were launched on 30 August, 2012, and many EMIC wave events have been observed below L=4. The Van Allen Probes observations confirm that the He-band of EMIC waves is a dominant band in the inner magnetosphere, but the observation of the He-band waves below L=4 is a new and quite unexpected result compared to our knowledge about EMIC waves before the Van Allen Probes era. In addition, observations show that almost all the He-band EMIC waves are linearly polarized in the region L < 4. This result is also new and unexpected. Here we will present an observational test of the generation mechanism for the He-band EMIC waves observed by Van Allen Probes at L 2.8 on 18 March, 2013. All the plasma parameters, DC magnetic field, and energetic ion distribution functions will be taken from the Van Allen Probes observations during the EMIC wave event to calculate growth rates of EMIC waves. We will then identify the energetic ions responsible for instability, frequencies and normals generated, and physical mechanism of instability.

  17. Investigation of the enhanced spatial density of submicron lunar ejecta between L values 1.2 and 3.0 in the earth's magnetosphere: Theory

    NASA Technical Reports Server (NTRS)

    Alexander, W. M.; Tanner, W. G.; Goad, H. S.

    1987-01-01

    Initial results from the measurement conducted by the dust particle experiment on the lunar orbiting satellite Lunar Explorer 35 (LE 35) were reported with the data interpreted as indicating that the moon is a significant source of micrometeroids. Primary sporadic and stream meteoroids impacting the surface of the moon at hypervelocity was proposed as the source of micron and submicron particles that leave the lunar craters with velocities sufficient to escape the moon's gravitational sphere of influence. No enhanced flux of lunar ejecta with masses greater than a nanogram was detected by LE 35 or the Lunar Orbiters. Hypervelocity meteoroid simulation experiments concentrating on ejecta production combined with extensive analyses of the orbital dynamics of micron and submicron lunar ejecta in selenocentric, cislunar, and geocentric space have shown that a pulse of these lunar ejecta, with a time correlation relative to the position of the moon relative to the earth, intercepts the earth's magnetopause surface (EMPs). As shown, a strong reason exists for expecting a significant enhancement of submicron dust particles in the region of the magnetosphere between L values of 1.2 and 3.0. This is the basis for the proposal of a series of experiments to investigate the enhancement or even trapping of submicron lunar ejecta in this region. The subsequent interaction of this mass with the upper-lower atmosphere of the earth and possible geophysical effects can then be studied.

  18. Development of a low-energy charged particle detector with on-anode ASIC for in-situ plasma measurement in the Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Saito, M.; Saito, Y.; Mukai, T.; Asamura, K.

    2009-06-01

    The future magnetospheric exploration missions (ex. SCOPE: cross Scale COupling in the Plasma universE) aim to obtain electron 3D distribution function with very fast time resolution below 10 ms to investigate the electron dynamics that is regarded as pivotal in understanding the space plasma phenomena such as magnetic reconnection. This can be achieved by developing a new plasma detector system which is fast in signal processing with small size, light weight and low power consumption. The new detector system consists of stacked micro channel plates and a position sensitive multi-anode detector with on-anode analogue ASIC (Application Specific Integrated Circuits). Multi-anode system usually suffers from false signals caused by mainly two effects. One is the effect of the electrostatic crosstalk between the discrete anodes since our new detector consists of many adjacent anodes with small gaps to increase the detection areas. Our experimental results show that there exists electrostatic crosstalk effect of approximately 10% from the adjacent anodes. The effect of 10% electrostatic crosstalk can be effectively avoided by a suitable discrimination level of the signal processing circuit. Non negligible charge cloud size on the anode also causes false counts. Optimized ASIC for in-situ plasma measurement in the Earth's magnetosphere is under development. The initial electron cloud at the MCP output has angular divergence. Furthermore, space charge effects may broaden the size of the charge cloud. We have obtained the charge cloud size both experimentally and theoretically. Our test model detector shows expected performance that is explained by our studies above.

  19. Near Earth Inner-Source and Interstellar Pickup Ions Observed with the Hot Plasma Composition Analyzer of the Magnetospheric Multiscale Mission Mms-Hpca

    NASA Astrophysics Data System (ADS)

    Gomez, R. G.; Fuselier, S. A.; Mukherjee, J.; Gonzalez, C. A.

    2017-12-01

    Pickup ions found near the earth are generally picked up in the rest frame of the solar wind, and propagate radially outward from their point of origin. While propagating, they simultaneously gyrate about the magnetic field. Pickup ions come in two general populations; interstellar and inner source ions. Interstellar ions originate in the interstellar medium, enter the solar system in a neutral charge state, are gravitationally focused on the side of the sun opposite their arrival direction and, are ionized when they travel near the sun. Inner-source ions originate at a location within the solar system and between the sun and the observation point. Both pickup ion populations share similarities in composition and charge states, so measuring of their dynamics, using their velocity distribution functions, f(v)'s, is absolutely essential to distinguishing them, and to determining their spatial and temporal origins. Presented here will be the results of studies conducted with the four Hot Plasma Composition Analyzers of the Magnetospheric Multiscale Mission (MMS-HPCA). These instruments measure the full sky (4π steradians) distribution functions of near earth plasmas at a 10 second cadence in an energy-to-charge range 0.001-40 keV/e. The instruments are also capable of parsing this combined energy-solid angle phase space with 22.5° resolution polar angle, and 11.25° in azimuthal angle, allowing for clear measurement of the pitch angle scattering of the ions.

  20. Magnetospheric Multiscale Mission Examination of Stress Balance in FTE-Type Flux Ropes at the Earth's Magnetopause

    NASA Astrophysics Data System (ADS)

    Akhavan-Tafti, M.; Slavin, J. A.; Le, G.; Eastwood, J. P.; Strangeway, R. J.; Russell, C. T.; Nakamura, R.; Baumjohann, W.; Torbert, R. B.; Giles, B. L.; Gershman, D. J.; Burch, J. L.

    2016-12-01

    Determining the magnetic field structure, electric currents, and plasma distribution within flux transfer event (FTE)-type flux ropes is critical to the understanding of their origin, evolution, and dynamics. We analyze FTEs observed by the Magnetospheric Multiscale (MMS) mission in the vicinity of the sub-solar magnetopause, i.e. 12 ± 22.5' Local Time and XGSM > 7 RE. High-resolution data from the Fluxgate Magnetometer (FGM) and Fast Plasma Investigation (FPI) are used to determine and compare the extent to which large (> 1 RE) and small (ion scale) diameter FTEs are force-free, i.e. J×B=0, or non-force-free, i.e. J×B= gradP. Three independent methods are used: i) current density parallel and perpendicular to the magnetic field derived from the plasma measurements or magnetic field using the curlometer technique; ii) direct measurement of the plasma pressure gradient by FPI; and iii) fitting magnetic field to force-free (J=αB) flux rope models. Our initial results indicate that the plasma content of the ion-scale FTEs often exceeds that of larger FTEs. This results in higher plasma pressure gradients inside smaller FTEs and a magnetic field that is less force-free than the larger flux ropes.

  1. Developing a global model of magnetospheric substorms

    NASA Astrophysics Data System (ADS)

    Kan, J. R.

    1990-09-01

    Competing models of magnetospheric substorms are discussed. The definitions of the three substorm phases are presented, and the advantages and drawbacks of the near-earth X-line model, magnetosphere-ionosphere coupling model, low-latitude boundary layer model, and thermal catastrophe model are examined. It is shown that the main challenge to achieving a quantitative understanding of the magnetospheric signatures of substorms is to understand the anomalous dissipation processes in collisionless plasmas.

  2. Pulsars Magnetospheres

    NASA Technical Reports Server (NTRS)

    Timokhin, Andrey

    2012-01-01

    Current density determines the plasma flow regime. Cascades are non-stationary. ALWAYS. All flow regimes look different: multiple components (?) Return current regions should have particle accelerating zones in the outer magnetosphere: y-ray pulsars (?) Plasma oscillations in discharges: direct radio emission (?)

  3. Currents and Flows in Distant Magnetospheres

    NASA Technical Reports Server (NTRS)

    Kivelson, Margaret Galland

    2000-01-01

    Space scientists have explored, described, and explained the terrestrial magnetosphere for four decades. Rarely do they point out that the planetary and solar wind parameters controlling the size, shape, and activity of Earth's magnetosphere map out only a small portion of the space of dimensionless parameters that govern magnetospheric properties. With the discovery of Ganymede's magnetosphere, the range of parameters relevant to magnetospheric studies has grown by orders of magnitude. Consider the extremes of Ganymede's and Jupiter's magnetospheres. Jupiter's magnetosphere forms within a plasma flowing at super-Alfvenic speed, whereas Ganymede's forms in a sub-Alfvenic flow. The scale sizes of these magnetospheres, characterized by distances to the magnetopause of order 7x10(exp 6) km and 5x10(exp 3) km, respectively, differ by three orders of magnitude, ranging from 100 to 0.1 times the scale of Earth's magnetosphere. The current systems that control the structure and dynamics of a magnetosphere depend on specific plasma and field properties. Magnetopause currents at Ganymede differ greatly from the forms familiar for Earth and Jupiter, principally because the Mach number of the ambient plasma flow greatly influences the shape of the magnetosphere. A magnetodisk current, present at Jupiter because of its rapid rotation, is absent at Earth and Ganymede. The ring current, extensively investigated at Earth, is probably unimportant at Ganymede because the dynamical variations of the external flow are slow. The ring current is subsumed within the magnetodisk current at Jupiter. This paper describes and contrasts aspects of these and other current systems for the three bodies.

  4. New Insights into the Nature of Turbulence in the Earth's Magnetosheath Using Magnetospheric MultiScale Mission Data

    NASA Astrophysics Data System (ADS)

    Breuillard, H.; Matteini, L.; Argall, M. R.; Sahraoui, F.; Andriopoulou, M.; Le Contel, O.; Retinò, A.; Mirioni, L.; Huang, S. Y.; Gershman, D. J.; Ergun, R. E.; Wilder, F. D.; Goodrich, K. A.; Ahmadi, N.; Yordanova, E.; Vaivads, A.; Turner, D. L.; Khotyaintsev, Yu. V.; Graham, D. B.; Lindqvist, P.-A.; Chasapis, A.; Burch, J. L.; Torbert, R. B.; Russell, C. T.; Magnes, W.; Strangeway, R. J.; Plaschke, F.; Moore, T. E.; Giles, B. L.; Paterson, W. R.; Pollock, C. J.; Lavraud, B.; Fuselier, S. A.; Cohen, I. J.

    2018-06-01

    The Earth’s magnetosheath, which is characterized by highly turbulent fluctuations, is usually divided into two regions of different properties as a function of the angle between the interplanetary magnetic field and the shock normal. In this study, we make use of high-time resolution instruments on board the Magnetospheric MultiScale spacecraft to determine and compare the properties of subsolar magnetosheath turbulence in both regions, i.e., downstream of the quasi-parallel and quasi-perpendicular bow shocks. In particular, we take advantage of the unprecedented temporal resolution of the Fast Plasma Investigation instrument to show the density fluctuations down to sub-ion scales for the first time. We show that the nature of turbulence is highly compressible down to electron scales, particularly in the quasi-parallel magnetosheath. In this region, the magnetic turbulence also shows an inertial (Kolmogorov-like) range, indicating that the fluctuations are not formed locally, in contrast with the quasi-perpendicular magnetosheath. We also show that the electromagnetic turbulence is dominated by electric fluctuations at sub-ion scales (f > 1 Hz) and that magnetic and electric spectra steepen at the largest-electron scale. The latter indicates a change in the nature of turbulence at electron scales. Finally, we show that the electric fluctuations around the electron gyrofrequency are mostly parallel in the quasi-perpendicular magnetosheath, where intense whistlers are observed. This result suggests that energy dissipation, plasma heating, and acceleration might be driven by intense electrostatic parallel structures/waves, which can be linked to whistler waves.

  5. Plasma pressure distribution in the surrounding the Earth plasma ring and its role in the magnetospheric dynamics

    NASA Astrophysics Data System (ADS)

    Antonova, E. E.; Kirpichev, I. P.; Stepanova, M. V.

    2014-08-01

    We analyzed the characteristics of the plasma region surrounding the Earth at the geocentric distances between 6 and 15RE using the data of THEMIS mission from April 2007 to September 2012. The obtained averaged distributions of plasma pressure, of pressure anisotropy, and of magnetic field near the equatorial plane showed the presence of a ring-shaped structure surrounding the Earth. It was found that for quiet geomagnetic conditions the plasma pressure is nearly isotropic for all magnetic local times at geocentric distances >6RE. Taking into consideration that the minimal values of the magnetic field at the field lines near noon are shifted from the equatorial plane, we estimate the value of plasma beta parameter in the region of minimal values of the magnetic field using the Tsyganenko-2001 magnetic field model. It was found that the values of plasma beta parameter are of the order of unity for the nightside part of the ring-shaped structure in the equatorial plane and for the region of minimal values of the magnetic field in the dayside, indicating that the ring-shaped structure should play an active role in the magnetic field distortion. Comparison of obtained distribution of plasma pressure at the equatorial plane with the values of plasma pressure at low altitudes, showed that the considerable part of the auroral oval can be mapped into the analyzed plasma ring. The role of the high-beta plasma ring surrounding the Earth for Earth-Sun System disturbances is discussed.

  6. Plasma Turbulence in Earth's Magnetosheath Observed by the Magnetospheric Multiscale Mission over the First Sub-Solar Apogee Pass

    NASA Astrophysics Data System (ADS)

    Mackler, D. A.; Avanov, L. A.; Boardsen, S. A.; Giles, B. L.; Pollock, C.; Smith, S. E.; Uritsky, V. M.

    2016-12-01

    Magnetic reconnection, a process in which the magnetic topology undergoes multi-scale changes, is a significant mechanism for particle energization as well as energy dissipation. Reconnection is observed to occur in thin current sheets generated between two regions of magnetized plasma merging with a non-zero shear angle. Within a thinning current sheet, the dominant scale size approaches first the ion and then electron kinetic scale. The plasma becomes demagnetized, field lines transform, then once again the plasma becomes frozen-in. The reconnection process accelerates particles, leading to heated jets of plasma. Turbulence is another fundamental process in collisionless plasmas. Despite decades of turbulence studies, an essential science question remains as to how turbulent energy dissipates at small scales by heating and accelerating particles. Turbulence in both plasmas and fluids has a fundamental property in that it follows an energy cascade into smaller scales. Energy introduced into a fluid or plasma can cause large scale motion, introducing vorticity, which merge and interact to make increasingly smaller eddies. It has been hypothesized that turbulent energy in magnetized plasmas may be dissipated by magnetic reconnection, just as viscosity dissipates energy in neutral fluid turbulence. The focus of this study is to use the new high temporal resolution suite of instruments on board the Magnetospheric MultiScale (MMS) mission to explore this hypothesis. An observable feature of the energy cascade in a turbulent magnetized plasma is its similarity to classical hydrodynamics in that the Power Spectral Density (PSD) of turbulent fluctuations follows a Kolmogorov-like power law (f -5/3). We use highly accurate (0.1 nT) Flux Gate Magnetometer (FGM) data to derive the PSD as a function of frequency in the magnetic fluctuations. Given that we are able to confirm the turbulent nature of the flow field; we apply the method of Partial Variance of Increments (PVI) to

  7. Anomalous momentum and energy transfer rates for electrostatic ion-cyclotron turbulence in downward auroral-current regions of the Earth's magnetosphere. III

    SciTech Connect

    Jasperse, John R.; Basu, Bamandas; Lund, Eric J.

    2010-06-15

    Recently, a new multimoment fluid theory was developed for inhomogeneous, nonuniformly magnetized plasma in the guiding-center and gyrotropic approximation that includes the effect of electrostatic, turbulent, wave-particle interactions (see Jasperse et al. [Phys. Plasmas 13, 072903 (2006); ibid.13, 112902 (2006)]). In the present paper, which is intended as a sequel, it is concluded from FAST satellite data that the electrostatic ion-cyclotron turbulence that appears is due to the operation of an electron, bump-on-tail-driven ion-cyclotron instability for downward currents in the long-range potential region of the Earth's magnetosphere. Approximate closed-form expressions for the anomalous momentum and energy transfer rates for themore » ion-cyclotron turbulence are obtained. The turbulent, inhomogeneous, nonuniformly magnetized, multimoment fluid theory given above, in the limit of a turbulent, homogeneous, uniformly magnetized, quasisteady plasma, yields the well-known formula for the anomalous resistivity given by Gary and Paul [Phys. Rev. Lett. 26, 1097 (1971)] and Tange and Ichimaru [J. Phys. Soc. Jpn. 36, 1437 (1974)].« less

  8. Origin, transport, and losses of energetic He(+) and He(2+) ions in the magnetosphere of the Earth - AMPTE/CCE observations

    NASA Technical Reports Server (NTRS)

    Kremser, G.; Wilken, B.; Gloeckler, G.; Hamilton, D. C.; Ipavich, F. M.; Kistler, L. M.; Tanskanen, P.

    1993-01-01

    Data from the ion charge-energy-mass spectrometer CHEM flown on AMPTE/CCE spacecraft are used to investigate the origin, transport, and losses of energetic He(+) and He(2+) ions in the earth's magnetosphere. The L profiles of the average ion phase space density f were determined as a function of the magnetic momentum. It is shown that the L profiles have an inner part, where f increases with L for both He(+) adn He(2+) and where steady-state conditions are fulfilled. The outer boundary L(lim) of this region is located at a distance that depends on the ion species and the geomagnetic activity level. Steady-state conditions continue outside L(lim) for He(+) ions, while the He(2+) ion distribution outside L(lim) is strongly influenced by ion convection causing a lack of steady-state conditions. It is concluded that solar wind is the origin of the He(2+), while a mixed origin is suggested for the He(+) ions, in which the major contribution is from the solar wind via charge exchange production from the He(2+) ions.

  9. Magnetospheric electrons

    NASA Technical Reports Server (NTRS)

    Coroniti, F. V.; Thorne, R. M.

    1972-01-01

    Coupling of source, transport, and sink processes produces a fairly accurate model for the macroscopic structure and dynamics of magnetospheric electrons. Auroral electrons are controlled by convective transport from a plasma sheet source coupled with a precipitation loss due to whistler and electrostatic plasma turbulence. Outer and inner zone electrons are governed by radial diffusion transport from convection and acceleration sources external to the plasmapause and by parasitic precipitation losses arising from cyclotron and Landau interactions with whistler and ion cyclotron turbulence.

  10. Characteristics of plasma ring, surrounding the Earth at geocentric distances ˜7-10RE, and magnetospheric current systems

    NASA Astrophysics Data System (ADS)

    Antonova, E. E.; Kirpichev, I. P.; Vovchenko, V. V.; Stepanova, M. V.; Riazantseva, M. O.; Pulinets, M. S.; Ovchinnikov, I. L.; Znatkova, S. S.

    2013-07-01

    There are strong experimental evidences of the existence of plasma domain forming a closed plasma ring around the Earth at geocentric distances ∼7-10RE. In this work, we analyze the main properties of this ring, using the data of the THEMIS satellite mission, acquired between April 2007 and September 2011. We also analyze the contribution of this ring to the storm dynamics. In particular, it is shown that the distribution of plasma pressure at ∼7-10RE is nearly azimuthally symmetric. However, the daytime compression of the magnetic field lines and the shift of the minimal value of the magnetic field to higher latitudes lead to the spreading of the transverse current along field lines and splitting of the daytime integral transverse current into two branches in Z direction. The CRC is the high latitude continuation of the ordinary ring current (RC), generated by plasma pressure gradients, directed to the Earth. We evaluated the contribution of the azimuthally symmetric part of the plasma ring to the Dst index for strong geomagnetic storms using the AMPTE/CCE radial profiles of plasma pressure published before, and showed that the contribution of the ring current including both RC and CRC is sufficient to obtain the observed Dst variation without the necessity to include the tail current system.

  11. Jupiter's magnetosphere and radiation belts

    NASA Technical Reports Server (NTRS)

    Kennel, C. F.; Coroniti, F. V.

    1979-01-01

    Radioastronomy and Pioneer data reveal the Jovian magnetosphere as a rotating magnetized source of relativistic particles and radio emission, comparable to astrophysical cosmic ray and radio sources, such as pulsars. According to Pioneer data, the magnetic field in the outer magnetosphere is radially extended into a highly time variable disk-shaped configuration which differs fundamentally from the earth's magnetosphere. The outer disk region, and the energetic particles confined in it, are modulated by Jupiter's 10 hr rotation period. The entire outer magnetosphere appears to change drastically on time scales of a few days to a week. In addition to its known modulation of the Jovian decametric radio bursts, Io was found to absorb some radiation belt particles and to accelerate others, and most importantly, to be a source of neutral atoms, and by inference, a heavy ion plasma which may significantly affect the hydrodynamic flow in the magnetosphere. Another important Pioneer finding is that the Jovian outer magnetosphere generates, or permits to escape, fluxes of relativistic electrons of such intensities that Jupiter may be regarded as the dominant source of 1 to 30 MeV cosmic ray electrons in the heliosphere.

  12. Ray-tracing studies and path-integrated gains of ELF unducted whistler mode waves in the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Huang, C. Y.; Goertz, C. K.

    1983-01-01

    Gyroresonance and Landau resonance interactions between unducted low-frequency whistler waves and trapped electrons in the earth's plasmasphere have been studied. Ray paths for waves launched near the plasmapause have been traced. In agreement with recent findings by Thorne et al. (1979), waves have been found which return through the equatorial zone with field-aligned wave normal angles. However, when the growth along the ray path is calculated for such waves, assuming an electron distribution function of the form E exp -n sin exp m alpha, it is found that for all the waves considered, the local growth rate becomes negative before plasmapause reflection, limiting the total gain to small values. Most waves reach zero gain before reflection. This is the result of Landau damping at oblique propagation angles, which necessarily occurs before reflection can take place. It is concluded that the concept of cyclic ray paths does not provide an explanation for the generation of unguided plasmaspheric hiss.

  13. A Massively Parallel Particle Code for Rarefied Ionized and Neutral Gas Flows in Earth and Planetary Atmospheres, Ionospheres and Magnetospheres

    NASA Technical Reports Server (NTRS)

    Combi, Michael R.

    2004-01-01

    In order to understand the global structure, dynamics, and physical and chemical processes occurring in the upper atmospheres, exospheres, and ionospheres of the Earth, the other planets, comets and planetary satellites and their interactions with their outer particles and fields environs, it is often necessary to address the fundamentally non-equilibrium aspects of the physical environment. These are regions where complex chemistry, energetics, and electromagnetic field influences are important. Traditional approaches are based largely on hydrodynamic or magnetohydrodynamic MHD) formulations and are very important and highly useful. However, these methods often have limitations in rarefied physical regimes where the molecular collision rates and ion gyrofrequencies are small and where interactions with ionospheres and upper neutral atmospheres are important.

  14. Ion transport and loss in the Earth's quiet ring current. 2: Diffusion and magnetosphere-ionosphere coupling

    NASA Technical Reports Server (NTRS)

    Sheldon, R. B.

    1994-01-01

    We have studied the transport and loss of H(+), He(+), and He(++) ions in the Earth's quiet time ring current (1 to 300 keV/e, 3 to 7 R(sub E), Kp less than 2+, absolute value of Dst less than 11, 70 to 110 degs pitchangles, all LT) comparing the standard radial diffusion model developed for the higher-energy radiation belt particles with measurements of the lower energy ring current ions in a previous paper. Large deviations of that model, which fit only 50% of the data to within a factor of 10, suggested that another transport mechanism is operating in the ring current. Here we derive a modified diffusion coefficient corrected for electric field effects on ring current energy ions that fit nearly 80% of the data to within a factor of 2. Thus we infer that electric field fluctuations from the low-latitude to midlatitude ionosphere (ionospheric dynamo) dominated the ring current transport, rather than high-latitude or solar wind fluctuations. Much of the remaining deviation may arise from convective electric field transport of the E less than 30 keV particles. Since convection effects cannot be correctly treated with this azimuthally symmetric model, we defer treatment of the lowest-energy ions to a another paper. We give chi(exp 2) contours for the best fit, showing the dependence of the fit upon the internal/external spectral power of the predicted electric and magnetic field fluctuations.

  15. Features in the Behavior of the Solar Wind behind the Bow Shock Front near the Boundary of the Earth's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Grib, S. A.; Leora, S. N.

    2017-12-01

    Macroscopic discontinuous structures observed in the solar wind are considered in the framework of magnetic hydrodynamics. The interaction of strong discontinuities is studied based on the solution of the generalized Riemann-Kochin problem. The appearance of discontinuities inside the magnetosheath after the collision of the solar wind shock wave with the bow shock front is taken into account. The propagation of secondary waves appearing in the magnetosheath is considered in the approximation of one-dimensional ideal magnetohydrodynamics. The appearance of a compression wave reflected from the magnetopause is indicated. The wave can nonlinearly break with the formation of a backward shock wave and cause the motion of the bow shock towards the Sun. The interaction between shock waves is considered with the well-known trial calculation method. It is assumed that the velocity of discontinuities in the magnetosheath in the first approximation is constant on the average. All reasonings and calculations correspond to consideration of a flow region with a velocity less than the magnetosonic speed near the Earth-Sun line. It is indicated that the results agree with the data from observations carried out on the WIND and Cluster spacecrafts.

  16. Large-scale variation of electron parameters from Quasi-Thermal Noise during WIND perigees in the Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Issautier, Karine; Ongala-Edoumou, Samuel; Moncuquet, Michel

    2016-04-01

    The quasi-thermal noise (QTN) method consists in measuring the electrostatic fluctuations produced by the thermal motion of the ambient particles. This noise is detected with a sensitive wave receiver and measured at the terminal of a passive electric antenna, which is immersed in a stable plasma. The analysis of the so-called QTN provides in situ measurements, mainly the total electron density, with a good accuracy, and thermal temperature in a large number of space media. We create a preliminary electron database to analyse the anti-correlation between electron density and temperature deduced from WIND perigees in the Earth's plasmasphere. We analyse the radio power spectra measured by the Thermal Noise Receiver (TNR), using the 100-m long dipole antenna, onboard WIND spacecraft. We develop a systematic routine to determine the electron density, core and halo temperature and the magnitude of the magnetic field based on QTN in Bernstein modes. Indeed, the spectra are weakly banded between gyroharmonics below the upper hybrid frequency, from which we derive the local electron density. From the gyrofrequency determination, we obtain an independent measure of the magnetic field magnitude, which is in close agreement with the onboard magnetometer.

  17. Dynamic Theory of Relativistic Electrons Stochastic Heating by Whistler Mode Waves with Application to the Earth Magnetosphere

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.; Tel'nikhin, A. A.; Kronberg, T. K.

    2007-01-01

    In the Hamiltonian approach an electron motion in a coherent packet of the whistler mode waves propagating along the direction of an ambient magnetic field is studied. The physical processes by which these particles are accelerated to high energy are established. Equations governing a particle motion were transformed in to a closed pair of nonlinear difference equations. The solutions of these equations have shown there exists the energetic threshold below that the electron motion is regular, and when the initial energy is above the threshold an electron moves stochastically. Particle energy spectra and pitch angle electron scattering are described by the Fokker-Planck-Kolmogorov equations. Calculating the stochastic diffusion of electrons due to a spectrum of whistler modes is presented. The parametric dependence of the diffusion coefficients on the plasma particle density, magnitude of wave field, and the strength of magnetic field is studies. It is shown that significant pitch angle diffusion occurs for the Earth radiation belt electrons with energies from a few keV up to a few MeV.

  18. An MHD simulation of the effects of the interplanetary magnetic field By component on the interaction of the solar wind with the earth's magnetosphere during southward interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Ogino, T.; Walker, R. J.; Ashour-Abdalla, M.; Dawson, J. M.

    1986-01-01

    The interaction between the solar wind and the earth's magnetosphere has been studied by using a time-dependent three-dimensional MHD model in which the IMF pointed in several directions between dawnward and southward. When the IMF is dawnward, the dayside cusp and the tail lobes shift toward the morningside in the northern magnetosphere. The plasma sheet rotates toward the north on the dawnside of the tail and toward the south on the duskside. For an increasing southward IMF component, the plasma sheet becomes thinner and subsequently wavy because of patchy or localized tail reconnection. At the same time, the tail field-aligned currents have a filamentary layered structure. When projected onto the northern polar cap, the filamentary field-aligned currents are located in the same area as the region 1 currents, with a pattern similar to that associated with auroral surges. Magnetic reconnection also occurs on the dayside magnetopause for southward IMF.

  19. The Inner Magnetosphere Imager mission

    NASA Technical Reports Server (NTRS)

    Gallagher, D. L.

    1994-01-01

    The Inner Magnetosphere Imager (IMI) mission will carry instruments to globally image energetic neutral atoms, far and extreme ultraviolet light, and X-rays. These imagers will see the ring current, inner plasmasheet, plasmasphere, aurora, and geocorona. With these observations it will be possible, for the first time, to develop an understanding of the global shape of the inner magnetosphere and the interrelationships between its parts. Seven instruments are currently envisioned on a single spinning spacecraft with a despun platform. IMI will be launched into an elliptical, polar orbit with an apogee of approximately 7 Earth radii altitude and perigee of 4800 km altitude.

  20. The magnetospheric currents - An introduction

    NASA Technical Reports Server (NTRS)

    Akasofu, S.-I.

    1984-01-01

    It is pointed out that the scientific discipline concerned with magnetospheric currents has grown out from geomagnetism and, in particular, from geomagnetic storm studies. The International Geophysical Year (IGY) introduced a new area for this discipline by making 'man-made satellites' available for the exploration of space around the earth. In this investigation, a brief description is provided of the magnetospheric currents in terms of eight component current systems. Attention is given to the Sq current, the Chapman-Ferraro current, the ring current (the symmetric component), the current systems driven by the solar wind-magnetosphere dynamo (SMD), the cross-tail current system, the average ionospheric current pattern, an example of an instantaneous current pattern, field-aligned currents, and driving mechanisms and models.

  1. Magnetospheric Multiscale (MMS)

    NASA Image and Video Library

    2017-12-08

    MMS Four Separate – View of all four spacecraft in the MMS Cleanroom getting prepared for stacking operations. Learn more about MMS at www.nasa.gov/mms Credit NASA/Chris Gunn The Magnetospheric Multiscale, or MMS, will study how the sun and the Earth's magnetic fields connect and disconnect, an explosive process that can accelerate particles through space to nearly the speed of light. This process is called magnetic reconnection and can occur throughout all space. NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  2. Magnetospheric Multiscale (MMS)

    NASA Image and Video Library

    2014-05-09

    MMS Stacked – View of the fully stacked MMS prior to being bagged for vibration tests. Learn more about MMS at www.nasa.gov/mms Credit NASA/Chris Gunn The Magnetospheric Multiscale, or MMS, will study how the sun and the Earth's magnetic fields connect and disconnect, an explosive process that can accelerate particles through space to nearly the speed of light. This process is called magnetic reconnection and can occur throughout all space. NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  3. Magnetospheric Multiscale (MMS)

    NASA Image and Video Library

    2014-05-09

    Observatory #1 is shown here on the Ransome table, tilted in a vertical position to provide better access for the engineers and technicians. Learn more about MMS at www.nasa.gov/mms Credit NASA/Goddard The Magnetospheric Multiscale, or MMS, will study how the sun and the Earth's magnetic fields connect and disconnect, an explosive process that can accelerate particles through space to nearly the speed of light. This process is called magnetic reconnection and can occur throughout all space. NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  4. Magnetospheric Multiscale (MMS)

    NASA Image and Video Library

    2014-05-09

    Electrical technicians work diligently to build the connector harnessing for the Command and Data Handling (C&DH) unit, (black box with two red handles) that is installed on spacecraft Deck for MMS #4. Learn more about MMS at www.nasa.gov/mms Credit NASA/Goddard The Magnetospheric Multiscale, or MMS, will study how the sun and the Earth's magnetic fields connect and disconnect, an explosive process that can accelerate particles through space to nearly the speed of light. This process is called magnetic reconnection and can occur throughout all space. NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  5. Magnetospheric Multiscale (MMS)

    NASA Image and Video Library

    2014-05-09

    Propulsion engineer measures the flight filters during the receiving inspection. Learn more about MMS at www.nasa.gov/mms Credit NASA/Goddard The Magnetospheric Multiscale, or MMS, will study how the sun and the Earth's magnetic fields connect and disconnect, an explosive process that can accelerate particles through space to nearly the speed of light. This process is called magnetic reconnection and can occur throughout all space. NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  6. MESSENGER Observations of Mercury's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Slavin, James A.

    2010-01-01

    During MESSENGER's second and third flybys of Mercury on October 6, 2008 and September 29, 2009, respectively, southward interplanetary magnetic field (IMF) produced intense reconnection signatures in the dayside and nightside magnetosphere and markedly different system-level responses. The IMF during the second flyby was continuously southward and the magnetosphere appeared very active, with large magnetic field components normal to the magnetopause and the generation of flux transfer events at the magnetopause and plasmoids in the tail current sheet every 30 to 90 s. However, the strength and direction of the tail magnetic field was stable. In contrast, the IMF during the third flyby varied from north to south on timescales of minutes. Although the MESSENGER measurements were limited during that encounter to the nightside magnetosphere, numerous examples of plasmoid release in the tail were detected, but they were not periodic. Instead, plasmoid release was highly correlated with four large enhancements of the tail magnetic field (i.e. by factors > 2) with durations of approx. 2 - 3 min. The increased flaring of the magnetic field during these intervals indicates that the enhancements were caused by loading of the tail with magnetic flux transferred from the dayside magnetosphere. New analyses of the second and third flyby observations of reconnection and its system-level effects provide a basis for comparison and contrast with what is known about the response of the Earth s magnetosphere to variable versus steady southward IMF.

  7. Coronal mass ejection (CME) activity of low mass M stars as an important factor for the habitability of terrestrial exoplanets. I. CME impact on expected magnetospheres of Earth-like exoplanets in close-in habitable zones.

    PubMed

    Khodachenko, Maxim L; Ribas, Ignasi; Lammer, Helmut; Griessmeier, Jean-Mathias; Leitner, Martin; Selsis, Franck; Eiroa, Carlos; Hanslmeier, Arnold; Biernat, Helfried K; Farrugia, Charles J; Rucker, Helmut O

    2007-02-01

    Low mass M- and K-type stars are much more numerous in the solar neighborhood than solar-like G-type stars. Therefore, some of them may appear as interesting candidates for the target star lists of terrestrial exoplanet (i.e., planets with mass, radius, and internal parameters identical to Earth) search programs like Darwin (ESA) or the Terrestrial Planet Finder Coronagraph/Inferometer (NASA). The higher level of stellar activity of low mass M stars, as compared to solar-like G stars, as well as the closer orbital distances of their habitable zones (HZs), means that terrestrial-type exoplanets within HZs of these stars are more influenced by stellar activity than one would expect for a planet in an HZ of a solar-like star. Here we examine the influences of stellar coronal mass ejection (CME) activity on planetary environments and the role CMEs may play in the definition of habitability criterion for the terrestrial type exoplanets near M stars. We pay attention to the fact that exoplanets within HZs that are in close proximity to low mass M stars may become tidally locked, which, in turn, can result in relatively weak intrinsic planetary magnetic moments. Taking into account existing observational data and models that involve the Sun and related hypothetical parameters of extrasolar CMEs (density, velocity, size, and occurrence rate), we show that Earth-like exoplanets within close-in HZs should experience a continuous CME exposure over long periods of time. This fact, together with small magnetic moments of tidally locked exoplanets, may result in little or no magnetospheric protection of planetary atmospheres from a dense flow of CME plasma. Magnetospheric standoff distances of weakly magnetized Earth-like exoplanets at orbital distances magnetospheres may have crucial consequences for atmospheric erosion processes.

  8. Reconnection in Planetary Magnetospheres

    NASA Technical Reports Server (NTRS)

    Russell, C. T.

    2000-01-01

    Current sheets in planetary magnetospheres that lie between regions of "oppositely-directed" magnetic field are either magnetopause-like, separating plasmas with different properties, or tail-like, separating plasmas of rather similar properties. The magnetopause current sheets generally have a nearly limitless supply of magnetized plasma that can reconnect, possibly setting up steady-state reconnection. In contrast, the plasma on either side of a tail current sheet is stratified so that, as reconnection occurs, the plasma properties, in particular the Alfven velocity, change. If the density drops and the magnetic field increases markedly perpendicular to the sheet, explosive reconnection can occur. Even though steady state reconnection can take place at magnetopause current sheets, the process often appears to be periodic as if a certain low average rate was demanded by the conditions but only a rapid rate was available. Reconnection of sheared fields has been postulated to create magnetic ropes in the solar corona, at the Earth's magnetopause, and in the magnetotail. However, this is not the only way to produce magnetic ropes as the Venus ionosphere shows. The geometry of the reconnecting regions and the plasma conditions both can affect the rate of reconnection. Sorting out the various controlling factors can be assisted through the examination of reconnection in planetary settings. In particular we observe similar small-scale tearing in the magnetopause current layers of the Earth, Saturn. Uranus and Neptune and the magnetodisk current sheet at Jupiter. These sites may be seeds for rapid reconnection if the reconnection site reaches a high Alfven velocity region. In the Jupiter magnetosphere this appears to be achieved with resultant substorm activity. Similar seeds may be present in the Earth's magnetotail with the first one to reach explosive growth dominating the dynamics of the tail.

  9. The solar wind-magnetosphere-ionosphere system

    PubMed

    Lyon

    2000-06-16

    The solar wind, magnetosphere, and ionosphere form a single system driven by the transfer of energy and momentum from the solar wind to the magnetosphere and ionosphere. Variations in the solar wind can lead to disruptions of space- and ground-based systems caused by enhanced currents flowing into the ionosphere and increased radiation in the near-Earth environment. The coupling between the solar wind and the magnetosphere is mediated and controlled by the magnetic field in the solar wind through the process of magnetic reconnection. Understanding of the global behavior of this system has improved markedly in the recent past from coordinated observations with a constellation of satellite and ground instruments.

  10. Global Magnetospheric Imaging from the Deep Space Gateway in Lunar Orbit

    NASA Astrophysics Data System (ADS)

    Chua, D. H.; Socker, D. G.; Englert, C. R.; Carter, M. T.; Plunkett, S. P.; Korendyke, C. M.; Meier, R. R.

    2018-02-01

    We propose to use the Deep Space Gateway as an observing platform for a magnetospheric imager that will capture the first direct global images of the interface between the incident solar wind and the Earth's magnetosphere.

  11. Energetics of the magnetosphere

    NASA Technical Reports Server (NTRS)

    Stern, D. P.

    1980-01-01

    The approximate magnitudes of several power inputs and energies associated with the Earth's magnetosphere will be derived. They include: Solar wind power impinging on the dayside magnetopause approximately 1.4 10 to the 13th power watt; power input to cross tail current approximately 3 10 to the 11th power watt; energy of moderate magnetic storm approximately 2 10 to the 15th power joule; power related to the flow of j approximately 1 to 3 10 to the 11th power watt; average power deposited by the aurora approximately 2 10 to the 10th power watt. Stored magnetic energy: released in a substorm approximately 1.5 10 to the 14th power joule. Compared to the above, the rate at which energy is released locally in magnetospheric regions where magnetic merging occurs is probably small. Merging is essential, however, for the existence of open field lines, which provide the most likely explanation for some major energy inputs listed here. Merging is also required if part of the open flux of the tail lobes is converted into closed flux, as seems to happen during substorms. Again, most of the energy release becomes evident only beyond the merging region, though some particles may gain appreciable energy in that region itself, if the plasma sheet is completely squeezed out and the high latitude lobes interact directly.

  12. GAMERA - The New Magnetospheric Code

    NASA Astrophysics Data System (ADS)

    Lyon, J.; Sorathia, K.; Zhang, B.; Merkin, V. G.; Wiltberger, M. J.; Daldorff, L. K. S.

    2017-12-01

    The Lyon-Fedder-Mobarry (LFM) code has been a main-line magnetospheric simulation code for 30 years. The code base, designed in the age of memory to memory vector ma- chines,is still in wide use for science production but needs upgrading to ensure the long term sustainability. In this presentation, we will discuss our recent efforts to update and improve that code base and also highlight some recent results. The new project GAM- ERA, Grid Agnostic MHD for Extended Research Applications, has kept the original design characteristics of the LFM and made significant improvements. The original de- sign included high order numerical differencing with very aggressive limiting, the ability to use arbitrary, but logically rectangular, grids, and maintenance of div B = 0 through the use of the Yee grid. Significant improvements include high-order upwinding and a non-clipping limiter. One other improvement with wider applicability is an im- proved averaging technique for the singularities in polar and spherical grids. The new code adopts a hybrid structure - multi-threaded OpenMP with an overarching MPI layer for large scale and coupled applications. The MPI layer uses a combination of standard MPI and the Global Array Toolkit from PNL to provide a lightweight mechanism for coupling codes together concurrently. The single processor code is highly efficient and can run magnetospheric simulations at the default CCMC resolution faster than real time on a MacBook pro. We have run the new code through the Athena suite of tests, and the results compare favorably with the codes available to the astrophysics community. LFM/GAMERA has been applied to many different situations ranging from the inner and outer heliosphere and magnetospheres of Venus, the Earth, Jupiter and Saturn. We present example results the Earth's magnetosphere including a coupled ring current (RCM), the magnetospheres of Jupiter and Saturn, and the inner heliosphere.

  13. Mercury's Dynamic Magnetosphere

    NASA Astrophysics Data System (ADS)

    Imber, S. M.

    2018-05-01

    The global dynamics of Mercury's magnetosphere will be discussed, focussing on observed asymmetries in the magnetotail and on the precipitation of particles of magnetospheric origin onto the nightside planetary surface.

  14. Giant planet magnetospheres

    NASA Technical Reports Server (NTRS)

    Bagenal, Fran

    1992-01-01

    The classification of the giant planet magnetospheres into two varieties is examined: the large symmetric magnetospheres of Jupiter and Saturn and the smaller irregular ones of Uranus and Neptune. The characteristics of the plasma and the current understanding of the magnetospheric processes are considered for each planet. The energetic particle populations, radio emissions, and remote sensing of magnetospheric processes in the giant planet magneotospheres are discussed.

  15. The mirage of Mars magnetosphere

    NASA Astrophysics Data System (ADS)

    Mordovskaya, V.

    The spacecraft Phobos 2 has been on the circular orbit around Mars at the distance of 2 Mars's radiuses for a whole month. There are a lot of data and so we can speak about some statistics. The dependence of the perturbed magnetic field in the Mars wake on the density of the ambient solar wind plasma is traced but the same dependence from the velocity is absent. The picture of the solar wind interaction with Martian obstacle is not typical for magnetosphere. For high plasma density the value of the perturbed magnetic field in the wake of Mars and its size increase considerably and the perturbed region swells. The magnetosphere of Earth is compressed in the same cases. This points out that Mars has the weak protective magnetic screen. The estimation of its size gives the value about 160-220 km. Because of the lack of the protective magnetic screen, it seems, the solar wind with the density lower than 1 cm-3 interacts with the Martian atmosphere directly. The density of the ambient plasma is usually about 1 cm-3 and the thickness of the skin layers exceeds the scale of the Martian protective magnetic screen, the field freely passes over. The magnetosphere of Mars "disappears". The existence of the regions of the rarefied plasma behind Mars, due to a shading of particles of the solar wind plasma is an argument in favors of the disappearance of the Martian magnetosphere.

  16. Statistical study of phase relationships between magnetic and plasma thermal pressures in the near-earth magnetosphere using the THEMIS satellites

    NASA Astrophysics Data System (ADS)

    Nishi, K.; Kazuo, S.

    2017-12-01

    The auroral finger-like structures appear in the equatorward part of the auroral oval in the diffuse auroral region, and contribute to the auroral fragmentation into patches during substorm recovery phase. In our previous presentations, we reported the first conjugate observation of auroral finger-like structures using the THEMIS GBO cameras and the THEMIS satellites, which was located at a radial distance of 9 Re in the dawnside plasma sheet. In this conjugate event, we found anti-phase fluctuation of plasma pressure and magnetic pressure with a time scale of 5-20 min in the plasma sheet. This observational fact is consistent with the idea that the finger-like structures are caused by a pressure-driven instability in the balance of plasma and magnetic pressures in the magnetosphere. Then we also searched simultaneous observation events of auroral finger-like structures with the RBSP satellites which have an apogee of 5.8 Re in the inner magnetosphere. Contrary to the first result, the observed variation of plasma and magnetic pressures do not show systematic phase relationship. In order to investigate these phase relationships between plasma and magnetic pressures in the magnetosphere, we statistically analyzed these pressure data using the THEMIS-E satellite for one year in 2011. In the preliminary analysis of pressure variation spectra, we found that out of phase relationship between magnetic and plasma pressures occupied 40 % of the entire period of study. In the presentation, we will discuss these results in the context of relationships between the pressure fluctuations and the magnetospheric instabilities that can cause auroral finger-like structures.

  17. Jovian Substorms: A Study of Processes Leading to Transient Behavior in the Jovian Magnetosphere

    NASA Technical Reports Server (NTRS)

    Russell, C. T.

    2000-01-01

    Solar system magnetospheres can be divided into two groups: induced and intrinsic. The induced magnetospheres are produced in the solar wind interaction of the magnetized solar wind with planetary obstacles. Examples of these magnetospheres are those of comets, Venus and Mars. Intrinsic magnetospheres are the cavities formed in the solar wind by the magnetic fields produced by dynamo current systems inside the planets: Mercury, Earth, Jupiter, Saturn, Uranus and Neptune are known to have intrinsic magnetospheres. Intrinsic magnetospheres can be further subdivided as to how the circulating plasma is driven by external or internal processes. The magnetospheres of Mercury and Earth are driven by the solar wind. The magnetospheres of Jupiter and possibly of Saturn are principally driven by internal processes. These processes provide the energy for the powerful jovian radio signals that can be detected easily on the surface of the Earth.

  18. Global three-dimensional simulation of Earth's dayside reconnection using a two-way coupled magnetohydrodynamics with embedded particle-in-cell model: initial results: 3D MHD-EPIC simulation of magnetosphere

    DOE PAGES

    Chen, Yuxi; Tóth, Gábor; Cassak, Paul; ...

    2017-09-18

    Here, we perform a three-dimensional (3D) global simulation of Earth's magnetosphere with kinetic reconnection physics to study the flux transfer events (FTEs) and dayside magnetic reconnection with the recently developed magnetohydrodynamics with embedded particle-in-cell model (MHD-EPIC). During the one-hour long simulation, the FTEs are generated quasi-periodically near the subsolar point and move toward the poles. We also find the magnetic field signature of FTEs at their early formation stage is similar to a ‘crater FTE’, which is characterized by a magnetic field strength dip at the FTE center. After the FTE core field grows to a significant value, it becomesmore » an FTE with typical flux rope structure. When an FTE moves across the cusp, reconnection between the FTE field lines and the cusp field lines can dissipate the FTE. The kinetic features are also captured by our model. A crescent electron phase space distribution is found near the reconnection site. A similar distribution is found for ions at the location where the Larmor electric field appears. The lower hybrid drift instability (LHDI) along the current sheet direction also arises at the interface of magnetosheath and magnetosphere plasma. Finally, the LHDI electric field is about 8 mV/m and its dominant wavelength relative to the electron gyroradius agrees reasonably with MMS observations.« less

  19. Global three-dimensional simulation of Earth's dayside reconnection using a two-way coupled magnetohydrodynamics with embedded particle-in-cell model: initial results: 3D MHD-EPIC simulation of magnetosphere

    SciTech Connect

    Chen, Yuxi; Tóth, Gábor; Cassak, Paul

    Here, we perform a three-dimensional (3D) global simulation of Earth's magnetosphere with kinetic reconnection physics to study the flux transfer events (FTEs) and dayside magnetic reconnection with the recently developed magnetohydrodynamics with embedded particle-in-cell model (MHD-EPIC). During the one-hour long simulation, the FTEs are generated quasi-periodically near the subsolar point and move toward the poles. We also find the magnetic field signature of FTEs at their early formation stage is similar to a ‘crater FTE’, which is characterized by a magnetic field strength dip at the FTE center. After the FTE core field grows to a significant value, it becomesmore » an FTE with typical flux rope structure. When an FTE moves across the cusp, reconnection between the FTE field lines and the cusp field lines can dissipate the FTE. The kinetic features are also captured by our model. A crescent electron phase space distribution is found near the reconnection site. A similar distribution is found for ions at the location where the Larmor electric field appears. The lower hybrid drift instability (LHDI) along the current sheet direction also arises at the interface of magnetosheath and magnetosphere plasma. Finally, the LHDI electric field is about 8 mV/m and its dominant wavelength relative to the electron gyroradius agrees reasonably with MMS observations.« less

  20. Comprehensive Quantitative Model of Inner-Magnetosphere Dynamics

    NASA Technical Reports Server (NTRS)

    Wolf, Richard A.

    2002-01-01

    This report includes descriptions of papers, a thesis, and works still in progress which cover observations of space weather in the Earth's magnetosphere. The topics discussed include: 1) modelling of magnetosphere activity; 2) magnetic storms; 3) high energy electrons; and 4) plasmas.

  1. Solar wind and magnetosphere interactions

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Allen, J. H.; Cauffman, D. P.; Feynman, J.; Greenstadt, E. W.; Holzer, R. E.; Kaye, S. M.; Slavin, J. A.; Manka, R. H.; Rostoker, G.

    1979-01-01

    The relationship between the magnetosphere and the solar wind is addressed. It is noted that this interface determines how much of the solar plasma and field energy is transferred to the Earth's environment, and that this coupling not only varies in time, responding to major solar disturbances, but also to small changes in solar wind conditions and interplanetary field directions. It is recommended that the conditions of the solar wind and interplanetary medium be continuously monitored, as well as the state of the magnetosphere. Other recommendations include further study of the geomagnetic tail, tests of Pc 3,4 magnetic pulsations as diagnostics of the solar wind, and tests of kilometric radiation as a remote monitor of the auroral electrojet.

  2. Origins of magnetospheric physics

    SciTech Connect

    Van Allen, J.A.

    1983-01-01

    The history of the scientific investigation of the earth magnetosphere during the period 1946-1960 is reviewed, with a focus on satellite missions leading to the discovery of the inner and outer radiation belts. Chapters are devoted to ground-based studies of the earth magnetic field through the 1930s, the first U.S. rocket flights carrying scientific instruments, the rockoon flights from the polar regions (1952-1957), U.S. planning for scientific use of artificial satellites (1956), the launch of Sputnik I (1957), the discovery of the inner belt by Explorers I and III (1958), the Argus high-altitude atomic-explosion tests (1958), the confirmation of themore » inner belt and discovery of the outer belt by Explorer IV and Pioneers I-V, related studies by Sputniks II and III and Luniks I-III, and the observational and theoretical advances of 1959-1961. Photographs, drawings, diagrams, graphs, and copies of original notes and research proposals are provided. 227 references.« less

  3. Survey of the spectral properties of turbulence in the solar wind, the magnetospheres of Venus and Earth, at solar minimum and maximum

    NASA Astrophysics Data System (ADS)

    Echim, Marius M.

    2014-05-01

    In the framework of the European FP7 project STORM ("Solar system plasma Turbulence: Observations, inteRmittency and Multifractals") we analyze the properties of turbulence in various regions of the solar system, for the minimum and respectively maximum of the solar activity. The main scientific objective of STORM is to advance the understanding of the turbulent energy transfer, intermittency and multifractals in space plasmas. Specific analysis methods are applied on magnetic field and plasma data provided by Ulysses, Venus Express and Cluster, as well as other solar system missions (e.g. Giotto, Cassini). In this paper we provide an overview of the spectral properties of turbulence derived from Power Spectral Densities (PSD) computed in the solar wind (from Ulysses, Cluster, Venus Express) and at the interface of planetary magnetospheres with the solar wind (from Venus Express, Cluster). Ulysses provides data in the solar wind between 1992 and 2008, out of the ecliptic, at radial distances ranging between 1.3 and 5.4 AU. We selected only those Ulysses data that satisfy a consolidated set of selection criteria able to identify "pure" fast and slow wind. We analyzed Venus Express data close to the orbital apogee, in the solar wind, at 0.72 AU, and in the Venus magnetosheath. We investigated Cluster data in the solar wind (for time intervals not affected by planetary ions effects), the magnetosheath and few crossings of other key magnetospheric regions (cusp, plasma sheet). We organize our PSD results in three solar wind data bases (one for the solar maximum, 1999-2001, two for the solar minimum, 1997-1998 and respectively, 2007-2008), and two planetary databases (one for the solar maximum, 2000-2001, that includes PSD obtained in the terrestrial magnetosphere, and one for the solar minimum, 2007-2008, that includes PSD obtained in the terrestrial and Venus magnetospheres and magnetosheaths). In addition to investigating the properties of turbulence for the minimum

  4. Magnetospheric turbulence and substorm expansion phase onset

    NASA Astrophysics Data System (ADS)

    Antonova, Elizaveta; Stepanova, Marina; Kirpichev, Igor; Pulinets, Maria; Znatkova, Svetlana; Ovchinnikov, Ilya; Kornilov, Ilya; Kornilova, Tatyana

    Magnetosphere of the Earth is formed in the process of turbulent solar wind flow around the obstacle -magnetic field of the Earth. The level of turbulence in the magnetosheath and geo-magnetic tail is very high even during periods of comparatively stable solar wind parameters. Such situation requires checking of the most popular concepts of the nature of magnetospheric activity. Properties of magnetosheath and magnetospheric turbulence are analyzed in connec-tion with the problem of the nature of substorms and localization of substorm onset. The large-scale picture of the plasma velocity fluctuations obtained using data of INTERBALL and Geotail observations is analyzed. It is shown that it is possible to select surrounding the Earth at geocentric distances from 7Re till 10Re plasma ring with comparatively low level of fluctuations. Results of observations demonstrating isolated substorm onset inside this ring are summarized. It is shown that the non-contradictory picture of large-scale magnetospheric convection and substorm dynamics can be obtained taking into account high level of magne-tosheath and magnetospheric turbulence.

  5. Inner Magnetospheric Physics

    NASA Technical Reports Server (NTRS)

    Gallagher, Dennis

    2018-01-01

    Outline - Inner Magnetosphere Effects: Historical Background; Main regions and transport processes: Ionosphere, Plasmasphere, Plasma sheet, Ring current, Radiation belt; Geomagnetic Activity: Storms, Substorm; Models.

  6. Magnetic reconnection during steady magnetospheric convection and other magnetospheric modes

    NASA Astrophysics Data System (ADS)

    Hubert, Benoit; Gérard, Jean-Claude; Milan, Steve E.; Cowley, Stanley W. H.

    2017-03-01

    We use remote sensing of the proton aurora with the IMAGE-FUV SI12 (Imager for Magnetopause to Aurora Global Exploration-Far Ultraviolet-Spectrographic Imaging at 121.8 nm) instrument and radar measurements of the ionospheric convection from the SuperDARN (Super Dual Aurora Radar Network) facility to estimate the open magnetic flux in the Earth's magnetosphere and the reconnection rates at the dayside magnetopause and in the magnetotail during intervals of steady magnetospheric convection (SMC). We find that SMC intervals occur with relatively high open magnetic flux (average ˜ 0.745 GWb, standard deviation ˜ 0.16 GWb), which is often found to be nearly steady, when the magnetic flux opening and closure rates approximately balance around 55 kV on average, with a standard deviation of 21 kV. We find that the residence timescale of open magnetic flux, defined as the ratio between the open magnetospheric flux and the flux closure rate, is roughly 4 h during SMCs. Interestingly, this number is approximately what can be deduced from the discussion of the length of the tail published by Dungey (1965), assuming a solar wind speed of ˜ 450 km s-1. We also infer an enhanced convection velocity in the tail, driving open magnetic flux to the nightside reconnection site. We compare our results with previously published studies in order to identify different magnetospheric modes. These are ordered by increasing open magnetic flux and reconnection rate as quiet conditions, SMCs, substorms (with an important overlap between these last two) and sawtooth intervals.

  7. A mechanism for magnetospheric substorms

    NASA Technical Reports Server (NTRS)

    Erickson, G. M.; Heinemann, M.

    1994-01-01

    Energy-principle analysis performed on two-dimensional, self-consistent solutions for magnetospheric convection indicates that the magnetosphere is unstable to isobaric (yet still frozen-in) fluctuations of plasma-sheet flux tubes. Normally, pdV work associated with compression maintains stability of the inward/outward oscillating normal mode. However, if Earth's ionosphere can provide sufficient mass flux, isobaric expansion of flux tubes can occur. The growth of a field-aligned potential drop in the near-Earth, midnight portion of the plasma sheet, associated with upward field-aligned currents responsible for the Harang discontinuity, redistributes plasma along field lines in a manner that destabilizes the normal mode. The growth of this unstable mode results in an out-of-equilibrium situation near the inner edge. When this occurs over a downtail extent comparable to the half-thickness of the plasma sheet, collapse ensues and forces thinning of the plasma sheet whereby conditions favorable to reconnection occur. This scenario for substorm onset is consistent with observed upward fluxes of ions, parallel potential drops, and observations of substorm onset. These observations include near Earth onset, pseudobreakups, the substorm current wedge, and local variations of plasma-sheet thickness.

  8. A Global Magnetohydrodynamic Model of Jovian Magnetosphere

    NASA Technical Reports Server (NTRS)

    Walker, Raymond J.; Sharber, James (Technical Monitor)

    2001-01-01

    The goal of this project was to develop a new global magnetohydrodynamic model of the interaction of the Jovian magnetosphere with the solar wind. Observations from 28 orbits of Jupiter by Galileo along with those from previous spacecraft at Jupiter, Pioneer 10 and 11, Voyager I and 2 and Ulysses, have revealed that the Jovian magnetosphere is a vast, complicated system. The Jovian aurora also has been monitored for several years. Like auroral observations at Earth, these measurements provide us with a global picture of magnetospheric dynamics. Despite this wide range of observations, we have limited quantitative understanding of the Jovian magnetosphere and how it interacts with the solar wind. For the past several years we have been working toward a quantitative understanding of the Jovian magnetosphere and its interaction with the solar wind by employing global magnetohydrodynamic simulations to model the magnetosphere. Our model has been an explicit MHD code (previously used to model the Earth's magnetosphere) to study Jupiter's magnetosphere. We continue to obtain important insights with this code, but it suffers from some severe limitations. In particular with this code we are limited to considering the region outside of 15RJ, with cell sizes of about 1.5R(sub J). The problem arises because of the presence of widely separated time scales throughout the magnetosphere. The numerical stability criterion for explicit MHD codes is the CFL limit and is given by C(sub max)(Delta)t/(Delta)x less than 1 where C(sub max) is the maximum group velocity in a given cell, (Delta)x is the grid spacing and (Delta)t is the time step. If the maximum wave velocity is C(sub w) and the flow speed is C(sub f), C(sub max) = C(sub w) + C(sub f). Near Jupiter the Alfven wave speed becomes very large (it approaches the speed of light at one Jovian radius). Operating with this time step makes the calculation essentially intractable. Therefore under this funding we have been designing a

  9. Validation of Magnetospheric Magnetohydrodynamic Models

    NASA Astrophysics Data System (ADS)

    Curtis, Brian

    Magnetospheric magnetohydrodynamic (MHD) models are commonly used for both prediction and modeling of Earth's magnetosphere. To date, very little validation has been performed to determine their limits, uncertainties, and differences. In this work, we performed a comprehensive analysis using several commonly used validation techniques in the atmospheric sciences to MHD-based models of Earth's magnetosphere for the first time. The validation techniques of parameter variability/sensitivity analysis and comparison to other models were used on the OpenGGCM, BATS-R-US, and SWMF magnetospheric MHD models to answer several questions about how these models compare. The questions include: (1) the difference between the model's predictions prior to and following to a reversal of Bz in the upstream interplanetary field (IMF) from positive to negative, (2) the influence of the preconditioning duration, and (3) the differences between models under extreme solar wind conditions. A differencing visualization tool was developed and used to address these three questions. We find: (1) For a reversal in IMF Bz from positive to negative, the OpenGGCM magnetopause is closest to Earth as it has the weakest magnetic pressure near-Earth. The differences in magnetopause positions between BATS-R-US and SWMF are explained by the influence of the ring current, which is included in SWMF. Densities are highest for SWMF and lowest for OpenGGCM. The OpenGGCM tail currents differ significantly from BATS-R-US and SWMF; (2) A longer preconditioning time allowed the magnetosphere to relax more, giving different positions for the magnetopause with all three models before the IMF Bz reversal. There were differences greater than 100% for all three models before the IMF Bz reversal. The differences in the current sheet region for the OpenGGCM were small after the IMF Bz reversal. The BATS-R-US and SWMF differences decreased after the IMF Bz reversal to near zero; (3) For extreme conditions in the solar

  10. An Introduction to Magnetospheric Physics by Means of Simple Models

    NASA Technical Reports Server (NTRS)

    Stern, D. P.

    1981-01-01

    The large scale structure and behavior of the Earth's magnetosphere is discussed. The model is suitable for inclusion in courses on space physics, plasmas, astrophysics or the Earth's environment, as well as for self-study. Nine quantitative problems, dealing with properties of linear superpositions of a dipole and a constant field are presented. Topics covered include: open and closed models of the magnetosphere; field line motion; the role of magnetic merging (reconnection); magnetospheric convection; and the origin of the magnetopause, polar cusps, and high latitude lobes.

  11. Saturn's Magnetic Field and Magnetosphere.

    PubMed

    Smith, E J; Davis, L; Jones, D E; Coleman, P J; Colburn, D S; Dyal, P; Sonett, C P

    1980-01-25

    The Pioneer Saturn vector helium magnetometer has detected a bow shock and magnetopause at Saturn and has provided an accurate characterization of the planetary field. The equatorial surface field is 0.20 gauss, a factor of 3 to 5 times smaller than anticipated on the basis of attempted scalings from Earth and Jupiter. The tilt angle between the magnetic dipole axis and Saturn's rotation axis is < 1 degrees , a surprisingly small value. Spherical harmonic analysis of the measurements shows that the ratio of quadrupole to dipole moments is < 10 percent, indicating that the field is more uniform than those of the Earth or Jupiter and consistent with Saturn having a relatively small core. The field in the outer magnetosphere shows systematic departures from the dipole field, principally a compression of the field near noon and an equatorial orientation associated with a current sheet near dawn. A hydromagnetic wake resulting from the interaction of Titan with the rotating magnetosphere appears to have been observed.

  12. Characteristics of magnetospheric radio noise spectra

    NASA Technical Reports Server (NTRS)

    Herman, J. R.

    1976-01-01

    Magnetospheric radio noise spectra (30 kHz to 10 MHz) taken by IMP-6 and RAE-2 exhibit time-varying characteristics which are related to spacecraft position and magnetospheric processes. In the mid-frequency range (100-1,000 kHz) intense noise peaks rise by a factor of 100 or more above background; 80% of the peak frequencies are within the band 125 kHz to 600 kHz, and the peak occurs most often (18% of the time) at 280 kHz. This intense mid-frequency noise has been detected at radial distances from 1.3 Re to 60 Re on all sides of the Earth during magnetically quiet as well as disturbed periods. Maximum occurrence of the mid-frequency noise is in the evening to midnight hours where splash-type energetic particle precipitation takes place. ""Magnetospheric lightning'' can be invoked to explain the spectral shape of the observed spectra.

  13. Magnetosphere Modeling: From Cartoons to Simulations

    NASA Astrophysics Data System (ADS)

    Gombosi, T. I.

    2017-12-01

    Over the last half a century physics-based global computer simulations became a bridge between experiment and basic theory and now it represents the "third pillar" of geospace research. Today, many of our scientific publications utilize large-scale simulations to interpret observations, test new ideas, plan campaigns, or design new instruments. Realistic simulations of the complex Sun-Earth system have been made possible by the dramatically increased power of both computing hardware and numerical algorithms. Early magnetosphere models were based on simple E&M concepts (like the Chapman-Ferraro cavity) and hydrodynamic analogies (bow shock). At the beginning of the space age current system models were developed culminating in the sophisticated Tsyganenko-type description of the magnetic configuration. The first 3D MHD simulations of the magnetosphere were published in the early 1980s. A decade later there were several competing global models that were able to reproduce many fundamental properties of the magnetosphere. The leading models included the impact of the ionosphere by using a height-integrated electric potential description. Dynamic coupling of global and regional models started in the early 2000s by integrating a ring current and a global magnetosphere model. It has been recognized for quite some time that plasma kinetic effects play an important role. Presently, global hybrid simulations of the dynamic magnetosphere are expected to be possible on exascale supercomputers, while fully kinetic simulations with realistic mass ratios are still decades away. In the 2010s several groups started to experiment with PIC simulations embedded in large-scale 3D MHD models. Presently this integrated MHD-PIC approach is at the forefront of magnetosphere simulations and this technique is expected to lead to some important advances in our understanding of magnetosheric physics. This talk will review the evolution of magnetosphere modeling from cartoons to current systems

  14. The magnetosphere of Saturn

    NASA Technical Reports Server (NTRS)

    Schardt, A. W.

    1982-01-01

    Information about the magnetosphere of Saturn is provided: the magnetic dipole moment is axisymmetric, the bow shock stand-off distance is about 22 R sub S. The satellites Titan, Dione, and Tethys are probably the primary sources of magnetospheric plasma. Outside of approx. 4 R sub S, energetic particles are energized by diffusing inward while conserving their first and second adiabatic invariants. Particles are lost by satellite sweep-out, absorption byt the E ring and probably also by plasma interactions. The inner magnetosphere is characterized.

  15. Magnetospheric Science at Uranus and Neptune

    NASA Astrophysics Data System (ADS)

    Hospodarsky, G. B.; Masters, A.; Soderlund, K. M.; Mandt, K. E.

    2017-12-01

    The magnetospheres of the Ice Giant planets Uranus and Neptune have only been sampled in-situ by the Voyager 2 spacecraft, which revealed a very complicated and dynamic system. In combination with the much weaker solar wind at these distances, the large diurnal and seasonal variability of the magnetospheres' orientation with respect to the solar wind, results in characteristics that are very different from the magnetospheres of Earth and the Gas Giants, Jupiter and Saturn. Studying these magnetospheres is important for furthering our understanding of fundamental physical and chemical processes in the Solar System, and may help in understanding the magnetic fields of exoplanets as well. A number of studies, proposals, and reports, including the recently completed "Ice Giants Pre-Decadal Survey Mission Study Report" have demonstrated the interest in a new mission to the Ice Giants. We will review the magnetospheric results from Voyager 2, summarize outstanding science questions, and discuss possible goals of a future mission to Uranus and/or Neptune.

  16. The Magnetosphere Imager Mission Concept Definition Study

    NASA Technical Reports Server (NTRS)

    Johnson, L.; Herrmann, M.; Alexander, Reggie; Beabout, Brent; Blevins, Harold; Bridge, Scott; Burruss, Glenda; Buzbee, Tom; Carrington, Connie; Chandler, Holly; hide

    1997-01-01

    For three decades, magnetospheric field and plasma measurements have been made by diverse instruments flown on spacecraft in many different orbits, widely separated in space and time, and under various solar and magnetospheric conditions. Scientists have used this information to piece together an intricate, yet incomplete view of the magnetosphere. A simultaneous global view, using various light wavelengths and energetic neutral atoms, could reveal exciting new data and help explain complex magnetospheric processes, thus providing us with a clear picture of this region of space. The George C. Marshall Space Flight Center (MSFC) is responsible for defining the Magnetosphere Imager mission which will study this region of space. A core instrument complement of three imagers (with the potential addition of one or more mission enhancing instrument) will fly in an elliptical polar Earth orbit with an apogee of 44,600 kilometers and a perigee of 4,800 km. This report will address the mission objectives, spacecraft design concepts, and the results of the MSFC concept definition study.

  17. The self-consistent parallel electric field due to electrostatic ion-cyclotron turbulence in downward auroral-current regions of the Earth's magnetosphere. IV

    NASA Astrophysics Data System (ADS)

    Jasperse, John R.; Basu, Bamandas; Lund, Eric J.; Grossbard, Neil

    2010-06-01

    The physical processes that determine the self-consistent electric field (E∥) parallel to the magnetic field have been an unresolved problem in magnetospheric physics for over 40 years. Recently, a new multimoment fluid theory was developed for inhomogeneous, nonuniformly magnetized plasma in the guiding-center and gyrotropic approximation that includes the effect of electrostatic, turbulent, wave-particle interactions (see Jasperse et al. [Phys. Plasmas 13, 072903 (2006); Jasperse et al., Phys. Plasmas13, 112902 (2006)]). In the present paper and its companion paper [Jasperse et al., Phys. Plasmas 17, 062903 (2010)], which are intended as sequels to the earlier work, a fundamental model for downward, magnetic field-aligned (Birkeland) currents for quasisteady conditions is presented. The model includes the production of electrostatic ion-cyclotron turbulence in the long-range potential region by an electron, bump-on-tail-driven ion-cyclotron instability. Anomalous momentum transfer (anomalous resistivity) by itself is found to produce a very small contribution to E∥; however, the presence of electrostatic, ion-cyclotron turbulence has a very large effect on the altitude dependence of the entire quasisteady solution. Anomalous energy transfer (anomalous heating and cooling) modifies the density, drift, and temperature altitude profiles and hence the generalized parallel-pressure gradients and mirror forces in the electron and ion momentum-balance equations. As a result, |E∥| is enhanced by nearly a factor of 40 compared to its value when turbulence is absent. The space-averaged potential increase associated with the strong double layer at the bottom of the downward-current sheet is estimated using the FAST satellite data and the multimoment fluid theory.

  18. Ionospheric Outflow in the Magnetosphere: Circulation and Consequences

    NASA Astrophysics Data System (ADS)

    Welling, D. T.; Liemohn, M. W.

    2017-12-01

    Including ionospheric outflow in global magnetohydrodynamic models of near-Earth outer space has become an important step towards understanding the role of this plasma source in the magnetosphere. Such simulations have revealed the importance of outflow in populating the plasma sheet and inner magnetosphere as a function of outflow source characteristics. More importantly, these experiments have shown how outflow can control global dynamics, including tail dynamics and dayside reconnection rate. The broad impact of light and heavy ion outflow can create non-linear feedback loops between outflow and the magnetosphere. This paper reviews some of the most important revelations from global magnetospheric modeling that includes ionospheric outflow of light and heavy ions. It also introduces new advances in outflow modeling and coupling outflow to the magnetosphere.

  19. The magnetosphere of Neptune - Its response to daily rotation

    NASA Technical Reports Server (NTRS)

    Voigt, Gerd-Hannes; Ness, Norman F.

    1990-01-01

    The Neptunian magnetosphere periodically changes every eight hours between a pole-on magnetosphere with only one polar cusp and an earth-type magnetosphere with two polar cusps. In the pole-on configuration, the tail current sheet has an almost circular shape with plasma currents closing entirely within the magnetosphere. Eight hours later the tail current sheet assumes an almost flat shape with plasma currents touching the magnetotail boundary and closing over the tail magnetopause. Magnetic field and tail current sheet configurations have been calculated in a three-dimensional model, but the plasma- and thermodynamic conditions were investigated in a simplified two-dimensional MHD equilibrium magnetosphere. It was found that the free energy in the tail region of the two-dimensional model becomes independent of the dipole tilt angle. It is conjectured that the Neptunian magnetotail might assume quasi-static equilibrium states that make the free energy of the system independent of its daily rotation.

  20. Solar and magnetospheric science

    NASA Technical Reports Server (NTRS)

    Timothy, A. F.; Schmerling, E. R.; Chapman, R. D.

    1976-01-01

    The current status of the Solar Physics Program and the Magnetospheric Physics Program is discussed. The scientific context for each of the programs is presented, then the current programs and future plans are outlined.

  1. Modeling Magnetospheric Sources

    NASA Technical Reports Server (NTRS)

    Walker, Raymond J.; Ashour-Abdalla, Maha; Ogino, Tatsuki; Peroomian, Vahe; Richard, Robert L.

    2001-01-01

    We have used global magnetohydrodynamic, simulations of the interaction between the solar wind and magnetosphere together with single particle trajectory calculations to investigate the sources of plasma entering the magnetosphere. In all of our calculations solar wind plasma primarily enters the magnetosphere when the field line on which it is convecting reconnects. When the interplanetary magnetic field has a northward component the reconnection is in the polar cusp region. In the simulations plasma in the low latitude boundary layer (LLBL) can be on either open or closed field lines. Open field lines occur when the high latitude reconnection occurs in only one cusp. In the MHD calculations the ionosphere does not contribute significantly to the LLBL for northward IMF. The particle trajectory calculations show that ions preferentially enter in the cusp region where they can be accelerated by non-adiabatic motion across the high latitude electric field. For southward IMF in the MHD simulations the plasma in the middle and inner magnetosphere comes from the inner (ionospheric) boundary of the simulation. Solar wind plasma on open field lines is confined to high latitudes and exits the tailward boundary of the simulation without reaching the plasma sheet. The LLBL is populated by both ionospheric and solar wind plasma. When the particle trajectories are included solar wind ions can enter the middle magnetosphere. We have used both the MHD simulations and the particle calculations to estimate source rates for the magnetosphere which are consistent with those inferred from observations.

  2. Plasma pressure distribution in the equatorial plane of the Earth's magnetosphere at geocentric distances of 6-10 R E according to the international THEMIS mission data

    NASA Astrophysics Data System (ADS)

    Kirpichev, I. P.; Antonova, E. E.

    2011-08-01

    The structure of the averaged plasma pressure distribution in the plasma ring around the Earth at geocentric distances of ˜6-10 R E has been determined. The distribution function moments measured on the international THEMIS mission satellites have been used. The plasma pressure distribution in the equatorial plane at 15 R E > XSM > -15 R E and 15 R E > YSM > -15 R E has been statistically studied. The radial dependence of the plasma pressure at the day-night and morning-evening meridians has been analyzed. It has been indicated that the plasma ring around the Earth has a structure, which is close to being azimuthally symmetric. The achieved results have been compared with the pressure distributions obtained previously. It has been indicated that in the overlapping regions, the achieved results agree with the previously obtained data within the pressure determination errors.

  3. On the Magnetospheric Heating Problem

    NASA Astrophysics Data System (ADS)

    Nykyri, K.; Moore, T.; Dimmock, A. P.; Ma, X.; Johnson, J.; Delamere, P. A.

    2016-12-01

    In the Earth's magnetosphere the specific entropy, increases by approximately two orders of magnitude when transitioning from the magnetosheath into the magnetosphere. However, the origin of this non-adiabatic heating is not well understood. In addition, there exists a dawn-dusk temperature asymmetry in the flanks of the plasma sheet - the cold component ions are hotter by 30-40% at the dawnside plasma sheet compared to the duskside plasma sheet. Our recent statistical study of magnetosheath temperatures using 7 years of THEMIS data indicates that ion magnetosheath temperatures downstream of quasi-parallel (dawn-flank for the Parker-Spiral IMF) bow shock are only 15 percent higher than downstream of the quasi-perpendicular shock. This magnetosheath temperature asymmetry is therefore inadequate to cause the observed level of the plasma sheet temperature asymmetry. In this presentation we address the origin of non-adiabatic heating from the magnetosheath into the plasma sheet by utilizing small Cluster spacecraft separations, 9 years of statistical THEMIS data as well as Hall-MHD and hybrid simulations. We present evidence of a new physical mechanism capable of cross-scale energy transport at the flank magnetopause with strong contributions to the non-adiabatic heating observed between the magnetosheath and plasma sheet. This same heating mechanism may occur and drive asymmetries also in the magnetospheres of gas giants: Jupiter and Saturn, as well as play role elsewhere in the universe where significant flow shears are present such as in the solar corona, and other astrophysical and laboratory plasmas.

  4. Ganymede's magnetosphere: Magnetometer overview

    NASA Astrophysics Data System (ADS)

    Kivelson, M. G.; Warnecke, J.; Bennett, L.; Joy, S.; Khurana, K. K.; Linker, J. A.; Russell, C. T.; Walker, R. J.; Polanskey, C.

    1998-09-01

    Ganymede presents a unique example of an internally magnetized moon whose intrinsic magnetic field excludes the plasma present at its orbit, thereby forming a magnetospheric cavity. We describe some of the properties of this mini-magnetosphere, embedded in a sub-Alfvénic flow and formed within a planetary magnetosphere. A vacuum superposition model (obtained by adding the internal field of Ganymede to the field imposed by Jupiter) organizes the data acquired by the Galileo magnetometer on four close passes in a useful, intuitive fashion. The last field line that links to Ganymede at both ends extends to ~2 Ganymede radii, and the transverse scale of the magnetosphere is ~5.5 Ganymede radii. Departures from this simple model arise from currents flowing in the Alfvén wings and elsewhere on the magnetopause. The four passes give different cuts through the magnetosphere from which we develop a geometric model for the magnetopause surface as a function of the System III location of Ganymede. On one of the passes, Ganymede was located near the center of Jupiter's plasma disk. For this pass we identify probable Kelvin-Helmholtz surface waves on the magnetopause. After entering the relatively low-latitude upstream magnetosphere, Galileo apparently penetrated the region of closed field lines (ones that link to Ganymede at both ends), where we identify predominantly transverse fluctuations at frequencies reasonable for field line resonances. We argue that magnetic field measurements, when combined with flow measurements, show that reconnection is extremely efficient. Downstream reconnection, consequently, may account for heated plasma observed in a distant crossing of Ganymede's wake. We note some of the ways in which Ganymede's unusual magnetosphere corresponds to familiar planetary magnetospheres (viz., the magnetospheric topology and an electron ring current). We also comment on some of the ways in which it differs from familiar planetary magnetospheres (viz., relative

  5. A Voyager Perspective of Ice Giant Magnetospheres: What Next?

    NASA Astrophysics Data System (ADS)

    Kurth, W. S.; Hospodarsky, G. B.

    2017-12-01

    Voyager 2 provided our only in situ observations of the magnetospheres of Uranus (in 1986) and Neptune (in 1989). And, given that Earth-based radio observations have not acquired auroral radio emissions from these planets, the only remote observations of magnetospheric phenomena at these planets are of their auroras. This paper provides an overview of the Voyager observations of these ice giant magnetospheres as a stepping off point for the possibility of missions launching to one or both of these planets in the next decade or so. Both of these magnetospheres are rich in phenomena found in other planetary magnetospheres including plasmas and energetic particles, currents, radio and plasma waves, auroras, and dust. Perhaps the thing that sets these magnetospheres off from those of Earth, Jupiter, and Saturn are the very large tilt of their magnetic moments with respect to their rotation axes. With such tilts, the magnetospheres can be reconfigured every rotation as the magnetic configuration with respect to the impinging solar wind continually changes. The Voyager flybys provided only hints of how these reconfigurations work. Certainly even another flyby mission would effectively double the range of states observed for them. But, a mission including an orbiter would provide an amazing opportunity to observe these dramatic changes through not only a cycle, but repeatedly. A suitably instrumented spacecraft could provide understanding for how these planets work as systems including satellites, rings, and magnetic fields tying them to the ice giant.

  6. Magnetospheric convection during quiet or moderately disturbed times

    NASA Technical Reports Server (NTRS)

    Caudal, G.; Blanc, M.

    1988-01-01

    The processes which contribute to the large-scale plasma circulation in the earth's environment during quiet times, or during reasonable stable magnetic conditions are reviewed. The various sources of field-aligned current generation in the solar wind and the magnetosphere are presented. The generation of field-aligned currents on open field lines connected to either polar cap and the generation of closed field lines of the inner magnetosphere are examined. Consideration is given to the hypothesis of Caudal (1987) that loss processes of trapped particles are competing with adiabatic motions in the generation of field-aligned currents in the inner magnetosphere.

  7. Auroral magnetosphere-ionosphere coupling: A brief topical review

    NASA Technical Reports Server (NTRS)

    Chiu, Y. T.; Schulz, M.; Cornwall, J. M.

    1979-01-01

    Auroral arcs result from the acceleration and precipitation of magnetospheric plasma in narrow regions characterized by strong electric fields both perpendicular and parallel to the earth's magnetic field. The various mechanisms that were proposed for the origin of such strong electric fields are often complementary Such mechanisms include: (1) electrostatic double layers; (2) double reverse shock; (3) anomalous resistivity; (4) magnetic mirroring of hot plasma; and (5) mapping of the magnetospheric-convection electric field through an auroral discontinuity.

  8. The Nonlinear Magnetosphere: Expressions in MHD and in Kinetic Models

    NASA Technical Reports Server (NTRS)

    Hesse, Michael; Birn, Joachim

    2011-01-01

    Like most plasma systems, the magnetosphere of the Earth is governed by nonlinear dynamic evolution equations. The impact of nonlinearities ranges from large scales, where overall dynamics features are exhibiting nonlinear behavior, to small scale, kinetic, processes, where nonlinear behavior governs, among others, energy conversion and dissipation. In this talk we present a select set of examples of such behavior, with a specific emphasis on how nonlinear effects manifest themselves in MHD and in kinetic models of magnetospheric plasma dynamics.

  9. Continuum radiation in planetary magnetospheres

    NASA Technical Reports Server (NTRS)

    Kurth, W. S.

    1991-01-01

    With the completion of the Voyager tour of the outer planets, radio and plasma wave instruments have executed the first survey of the wave spectra of Earth, Jupiter, Saturn, Uranus, and Neptune. One of the most notable conclusions of this survey is that there is a great deal of qualitative similarity in both the plasma wave and radio wave spectra from one magnetosphere to the next. In particular, in spite of detailed differences, most of the radio emissions at each of the planets have been tentatively classified into two primary categories. First, the most intense emissions are generally associated with the cyclotron maser instability. Second, a class of weaker emissions can be found at each of the magnetospheres which appears to be the result of conversion from intense electrostatic emissions at the upper hybrid resonance frequency into (primarily) ordinary mode radio emission. It is this second category, often referred to as nonthermal continuum radiation, which we will discuss in this review. We review the characteristics of the continuum spectrum at each of the planets, discuss the source region and direct observations of the generation of the emissions where available, and briefly describe the theories for the generation of the emissions. Over the past few years evidence has increased that the linear mode conversion of electrostatic waves into the ordinary mode can account for at least some of the continuum radiation observed. There is no definitive evidence which precludes the possibility that a nonlinear mechanism may also be important.

  10. Energetics of the magnetosphere, revised

    NASA Technical Reports Server (NTRS)

    Stern, D. P.

    1984-01-01

    The approximate magnitudes of power inputs and energies associated with the Earth's magnetosphere were derived. The nearest 40 R sub E of the plasma sheet current receive some 3.10 to the 11th power watt, and much of this goes to the Birkeland currents, which require 1-3 10 to the 11th power watt. Of that energy, about 30% appears as the energy of auroral particles and most of the rest as ionosphere joule heating. The ring current contains about 10 to the 15th power joule at quiet times, several times as much during magnetic storms, and the magnetic energy stored in the tail lobes is comparable. Substorm energy releases may range at 1.5 to 30 10 to the 11th power watt. Compared to these, the local energy release rate by magnetic merging in the magnetosphere is small. Merging is essential for the existence of open field lines, which make such inputs possible. Merging also seems to be implicated in substorms: most of the released energy only becomes evident far from the merging region, though some particles may gain appreciable energy in that region itself, if the plasma sheet is squeezed out completely and the high latitude lobes interact directly.

  11. Global MHD simulation of magnetosphere using HPF

    NASA Astrophysics Data System (ADS)

    Ogino, T.

    We have translated a 3-dimensional magnetohydrodynamic (MHD) simulation code of the Earth's magnetosphere from VPP Fortran to HPF/JA on the Fujitsu VPP5000/56 vector-parallel supercomputer and the MHD code was fully vectorized and fully parallelized in VPP Fortran. The entire performance and capability of the HPF MHD code could be shown to be almost comparable to that of VPP Fortran. A 3-dimensional global MHD simulation of the earth's magnetosphere was performed at a speed of over 400 Gflops with an efficiency of 76.5% using 56 PEs of Fujitsu VPP5000/56 in vector and parallel computation that permitted comparison with catalog values. We have concluded that fluid and MHD codes that are fully vectorized and fully parallelized in VPP Fortran can be translated with relative ease to HPF/JA, and a code in HPF/JA may be expected to perform comparably to the same code written in VPP Fortran.

  12. Predicting the magnetospheric plasma of weather

    NASA Technical Reports Server (NTRS)

    Dawson, John M.

    1986-01-01

    The prediction of the plasma environment in time, the plasma weather, is discussed. It is important to be able to predict when large magnetic storms will produce auroras, which will affect the space station operating in low orbit, and what precautions to take both for personnel and sensitive control (computer) equipment onboard. It is also important to start to establish a set of plasma weather records and a record of the ability to predict this weather. A successful forecasting system requires a set of satellite weather stations to provide data from which predictions can be made and a set of plasma weather codes capable of accurately forecasting the status of the Earth's magnetosphere. A numerical magnetohydrodynamic fluid model which is used to model the flow in the magnetosphere, the currents flowing into and out of the auroral regions, the magnetopause, the bow shock location and the magnetotail of the Earth is discussed.

  13. Modeling of Inner Magnetosphere Coupling Processes

    NASA Technical Reports Server (NTRS)

    Khazanov, George V.

    2011-01-01

    The Ring Current (RC) is the biggest energy player in the inner magnetosphere. It is the source of free energy for Electromagnetic Ion Cyclotron (EMIC) wave excitation provided by a temperature anisotropy of RC ions, which develops naturally during inward E B convection from the plasmasheet. The cold plasmasphere, which is under the strong influence of the magnetospheric electric field, strongly mediates the RC-EMIC wave-particle-coupling process and ultimately becomes part of the particle and energy interplay. On the other hand, there is a strong influence of the RC on the inner magnetospheric electric and magnetic field configurations and these configurations, in turn, are important to RC dynamics. Therefore, one of the biggest needs for inner magnetospheric research is the continued progression toward a coupled, interconnected system with the inclusion of nonlinear feedback mechanisms between the plasma populations, the electric and magnetic fields, and plasma waves. As we clearly demonstrated in our studies, EMIC waves strongly interact with electrons and ions of energies ranging from approx.1 eV to approx.10 MeV, and that these waves strongly affect the dynamics of resonant RC ions, thermal electrons and ions, and the outer RB relativistic electrons. As we found, the rate of ion and electron scattering/heating in the Earth's magnetosphere is not only controlled by the wave intensity-spatial-temporal distribution but also strongly depends on the spectral distribution of the wave power. The latter is also a function of the plasmaspheric heavy ion content, and the plasma density and temperature distributions along the magnetic field lines. The above discussion places RC-EMIC wave coupling dynamics in context with inner magnetospheric coupling processes and, ultimately, relates RC studies with plasmaspheric and Superthermal Electrons formation processes as well as with outer RB physics.

  14. MESSENGER: Exploring Mercury's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Slavin, James A.; Krimigis, Stamatios M.; Acuna, Mario H.; Anderson, Brian J.; Baker, Daniel N.; Koehn, Patrick L.; Korth, Haje; Levi, Stefano; Mauk, Barry H.; Solomon, Sean C.; hide

    2005-01-01

    The MESSENGER mission to Mercury offers our first opportunity to explore this planet s miniature magnetosphere since the brief flybys of Mariner 10. Mercury s magnetosphere is unique in many respects. The magnetosphere of Mercury is among the smallest in the solar system; its magnetic field typically stands off the solar wind only - 1000 to 2000 km above the surface. For this reason there are no closed drift paths for energetic particles and, hence, no radiation belts. The characteristic time scales for wave propagation and convective transport are short and kinetic and fluid modes may be coupled. Magnetic reconnection at the dayside magnetopause may erode the subsolar magnetosphere allowing solar wind ions to impact directly the regolith. Inductive currents in Mercury s interior may act to modify the solar wind interaction by resisting changes due to solar wind pressure variations. Indeed, observations of these induction effects may be an important source of information on the state of Mercury s interior. In addition, Mercury s magnetosphere is the only one with its defining magnetic flux tubes rooted in a planetary regolith as opposed to an atmosphere with a conductive ionospheric layer. This lack of an ionosphere is probably the underlying reason for the brevity of the very intense, but short-lived, - 1-2 min, substorm-like energetic particle events observed by Mariner 10 during its first traversal of Mercury s magnetic tail. Because of Mercury s proximity to the sun, 0.3 - 0.5 AU, this magnetosphere experiences the most extreme driving forces in the solar system. All of these factors are expected to produce complicated interactions involving the exchange and re-cycling of neutrals and ions between the solar wind, magnetosphere, and regolith. The electrodynamics of Mercury s magnetosphere are expected to be equally complex, with strong forcing by the solar wind, magnetic reconnection at the magnetopause and in the tail, and the pick-up of planetary ions all

  15. Geospace Magnetospheric Dynamics Mission

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Kluever, C.; Burch, J. L.; Fennell, J. F.; Hack, K.; Hillard, G. B.; Kurth, W. S.; Lopez, R. E.; Luhmann, J. G.; Martin, J. B.; hide

    1998-01-01

    The Geospace Magnetospheric Dynamics (GMD) mission is designed to provide very closely spaced, multipoint measurements in the thin current sheets of the magnetosphere to determine the relation between small scale processes and the global dynamics of the magnetosphere. Its trajectory is specifically designed to optimize the time spent in the current layers and to minimize radiation damage to the spacecraft. Observations are concentrated in the region 8 to 40 R(sub E) The mission consists of three phases. After a launch into geostationary transfer orbit the orbits are circularized to probe the region between geostationary orbit and the magnetopause; next the orbit is elongated keeping perigee at the magnetopause while keeping the line of apsides down the tail. Finally, once apogee reaches 40 R(sub E) the inclination is changed so that the orbit will match the profile of the noon-midnight meridian of the magnetosphere. This mission consists of 4 solar electrically propelled vehicles, each with a single NSTAR thruster utilizing 100 kg of Xe to tour the magnetosphere in the course of a 4.4 year mission, the same thrusters that have been successfully tested on the Deep Space-1 mission.

  16. Physics of Magnetospheric Variability

    NASA Astrophysics Data System (ADS)

    Vasyliūnas, Vytenis M.

    2011-01-01

    Many widely used methods for describing and understanding the magnetosphere are based on balance conditions for quasi-static equilibrium (this is particularly true of the classical theory of magnetosphere/ionosphere coupling, which in addition presupposes the equilibrium to be stable); they may therefore be of limited applicability for dealing with time-variable phenomena as well as for determining cause-effect relations. The large-scale variability of the magnetosphere can be produced both by changing external (solar-wind) conditions and by non-equilibrium internal dynamics. Its developments are governed by the basic equations of physics, especially Maxwell's equations combined with the unique constraints of large-scale plasma; the requirement of charge quasi-neutrality constrains the electric field to be determined by plasma dynamics (generalized Ohm's law) and the electric current to match the existing curl of the magnetic field. The structure and dynamics of the ionosphere/magnetosphere/solar-wind system can then be described in terms of three interrelated processes: (1) stress equilibrium and disequilibrium, (2) magnetic flux transport, (3) energy conversion and dissipation. This provides a framework for a unified formulation of settled as well as of controversial issues concerning, e.g., magnetospheric substorms and magnetic storms.

  17. The magnetosphere as system

    NASA Astrophysics Data System (ADS)

    Siscoe, G. L.

    2012-12-01

    What is a system? A group of elements interacting with each other so as to create feedback loops. A system gets complex as the number of feedback loops increases and as the feedback loops exhibit time delays. Positive and negative feedback loops with time delays can give a system intrinsic time dependence and emergent properties. A system generally has input and output flows of something (matter, energy, money), which, if time variable, add an extrinsic component to its behavior. The magnetosphere is a group of elements interacting through feedback loops, some with time delays, driven by energy and mass inflow from a variable solar wind and outflow into the atmosphere and solar wind. The magnetosphere is a complex system. With no solar wind, there is no behavior. With solar wind, there is behavior from intrinsic and extrinsic causes. As a contribution to taking a macroscopic view of magnetospheric dynamics, to treating the magnetosphere as a globally integrated, complex entity, I will discus the magnetosphere as a system, its feedback loops, time delays, emergent behavior, and intrinsic and extrinsic behavior modes.

  18. Magnetospheres of the outer planets

    NASA Technical Reports Server (NTRS)

    Vanallen, James A.

    1987-01-01

    The five qualitatively different types of magnetism that a planet body can exhibit are outlined. Potential sources of energetic particles in a planetary magnetosphere are discussed. The magnetosphere of Uranus and Neptune are then described using Pioneer 10 data.

  19. Initial assessment of the effects of energetic ion injections in the magnetosphere due to the transport of satellite power system components from low earth orbit to geosynchronous earth orbit

    NASA Astrophysics Data System (ADS)

    Curtis, S. A.; Grebowsky, J. M.

    1980-07-01

    Potentially serious environmental effects exist when cargo orbital transfer vehicle (COTV) ion propulsion is used on the scale proposed in the preliminary definition studies of the Satellite Power System. These effects of the large scale injections of ion propulsion exhaust in the plasmasphere and in the outer magnetosphere were shown to be highly model dependent with major differences existing in the predicted effects of two models, the ion cloud model and the ion sheath model. The expected total number density deposition of the propellant Ar(+) in the plasmasphere, the energy spectra of the deposited Ar(+) and time dependent behavior of the Ar(+) injected into the plasmasphere by a fleet of COTV vehicles differ drastically between the two models. The ion sheath model was demonstrated to be applicable to the proposed Ar(+) beam physics if the beam was divergent and turbulent whereas the ion cloud model was not a realistic approximation for such a beam because the "frozen-field" assumption on which it is based is not valid.

  20. Jupiter's Magnetosphere: Plasma Description from the Ulysses Flyby.

    PubMed

    Bame, S J; Barraclough, B L; Feldman, W C; Gisler, G R; Gosling, J T; McComas, D J; Phillips, J L; Thomsen, M F; Goldstein, B E; Neugebauer, M

    1992-09-11

    Plasma observations at Jupiter show that the outer regions of the Jovian magnetosphere are remarkably similar to those of Earth. Bow-shock precursor electrons and ions were detected in the upstream solar wind, as at Earth. Plasma changes across the bow shock and properties of the magnetosheath electrons were much like those at Earth, indicating that similar processes are operating. A boundary layer populated by a varying mixture of solar wind and magnetospheric plasmas was found inside the magnetopause, again as at Earth. In the middle magnetosphere, large electron density excursions were detected with a 10-hour periodicity as planetary rotation carried the tilted plasma sheet past Ulysses. Deep in the magnetosphere, Ulysses crossed a region, tentatively described as magnetically connected to the Jovian polar cap on one end and to the interplanetary magnetic field on the other. In the inner magnetosphere and lo torus, where corotation plays a dominant role, measurements could not be made because of extreme background rates from penetrating radiation belt particles.

  1. Ionosphere-magnetosphere coupling

    NASA Technical Reports Server (NTRS)

    Kaufmann, Richard L.

    1994-01-01

    Principal results are presented for the four papers that were supported from this grant. These papers include: 'Mapping and Energization in the Magnetotail. 1. Magnetospheric Boundaries; 'Mapping and Energization in the Magnetotail. 2. Particle Acceleration'; 'Cross-Tail Current: Resonant Orbits'; and 'Cross-Tail Current, Field-Aligned Current, and B(sub y)'.

  2. Magnetosphere of Mercury

    NASA Technical Reports Server (NTRS)

    Whang, Y. C.

    1975-01-01

    A model magnetosphere of Mercury using Mariner 10 data is presented. Diagrams of the bow shock wave and magnetopause are shown. The analysis of Mariner 10 data indicates that the magnetic field of the planet is intrinsic. The magnetic tail and secondary magnetic fields, and the influence of the solar wind are also discussed.

  3. Global Magnetospheric Evolution Effected by Sudden Ring Current Injection

    NASA Astrophysics Data System (ADS)

    Park, Geunseok; No, Jincheol; Kim, Kap-Sung; Choe, Gwangson; Lee, Junggi

    2016-04-01

    The dynamical evolution of the Earth's magnetosphere loaded with a transiently enhanced ring current is investigated by global magnetohydrodynamic simulations. Two cases with different values of the primitive ring current are considered. In one case, the initial ring current is strong enough to create a magnetic island in the magnetosphere. The magnetic island readily reconnects with the earth-connected ambient field and is destroyed as the system approaches a steady equilibrium. In the other case, the initial ring current is not so strong, and the initial magnetic field configuration bears no magnetic island, but features a wake of bent field lines, which is smoothed out through the relaxing evolution of the magnetosphere. The relaxation time of the magnetosphere is found to be about five to six minutes, over which the ring current is reduced to about a quarter of its initial value. Before reaching a quasi-steady state, the magnetosphere is found to undergo an overshooting expansion and a subsequent contraction. Fast and slow magnetosonic waves are identified to play an important role in the relaxation toward equilibrium. Our study suggests that a sudden injection of the ring current can generate an appreciable global pulsation of the magnetosphere.

  4. Expected Navigation Flight Performance for the Magnetospheric Multiscale (MMS) Mission

    NASA Technical Reports Server (NTRS)

    Olson, Corwin; Wright, Cinnamon; Long, Anne

    2012-01-01

    The Magnetospheric Multiscale (MMS) mission consists of four formation-flying spacecraft placed in highly eccentric elliptical orbits about the Earth. The primary scientific mission objective is to study magnetic reconnection within the Earth s magnetosphere. The baseline navigation concept is the independent estimation of each spacecraft state using GPS pseudorange measurements (referenced to an onboard Ultra Stable Oscillator) and accelerometer measurements during maneuvers. State estimation for the MMS spacecraft is performed onboard each vehicle using the Goddard Enhanced Onboard Navigation System, which is embedded in the Navigator GPS receiver. This paper describes the latest efforts to characterize expected navigation flight performance using upgraded simulation models derived from recent analyses.

  5. Global Particle-in-Cell Simulations of Mercury's Magnetosphere

    NASA Astrophysics Data System (ADS)

    Schriver, D.; Travnicek, P. M.; Lapenta, G.; Amaya, J.; Gonzalez, D.; Richard, R. L.; Berchem, J.; Hellinger, P.

    2017-12-01

    Spacecraft observations of Mercury's magnetosphere have shown that kinetic ion and electron particle effects play a major role in the transport, acceleration, and loss of plasma within the magnetospheric system. Kinetic processes include reconnection, the breakdown of particle adiabaticity and wave-particle interactions. Because of the vast range in spatial scales involved in magnetospheric dynamics, from local electron Debye length scales ( meters) to solar wind/planetary magnetic scale lengths (tens to hundreds of planetary radii), fully self-consistent kinetic simulations of a global planetary magnetosphere remain challenging. Most global simulations of Earth's and other planet's magnetosphere are carried out using MHD, enhanced MHD (e.g., Hall MHD), hybrid, or a combination of MHD and particle in cell (PIC) simulations. Here, 3D kinetic self-consistent hybrid (ion particle, electron fluid) and full PIC (ion and electron particle) simulations of the solar wind interaction with Mercury's magnetosphere are carried out. Using the implicit PIC and hybrid simulations, Mercury's relatively small, but highly kinetic magnetosphere will be examined to determine how the self-consistent inclusion of electrons affects magnetic reconnection, particle transport and acceleration of plasma at Mercury. Also the spatial and energy profiles of precipitating magnetospheric ions and electrons onto Mercury's surface, which can strongly affect the regolith in terms of space weathering and particle outflow, will be examined with the PIC and hybrid codes. MESSENGER spacecraft observations are used both to initiate and validate the global kinetic simulations to achieve a deeper understanding of the role kinetic physics play in magnetospheric dynamics.

  6. Dusty Plasmas in Planetary Magnetospheres Award

    NASA Technical Reports Server (NTRS)

    Horanyi, Mihaly

    2005-01-01

    This is my final report for the grant Dusty Plasmas in Planetary Magnetospheres. The funding from this grant supported our research on dusty plasmas to study: a) dust plasma interactions in general plasma environments, and b) dusty plasma processes in planetary magnetospheres (Earth, Jupiter and Saturn). We have developed a general purpose transport code in order to follow the spatial and temporal evolution of dust density distributions in magnetized plasma environments. The code allows the central body to be represented by a multipole expansion of its gravitational and magnetic fields. The density and the temperature of the possibly many-component plasma environment can be pre-defined as a function of coordinates and, if necessary, the time as well. The code simultaneously integrates the equations of motion with the equations describing the charging processes. The charging currents are dependent not only on the instantaneous plasma parameters but on the velocity, as well as on the previous charging history of the dust grains.

  7. The electromagnetic field for an open magnetosphere

    NASA Technical Reports Server (NTRS)

    Heikkila, W. J.

    1984-01-01

    The boundary-layer-dominated models of the earth EM field developed by Heikkila (1975, 1978, 1982, and 1983) and Heikkila et al. (1979) to account for deficiencies in the electric-field descriptions of quasi-steady-state magnetic-field-reconnection models (such as that of Cowley, 1980) are characterized, reviewing the arguments and indicating the most important implications. The mechanisms of boundary-layer formation and field direction reversal are explained and illustrated with diagrams, and it is inferred that boundary-layer phenomena rather than magnetic reconnection may be the cause of large-scale magnetospheric circulation, convection, plasma-sheet formation and sunward convection, and auroras, the boundary layer acting basically as a viscous process mediating solar-wind/magnetosphere interactions.

  8. Plasmas in Saturn's magnetosphere

    NASA Technical Reports Server (NTRS)

    Frank, L. A.; Burek, B. G.; Ackerson, K. L.; Wolfe, J. H.; Mihalov, J. D.

    1980-01-01

    The solar wind plasma analyzer on board Pioneer 2 provides first observations of low-energy positive ions in the magnetosphere of Saturn. Measurable intensities of ions within the energy-per-unit charge (E/Q) range 100 eV to 8 keV are present over the planetocentric radial distance range about 4 to 16 R sub S in the dayside magnetosphere. The plasmas are found to be rigidly corotating with the planet out to distances of at least 10 R sub S. At radial distances beyond 10 R sub S, the bulk flows appear to be in the corotation direction but with lesser speeds than those expected from rigid corotation. At radial distances beyond the orbit of Rhea at 8.8 R sub S, the dominant ions are most likely protons and the corresponding typical densities and temperatures are 0.5/cu cm and 1,000,000 K, respectively, with substantial fluctuations. It is concluded that the most likely source of these plasmas in the photodissociation of water frost on the surface of the ring material with subsequent ionization of the products and radially outward diffusion. The presence of this plasma torus is expected to have a large influence on the dynamics of Saturn's magnetosphere since the pressure ratio beta of these plasmas approaches unity at radial distances as close to the planet as 6.5 R sub S. On the basis of these observational evidences it is anticipated that quasi-periodic outward flows of plasma, accompanied with a reconfiguration of the magnetosphere beyond about 6.5 R sub S, will occur in the local night sector in order to relieve the plasma pressure from accretion of plasma from the rings.

  9. Circulation of Heavy Ions and Their Dynamical Effects in the Magnetosphere: Recent Observations and Models

    NASA Astrophysics Data System (ADS)

    Kronberg, Elena A.; Ashour-Abdalla, Maha; Dandouras, Iannis; Delcourt, Dominique C.; Grigorenko, Elena E.; Kistler, Lynn M.; Kuzichev, Ilya V.; Liao, Jing; Maggiolo, Romain; Malova, Helmi V.; Orlova, Ksenia G.; Peroomian, Vahe; Shklyar, David R.; Shprits, Yuri Y.; Welling, Daniel T.; Zelenyi, Lev M.

    2014-11-01

    Knowledge of the ion composition in the near-Earth's magnetosphere and plasma sheet is essential for the understanding of magnetospheric processes and instabilities. The presence of heavy ions of ionospheric origin in the magnetosphere, in particular oxygen (O+), influences the plasma sheet bulk properties, current sheet (CS) thickness and its structure. It affects reconnection rates and the formation of Kelvin-Helmholtz instabilities. This has profound consequences for the global magnetospheric dynamics, including geomagnetic storms and substorm-like events. The formation and demise of the ring current and the radiation belts are also dependent on the presence of heavy ions. In this review we cover recent advances in observations and models of the circulation of heavy ions in the magnetosphere, considering sources, transport, acceleration, bulk properties, and the influence on the magnetospheric dynamics. We identify important open questions and promising avenues for future research.

  10. REVIEWS OF TOPICAL PROBLEMS: Magnetospheres of planets with an intrinsic magnetic field

    NASA Astrophysics Data System (ADS)

    Belenkaya, Elena S.

    2009-08-01

    This review presents modern views on the physics of magnetospheres of Solar System planets having an intrinsic magnetic field, and on the structure of magnetospheric magnetic fields. Magnetic fields are generated in the interiors of Mercury, Earth, Jupiter, Saturn, Uranus, and Neptune via the dynamo mechanism. These fields are so strong that they serve as obstacles for the plasma stream of the solar wind. A magnetosphere surrounding a planet forms as the result of interaction between the solar wind and the planetary magnetic field. The dynamics of magnetospheres are primary enforced by solar wind variations. Each magnetosphere is unique. The review considers common and individual sources of magnetic fields and the properties of planetary magnetospheres.

  11. AXIOM: Advanced X-ray Imaging of the Magnetosphere

    NASA Technical Reports Server (NTRS)

    Branduardi-Raymont, G.; Sembay, S. F.; Eastwood, J. P.; Sibeck, D. G.; Abbey, A.; Brown, P.; Carter, J. A.; Carr, C. M.; Forsyth, C.; Kataria, D.; hide

    2012-01-01

    Planetary plasma and magnetic field environments can be studied in two complementary ways - by in situ measurements, or by remote sensing. While the former provide precise information about plasma behaviour, instabilities and dynamics on local scales, the latter offers the global view necessary to understand the overall interaction of the magnetospheric plasma with the solar wind. Some parts of the Earth's magnetosphere have been remotely sensed, but the majority remains unexplored by this type of measurements. Here we propose a novel and more elegant approach employing remote X-ray imaging techniques. which are now possible thanks to the relatively recent discovery of solar wind charge exchange X-ray emissions in the vicinity of the Earth's magnetosphere. In this article we describe how an appropriately designed and located. X-ray telescope, supported by simultaneous in situ measurements of the solar wind, can be used to image the dayside magnetosphere, magnetosheath and bow shock. with a temporal and spatial resolution sufficient to address several key outstanding questions concerning how the solar wind interacts with the Earth's magnetosphere on a global level. Global images of the dayside magnetospheric boundaries require vantage points well outside the magnetosphere. Our studies have led us to propose 'AXIOM: Advanced X-ray Imaging Of the Magnetosphere', a concept mission using a Vega launcher with a LISA Pathfinder-type Propulsion Module to place the spacecraft in a Lissajous orbit around the Earth - Moon Ll point. The model payload consists of an X-ray Wide Field Imager, capable of both imaging and spectroscopy, and an in situ plasma and magnetic field measurement package. This package comprises a Proton-Alpha Sensor, designed to measure the bulk properties of the solar wind, an Ion Composition Analyser, to characterize the minor ion populations in the solar wind that cause charge exchange emission, and a Magnetometer, designed to measure the strength and

  12. AXIOM: Advanced X-Ray Imaging of the Magnetosphere

    NASA Technical Reports Server (NTRS)

    Branduardi-Raymont, G.; Sembay, S. F.; Eastwood, J. P.; Sibeck, D. G.; Abbey, A.; Brown, P.; Carter, J. A.; Carr, C. M.; Forsyth, C.; Kataria, D.; hide

    2011-01-01

    Planetary plasma and magnetic field environments can be studied in two complementary ways by in situ measurements, or by remote sensing. While the former provide precise information about plasma behaviour, instabilities and dynamics on local scales, the latter offers the global view necessary to understand the overall interaction of the magnetospheric plasma with the solar wind. Some parts of the Earth's magnetosphere have been remotely sensed, but the majority remains unexplored by this type of measurements. Here we propose a novel and more elegant approach employing remote X-ray imaging techniques, which are now possible thanks to the relatively recent discovery of solar wind charge exchange X-ray emissions in the vicinity of the Earth's magnetosphere. In this article we describe how an appropriately designed and located X-ray telescope, supported by simultaneous in situ measurements of the solar wind, can be used to image the dayside magnetosphere, magnetosheath and bow shock, with a temporal and spatial resolution sufficient to address several key outstanding questions concerning how the solar wind interacts with the Earth's magnetosphere on a global level. Global images of the dayside magnetospheric boundaries require vantage points well outside the magnetosphere. Our studies have led us to propose AXIOM: Advanced X-ray Imaging Of the Magnetosphere, a concept mission using a Vega launcher with a LISA Pathfinder-type Propulsion Module to place the spacecraft in a Lissajous orbit around the Earth Moon L1 point. The model payload consists of an X-ray Wide Field Imager, capable of both imaging and spectroscopy, and an in situ plasma and magnetic field measurement package. This package comprises a Proton-Alpha Sensor, designed to measure the bulk properties of the solar wind, an Ion Composition Analyser, to characterize the minor ion populations in the solar wind that cause charge exchange emission, and a Magnetometer, designed to measure the strength and direction

  13. Saturn: atmosphere, ionosphere, and magnetosphere.

    PubMed

    Gombosi, Tamas I; Ingersoll, Andrew P

    2010-03-19

    The Cassini spacecraft has been in orbit around Saturn since 30 June 2004, yielding a wealth of data about the Saturn system. This review focuses on the atmosphere and magnetosphere and briefly outlines the state of our knowledge after the Cassini prime mission. The mission has addressed a host of fundamental questions: What processes control the physics, chemistry, and dynamics of the atmosphere? Where does the magnetospheric plasma come from? What are the physical processes coupling the ionosphere and magnetosphere? And, what are the rotation rates of Saturn's atmosphere and magnetosphere?

  14. Earth

    NASA Image and Video Library

    2012-01-30

    Behold one of the more detailed images of the Earth yet created. This Blue Marble Earth montage shown above -- created from photographs taken by the Visible/Infrared Imager Radiometer Suite (VIIRS) instrument on board the new Suomi NPP satellite -- shows many stunning details of our home planet. The Suomi NPP satellite was launched last October and renamed last week after Verner Suomi, commonly deemed the father of satellite meteorology. The composite was created from the data collected during four orbits of the robotic satellite taken earlier this month and digitally projected onto the globe. Many features of North America and the Western Hemisphere are particularly visible on a high resolution version of the image. http://photojournal.jpl.nasa.gov/catalog/PIA18033

  15. Mission Concept to Connect Magnetospheric Physical Processes to Ionospheric Phenomena

    NASA Astrophysics Data System (ADS)

    Dors, E. E.; MacDonald, E.; Kepko, L.; Borovsky, J.; Reeves, G. D.; Delzanno, G. L.; Thomsen, M. F.; Sanchez, E. R.; Henderson, M. G.; Nguyen, D. C.; Vaith, H.; Gilchrist, B. E.; Spanswick, E.; Marshall, R. A.; Donovan, E.; Neilson, J.; Carlsten, B. E.

    2017-12-01

    On the Earth's nightside the magnetic connections between the ionosphere and the dynamic magnetosphere have a great deal of uncertainty: this uncertainty prevents us from scientifically understanding what physical processes in the magnetosphere are driving the various phenomena in the ionosphere. Since the 1990s, the space plasma physics group at Los Alamos National Laboratory has been working on a concept to connect magnetospheric physical processes to auroral phenomena in the ionosphere by firing an electron beam from a magnetospheric spacecraft and optically imaging the beam spot in the ionosphere. The magnetospheric spacecraft will carry a steerable electron accelerator, a power-storage system, a plasma contactor, and instruments to measure magnetic and electric fields, plasma, and energetic particles. The spacecraft orbit will be coordinated with a ground-based network of cameras to (a) locate the electron beam spot in the upper atmosphere and (b) monitor the aurora. An overview of the mission concept will be presented, including recent enabling advancements based on (1) a new understanding of the dynamic spacecraft charging of the accelerator and plasma-contactor system in the tenuous magnetosphere based on ion emission rather than electron collection, (2) a new understanding of the propagation properties of pulsed MeV-class beams in the magnetosphere, and (3) the design of a compact high-power 1-MeV electron accelerator and power-storage system. This strategy to (a) determine the magnetosphere-to-ionosphere connections and (b) reduce accelerator- platform charging responds to one of the six emerging-technology needs called out in the most-recent National Academies Decadal Survey for Solar and Space Physics. [LA-UR-17-23614

  16. Investigating dynamical complexity in the magnetosphere using various entropy measures

    NASA Astrophysics Data System (ADS)

    Balasis, Georgios; Daglis, Ioannis A.; Papadimitriou, Constantinos; Kalimeri, Maria; Anastasiadis, Anastasios; Eftaxias, Konstantinos

    2009-09-01

    The complex system of the Earth's magnetosphere corresponds to an open spatially extended nonequilibrium (input-output) dynamical system. The nonextensive Tsallis entropy has been recently introduced as an appropriate information measure to investigate dynamical complexity in the magnetosphere. The method has been employed for analyzing Dst time series and gave promising results, detecting the complexity dissimilarity among different physiological and pathological magnetospheric states (i.e., prestorm activity and intense magnetic storms, respectively). This paper explores the applicability and effectiveness of a variety of computable entropy measures (e.g., block entropy, Kolmogorov entropy, T complexity, and approximate entropy) to the investigation of dynamical complexity in the magnetosphere. We show that as the magnetic storm approaches there is clear evidence of significant lower complexity in the magnetosphere. The observed higher degree of organization of the system agrees with that inferred previously, from an independent linear fractal spectral analysis based on wavelet transforms. This convergence between nonlinear and linear analyses provides a more reliable detection of the transition from the quiet time to the storm time magnetosphere, thus showing evidence that the occurrence of an intense magnetic storm is imminent. More precisely, we claim that our results suggest an important principle: significant complexity decrease and accession of persistency in Dst time series can be confirmed as the magnetic storm approaches, which can be used as diagnostic tools for the magnetospheric injury (global instability). Overall, approximate entropy and Tsallis entropy yield superior results for detecting dynamical complexity changes in the magnetosphere in comparison to the other entropy measures presented herein. Ultimately, the analysis tools developed in the course of this study for the treatment of Dst index can provide convenience for space weather

  17. MESSENGER Observations of Mercury's Dynamic Magnetosphere During Three Flybys

    NASA Astrophysics Data System (ADS)

    Slavin, James; Krimigis, Stamatios; Anderson, Brian J.; Benna, Mehdi; Gold, Robert E.; Ho, George; McNutt, Ralph; Raines, James; Schriver, David; Solomon, Sean C.

    MESSENGER's 14 January and 6 October 2008 and 29 September 2009 encounters with Mer-cury have provided new measurements of dynamic variations in the planet's coupled atmo-sphere-magnetosphere system. The three flybys took place under very different interplanetary magnetic field (IMF) conditions. Consistent with predictions of magnetospheric models for northward IMF, the neutral atmosphere was observed to have its strongest sources in the high latitude northern hemisphere for the first flyby. The southward IMF for the second encounter revealed a highly dynamic magnetosphere. Reconnection between the interplanetary and plan-etary magnetic fields is known to control the rate of energy transfer from the solar wind and to drive magnetospheric convection. The MESSENGER magnetic field measurements revealed that the rate at which interplanetary magnetic fields were reconnecting to the planetary fields was a factor of 10 greater than is usually observed at Earth. This extremely high reconnection rate results in a large magnetic field component normal to the magnetopause and the formation of flux transfer events that are much larger relative to the size of the forward magnetosphere than is observed at Earth. The resulting magnetospheric configuration allows the solar wind access to much of the dayside surface of Mercury. During MESSENGER's third Mercury flyby, a variable interplanetary magnetic field produced a series of several-minute-long enhancements of the tail magnetic field by factors of 2 to 3.5. The magnetic field flaring during these intervals indicates that they resulted from loading of the tail with magnetic flux transferred from the dayside magnetosphere. The unloading intervals were associated with plasmoids and traveling compression regions, signatures of tail reconnection. The peak tail magnetic flux during the smallest loading events equaled 30

  18. Structure and dynamics of Saturn's outer magnetosphere and boundary regions

    NASA Technical Reports Server (NTRS)

    Behannon, K. W.; Lepping, R. P.; Ness, N. F.

    1983-01-01

    In 1979-1981, the three USA spacecraft Pioneer 11 and Voyagers 1 and 2 discovered and explored the magnetosphere of Saturn to the limited extent possible on flyby trajectories. Considerable variation in the locations of the bow shock (BS) and magnetopause (MP) surfaces were observed in association with variable solar wind conditions and, during the Voyager 2 encounter, possible immersion in Jupiter's distant magnetic tail. The limited number of BS and MP crossings were concentrated near the subsolar region and the dawn terminator, and that fact, together with the temporal variability, makes it difficult to assess the three dimensional shape of the sunward magnetospheric boundary. The combined BS and MP crossing positions from the three spacecraft yield an average BS-to-MP stagnation point distance ratio of 1.29 +/- 0.10. This is near the 1.33 value for the Earth's magnetosphere, implying a similar sunward shape at Saturn. Study of the structure and dynamical behavior of the outer magnetosphere, both in the sunward hemisphere and the magnetotail region using combined plasma and magnetic field data, suggest that Saturn's magnetosphere is more similar to that of Earth than that of Jupiter.

  19. Magnetospheric State of Sawtooth Events

    NASA Technical Reports Server (NTRS)

    Fung, Shing F.; Tepper, Julia A.; Cai, Xia

    2016-01-01

    Magnetospheric sawtooth events, first identified in the early 1990s, are named for their characteristic appearance of multiple quasiperiodic intervals of slow decrease followed by sharp increase of proton differential energy fluxes in the geosynchronous region. The successive proton flux oscillations have been interpreted as recurrences of stretching and dipolarization of the nightside geomagnetic field. Due to their often extended intervals with 210 cycles, sawteeth occurrences are sometimes referred to as a magnetospheric mode. While studies of sawtooth events over the past two decades have yielded a wealth of information about such events, the magnetospheric state conditions for the occurrence of sawtooth events and how sawtooth oscillations may depend on the magnetospheric state conditions remain unclear. In this study, we investigate the characteristic magnetospheric state conditions (specified by Psw interplanetary magnetic field (IMF) Btot, IMF Bz Vsw, AE, Kp and Dst, all time shifted with respect to one another) associated with the intervals before, during, and after sawteeth occurrences. Applying a previously developed statistical technique, we have determined the most probable magnetospheric states propitious for the development and occurrence of sawtooth events, respectively. The statistically determined sawtooth magnetospheric state has also been validated by using out-of-sample events, confirming the notion that sawtooth intervals might represent a particular global state of the magnetosphere. We propose that the sawtooth state of the magnetosphere may be a state of marginal stability in which a slight enhancement in the loading rate of an otherwise continuous loading process can send the magnetosphere into the marginally unstable regime, causing it to shed limited amount of energy quickly and return to the marginally stable regime with the loading process continuing. Sawtooth oscillations result as the magnetosphere switches between the marginally

  20. Composite structures for magnetosphere imager spacecraft

    NASA Technical Reports Server (NTRS)

    Chu, Tsuchin

    1994-01-01

    Results of a trade study addressing the issues and benefits in using carbon fiber reinforced composites for the Magnetosphere Imager (MI) spacecraft are presented. The MI mission is now part of the Sun/Earth Connection Program. To qualify for this category, new technology and innovative methods to reduce the cost and size have to be considered. Topics addressed cover: (1) what is a composite, including advantages and disadvantages of composites and carbon/graphite fibers; and (2) structural design for MI, including composite design configuration, material selection, and analysis of composite structures.

  1. Communications Magnetospheric Substorms.

    DTIC Science & Technology

    1983-01-17

    Magnetospheric Study, edited by K . Knott and B . Battrick, D. Reidel Publ. Co., 345-364, 1976. 26. Bossen, M., R.L. McPherron, and C.T. Russell, A statistical...DUPG JIM AGNETIC SU]STORMS. THE FORMATICU-1 OF PARTIAL RING CURRENTS AND ITS RELATIONSHIP TD SDLAR WIND PARAIETERS AND THE RELATIONSHIP B -ETWEEN...noise amplified by the K -H instability which then couples to a resonance. Power spectra of Pc 3 pulsations at synchronous orbit often show multiple

  2. Plasma and magnetospheric research

    NASA Technical Reports Server (NTRS)

    Comfort, R. H.; Horwitz, J. L.

    1984-01-01

    Methods employed in the analysis of plasmas and the magnetosphere are examined. Computer programs which generate distribution functions are used in the analysis of charging phenomena and non maxwell plasmas in terms of density and average energy. An analytical model for spin curve analysis is presented. A program for the analysis of the differential ion flux probe on the space shuttle mission is complete. Satellite data analysis for ion heating, plasma flows in the polar cap, polar wind flow, and density and temperature profiles for several plasmasphere transits are included.

  3. A numerical code for a three-dimensional magnetospheric MHD equilibrium model

    NASA Technical Reports Server (NTRS)

    Voigt, G.-H.

    1992-01-01

    Two dimensional and three dimensional MHD equilibrium models were begun for Earth's magnetosphere. The original proposal was motivated by realizing that global, purely data based models of Earth's magnetosphere are inadequate for studying the underlying plasma physical principles according to which the magnetosphere evolves on the quasi-static convection time scale. Complex numerical grid generation schemes were established for a 3-D Poisson solver, and a robust Grad-Shafranov solver was coded for high beta MHD equilibria. Thus, the effects were calculated of both the magnetopause geometry and boundary conditions on the magnetotail current distribution.

  4. Magnetosphere of Mercury : Observations and Insights from MESSENGER

    NASA Astrophysics Data System (ADS)

    Krimigis, Stamatios

    The MESSENGER spacecraft executed three flyby encounters with Mercury in 2008 and 2009, was inserted into orbit about Mercury on 18 March 2011, and has returned a wealth of data on the magnetic field, plasma, and energetic particle environment of Mercury. These observations reveal a profoundly dynamic and active solar wind interaction. In addition to establishing the average structures of the bow shock, magnetopause, northern cusp, and tail plasma sheet, MESSENGER measurements document magnetopause boundary processes (reconnection and surface waves), global convection and dynamics (tail loading and unloading, magnetic flux transport, and Birkeland currents), surface precipitation of particles (protons and electrons), particle heating and acceleration, and wave generation processes (ions and electrons). Mercury’s solar wind interaction presents new challenges to our understanding of the physics of magnetospheres. The offset of the planetary moment relative to the geographic equator creates a larger hemispheric asymmetry relative to magnetospheric dimensions than at any other planet. The prevalence, magnitude, and repetition rates of flux transfer events at the magnetopause as well as plasmoids in the magnetotail indicate that, unlike at Earth, episodic convection may dominate over steady-state convection. The magnetopause reconnection rate is not only an order of magnitude greater than at Earth, but reconnection occurs over a much broader range of interplanetary magnetic field orientations than at Earth. Finally, the planetary body itself plays a significant role in Mercury’s magnetosphere. Birkeland currents close through the planet, induction at the planetary core-mantle boundary modifies the magnetospheric response to solar wind pressure excursions, the surface in darkness exhibits sporadic X-ray fluorescence consistent with precipitation of 10 to 100 keV electrons, magnetospheric plasmas precipitate directly onto the planetary surface and contribute to

  5. Statistical Mapping of Bursty Bulk Flows in the Magnetosphere Supported by the Virtual Magnetospheric Observatory

    NASA Astrophysics Data System (ADS)

    Merka, J.; Sibeck, D. G.; Narock, T. W.

    2011-12-01

    Fast transient plasma flows in the magnetosphere are usually associated with magnetic reconnection and/or rapid changes in the magnetospheric configuration. Using a common methodology to analyze data from the THEMIS satellites we map the statistical occurrence rate of bursty bulk flows (BBFs) in the magnetosphere. Such a task involves obtaining and processing of large amount of data (5 THEMIS satellites provide measurements since spring of 2007), then writing custom code and searching for intervals of interests. The existence of a Virtual Magnetospheric Observatory (VMO) offers, however, a less laborious alternative. We discuss how the VMO made our research faster and easier and also point out the inherent limitations of the VMO use. The VMO's goal is to help researches by creating a single point of uniform discovery, access, and use of magnetospheric data. Available data can be searched based on various criteria as, for example, spatial location, time of observation, measurement type, parameter values, etc. The results can then be saved, downloaded or displayed as, for example, spatial-temporal plots that quickly reveal where and how often was the searched-for phenomenon observed. Our analysis revealed that the BBFs were found more frequently with increasing distance from Earth and the peak occurrence rate of earthward BBFs was at Xgsm = 29 Re and Ygsm = -2 Re. The tailward BBFs were very rarely observed even between Xgsm = -20 and -30 Re but they occurred over a wide range of local times. The positions with highest BBF occurrence rates differ from previous reports that used IRM and ISEE2 data.

  6. Black Hole Magnetospheres

    NASA Astrophysics Data System (ADS)

    Nathanail, Antonios; Contopoulos, Ioannis

    2014-06-01

    We investigate the structure of the steady-state force-free magnetosphere around a Kerr black hole in various astrophysical settings. The solution Ψ(r, θ) depends on the distributions of the magnetic field line angular velocity ω(Ψ) and the poloidal electric current I(Ψ). These are obtained self-consistently as eigenfunctions that allow the solution to smoothly cross the two singular surfaces of the problem, the inner light surface inside the ergosphere, and the outer light surface, which is the generalization of the pulsar light cylinder. Magnetic field configurations that cross both singular surfaces (e.g., monopole, paraboloidal) are uniquely determined. Configurations that cross only one light surface (e.g., the artificial case of a rotating black hole embedded in a vertical magnetic field) are degenerate. We show that, similar to pulsars, black hole magnetospheres naturally develop an electric current sheet that potentially plays a very important role in the dissipation of black hole rotational energy and in the emission of high-energy radiation.

  7. Earth Science

    NASA Image and Video Library

    1991-01-01

    In July 1990, the Marshall Space Flight Center, in a joint project with the Department of Defense/Air Force Space Test Program, launched the Combined Release and Radiation Effects Satellite (CRRES) using an Atlas I launch vehicle. The mission was designed to study the effects of artificial ion clouds produced by chemical releases on the Earth's ionosphere and magnetosphere, and to monitor the effects of space radiation environment on sophisticated electronics.

  8. Global variations in Magnetosphere-Ionosphere system due to Sudden Impulses under different IMF By conditions

    NASA Astrophysics Data System (ADS)

    Ozturk, D. S.; Zou, S.; Slavin, J. A.; Ridley, A. J.

    2016-12-01

    A sudden impulse (SI) event is a rapid increase in solar wind dynamic pressure, which compresses the Earth's magnetosphere from the dayside and travels towards the Earth's tail. During the SI events, compression front reconfigures the Magnetosphere-Ionosphere (MI) current systems. This compression launches fast magnetosonic waves that carry the SI through magnetosphere and Alfven waves that enhance the field-aligned currents (FACs) at high-latitudes. FAC systems can be measured by Active Magnetosphere and Polar Electrodynamics Response Experiment (AMPERE). The propagation front also creates travelling convection vortices (TCVs) in the ionosphere that map to the equatorial flank regions of the Earth's magnetosphere. The TCVs then move from dayside to the nightside ionosphere. To understand these SI-driven disturbances globally, we use the University of Michigan Space Weather Modeling Framework (SWMF) with Global Magnetosphere (GM), Inner Magnetosphere (IM) and Ionosphere (IE) modules. We study the changes in the FAC systems, which link ionospheric and magnetospheric propagating disturbances under different IMF By conditions and trace the ionospheric disturbances to magnetospheric system to better understand the connection between two systems. As shown by previous studies, IMF By can cause asymmetries in the magnetic perturbations measured by the ground magnetometers. By using model results we determine the global latitudinal and longitudinal dependencies of the SI signatures on the ground. We also use the SWMF results to drive the Global Ionosphere Thermosphere Model (GITM) to reveal how the Ionosphere-Thermosphere system is affected by the SI propagation. Comparisons are carried out between the IE model output and high latitude convection patterns from Super Dual Auroral Radar Network (SuperDARN) measurements and SuperMAG ground magnetic field perturbations. In closing we have modeled the field-aligned currents, ionospheric convection patterns, temperature and

  9. A kinetic approach to magnetospheric modeling

    NASA Technical Reports Server (NTRS)

    Whipple, E. C., Jr.

    1979-01-01

    The earth's magnetosphere is caused by the interaction between the flowing solar wind and the earth's magnetic dipole, with the distorted magnetic field in the outer parts of the magnetosphere due to the current systems resulting from this interaction. It is surprising that even the conceptually simple problem of the collisionless interaction of a flowing plasma with a dipole magnetic field has not been solved. A kinetic approach is essential if one is to take into account the dispersion of particles with different energies and pitch angles and the fact that particles on different trajectories have different histories and may come from different sources. Solving the interaction problem involves finding the various types of possible trajectories, populating them with particles appropriately, and then treating the electric and magnetic fields self-consistently with the resulting particle densities and currents. This approach is illustrated by formulating a procedure for solving the collisionless interaction problem on open field lines in the case of a slowly flowing magnetized plasma interacting with a magnetic dipole.

  10. Corotating Magnetic Reconnection Site in Saturn’s Magnetosphere

    NASA Astrophysics Data System (ADS)

    Yao, Z. H.; Coates, A. J.; Ray, L. C.; Rae, I. J.; Grodent, D.; Jones, G. H.; Dougherty, M. K.; Owen, C. J.; Guo, R. L.; Dunn, W. R.; Radioti, A.; Pu, Z. Y.; Lewis, G. R.; Waite, J. H.; Gérard, J.-C.

    2017-09-01

    Using measurements from the Cassini spacecraft in Saturn’s magnetosphere, we propose a 3D physical picture of a corotating reconnection site, which can only be driven by an internally generated source. Our results demonstrate that the corotating magnetic reconnection can drive an expansion of the current sheet in Saturn’s magnetosphere and, consequently, can produce Fermi acceleration of electrons. This reconnection site lasted for longer than one of Saturn’s rotation period. The long-lasting and corotating natures of the magnetic reconnection site at Saturn suggest fundamentally different roles of magnetic reconnection in driving magnetospheric dynamics (e.g., the auroral precipitation) from the Earth. Our corotating reconnection picture could also potentially shed light on the fast rotating magnetized plasma environments in the solar system and beyond.

  11. The low energy plasma in the Uranian magnetosphere

    NASA Technical Reports Server (NTRS)

    Mcnutt, R. L., Jr.; Belcher, J.; Bridge, H.; Lazarus, A. J.; Richardson, J.; Sands, M.; Bagenal, F.; Eviatar, A.; Goertz, C.; Ogilvie, K.

    1987-01-01

    The Plasma Science experiment on Voyager 2 detected a magnetosphere filled with a tenuous plasma, rotating with the planet. Temperatures of the plasma, composed of protons and electrons, ranged from 10 eV to about 1 keV. The sources of these protons and electrons are probably the ionosphere of Uranus or the extended neutral hydrogen cloud surrounding the planet. As at earth, Jupiter, and Saturn, there is an extended magnetotail with a central plasma sheet. Although similar in global structure to the magnetospheres of these planets, the large angle between the rotation and magnetic axes of the planet and the orientation of the rotation axis with respect to the solar wind flow make the Uranian magnetosphere unique.

  12. Improving magnetosphere in situ observations using solar sails

    NASA Astrophysics Data System (ADS)

    Parsay, Khashayar; Schaub, Hanspeter; Schiff, Conrad; Williams, Trevor

    2018-01-01

    Past and current magnetosphere missions employ conventional spacecraft formations for in situ observations of the geomagnetic tail. Conventional spacecraft flying in inertially fixed Keplerian orbits are only aligned with the geomagnetic tail once per year, since the geomagnetic tail is always aligned with the Earth-Sun line, and therefore, rotates annually. Solar sails are able to artificially create sun-synchronous orbits such that the orbit apse line remains aligned with the geomagnetic tail line throughout the entire year. This continuous presence in the geomagnetic tail can significantly increase the science phase for magnetosphere missions. In this paper, the problem of solar sail formation design is explored using nonlinear programming to design optimal two-craft, triangle, and tetrahedron solar sail formations, in terms of formation quality and formation stability. The designed formations are directly compared to the formations used in NASA's Magnetospheric Multi-Scale mission.

  13. Precipitation of energetic magnetospheric electrons and accompanying solar wind characteristics

    NASA Astrophysics Data System (ADS)

    Bazilevskaya, G. A.; Kalinin, M. S.; Kvashnin, A. N.; Krainev, M. B.; Makhmutov, V. S.; Svirzhevskaya, A. K.; Svirzhevsky, N. S.; Stozhkov, Yu. I.; Balabin, Yu. V.; Gvozdevsky, B. B.

    2017-03-01

    From 1957 up to the present time, the Lebedev Physical Institute (LPI) has performed regular monitoring of ionizing radiation in the Earth's atmosphere. There are cases when the X-ray radiation generated by energetic magnetospheric electrons penetrates the atmosphere and is observed at polar latitudes. The vast majority of these events occurs against the background of high-velocity solar wind streams, while magnetospheric perturbations related to interplanetary coronal mass ejections (ICMEs) are noneffective for precipitation. It is shown in the paper that ICMEs do not cause acceleration of a sufficient amount of electrons in the magnetosphere. Favorable conditions for acceleration and subsequent scattering of electrons into the loss cone are created by magnetic storms with an extended recovery phase and with sufficiently frequent periods of negative Bz component of the interplanetary magnetic field (IMF). Such geomagnetic perturbations are typical for storms associated with high-velocity solar wind streams.

  14. The Extended Pulsar Magnetosphere

    NASA Technical Reports Server (NTRS)

    Constantinos, Kalapotharakos; Demosthenes, Kazanas; Ioannis, Contopoulos

    2012-01-01

    We present the structure of the 3D ideal MHD pulsar magnetosphere to a radius ten times that of the light cylinder, a distance about an order of magnitude larger than any previous such numerical treatment. Its overall structure exhibits a stable, smooth, well-defined undulating current sheet which approaches the kinematic split monopole solution of Bogovalov 1999 only after a careful introduction of diffusivity even in the highest resolution simulations. It also exhibits an intriguing spiral region at the crossing of two zero charge surfaces on the current sheet, which shows a destabilizing behavior more prominent in higher resolution simulations. We discuss the possibility that this region is physically (and not numerically) unstable. Finally, we present the spiral pulsar antenna radiation pattern.

  15. Globally Imaging the Magnetosphere

    NASA Astrophysics Data System (ADS)

    Sibeck, D. G.

    2017-12-01

    Over the past two decades, a host of missions have provided the multipoint in situ measurementsneeded to understand the meso- and micro-scale physics governing the solar wind-magnetosphereinteraction. Observations by the ISTP missions, Cluster, THEMIS, Double Star, and most recentlyMMS, have enabled us to identify the occurrence of some of the many proposed models for magneticreconnection and particle acceleration in a wide range of accessible magnetospheric contexts. However, todetermine which of these processes are most important to the overall interaction, we need globalobservations, from both ground-based instrumentation and imaging spacecraft. This talk outlinessome of the the global puzzles that remain to be solved and some of the very novel means that are availableto address them, including soft X-ray, energetic neutral atom, far and extreme ultraviolet imaging andenhanced arrays of ground observatories.

  16. The Magnetospheric Multiscale Constellation

    NASA Technical Reports Server (NTRS)

    Tooley, C. R.; Black, R. K.; Robertson, B. P.; Stone, J. M.; Pope, S. E.; Davis, G. T.

    2015-01-01

    The Magnetospheric Multiscale (MMS) mission is the fourth mission of the Solar Terrestrial Probe (STP) program of the National Aeronautics and Space Administration (NASA). The MMS mission was launched on March 12, 2015. The MMS mission consists of four identically instrumented spin-stabilized observatories which are flown in formation to perform the first definitive study of magnetic reconnection in space. The MMS mission was presented with numerous technical challenges, including the simultaneous construction and launch of four identical large spacecraft with 100 instruments total, stringent electromagnetic cleanliness requirements, closed-loop precision maneuvering and pointing of spinning flexible spacecraft, on-board GPS based orbit determination far above the GPS constellation, and a flight dynamics design that enables formation flying with separation distances as small as 10 km. This paper describes the overall mission design and presents an overview of the design, testing, and early on-orbit operation of the spacecraft systems and instrument suite.

  17. Argon ion pollution of the magnetosphere

    NASA Technical Reports Server (NTRS)

    Lopez, R. E.

    1985-01-01

    Construction of a Solar Power Satellite (SPS) would require the injection of large quantities of propellant to transport material from Low Earth Orbit (LEO) to the construction site at Geostationary Earth Orbit (GEO). This injection, in the form of approx 10 to the 32nd power, 2 KeV argon ions (and associated electrons) per SPS, is comparable to the content of the plasmasphere (approx 10 to the 31st power ions). In addition to the mass deposited, this represents a considerable injection of energy. The injection is examined in terms of a simple model for the expansion of the beam plasma. General features of the subsequent magnetospheric convection of the argon are also examined.

  18. Transmission of the convection electric field to the inner magnetosphere

    NASA Astrophysics Data System (ADS)

    Kikuchi, T.

    2003-12-01

    Low latitude magnetometer observations revealed that the partial ring current started to develop within several minutes after the onset of growth of the polar cap potential (PCP), and decayed simultaneously with the decrease in the PCP (Hashimoto, Kikuchi and Ebihara., JGR 2002). The magnetometer observations also indicated that the DP2 ionospheric currents were driven by the convection electric field at mid latitudes as well as at high latitudes. These observational facts suggest that the ionospheric electric field plays a crucial role in driving the convection in the inner magnetosphere. A probable model for the electric field transmission should explain both the convection in the inner magnetosphere and the ionospheric currents at mid latitudes. The instantaneous transmission of the ionospheric electric field and currents from the polar ionosphere to the equator was explained by Kikuchi and Araki (JATP 1979) based on the TM0 mode in the Earth-ionosphere waveguide. In this paper, we attempt to explain the transmission of the convection electric field to the inner magnetosphere by applying the Earth-ionosphere waveguide. However, two issues remained unresolved in the paper by Kikuchi and Araki (1979). One is the excitation of the TM0 mode in the Earth-ionosphere waveguide, and the other is the attenuation under the nighttime ionospheric condition. To examine the excitation of the TM0 mode, we couple the Earth-ionosphere waveguide (transmission line) with a magnetospheric transmission line composed of a pair of field-aligned currents (e.g., R1 FACs). A fraction of the electromagnetic energy carried from the magnetosphere is transmitted into the Earth-ionosphere waveguide, although substantial energy is dissipated in the polar ionosphere intervening between the two transmission lines. The transmitted electromagnetic energy excites the TM0 mode in the Earth-ionosphere waveguide. We then evaluate the attenuation of the TM0 mode by calculating upward flow of energy

  19. Electron pitch angle distributions throughout the magnetosphere as observed on Ogo 5.

    NASA Technical Reports Server (NTRS)

    West, H. I., Jr.; Buck, R. M.; Walton, J. R.

    1973-01-01

    A survey of the equatorial pitch angle distributions of energetic electrons is provided for all local times out to radial distances of 20 earth radii on the night side of the earth and to the magnetopause on the day side of the earth. In much of the inner magnetosphere and in the outer magnetosphere on the day side of the earth, the normal loss cone distribution prevails. The effects of drift shell splitting - i.e., the appearance of pitch angle distributions with minimums at 90 deg, called butterfly distributions - become apparent in the early afternoon magnetosphere at extended distances, and the distribution is observed in to 5.5 earth radii in the nighttime magnetosphere. Inside about 9 earth radii the pitch angle effects are quite energy-dependent. Beyond about 9 earth radii in the premidnight magnetosphere during quiet times the butterfly distribution is often observed. It is shown that these electrons cannot survive a drift to dawn without being considerably modified. The role of substorm activity in modifying these distributions is identified.

  20. MESSENGER Observations of Reconnection and Its Effects on Mercury's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Slavin, James A.; Anderson, Brian J.; Baker, Daniel N.; Benna, Mehdi; Boardsen, Scott A.; Gloeckler, George; Gold, Robert E.; Ho, George C.; Imber, Suzanne M.; Korth, Haje; hide

    2010-01-01

    During MESSENGER's second and third flybys of Mercury on October 6, 2008 and September 29, 2009, respectively, southward interplanetary magnetic fields produced very intense reconnection signatures in the dayside and nightside magnetosphere and very different systemlevel responses. The IMF during the second flyby was continuously southward and the magnetosphere appeared very active with very large magnetic fields normal to the magnetopause and the generation of flux transfer events at the magnetopause and plasmoids in the tail current sheet every 30 s to 90 s. However, the strength and direction of the tail magnetic field was very stable. In contrast the third flyby experienced a variable IMF with it varying from north to south on timescales of minutes. Although the MESSENGER measurements were limited this time to the nightside magnetosphere, numerous examples of plasmoid release in the tail were detected, but they were not periodic. Rather, plasmoid release was highly correlated with the four large enhancements of the tail magnetic field (i.e. by factors > 2) with durations of approx. 2 - 3 min. The increased flaring of the magnetic field during these intervals indicates that the enhancements were caused by loading of the tail with magnetic flux transferred from the dayside magnetosphere. New analyses of the second and third flyby observations of reconnection and its system-level effects will be presented. The results will be examined in light of what is known about the response of the Earth's magnetosphere to variable versus steady southward IMF.

  1. Generation of region 1 current by magnetospheric pressure gradients

    NASA Technical Reports Server (NTRS)

    Yang, Y. S.; Spiro, R. W.; Wolf, R. A.

    1994-01-01

    The Rice Convection Model (RCM) is used to illustrate theoretical possibilities for generating region 1 Birkeland currents by pressure gradients on closed field lines in the Earth's magnetosphere. Inertial effects and viscous forces are neglected. The RCM is applied to idealized cases, to emphasize the basic physical ideas rather than realistic representation of the actual magnetosphere. Ionospheric conductance is taken to be uniform, and the simplest possible representations of the magnetospheric plasma are used. Three basic cases are considered: (1) the case of pure northward Interplanetary Magnetic Field (IMF), with cusp merging assumed to create new closed field lines near the nose of the magnetosphere, following the suggestion by Song and Russell (1992); (2) the case where Dungey-type reconnection occurs at the nose, but magnetosheath plasma somehow enters closed field lines on the dawnside and duskside of the merging region, causing a pressure-driven low-latitude boundary layer; and (3) the case where Dungey-type reconnection occurs at the nose, but region 1 currents flow on sunward drifting plasma sheet field lines. In case 1, currents of region 1 sense are generated by pressure gradients, but those currents do not supply the power for ionospheric convection. Results for case 2 suggest that pressure gradients at the inner edge of the low-latitude boundary layer might generate a large fraction of the region 1 Birkeland currents that drive magnetospheric convection. Results for case 3 indicate that pressure gradients in the plasma sheet could provide part of the region 1 current.

  2. Physics of magnetospheric boundary layers

    NASA Technical Reports Server (NTRS)

    Cairns, Iver H.

    1995-01-01

    This final report was concerned with the ideas that: (1) magnetospheric boundary layers link disparate regions of the magnetosphere-solar wind system together; and (2) global behavior of the magnetosphere can be understood only by understanding its internal linking mechanisms and those with the solar wind. The research project involved simultaneous research on the global-, meso-, and micro-scale physics of the magnetosphere and its boundary layers, which included the bow shock, the magnetosheath, the plasma sheet boundary layer, and the ionosphere. Analytic, numerical, and simulation projects were performed on these subjects, as well as comparisons of theoretical results with observational data. Other related activity included in the research included: (1) prediction of geomagnetic activity; (2) global MHD (magnetohydrodynamic) simulations; (3) Alfven resonance heating; and (4) Critical Ionization Velocity (CIV) effect. In the appendixes are list of personnel involved, list of papers published; and reprints or photocopies of papers produced for this report.

  3. The Magnetospheric Multiscale Mission

    NASA Astrophysics Data System (ADS)

    Burch, James

    Magnetospheric Multiscale (MMS), a NASA four-spacecraft mission scheduled for launch in November 2014, will investigate magnetic reconnection in the boundary regions of the Earth’s magnetosphere, particularly along its dayside boundary with the solar wind and the neutral sheet in the magnetic tail. Among the important questions about reconnection that will be addressed are the following: Under what conditions can magnetic-field energy be converted to plasma energy by the annihilation of magnetic field through reconnection? How does reconnection vary with time, and what factors influence its temporal behavior? What microscale processes are responsible for reconnection? What determines the rate of reconnection? In order to accomplish its goals the MMS spacecraft must probe both those regions in which the magnetic fields are very nearly antiparallel and regions where a significant guide field exists. From previous missions we know the approximate speeds with which reconnection layers move through space to be from tens to hundreds of km/s. For electron skin depths of 5 to 10 km, the full 3D electron population (10 eV to above 20 keV) has to be sampled at rates greater than 10/s. The MMS Fast-Plasma Instrument (FPI) will sample electrons at greater than 30/s. Because the ion skin depth is larger, FPI will make full ion measurements at rates of greater than 6/s. 3D E-field measurements will be made by MMS once every ms. MMS will use an Active Spacecraft Potential Control device (ASPOC), which emits indium ions to neutralize the photoelectron current and keep the spacecraft from charging to more than +4 V. Because ion dynamics in Hall reconnection depend sensitively on ion mass, MMS includes a new-generation Hot Plasma Composition Analyzer (HPCA) that corrects problems with high proton fluxes that have prevented accurate ion-composition measurements near the dayside magnetospheric boundary. Finally, Energetic Particle Detector (EPD) measurements of electrons and

  4. Physics of the Jovian Magnetosphere

    NASA Astrophysics Data System (ADS)

    Dessler, A. J.

    2002-08-01

    List of tables; Foreword James A. Van Allen; Preface; 1. Jupiter's magnetic field and magnetosphere Mario H. Acuña, Kenneth W. Behannon and J. E. P. Connerney; 2. Ionosphere Darrell F. Strobel and Sushil K. Atreya; 3. The low-energy plasma in the Jovian magnetosphere J. W. Belcher; 4. Low-energy particle population S. M. Krimigis and E. C. Roelof; 5. High-energy particles A. W. Schardt and C. K. Goertz; 6. Spectrophotometric studies of the Io torus Robert A. Brown, Carl B. Pilcher and Darrell F. Strobel; 7. Phenomenology of magnetospheric radio emissions T. D. Carr, M. D. Desch and J. K. Alexander; 8. Plasma waves in the Jovian magnetosphere D. A. Gurnett and F. L. Scarf; 9. Theories of radio emissions and plasma waves Melvyn L. Goldstein and C. K. Goertz; 10. Magnetospheric models T. W. Hill, A. J. Dessler and C. K. Goertz; 11. Plasma distribution and flow Vytenis M. Vasyliunas; 12. Microscopic plasma processes in the Jovian magnetosphere Richard Mansergh Thorne; Appendixes; References; Index.

  5. The Magnetospheric Multiscale Magnetometers

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Anderson, B. J.; Baumjohann, W.; Bromund, K. R.; Dearborn, D.; Fischer, D.; Le, G.; Leinweber, H. K.; Leneman, D.; Magnes, W.; hide

    2014-01-01

    The success of the Magnetospheric Multiscale mission depends on the accurate measurement of the magnetic field on all four spacecraft. To ensure this success, two independently designed and built fluxgate magnetometers were developed, avoiding single-point failures. The magnetometers were dubbed the digital fluxgate (DFG), which uses an ASIC implementation and was supplied by the Space Research Institute of the Austrian Academy of Sciences and the analogue magnetometer (AFG) with a more traditional circuit board design supplied by the University of California, Los Angeles. A stringent magnetic cleanliness program was executed under the supervision of the Johns Hopkins University,s Applied Physics Laboratory. To achieve mission objectives, the calibration determined on the ground will be refined in space to ensure all eight magnetometers are precisely inter-calibrated. Near real-time data plays a key role in the transmission of high-resolution observations stored onboard so rapid processing of the low-resolution data is required. This article describes these instruments, the magnetic cleanliness program, and the instrument pre-launch calibrations, the planned in-flight calibration program, and the information flow that provides the data on the rapid time scale needed for mission success.

  6. Ionospheric and magnetospheric plasmapauses'

    NASA Technical Reports Server (NTRS)

    Grebowsky, J. M.; Hoffman, J. H.; Maynard, N. C.

    1977-01-01

    During August 1972, Explorer 45 orbiting near the equatorial plane with an apogee of about 5.2 R sub e traversed magnetic field lines in close proximity to those simultaneously traversed by the topside ionospheric satellite ISIS 2 near dusk in the L range 2-5.4. The locations of the Explorer 45 plasmapause crossings during this month were compared to the latitudinal decreases of the H(+) density observed on ISIS 2 near the same magnetic field lines. The equatorially determined plasmapause field lines typically passed through or poleward of the minimum of the ionospheric light ion trough, with coincident satellite passes occurring for which the L separation between the plasmapause and trough field lines was between 1 and 2. Vertical flows of the H(+) ions in the light ion trough as detected by the magnetic ion mass spectrometer on ISIS were directed upward with velocities between 1 and 2 kilometers/sec near dusk on these passes. These velocities decreased to lower values on the low latitude side of the H(+) trough but did not show any noticeable change across the field lines corresponding to the magnetospheric plasmapause.

  7. Magnetospheric space plasma investigations

    NASA Technical Reports Server (NTRS)

    Comfort, Richard H.; Horwitz, James L.

    1995-01-01

    Topics and investigations covering this period of this semiannual report period (August 1994 - January 1995) are as follows: (1) Generalized SemiKinetic (GSK) modeling of the synergistic interaction of transverse heating of ionospheric ions and magnetospheric plasma-driven electric potentials on the auroral plasma transport. Also, presentations of GSK modeling of auroral electron precipitation effects on ionospheric plasma outflows, of ExB effects on such outflow, and on warm plasma thermalization and other effects during refilling with pre-existing warm plasmas; (2) Referees' reports received on the statistical study of the latitudinal distributions of core plasmas along the L = 4.6 field line using DE-1/RIMS data. Other work is concerned in the same field, field-aligned flows and trapped ion distributions; and (3) A short study has been carried out on heating processes in low density flux tubes in the outer plasmasphere. The purpose was to determine whether the high ion temperatures observed in these flux tubes were due to heat sources operating through the thermal electrons or directly to the ions. Other investigations center along the same area of plasmasphere-ionosphere coupling. The empirical techniques and model, the listing of hardware calibrated, and/or tested, and a description of notable meetings attended is included in this report, along with a list of all present publication in submission or accepted and those reference papers that have resulted from this work thus far.

  8. Convection in Neptune's magnetosphere

    NASA Technical Reports Server (NTRS)

    Hill, T. W.; Dessler, A. J.

    1990-01-01

    It is assumed that nonthermal escape from Triton's atmosphere produces a co-orbiting torus of unionized gas (presumably nitrogen and hydrogen) that subsequently becomes ionized by electron impact to populate a partial Triton plasma torus analogous to the Io plasma torus in Jupiter's magnetosphere. Centrifugal and magnetic-mirror forces confine the ions to a plasma sheet located between the magnetic and centrifugal equators. The ionization rate, and hence the torus ion concentration, is strongly peaked at the two points (approximately 180 deg apart in longitude) at which Triton's orbit intersects the plasma equator. During the course of Neptune's rotation these intersection points trace out two arcs roughly 75 deg in longitudinal extent, which we take to be the configuration of the resulting (partial) plasma torus. The implied partial ring currents produce a quadrupolar (four-cell) convection system that provides rapid outward transport of plasma from the arcs. Ring-current shielding, however, prevents this convection system from penetrating very far inside the plasma-arc distance. It is suggested that this convection/shielding process accounts for the radial confinement of trapped particles (150 keV or greater) within L = 14.3 as observed by the Voyager LECP instrument.

  9. Earth Science

    NASA Image and Video Library

    1992-07-18

    Workers at Launch Complex 17 Pad A, Kennedy Space Center (KSC) encapsulate the Geomagnetic Tail (GEOTAIL) spacecraft (upper) and attached payload Assist Module-D upper stage (lower) in the protective payload fairing. GEOTAIL project was designed to study the effects of Earth's magnetic field. The solar wind draws the Earth's magnetic field into a long tail on the night side of the Earth and stores energy in the stretched field lines of the magnetotail. During active periods, the tail couples with the near-Earth magnetosphere, sometimes releasing energy stored in the tail and activating auroras in the polar ionosphere. GEOTAIL measures the flow of energy and its transformation in the magnetotail and will help clarify the mechanisms that control the imput, transport, storage, release, and conversion of mass, momentum, and energy in the magnetotail.

  10. Solar Flares and Magnetospheric Particles: Investigations Based upon the ONR-602 and ONR-604 Experiments

    DTIC Science & Technology

    1990-02-14

    gamma rays, the interplanetary propagation of the particles to Earth, the access of these particles to the magnetosphere and the changes initiatcd in...geomagnetic disturbances on the availability and quality of !ong range, short wave radio communication is perhaps the best known of the solar effects. With...1987. (14) "Low Energy Protons at the Equator," presented by M. A. Miah at the Chapman Conference on Plasma Waves and Instabilities in Magnetospheres

  11. Magnetospheric MultiScale (MMS) System Manager

    NASA Technical Reports Server (NTRS)

    Schiff, Conrad; Maher, Francis Alfred; Henely, Sean Philip; Rand, David

    2014-01-01

    The Magnetospheric MultiScale (MMS) mission is an ambitious NASA space science mission in which 4 spacecraft are flown in tight formation about a highly elliptical orbit. Each spacecraft has multiple instruments that measure particle and field compositions in the Earths magnetosphere. By controlling the members relative motion, MMS can distinguish temporal and spatial fluctuations in a way that a single spacecraft cannot.To achieve this control, 2 sets of four maneuvers, distributed evenly across the spacecraft must be performed approximately every 14 days. Performing a single maneuver on an individual spacecraft is usually labor intensive and the complexity becomes clearly increases with four. As a result, the MMS flight dynamics team turned to the System Manager to put the routine or error-prone under machine control freeing the analysts for activities that require human judgment.The System Manager is an expert system that is capable of handling operations activities associated with performing MMS maneuvers. As an expert system, it can work off a known schedule, launching jobs based on a one-time occurrence or on a set reoccurring schedule. It is also able to detect situational changes and use event-driven programming to change schedules, adapt activities, or call for help.

  12. The Comprehensive Inner Magnetosphere-Ionosphere Model

    NASA Technical Reports Server (NTRS)

    Fok, M.-C.; Buzulukova, N. Y.; Chen, S.-H.; Glocer, A.; Nagai, T.; Valek, P.; Perez, J. D.

    2014-01-01

    Simulation studies of the Earth's radiation belts and ring current are very useful in understanding the acceleration, transport, and loss of energetic particles. Recently, the Comprehensive Ring Current Model (CRCM) and the Radiation Belt Environment (RBE) model were merged to form a Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model. CIMI solves for many essential quantities in the inner magnetosphere, including ion and electron distributions in the ring current and radiation belts, plasmaspheric density, Region 2 currents, convection potential, and precipitation in the ionosphere. It incorporates whistler mode chorus and hiss wave diffusion of energetic electrons in energy, pitch angle, and cross terms. CIMI thus represents a comprehensive model that considers the effects of the ring current and plasmasphere on the radiation belts. We have performed a CIMI simulation for the storm on 5-9 April 2010 and then compared our results with data from the Two Wide-angle Imaging Neutral-atom Spectrometers and Akebono satellites. We identify the dominant energization and loss processes for the ring current and radiation belts. We find that the interactions with the whistler mode chorus waves are the main cause of the flux increase of MeV electrons during the recovery phase of this particular storm. When a self-consistent electric field from the CRCM is used, the enhancement of MeV electrons is higher than when an empirical convection model is applied. We also demonstrate how CIMI can be a powerful tool for analyzing and interpreting data from the new Van Allen Probes mission.

  13. MESSENGER observations of magnetic reconnection in Mercury's magnetosphere.

    PubMed

    Slavin, James A; Acuña, Mario H; Anderson, Brian J; Baker, Daniel N; Benna, Mehdi; Boardsen, Scott A; Gloeckler, George; Gold, Robert E; Ho, George C; Korth, Haje; Krimigis, Stamatios M; McNutt, Ralph L; Raines, Jim M; Sarantos, Menelaos; Schriver, David; Solomon, Sean C; Trávnícek, Pavel; Zurbuchen, Thomas H

    2009-05-01

    Solar wind energy transfer to planetary magnetospheres and ionospheres is controlled by magnetic reconnection, a process that determines the degree of connectivity between the interplanetary magnetic field (IMF) and a planet's magnetic field. During MESSENGER's second flyby of Mercury, a steady southward IMF was observed and the magnetopause was threaded by a strong magnetic field, indicating a reconnection rate ~10 times that typical at Earth. Moreover, a large flux transfer event was observed in the magnetosheath, and a plasmoid and multiple traveling compression regions were observed in Mercury's magnetotail, all products of reconnection. These observations indicate that Mercury's magnetosphere is much more responsive to IMF direction and dominated by the effects of reconnection than that of Earth or the other magnetized planets.

  14. Magnetic energy storage and the nightside magnetosphere-ionosphere coupling

    SciTech Connect

    Horton, W.; Pekker, M.; Doxas, I.

    1998-05-01

    The change m in the magnetic energy stored m in the Earth`s magnetotail as a function of the solar wind, BIF conditions are investigated using an empirical magnetic field model. The results are used to calculate the two normal modes contained m in the low-dimensional global model called WINDMI for the solar wind driven magnetosphere-ionosphere system. The coupling of the magnetosphere-ionosphere (MI) through the nightside region 1 current loop transfers power to the ionosphere through two modes: a fast (period of minutes) oscillation and a slow (period of one hour) geotail cavity mode. The solar wind drives both modes mmore » in the substorm dynamics.« less

  15. A UBK-space Visualization Tool for the Magnetosphere

    NASA Astrophysics Data System (ADS)

    Mohan, M.; Sheldon, R. B.

    2001-12-01

    One of the stumbling blocks to understanding particle transport in the magnetosphere has been the difficulty to follow, track and model the motion of ions through the realistic magnetic and electric fields of the Earth. Under the weak assumption that the first two invariants remain conserved, Whipple [1978] found a coordinate transformation that makes all charged particles travel on straight lines in UBK-space. The transform permits the quantitative calculation of conservative phase space transport for all particles with energies less than ~100 MeV, especially ring current energies (Sheldon and Gaffey [1993]). Furthermore Sheldon and Eastman [1997] showed how this transform extended the validity of diffusion models to realistic magnetospheres over the entire energy range. However, widespread usage of this transform has been limited by its non-intuitive UBK coordinates. We present a Virtual Reality Meta Language (VRML) interface to the calculation of UBK transform demonstrating its usefulness in describing both static features of the magnetosphere, such as the plasmapause, and dynamic features, such as ring current injection and loss. The core software is written in C for speed, whereas the interface is constructed in Perl and Javascript. The code is freely available, and intended for portability and modularity. R.B. Sheldon and T. Eastman ``Particle Transport in the Magnetosphere: A New Diffusion Model", GRL, 24(7), 811-814, 1997. Whipple, Jr, E. C. ``(U,B,K) coordinates: A natural system for studying magnetospheric convection". JGR, 83, 4318-4326, 1978. Sheldon, R. B. and J. D. Gaffey, Jr. ``Particle tracing in the magnetosphere: New algorithms and results." GRL, 20, 767-770, 1993.

  16. Solar wind controls on Mercury's magnetospheric cusp

    NASA Astrophysics Data System (ADS)

    He, Maosheng; Vogt, Joachim; Heyner, Daniel; Zhong, Jun

    2017-06-01

    This study assesses the response of the cusp to solar wind changes comprehensively, using 2848 orbits of MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) observation. The assessment entails four steps: (1) propose and validate an approach to estimate the solar wind magnetic field (interplanetary magnetic field (IMF)) for MESSENGER's cusp transit; (2) define an index σ measuring the intensity of the magnetic disturbance which significantly peaks within the cusp and serves as an indicator of the cusp activity level; (3) construct an empirical model of σ as a function of IMF and Mercury's heliocentric distance rsun, through linear regression; and (4) use the model to estimate and compare the polar distribution of the disturbance σ under different conditions for a systematic comparison. The comparison illustrates that the disturbance peak over the cusp is strongest and widest extending in local time for negative IMF Bx and negative IMF Bz, and when Mercury is around the perihelion. Azimuthal shifts are associated with both IMF By and rsun: the cusp moves toward dawn when IMF By or rsun decrease. These dependences are explained in terms of the IMF Bx-controlled dayside magnetospheric topology, the component reconnection model applied to IMF By and Bz, and the variability of solar wind ram pressure associated with heliocentric distance rsun. The applicability of the component reconnection model on IMF By indicates that at Mercury reconnection occurs at lower shear angles than at Earth.Plain Language SummaryMercury's <span class="hlt">magnetosphere</span> was suggested to be particularly sensitive to solar wind conditions. This study investigates the response of the <span class="hlt">magnetospheric</span> cusp to solar wind conditions systematically. For this purpose, we analyze the statistical predictability of interplanetary magnetic field (IMF) at Mercury, develop an approach for estimating the solar wind magnetic field (IMF) for MErcury Surface</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM24A..03K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM24A..03K"><span>Dione's <span class="hlt">Magnetospheric</span> Interaction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kurth, W. S.; Hospodarsky, G. B.; Schippers, P.; Moncuquet, M.; Lecacheux, A.; Crary, F. J.; Khurana, K. K.; Mitchell, D. G.</p> <p>2015-12-01</p> <p>Cassini has executed four close flybys of Dione during its mission at Saturn with one additional flyby planned as of this writing. The Radio and Plasma Wave Science (RPWS) instrument observed the plasma wave spectrum during each of the four encounters and plans to make additional observations during the 17 August 2015 flyby. These observations are joined by those from the Cassini Plasma Spectrometer (CAPS), <span class="hlt">Magnetospheric</span> Imaging Instrument (MIMI), and the Magnetometer instrument (MAG), although neither CAPS nor MAG data were available for the fourth flyby. The first and fourth flybys were near polar passes while the second and third were near wake passes. The second flyby occurred during a time of hot plasma injections which are not thought to be specifically related to Dione. The Dione plasma wave environment is characterized by an intensification of the upper hybrid band and whistler mode chorus. The upper hybrid band shows frequency fluctuations with a period of order 1 minute that suggest density variations of up to 10%. These density variations are anti-correlated with the magnetic field magnitude, suggesting a mirror mode wave. Other than these periodic density fluctuations there appears to be no local plasma source which would be observed as a local enhancement in the density although variations in the electron distribution are apparent. Wake passages show a deep density depletion consistent with a plasma cavity downstream of the moon. Energetic particles show portions of the distribution apparently absorbed by the moon leading to anisotropies that likely drive both the intensification of the upper hybrid band as well as the whistler mode emissions. We investigate the role of electron anisotropies and enhanced hot electron fluxes in the intensification of the upper hybrid band and whistler mode emissions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27792387','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27792387"><span>Rippled Quasiperpendicular Shock Observed by the <span class="hlt">Magnetospheric</span> Multiscale Spacecraft.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Johlander, A; Schwartz, S J; Vaivads, A; Khotyaintsev, Yu V; Gingell, I; Peng, I B; Markidis, S; Lindqvist, P-A; Ergun, R E; Marklund, G T; Plaschke, F; Magnes, W; Strangeway, R J; Russell, C T; Wei, H; Torbert, R B; Paterson, W R; Gershman, D J; Dorelli, J C; Avanov, L A; Lavraud, B; Saito, Y; Giles, B L; Pollock, C J; Burch, J L</p> <p>2016-10-14</p> <p>Collisionless shock nonstationarity arising from microscale physics influences shock structure and particle acceleration mechanisms. Nonstationarity has been difficult to quantify due to the small spatial and temporal scales. We use the closely spaced (subgyroscale), high-time-resolution measurements from one rapid crossing of <span class="hlt">Earth</span>'s quasiperpendicular bow shock by the <span class="hlt">Magnetospheric</span> Multiscale (MMS) spacecraft to compare competing nonstationarity processes. Using MMS's high-cadence kinetic plasma measurements, we show that the shock exhibits nonstationarity in the form of ripples.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170003534&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DG%2526T','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170003534&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DG%2526T"><span>Rippled Quasiperpendicular Shock Observed by the <span class="hlt">Magnetospheric</span> Multiscale Spacecraft</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Johlander, A.; Schwartz, S. J.; Vaivads, A.; Khotyaintsev, Yu. V.; Gingell, I.; Peng, I. B.; Markidis, S.; Lindqvist, P.-A.; Ergun, R. E.; Marklund, G. T.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20170003534'); toggleEditAbsImage('author_20170003534_show'); toggleEditAbsImage('author_20170003534_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20170003534_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20170003534_hide"></p> <p>2016-01-01</p> <p>Collisionless shock nonstationarity arising from microscale physics influences shock structure and particle acceleration mechanisms. Nonstationarity has been difficult to quantify due to the small spatial and temporal scales. We use the closely spaced (subgyroscale), high-time-resolution measurements from one rapid crossing of <span class="hlt">Earths</span> quasiperpendicular bow shock by the <span class="hlt">Magnetospheric</span> Multiscale (MMS) spacecraft to compare competing nonstationarity processes. Using MMSs high-cadence kinetic plasma measurements, we show that the shock exhibits nonstationarity in the form of ripples.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUSMSM53A..01G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUSMSM53A..01G"><span>The Plasmaspheric Role in Coupled Inner <span class="hlt">Magnetospheric</span> Dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goldstein, J.</p> <p>2006-05-01</p> <p>The plasmasphere is a near-<span class="hlt">Earth</span> cold, dense, corotating plasma region that plays both passive and active roles in inner <span class="hlt">magnetospheric</span> coupling. The plasmasphere plays a passive role with respect to electrodynamic coupling associated with enhanced <span class="hlt">magnetospheric</span> convection; i.e., zero-order plasmaspheric dynamics result from convection. Following extended periods of quiet geomagnetic conditions, the equatorial extent of the plasmasphere can be several <span class="hlt">Earth</span> radii (RE), with an internal density distribution that contains a great deal of fine-scale (under 0.1 RE) and meso-scale (0.1 to 1 RE) density structure. Enhanced geomagnetic activity causes erosion of the plasmasphere, in which the outer plasma-filled flux tubes are caught up in the convection field and carried sunward, forming plumes of dense plasmaspheric material on the dayside. The electrodynamic coupling between the ring current and ionosphere (leading to shielding and sub-auroral polarization stream, or SAPS) can either reduce or intensify the global convection field that arises from solar-wind-<span class="hlt">magnetosphere</span> coupling, and the plasmasphere is subject to the variations of this convection. There is also good evidence that ionosphere-thermosphere coupling plays an important role in determination of the convection field during quiet conditions. The plasmasphere plays an active role in determining the global distribution of warmer inner <span class="hlt">magnetospheric</span> plasmas (ring current and radiation belts), by providing plasma conditions that can favor or discourage the growth of waves such as whistler, chorus, and electromagnetic ion-cyclotron (EMIC) waves, all of which are believed to be crucial in the various acceleration and loss processes that affect warmer particles. Thus, knowledge of the global plasmasphere configuration and composition is critical for understanding and predicting the behavior of the inner <span class="hlt">magnetosphere</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830040108&hterms=fine+dust&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfine%2Bdust','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830040108&hterms=fine+dust&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfine%2Bdust"><span>Charged dust in Saturn's <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mendis, D. A.; Hill, J. R.; Houpis, H. L. F.</p> <p>1983-01-01</p> <p>The overall distribution of fine dust in the Saturnian <span class="hlt">magnetosphere</span>, its behavior, the cosmogony of the Saturnian ring system, and observations of the <span class="hlt">magnetosphere</span> and ring system are synthesized and explained using gravito-electrodynamics. Among the phenomena discussed are the formation of waves in the F-ring, the cause of eccentricities of certain isolated ringlets, and the origin and morphology of the broad diffuse E-ring. Magnetogravitational resonance of charged dust with nearby satellites, gyro-orbital resonances, and magnetogravitational capture of exogenic dust by the <span class="hlt">magnetosphere</span> are used to explain individual observations. The effect of a ring current associated with the charged dust is evaluated. Finally, the cosmogonic implications of the magnetogravitational theory are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870054945&hterms=Electric+current&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DElectric%2Bcurrent','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870054945&hterms=Electric+current&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DElectric%2Bcurrent"><span><span class="hlt">Magnetospheric</span> electric fields and currents</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mauk, B. H.; Zanetti, L. J.</p> <p>1987-01-01</p> <p>The progress made in the years 1983-1986 in understanding the character and operation of <span class="hlt">magnetospheric</span> electric fields and electric currents is discussed, with emphasis placed on the connection with the interior regions. Special attention is given to determinations of global electric-field configurations, measurements of the response of <span class="hlt">magnetospheric</span> particle populations to the electric-field configurations, and observations of the <span class="hlt">magnetospheric</span> currents at high altitude and during northward IMF. Global simulations of current distributions are discussed, and the sources of global electric fields and currents are examined. The topics discussed in the area of impulsive and small-scale phenomena include substorm current systems, impulsive electric fields and associated currents, and field-aligned electrodynamics. A key finding of these studies is that the electric fields and currents are interrelated and cannot be viewed as separate entities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUSM..SM32D03K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUSM..SM32D03K"><span>Does Solar Wind also Drive Convection in Jupiter's <span class="hlt">Magnetosphere</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khurana, K. K.</p> <p>2001-05-01</p> <p>Using a simple model of magnetic field and plasma velocity, Brice and Ioannidis [1970] showed that the corotation electric field exceeds convection electric field throughout the Jovian <span class="hlt">magnetosphere</span>. Since that time it has been tacitly assumed that Jupiter's <span class="hlt">magnetosphere</span> is driven from within. If Brice and Ioannidis conjecture is correct then one would not expect major asymmetries in the field and plasma parameters in the middle <span class="hlt">magnetosphere</span> of Jupiter. Yet, new field and plasma observations from Galileo and simultaneous auroral observations from HST show that there are large dawn/dusk and day/night asymmetries in many <span class="hlt">magnetospheric</span> parameters. For example, the magnetic observations show that a partial ring current and an associated Region-2 type field-aligned current system exist in the <span class="hlt">magnetosphere</span> of Jupiter. In the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span> it is well known that the region-2 current system is created by the asymmetries imposed by a solar wind driven convection. Thus, we are getting first hints that the solar wind driven convection is important in Jupiter's <span class="hlt">magnetosphere</span> as well. Other in-situ observations also point to dawn-dusk asymmetries imposed by the solar wind. For example, first order anisotropies in the Energetic Particle Detector show that the plasma is close to corotational on the dawn side but lags behind corotation in the dusk sector. Magnetic field data show that the current sheet is thin and highly organized on the dawn side but thick and disturbed on the dusk side. I will discuss the reasons why Brice and Ioannidis calculation may not be valid. I will show that both the magnetic field and plasma velocity estimates used by Brice and Ioannidis were rather excessive. Using more modern estimates of the field and velocity values I show that the solar wind convection can penetrate as deep as 40 RJ on the dawnside. I will present a new model of convection that invokes in addition to a distant neutral line spanning the whole magnetotail, a near</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940016064','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940016064"><span>Modeling of the coupled <span class="hlt">magnetospheric</span> and neutral wind dynamos</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Thayer, Jeff P.</p> <p>1993-01-01</p> <p>The solar wind interaction with the <span class="hlt">earth</span>'s <span class="hlt">magnetosphere</span> generates electric fields and currents that flow from the <span class="hlt">magnetosphere</span> to the ionosphere at high latitudes. Consequently, the neutral atmosphere is subject to the dissipation and conversion of this electrical energy to thermal and mechanical energy through Joule heating and Lorentz forcing. As a result of the mechanical energy stored within the neutral wind (caused in part by Lorentz--and pressure gradient--forces set up by the <span class="hlt">magnetospheric</span> flux of electrical energy), electric currents and fields can be generated in the ionosphere through the neutral wind dynamo mechanism. At high latitudes this source of electrical energy has been largely ignored in past studies, owing to the assumed dominance of the solar wind/<span class="hlt">magnetospheric</span> dynamo as an electrical energy source to the ionosphere. However, other researchers have demonstrated that the available electrical energy provided by the neutral wind is significant at high latitudes, particularly in the midnight sector of the polar cap and in the region of the <span class="hlt">magnetospheric</span> convection reversal. As a result, the conclusions of a number of broad ranging high-latitude investigations may be modified if the neutral-wind contribution to high-latitude electrodynamics is properly accounted for. These include the following: studies assessing solar wind-<span class="hlt">magnetospheric</span> coupling by comparing the cross polar cap potential with solar wind parameters; research based on the alignment of particle precipitation with convection or field aligned current boundaries; and synoptic investigations attributing seasonal variations in the observed electric field and current patterns to external sources. These research topics have been initiated by satellite and ground-based observations and have been attributed to <span class="hlt">magnetospheric</span> causes. However, the contribution of the neutral wind to the high-latitude electric field and current systems and their seasonal and local time dependence has yet</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720017690','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720017690"><span>Unipolar induction in the <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stern, D. P.</p> <p>1972-01-01</p> <p>A theory is described for the production of electric currents in the <span class="hlt">magnetosphere</span> and for the transfer of energy from the solar wind to the <span class="hlt">magnetosphere</span>. Assuming that the magnetosheath has ohmic-type conduction properties, it is shown that unipolar induction can energize several current flows, explaining the correlation of the east-west component of the interplanetary magnetic field with polar electric fields and polar magnetic variations. In the tail region, unipolar induction can account for effects correlated with the north-south component of the interplanetary magnetic field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120016912','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120016912"><span>Linking Plasma Conditions in the <span class="hlt">Magnetosphere</span> with Ionospheric Signatures</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rastaetter, Lutz; Kozyra, Janet; Kuznetsova, Maria M.; Berrios, David H.</p> <p>2012-01-01</p> <p>Modeling of the full <span class="hlt">magnetosphere</span>, ring current and ionosphere system has become an indispensable tool in analyzing the series of events that occur during geomagnetic storms. The CCMC has a full model suite available for the <span class="hlt">magnetosphere</span>, together with visualization tools that allow a user to perform a large variety of analyses. The January, 21, 2005 storm was a moderate-size storm that has been found to feature a large penetration electric field and unusually large polar caps (low-latitude precipitation patterns) that are otherwise found in super storms. Based on simulations runs at CCMC we can outline the likely causes of this behavior. Using visualization tools available to the online user we compare results from different <span class="hlt">magnetosphere</span> models and present connections found between features in the <span class="hlt">magnetosphere</span> and the ionosphere that are connected magnetically. The range of magnetic mappings found with different models can be compared with statistical models (Tsyganenko) and the model's fidelity can be verified with observations from low <span class="hlt">earth</span> orbiting satellites such as DMSP and TIMED.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140017833','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140017833"><span><span class="hlt">Magnetosphere</span>-Ionosphere Energy Interchange in the Electron Diffuse Aurora</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Khazanov, George V.; Glocer, Alex; Himwich, E. W.</p> <p>2014-01-01</p> <p>The diffuse aurora has recently been shown to be a major contributor of energy flux into the <span class="hlt">Earth</span>'s ionosphere. Therefore, a comprehensive theoretical analysis is required to understand its role in energy redistribution in the coupled ionosphere-<span class="hlt">magnetosphere</span> system. In previous theoretical descriptions of precipitated <span class="hlt">magnetospheric</span> electrons (E is approximately 1 keV), the major focus has been the ionization and excitation rates of the neutral atmosphere and the energy deposition rate to thermal ionospheric electrons. However, these precipitating electrons will also produce secondary electrons via impact ionization of the neutral atmosphere. This paper presents the solution of the Boltzman-Landau kinetic equation that uniformly describes the entire electron distribution function in the diffuse aurora, including the affiliated production of secondary electrons (E greater than 600 eV) and their ionosphere-<span class="hlt">magnetosphere</span> coupling processes. In this article, we discuss for the first time how diffuse electron precipitation into the atmosphere and the associated secondary electron production participate in ionosphere-<span class="hlt">magnetosphere</span> energy redistribution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36..563A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36..563A"><span>Paraboloid <span class="hlt">magnetospheric</span> magnetic field model and the status of the model as an ISO standard</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alexeev, I.</p> <p></p> <p>A reliable representation of the magnetic field is crucial in the framework of radiation belt modelling especially for disturbed conditions The empirical model developed by Tsyganenko T96 is constructed by minimizing the rms deviation from the large <span class="hlt">magnetospheric</span> data base The applicability of the T96 model is limited mainly by quiet conditions in the solar wind along the <span class="hlt">Earth</span> orbit But contrary to the internal planet s field the external <span class="hlt">magnetospheric</span> magnetic field sources are much more time-dependent A reliable representation of the magnetic field is crucial in the framework of radiation belt modelling especially for disturbed conditions It is a reason why the method of the paraboloid <span class="hlt">magnetospheric</span> model construction based on the more accurate and physically consistent approach in which each source of the magnetic field would have its own relaxation timescale and a driving function based on an individual best fit combination of the solar wind and IMF parameters Such approach is based on a priori information about the global <span class="hlt">magnetospheric</span> current systems structure Each current system is included as a separate block module in the <span class="hlt">magnetospheric</span> model As it was shown by the spacecraft magnetometer data there are three current systems which are the main contributors to the external <span class="hlt">magnetospheric</span> magnetic field magnetopause currents ring current and tail current sheet Paraboloid model is based on an analytical solution of the Laplace equation for each of these large-scale current systems in the <span class="hlt">magnetosphere</span> with a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940017363','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940017363"><span>Physics of <span class="hlt">magnetospheric</span> boundary layers</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cairns, I. H.</p> <p>1993-01-01</p> <p>The central ideas of this grant are that the <span class="hlt">magnetospheric</span> boundary layers link disparate regions of the <span class="hlt">magnetosphere</span> together, and the global behavior of the <span class="hlt">magnetosphere</span> can be understood only by understanding the linking mechanisms. Accordingly the present grant includes simultaneous research on the global, meso-, and micro-scale physics of the <span class="hlt">magnetosphere</span> and its boundary layers. These boundary layers include the bow shock, magnetosheath, the plasma sheet boundary layer, and the ionosphere. Analytic, numerical and simulation projects have been performed on these subjects, as well as comparison of theoretical results with observational data. Very good progress has been made, with four papers published or in press and two additional papers submitted for publication during the six month period 1 June - 30 November 1993. At least two projects are currently being written up. In addition, members of the group have given papers at scientific meetings. The further structure of this report is as follows: section two contains brief accounts of research completed during the last six months, while section three describes the research projects intended for the grant's final period.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960008175','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960008175"><span><span class="hlt">Magnetosphere</span> imager science definition team interim report</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Armstrong, T. P.; Johnson, C. L.</p> <p>1995-01-01</p> <p>For three decades, <span class="hlt">magnetospheric</span> field and plasma measurements have been made by diverse instruments flown on spacecraft in may different orbits, widely separated in space and time, and under various solar and <span class="hlt">magnetospheric</span> conditions. Scientists have used this information to piece together an intricate, yet incomplete view of the <span class="hlt">magnetosphere</span>. A simultaneous global view, using various light wavelengths and energetic neutral atoms, could reveal exciting new data nd help explain complex <span class="hlt">magnetospheric</span> processes, thus providing a clear picture of this region of space. This report documents the scientific rational for such a <span class="hlt">magnetospheric</span> imaging mission and provides a mission concept for its implementation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960013900','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960013900"><span><span class="hlt">Magnetosphere</span> imager science definition team: Executive summary</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Armstrong, T. P.; Gallagher, D. L.; Johnson, C. L.</p> <p>1995-01-01</p> <p>For three decades, <span class="hlt">magnetospheric</span> field and plasma measurements have been made by diverse instruments flown on spacecraft in many different orbits, widely separated in space and time, and under various solar and <span class="hlt">magnetospheric</span> conditions. Scientists have used this information to piece together an intricate, yet incomplete view of the <span class="hlt">magnetosphere</span>. A simultaneous global view, using various light wavelengths and energetic neutral atoms, could reveal exciting new data and help explain complex <span class="hlt">magnetospheric</span> processes, thus providing a clear picture of this region of space. This report summarizes the scientific rationale for such a <span class="hlt">magnetospheric</span> imaging mission and outlines a mission concept for its implementation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820042725&hterms=Wind+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DWind%2Benergy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820042725&hterms=Wind+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DWind%2Benergy"><span>Solar wind energy transfer through the magnetopause of an open <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lee, L. C.; Roederer, J. G.</p> <p>1982-01-01</p> <p>An expression is derived for the total power, transferred from the solar wind to an open <span class="hlt">magnetosphere</span>, which consists of the electromagnetic energy rate and the particle kinetic energy rate. The total rate of energy transferred from the solar wind to an open <span class="hlt">magnetosphere</span> mainly consists of kinetic energy, and the kinetic energy flux is carried by particles, penetrating from the solar wind into the <span class="hlt">magnetosphere</span>, which may contribute to the observed flow in the plasma mantle and which will eventually be convected slowly toward the plasma sheet by the electric field as they flow down the tail. While the electromagnetic energy rate controls the near-<span class="hlt">earth</span> <span class="hlt">magnetospheric</span> activity, the kinetic energy rate should dominate the dynamics of the distant magnetotail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMPA24A..05R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMPA24A..05R"><span>Identifying "Carrington Events" in Solar, Solar Wind, and <span class="hlt">Magnetospheric</span> Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Russell, C. T.; Riley, P.; Luhmann, J. G.; Lai, H.</p> <p>2016-12-01</p> <p>Extreme space weather begins when extraordinary levels of stored magnetic energy in the photosphere rapidly destabilizes. This destabilization generally releases a rapidly expelled plasma and magnetic flux rope. Large fluxes of highly relativistic particles signal the event and at <span class="hlt">Earth</span> precede the expelled flux rope. The most recent such solar event did not encounter the <span class="hlt">Earth</span>, but was recorded by STEREO A on July 23, 2012. The energy density in the relativistic particles that preceded the rapidly expanding magnetic cloud was so intense that the compression front expanded with a sub fast mode speed (i.e. `subsonically') and the compression front became a slow mode wave. The peak magnetic field in the rope was 109 nT, larger than any previously reported field at 1 AU in the solar wind. An equally fast disturbance left the Sun on September 1, 1859, and caused intense induced currents when it reached the <span class="hlt">Earth</span>. It is likely that at least some of the <span class="hlt">magnetospheric</span> currents were caused by the accompanying magnetic cloud, but <span class="hlt">magnetospheric</span> diagnostics were scarce during this event. This first space weather event became the defining occurrence of extreme space weather. A second modern event not generally recognized as "Carrington" class, but arguably super-Carrington, arrived on August 4, 1972. Between the Apollo 16 and 17 missions. It was a strong producer of geomagnetic induced currents, but produced only a weak ring current, possibly because the part of the magnetic cloud in contact with the <span class="hlt">Earth</span> had a polarity that did not couple the solar wind momentum flux to the <span class="hlt">magnetosphere</span>. The pressure wave reached 1 AU in the shortest time of any recorded solar event and brought an energetic particle flux that would have harmed the astronauts had they been in space. To identify which solar events are capable of producing the most extreme space weather events, we must identify those that are expelled toward the <span class="hlt">Earth</span> at the highest speeds. How these events manifest their</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950033428&hterms=ultralow+power&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dultralow%2Bpower','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950033428&hterms=ultralow+power&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dultralow%2Bpower"><span>Statistical study of ULF wave occurrence in the dayside <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cao, M.; Mcpherron, R. L.; Russell, C. T.</p> <p>1994-01-01</p> <p>Ultralow-frequency (ULF) waves are observed almost everywhere in the dayside <span class="hlt">magnetosphere</span>. The mechanism by which these waves are generated and transformed in the dayside <span class="hlt">magnetosphere</span> is still not understood. Here we report a statistical study of these waves based on magnetic field data from the International Sun-<span class="hlt">Earth</span> Explorer 1 (ISEE 1) spacecraft. Data from the first traversal of the spacecraft through the entire dayside <span class="hlt">magnetosphere</span> have been examined to determine the spatial distribution of wave occurrence. Successive 20-min segments of data were transformed to a field-aligned coordinate system. The parallel component was detrended and all three components of the field spectrally analyzed. Wave occurrence was defined by the presence of significant peaks in the power spectra. Wave events were categorized by three wave frequency bands: Pc 3 with T approximately 10-45 s; Pc 4 with T approximately 45-150 s; the short-period part of the Pc 5 wave band with T approximately 150-324 s. Properties of the spectral peaks were then entered into a data base. The data base was next sorted to determine the spatial occurrence pattern for the waves. Our results show that Pc 3 waves most frequently occur just outside synchronous orbit and are approximately centered on local noon. Pc 4 waves have a similar distribution with its peak further out. Pc 5 waves have high occurrence rate at the two flanks of the <span class="hlt">magnetosphere</span>. Peaks in spectra obtained near the magnetopause are less clearly defined than those deeper in the <span class="hlt">magnetosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUSMSH51C..02P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUSMSH51C..02P"><span>Radiation Belts of Antiparticles in Planetary <span class="hlt">Magnetospheres</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pugacheva, G. I.; Gusev, A. A.; Jayanthi, U. B.; Martin, I. M.; Spjeldvik, W. N.</p> <p>2007-05-01</p> <p>The <span class="hlt">Earth</span>'s radiation belts could be populated, besides with electrons and protons, also by antiparticles, such as positrons (Basilova et al., 1982) and antiprotons (pbar). Positrons are born in the decay of pions that are directly produced in nuclear reactions of trapped relativistic inner zone protons with the residual atmosphere at altitudes in the range of about 500 to 3000 km over the <span class="hlt">Earth</span>'s surface. Antiprotons are born by high energy (E > 6 GeV) cosmic rays in p+p - p+p+p+ pbar and in p+p - p+p+n+nbar reactions. The trapping and storage of these charged anti-particles in the <span class="hlt">magnetosphere</span> result in radiation belts similar to the classical Van Allen belts of protons and electrons. We describe the mathematical techniques used for numerical simulation of the trapped positron and antiproton belt fluxes. The pion and antiproton yields were simulated on the basis of the Russian nuclear reaction computer code MSDM, a Multy Stage Dynamical Model, Monte Carlo code, (i.e., Dementyev and Sobolevsky, 1999). For estimates of positron flux there we have accounted for ionisation, bremsstrahlung, and synchrotron energy losses. The resulting numerical estimates show that the positron flux with energy >100 MeV trapped into the radiation belt at L=1.2 is of the order ~1000 m-2 s-1 sr-1, and that it is very sensitive to the shape of the trapped proton spectrum. This confined positron flux is found to be greater than that albedo, not trapped, mixed electron/positron flux of about 50 m-2 s-1 sr-1 produced by CR in the same region at the top of the geomagnetic field line at L=1.2. As we show in report, this albedo flux also consists mostly of positrons. The trapped antiproton fluxes produced by CR in the <span class="hlt">Earth</span>'s upper rarified atmosphere were calculated in the energy range from 10 MeV to several GeV. In the simulations we included a mathematic consideration of the radial diffusion process, both an inner and an outer antiproton source, losses of particles due to ionization process</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890043876&hterms=Open+Field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DOpen%2BField','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890043876&hterms=Open+Field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DOpen%2BField"><span>Where do field lines go in the quiet <span class="hlt">magnetosphere</span>?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stern, David P.; Alekseev, Igor' I.</p> <p>1988-01-01</p> <p>The state of knowledge concerning the global pattern of geomagnetic field lines is reviewed. Sources of information on that pattern include (1) magnetic-field models, derived directly from magnetic data or indirectly from generally observed properties and from physics; (2) the tracing of <span class="hlt">magnetospheric</span> features (e.g., polar cusps or the inner edge of the plasma sheet); (3) matching of magnetic flux; and (4) analysis of magnetic fields. Field-line structure inside about 8 <span class="hlt">earth</span> radii is known fairly well, but beyond that, especially in the tail, the situation becomes rather uncertain and variable. Two particularly difficult problems are the linkage between open field lines and the interplanetary field and the field-line structure of the quiescent <span class="hlt">magnetosphere</span> following periods of prolonged northward Bz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040171608','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040171608"><span>Advances in Inner <span class="hlt">Magnetosphere</span> Passive and Active Wave Research</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Green, James L.; Fung, Shing F.</p> <p>2004-01-01</p> <p>This review identifies a number of the principal research advancements that have occurred over the last five years in the study of electromagnetic (EM) waves in the <span class="hlt">Earth</span>'s inner <span class="hlt">magnetosphere</span>. The observations used in this study are from the plasma wave instruments and radio sounders on Cluster, IMAGE, Geotail, Wind, Polar, Interball, and others. The data from passive plasma wave instruments have led to a number of advances such as: determining the origin and importance of whistler mode waves in the plasmasphere, discovery of the source of kilometric continuum radiation, mapping AKR source regions with "pinpoint" accuracy, and correlating the AKR source location with dipole tilt angle. Active <span class="hlt">magnetospheric</span> wave experiments have shown that long range ducted and direct echoes can be used to obtain the density distribution of electrons in the polar cap and along plasmaspheric field lines, providing key information on plasmaspheric filling rates and polar cap outflows.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160010499','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160010499"><span><span class="hlt">Magnetospheric</span> Multiscale Mission Attitude Dynamics: Observations from Flight Data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Williams, Trevor; Shulman, Seth; Sedlak, Joseph E.; Ottenstein, Neil; Lounsbury, Brian</p> <p>2016-01-01</p> <p>The NASA <span class="hlt">Magnetospheric</span> Multiscale mission, launched on Mar. 12, 2015, is flying four spinning spacecraft in highly elliptical orbits to study the <span class="hlt">magnetosphere</span> of the <span class="hlt">Earth</span>. Extensive attitude data is being collected, including spin rate, spin axis orientation, and nutation rate. The paper will discuss the various environmental disturbance torques that act on the spacecraft, and will describe the observed results of these torques. In addition, a slow decay in spin rate has been observed for all four spacecraft in the extended periods between maneuvers. It is shown that this despin is consistent with the effects of an additional disturbance mechanism, namely that produced by the Active Spacecraft Potential Control devices. Finally, attitude dynamics data is used to analyze a micrometeoroid/orbital debris impact event with MMS4 that occurred on Feb. 2, 2016.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Ge%26Ae..58..252C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Ge%26Ae..58..252C"><span><span class="hlt">Magnetospheric</span> Effects during the Approach of the Chelyabinsk Meteoroid</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chernogor, L. F.</p> <p>2018-03-01</p> <p>We have analyzed the observational results for variations in the main geomagnetic field and its fluctuations in the range of periods 1-1000 s that accompanied the approach of the Chelyabinsk space body to the <span class="hlt">magnetosphere</span> and ionosphere of the <span class="hlt">Earth</span>. The measurements were conducted with a magnetometerfluxmeter near the city of Kharkiv, as well as with the network of magnetometers located at the observatories of Novosibirsk, Kyiv, Lviv, Almaty, Khabarovsk, Arti, Borok, and Yakutsk. Variations in the main geomagnetic field and its fluctuations approximately 33-47 min prior to the explosion of the Chelyabinsk meteoroid have been discovered; they persisted for 25-35 min and were probably associated with meteoroid passage through the <span class="hlt">magnetosphere</span>. The amplitude of variations reached 1-6 nT. We have proposed a model of the generation of aperiodic, quasi-periodic, and noise-like variations in the geomagnetic field induced by the approach of a space body.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRA..119.2494N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRA..119.2494N"><span><span class="hlt">Magnetospheric</span> conditions for sawtooth event development</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Noah, M. A.; Burke, W. J.</p> <p>2014-04-01</p> <p>This paper addresses two topics concerning the <span class="hlt">magnetospheric</span> conditions that allow sawtooth events (STEs) to develop during "nonstorm" intervals yet fail to yield them during many intense/super storms. A statistical analysis by Cai et al. (2011) reported that while only 5.4% of STEs occurred outside the context of magnetic storms, their occurrence rate during intense storms was just 63.5%. They concluded that (1) STEs are not necessarily storm time phenomena and (2) particular interplanetary conditions are needed to drive the class of storms in which STEs are generated. Traces of Sym-H indices and cross polar cap potentials during "nonstorm" STEs indicate that ring current energy remained above normal, quiet time values and open flux was continually being transferred to the magnetotail. We combined two independently generated lists of intense/super storms from the 1996 to 2007 period and found that 46 of them did not appear on the STE list of Cai et al. (2011). They divide three categories of storms in which (1) information needed to establish the presence/absence of STEs is insufficient, (2) STE signatures were present but overlooked, and (3) the magnetopause moved earthward of 6.6 RE so that energetic particles cannot gradient-curvature drift to geosynchronous satellites in the magnetosheath near local noon. We conclude that STE identification criteria be expanded to include compressed cases in which quasiperiodic nightside injections occur. Super storms with no nightside injections are attributed to episodes of severe ring current inflation of the inner <span class="hlt">magnetosphere</span> that inhibited the formation of sustained near-<span class="hlt">Earth</span> neutral lines.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780026072','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780026072"><span>Particle acceleration in pulsar <span class="hlt">magnetospheres</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Baker, K. B.</p> <p>1978-01-01</p> <p>The structure of pulsar <span class="hlt">magnetospheres</span> and the acceleration mechanism for charged particles in the <span class="hlt">magnetosphere</span> was studied using a pulsar model which required large acceleration of the particles near the surface of the star. A theorem was developed which showed that particle acceleration cannot be expected when the angle between the magnetic field lines and the rotation axis is constant (e.g. radial field lines). If this angle is not constant, however, acceleration must occur. The more realistic model of an axisymmetric neutron star with a strong dipole magnetic field aligned with the rotation axis was investigated. In this case, acceleration occurred at large distances from the surface of the star. The magnitude of the current can be determined using the model presented. In the case of nonaxisymmetric systems, the acceleration is expected to occur nearer to the surface of the star.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997NYASA.822..583Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997NYASA.822..583Z"><span><span class="hlt">Magnetospheric</span> Effects as a New Aspect of the Asteroid Impact Problem: Necessity and Possibilities of Laboratory Simulation Experiments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zakharov, Yuri P.; Nikitin, Sergei A.; Ponomarenko, Arnold G.; Minami, Shigeyuki</p> <p>1997-05-01</p> <p>This paper discusses the possible consequences to the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>, when due to too short an advanced warning, attempts at mitigation of a near-<span class="hlt">Earth</span> object (NEO) must be made in close proximity to the <span class="hlt">Earth</span>. The energy Eo, and explosive plasma release during impact may be compared with the kinetic energy Ek of the NEO and with the energy, Ee (Ee approximately Ek), needed for NEO deflection by a strong (protective force) explosive, at distances close to the scale of the <span class="hlt">magnetosphere</span>. If the energy, Em, of the <span class="hlt">Earth</span>'s dipole field latter is relatively small (Em is less than Eo for a NEO size approximately 1 km), global or even catastrophic disturbances could occur. These ecologically important <span class="hlt">magnetospheric</span> aspects of the NEO impact problem have been discussed recently; particularly in the context of the comet SL-9/Jupiter impact. In the latter case, the effect on Jupiter's <span class="hlt">magnetosphere</span> of the 'NEO' explosions was very small (x equals Eo/Em approximately 0.001, where Em is the 'outer' magnetic energy of the planetary dipole field) and the corresponding model of its 'fireball' development could be simulated numerically in 'zero' approximation, with the assumption of an undisturbed <span class="hlt">magnetospheric</span> media as a whole. However, in general, and, in the rather probable case of NEO impacts with values x approximately 1, the development of such 3D, nonstationary MHD or PIC-models at this time. Such information can be obtained from new kinds of simulation experiments with the laboratory <span class="hlt">magnetosphere</span>, the so-called 'terrella'.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM14A..06M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM14A..06M"><span>Perturbed-input-data ensemble modeling of <span class="hlt">magnetospheric</span> dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morley, S.; Steinberg, J. T.; Haiducek, J. D.; Welling, D. T.; Hassan, E.; Weaver, B. P.</p> <p>2017-12-01</p> <p>Many models of <span class="hlt">Earth</span>'s <span class="hlt">magnetospheric</span> dynamics - including global magnetohydrodynamic models, reduced complexity models of substorms and empirical models - are driven by solar wind parameters. To provide consistent coverage of the upstream solar wind these measurements are generally taken near the first Lagrangian point (L1) and algorithmically propagated to the nose of <span class="hlt">Earth</span>'s bow shock. However, the plasma and magnetic field measured near L1 is a point measurement of an inhomogeneous medium, so the individual measurement may not be sufficiently representative of the broader region near L1. The measured plasma may not actually interact with the <span class="hlt">Earth</span>, and the solar wind structure may evolve between L1 and the bow shock. To quantify uncertainties in simulations, as well as to provide probabilistic forecasts, it is desirable to use perturbed input ensembles of <span class="hlt">magnetospheric</span> and space weather forecasting models. By using concurrent measurements of the solar wind near L1 and near the <span class="hlt">Earth</span>, we construct a statistical model of the distributions of solar wind parameters conditioned on their upstream value. So that we can draw random variates from our model we specify the conditional probability distributions using Kernel Density Estimation. We demonstrate the utility of this approach using ensemble runs of selected models that can be used for space weather prediction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...595A..69V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...595A..69V"><span>Radio emission in Mercury <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Varela, J.; Reville, V.; Brun, A. S.; Pantellini, F.; Zarka, P.</p> <p>2016-10-01</p> <p>Context. Active stars possess magnetized wind that has a direct impact on planets that can lead to radio emission. Mercury is a good test case to study the effect of the solar wind and interplanetary magnetic field (IMF) on radio emission driven in the planet <span class="hlt">magnetosphere</span>. Such studies could be used as proxies to characterize the magnetic field topology and intensity of exoplanets. Aims: The aim of this study is to quantify the radio emission in the Hermean <span class="hlt">magnetosphere</span>. Methods: We use the magnetohydrodynamic code PLUTO in spherical coordinates with an axisymmetric multipolar expansion for the Hermean magnetic field, to analyze the effect of the IMF orientation and intensity, as well as the hydrodynamic parameters of the solar wind (velocity, density and temperature), on the net power dissipated on the Hermean day and night side. We apply the formalism derived by Zarka et al. (2001, Astrophys. Space Sci., 277, 293), Zarka (2007, Planet. Space Sci., 55, 598) to infer the radio emission level from the net dissipated power. We perform a set of simulations with different hydrodynamic parameters of the solar wind, IMF orientations and intensities, that allow us to calculate the dissipated power distribution and infer the existence of radio emission hot spots on the planet day side, and to calculate the integrated radio emission of the Hermean <span class="hlt">magnetosphere</span>. Results: The obtained radio emission distribution of dissipated power is determined by the IMF orientation (associated with the reconnection regions in the <span class="hlt">magnetosphere</span>), although the radio emission strength is dependent on the IMF intensity and solar wind hydro parameters. The calculated total radio emission level is in agreement with the one estimated in Zarka et al. (2001, Astrophys. Space Sci., 277, 293) , between 5 × 105 and 2 × 106 W.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950005388','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950005388"><span><span class="hlt">Magnetospheric</span>-ionospheric Poynting flux</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Thayer, Jeffrey P.</p> <p>1994-01-01</p> <p>Over the past three years of funding SRI, in collaboration with the University of Texas at Dallas, has been involved in determining the total electromagnetic energy flux into the upper atmosphere from DE-B electric and magnetic field measurements and modeling the electromagnetic energy flux at high latitudes, taking into account the coupled <span class="hlt">magnetosphere</span>-ionosphere system. This effort has been very successful in establishing the DC Poynting flux as a fundamental quantity in describing the coupling of electromagnetic energy between the <span class="hlt">magnetosphere</span> and ionosphere. The DE-B satellite electric and magnetic field measurements were carefully scrutinized to provide, for the first time, a large data set of DC, field-aligned, Poynting flux measurement. Investigations describing the field-aligned Poynting flux observations from DE-B orbits under specific geomagnetic conditions and from many orbits were conducted to provide a statistical average of the Poynting flux distribution over the polar cap. The theoretical modeling effort has provided insight into the observations by formulating the connection between Poynting's theorem and the electromagnetic energy conversion processes that occur in the ionosphere. Modeling and evaluation of these processes has helped interpret the satellite observations of the DC Poynting flux and improved our understanding of the coupling between the ionosphere and <span class="hlt">magnetosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37.2701S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.2701S"><span>SCOPE : Future Formation-Flying <span class="hlt">Magnetospheric</span> Satellite Mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saito, Yoshifumi</p> <p></p> <p>A formation flight satellite mission "SCOPE" is now under study aiming at launching in 2017. "SCOPE" stands for ‘cross Scale COupling in the Plasma universE'. The main purpose of this mission is to investigate the dynamic behaviors of plasma in the terrestrial <span class="hlt">magnetosphere</span> that range over magnitudes of both temporal and spatial scales. The basic idea of the SCOPE mission is to distinguish temporal and spatial variations of physical processes by putting five formation flight spacecraft into the key regions of the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>. The formation consists of one large mother satellite and four small daughter satellites. Three of the four daughter satellites surround the mother satellite 3-dimensionally maintaining the mutual distances of variable ranges between 5 km and 5000 km. The fourth daughter satellite stays near the mother satellite with the distance between 5 km and 100 km. By this configuration, we can obtain both the macro-scale (1000 km - 5000 km) and micro-scale (¡ 100 km) information about the plasma disturbances at the same time. The launcher for SCOPE has been assumed to be M-V rocket (or its succession rocket) of JAXA. However, due to the termination of M-V rocket, we are now considering to use HIIA. The orbits of SCOPE satellites are all highly elliptical with its apogee 30Re from the <span class="hlt">Earth</span> center. The inter-satellite link is used for telemetry/command operation as well as ranging to determine the relative orbits of the 5 satellites in small distances. The SCOPE mission is designed such that observational studies from the new perspective, the crossscale coupling, should be conducted. The orbit of the formation flight are designed such that the spacecraft will visit most of the key regions in the <span class="hlt">magnetosphere</span>, including the bow shock, the <span class="hlt">magnetospheric</span> boundary, the inner-<span class="hlt">magnetosphere</span>, and the near-<span class="hlt">Earth</span> magnetotail. The key issues for the realization of this mission are: (1) The need for high temporal resolution of electron measurements</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFMSM31A0293J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFMSM31A0293J"><span>THE Role OF Anisotropy AND Intermittency IN Solar Wind/<span class="hlt">Magnetosphere</span> Coupling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jankovicova, D.; Voros, Z.</p> <p>2006-12-01</p> <p>Turbulent fluctuations are common in the solar wind as well as in the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>. The fluctuations of both magnetic field and plasma parameters exhibit non-Gaussian statistics. Neither the amplitude of these fluctuations nor their spectral characteristics can provide a full statistical description of multi-scale features in turbulence. It substantiates a statistical approach including the estimation of experimentally accessible statistical moments. In this contribution, we will directly estimate the third (skewness) and the fourth (kurtosis) statistical moments from the available time series of magnetic measurements in the solar wind (ACE and WIND spacecraft) and in the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span> (SYM-H index). Then we evaluate how the statistical moments change during strong and weak solar wind/<span class="hlt">magnetosphere</span> coupling intervals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM13A2353H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM13A2353H"><span>Does the <span class="hlt">Magnetosphere</span> go to Sleep?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hesse, M.; Moretto, T.; Friis-Christensen, E. A.; Kuznetsova, M.; Østgaard, N.; Tenfjord, P.; Opgenoorth, H. J.</p> <p>2017-12-01</p> <p>An interesting question in <span class="hlt">magnetospheric</span> research is related to the transition between <span class="hlt">magnetospheric</span> configurations under substantial solar wind driving, and a putative relaxed state after the driving ceases. While it is conceivable that the latter state may be unique and only dependent on residual solar wind driving, a more likely scenario has <span class="hlt">magnetospheric</span> memory playing a key role. Memory processes may be manifold: constraints from conservation of flux tube entropy to neutral wind inertia in the upper atmosphere may all contribute. In this presentation, we use high-resolution, global, MHD simulations to begin to shed light on this transition, as well as on the concept of a quiet state of the <span class="hlt">magnetosphere</span>. We will discuss key elements of <span class="hlt">magnetospheric</span> memory, and demonstrate their influence, as well as the actual memory time scale, through simulations and analytical estimates. Finally, we will point out processes with the potential to effect <span class="hlt">magnetospheric</span> memory loss.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050181990','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050181990"><span>Magnetohydrodynamic Modeling of the Jovian <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Walker, Raymond</p> <p>2005-01-01</p> <p>Under this grant we have undertaken a series of magnetohydrodynamic (MHD) simulation and data analysis studies to help better understand the configuration and dynamics of Jupiter's <span class="hlt">magnetosphere</span>. We approached our studies of Jupiter's <span class="hlt">magnetosphere</span> in two ways. First we carried out a number of studies using our existing MHD code. We carried out simulation studies of Jupiter s <span class="hlt">magnetospheric</span> boundaries and their dependence on solar wind parameters, we studied the current systems which give the Jovian <span class="hlt">magnetosphere</span> its unique configuration and we modeled the dynamics of Jupiter s <span class="hlt">magnetosphere</span> following a northward turning of the interplanetary magnetic field (IMF). Second we worked to develop a new simulation code for studies of outer planet <span class="hlt">magnetospheres</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1910580R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1910580R"><span><span class="hlt">Magnetospheric</span> particle precipitation at Titan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Royer, Emilie; Esposito, Larry; Crary, Frank; Wahlund, Jan-Erik</p> <p>2017-04-01</p> <p>Although solar XUV radiation is known to be the main source of ionization in Titan's upper atmosphere around 1100 km of altitude, <span class="hlt">magnetospheric</span> particle precipitation can also account for about 10% of the ionization process. <span class="hlt">Magnetospheric</span> particle precipitation is expected to be the most intense on the nightside of the satelllite and when Titan's orbital position around Saturn is the closest to Noon Saturn Local Time (SLT). In addition, on several occasion throughout the Cassini mission, Titan has been observed while in the magnetosheath. We are reporting here Ultraviolet (UV) observations of Titan airglow enhancements correlated to these <span class="hlt">magnetospheric</span> changing conditions occurring while the spacecraft, and thus Titan, are known to have crossed Saturn's magnetopause and have been exposed to the magnetosheath environnment. Using Cassini-Ultraviolet Imaging Spectrograph (UVIS) observations of Titan around 12PM SLT as our primary set of data, we present evidence of Titan's upper atmosphere response to a fluctuating <span class="hlt">magnetospheric</span> environment. Pattern recognition software based on 2D UVIS detector images has been used to retrieve observations of interest, looking for airglow enhancement of a factor of 2. A 2D UVIS detector image, created for each UVIS observation of Titan, displays the spatial dimension of the UVIS slit on the x-axis and the time on the y-axis. In addition, data from the T32 flyby and from April 17, 2005 from in-situ Cassini instruments are used. Correlations with data from simultaneous observations of in-situ Cassini instruments (CAPS, RPWS and MIMI) has been possible on few occasions and events such as electron burst and reconnections can be associated with unusual behaviors of the Titan airglow. CAPS in-situ measurements acquired during the T32 flyby are consistent with an electron burst observed at the spacecraft as the cause of the UV emission. Moreover, on April 17, 2005 the UVIS observation displays feature similar to what could be a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120015980','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120015980"><span>The Sun and <span class="hlt">Earth</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gopalswamy, Natchimuthuk</p> <p>2012-01-01</p> <p>Thus the Sun forms the basis for life on <span class="hlt">Earth</span> via the black body radiation it emits. The Sun also emits mass in the form of the solar wind and the coronal mass ejections (CMEs). Mass emission also occurs in the form of solar energetic particles (SEPs), which happens during CMEs and solar flares. Both the mass and electromagnetic energy output of the Sun vary over a wide range of time scales, thus introducing disturbances on the space environment that extends from the Sun through the entire heliosphere including the <span class="hlt">magnetospheres</span> and ionospheres of planets and moons of the solar system. Although our habitat is located in the neutral atmosphere of <span class="hlt">Earth</span>, we are intimately connected to the non-neutral space environment starting from the ionosphere to the <span class="hlt">magnetosphere</span> and to the vast interplanetary space. The variability of the solar mass emissions results in the interaction between the solar wind plasma and the <span class="hlt">magnetospheric</span> plasma leading to huge disturbances in the geospace. The Sun ionizes our atmosphere and creates the ionosphere. The ionosphere can be severely disturbed by the transient energy input from solar flares and the solar wind during geomagnetic storms. The complex interplay between <span class="hlt">Earth</span>'s magnetic field and the solar magnetic field carried by the solar wind presents varying conditions that are both beneficial and hazardous to life on <span class="hlt">earth</span>. This seminar presents some of the key aspects of this Sun-<span class="hlt">Earth</span> connection that we have learned since the birth of space science as a scientific discipline some half a century ago.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM32B..08L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM32B..08L"><span>Fast Flows in the Magnetotail and Energetic Particle Transport: Multiscale Coupling in the <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, Y.; Wang, X.; Fok, M. C. H.; Buzulukova, N.; Perez, J. D.; Chen, L. J.</p> <p>2017-12-01</p> <p>The interaction between the <span class="hlt">Earth</span>'s inner and outer <span class="hlt">magnetospheric</span> regions associated with the tail fast flows is calculated by coupling the Auburn 3-D global hybrid simulation code (ANGIE3D) to the Comprehensive Inner <span class="hlt">Magnetosphere</span>/Ionosphere (CIMI) model. The global hybrid code solves fully kinetic equations governing the ions and a fluid model for electrons in the self-consistent electromagnetic field of the dayside and night side outer <span class="hlt">magnetosphere</span>. In the integrated computation model, the hybrid simulation provides the CIMI model with field data in the CIMI 3-D domain and particle data at its boundary, and the transport in the inner <span class="hlt">magnetosphere</span> is calculated by the CIMI model. By joining the two existing codes, effects of the solar wind on particle transport through the outer <span class="hlt">magnetosphere</span> into the inner <span class="hlt">magnetosphere</span> are investigated. Our simulation shows that fast flows and flux ropes are localized transients in the magnetotail plasma sheet and their overall structures have a dawn-dusk asymmetry. Strong perpendicular ion heating is found at the fast flow braking, which affects the earthward transport of entropy-depleted bubbles. We report on the impacts from the temperature anisotropy and non-Maxwellian ion distributions associated with the fast flows on the ring current and the convection electric field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4508929','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4508929"><span>Ensemble downscaling in coupled solar wind-<span class="hlt">magnetosphere</span> modeling for space weather forecasting</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Owens, M J; Horbury, T S; Wicks, R T; McGregor, S L; Savani, N P; Xiong, M</p> <p>2014-01-01</p> <p>Advanced forecasting of space weather requires simulation of the whole Sun-to-<span class="hlt">Earth</span> system, which necessitates driving <span class="hlt">magnetospheric</span> models with the outputs from solar wind models. This presents a fundamental difficulty, as the <span class="hlt">magnetosphere</span> is sensitive to both large-scale solar wind structures, which can be captured by solar wind models, and small-scale solar wind “noise,” which is far below typical solar wind model resolution and results primarily from stochastic processes. Following similar approaches in terrestrial climate modeling, we propose statistical “downscaling” of solar wind model results prior to their use as input to a <span class="hlt">magnetospheric</span> model. As <span class="hlt">magnetospheric</span> response can be highly nonlinear, this is preferable to downscaling the results of <span class="hlt">magnetospheric</span> modeling. To demonstrate the benefit of this approach, we first approximate solar wind model output by smoothing solar wind observations with an 8 h filter, then add small-scale structure back in through the addition of random noise with the observed spectral characteristics. Here we use a very simple parameterization of noise based upon the observed probability distribution functions of solar wind parameters, but more sophisticated methods will be developed in the future. An ensemble of results from the simple downscaling scheme are tested using a model-independent method and shown to add value to the <span class="hlt">magnetospheric</span> forecast, both improving the best estimate and quantifying the uncertainty. We suggest a number of features desirable in an operational solar wind downscaling scheme. Key Points Solar wind models must be downscaled in order to drive <span class="hlt">magnetospheric</span> models Ensemble downscaling is more effective than deterministic downscaling The <span class="hlt">magnetosphere</span> responds nonlinearly to small-scale solar wind fluctuations PMID:26213518</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26213518','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26213518"><span>Ensemble downscaling in coupled solar wind-<span class="hlt">magnetosphere</span> modeling for space weather forecasting.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Owens, M J; Horbury, T S; Wicks, R T; McGregor, S L; Savani, N P; Xiong, M</p> <p>2014-06-01</p> <p>Advanced forecasting of space weather requires simulation of the whole Sun-to-<span class="hlt">Earth</span> system, which necessitates driving <span class="hlt">magnetospheric</span> models with the outputs from solar wind models. This presents a fundamental difficulty, as the <span class="hlt">magnetosphere</span> is sensitive to both large-scale solar wind structures, which can be captured by solar wind models, and small-scale solar wind "noise," which is far below typical solar wind model resolution and results primarily from stochastic processes. Following similar approaches in terrestrial climate modeling, we propose statistical "downscaling" of solar wind model results prior to their use as input to a <span class="hlt">magnetospheric</span> model. As <span class="hlt">magnetospheric</span> response can be highly nonlinear, this is preferable to downscaling the results of <span class="hlt">magnetospheric</span> modeling. To demonstrate the benefit of this approach, we first approximate solar wind model output by smoothing solar wind observations with an 8 h filter, then add small-scale structure back in through the addition of random noise with the observed spectral characteristics. Here we use a very simple parameterization of noise based upon the observed probability distribution functions of solar wind parameters, but more sophisticated methods will be developed in the future. An ensemble of results from the simple downscaling scheme are tested using a model-independent method and shown to add value to the <span class="hlt">magnetospheric</span> forecast, both improving the best estimate and quantifying the uncertainty. We suggest a number of features desirable in an operational solar wind downscaling scheme. Solar wind models must be downscaled in order to drive <span class="hlt">magnetospheric</span> models Ensemble downscaling is more effective than deterministic downscaling The <span class="hlt">magnetosphere</span> responds nonlinearly to small-scale solar wind fluctuations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EGSGA..27.6198V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27.6198V"><span>Relationship of The Tropical Cyclogenesis With Solar and <span class="hlt">Magnetospheric</span> Activities</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vishnevsky, O. V.; Pankov, V. M.; Erokhine, N. S.</p> <p></p> <p>Formation of tropical cyclones is a badly studied period in their life cycle even though there are many papers dedicated to analysis of influence of different parameters upon cyclones occurrence frequency (see e.g., Gray W.M.). Present paper is dedicated to study of correlation of solar and <span class="hlt">magnetospheric</span> activity with the appearance of tropical cyclones in north-west region of Pacific ocean. Study of correlation was performed by using both classical statistical methods (including maximum entropy method) and quite modern ones, for example multifractal analysis. Information about Wolf's numbers and cyclogenesis intensity in period of 1944-2000 was received from different Internet databases. It was shown that power spectra maximums of Wolf's numbers and appeared tropical cyclones ones corresponds to 11-year period; solar activity and cyclogenesis processes intensity are in antiphase; maximum of mutual correlation coefficient (~ 0.8) between Wolf's numbers and cyclogenesis intensity is in South-China sea. There is a relation of multifractal characteristics calculated for both time series with the mutual correlation function that is another indicator of correlation between tropical cyclogenesis and solar-<span class="hlt">magnetospheric</span> activity. So, there is the correlation between solar-<span class="hlt">magnetospheric</span> activity and tropical cyclone intensity in this region. Possible physical mechanisms of such correlation including anomalous precipitations charged particles from the <span class="hlt">Earth</span> radiation belts and wind intensity amplification in the troposphere are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EGSGA..27.5584V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27.5584V"><span>Relationship of The Tropical Cyclogenesis With Solar and <span class="hlt">Magnetospheric</span> Activities</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vishnevsky, O.; Pankov, V.; Erokhine, N.</p> <p></p> <p>Formation of tropical cyclones is a badly studied period in their life cycle even though there are many papers dedicated to analysis of influence of different parameters upon cyclones occurrence frequency (see e.g., Gray W.M.). Present paper is dedicated to study of correlation of solar and <span class="hlt">magnetospheric</span> activity with the appearance of tropi- cal cyclones in north-west region of Pacific ocean. Study of correlation was performed by using both classical statistical methods (including maximum entropy method) and quite modern ones, for example multifractal analysis. Information about Wolf's num- bers and cyclogenesis intensity in period of 1944-2000 was received from different Internet databases. It was shown that power spectra maximums of Wolf's numbers and appeared tropical cyclones ones corresponds to 11-year period; solar activity and cyclogenesis processes intensity are in antiphase; maximum of mutual correlation co- efficient ( 0.8) between Wolf's numbers and cyclogenesis intensity is in South-China sea. There is a relation of multifractal characteristics calculated for both time series with the mutual correlation function that is another indicator of correlation between tropical cyclogenesis and solar-<span class="hlt">magnetospheric</span> activity. So, there is the correlation between solar-<span class="hlt">magnetospheric</span> activity and tropical cyclone intensity in this region. Possible physical mechanisms of such correlation including anomalous precipitations charged particles from the <span class="hlt">Earth</span> radiation belts and wind intensity amplification in the troposphere are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/5508092-energetic-particle-drift-motions-outer-dayside-magnetosphere','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5508092-energetic-particle-drift-motions-outer-dayside-magnetosphere"><span>Energetic-particle drift motions in the outer dayside <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Buck, R.C.</p> <p>1987-01-01</p> <p>Models of the geomagnetic field predict that within a distance of approximately one <span class="hlt">earth</span> radius inside the dayside magnetopause, magnetic fields produced by the Chapman-Ferraro magnetopause currents create high-latitude minimum-B pockets in the geomagnetic field. These pockets are theoretically capable of temporarily trapping azimuthally-drifting electrons and modifying electron directional distributions. The Lawrence Livermore National Laboratory's scanning electron spectrometer aboard the OGO-5 satellite provided detailed energetic (E > 70 keV) electron pitch-angle distributions throughout the <span class="hlt">magnetosphere</span>. Distributions obtained in the outer dayside <span class="hlt">magnetosphere</span> over a wide range of longitudes show unusual flux features. This study analyzes drift-shell branching caused by themore » minimum-B pockets, and interprets the observed flux features in terms of an adiabatic-shell branching and rejoining process. The author examines the shell-branching process for a static field in detail, using the Choe-Beard 1974 <span class="hlt">magnetospheric</span> magnetic field mode. He finds that shell branching and rejoining conserves the particle mirror field B/sub M/, the fieldline integral invariant I, and the directional electron flux j. He also finds a good correlation between the itch angles that mark the transition from branched to unbranched shells in the model and the distinctive features of the OGO-5 distributions.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110022647','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110022647"><span>Global <span class="hlt">Magnetospheric</span> Response to an Interplanetary Shock: THEMIS Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zhang, Hui; Sibeck, David G.; Zong, Q.-G.; McFadden, James P.; Larson, Davin; Glassmeier, K.-H.; Angelopoulos, V.</p> <p>2011-01-01</p> <p>We investigate the global response of geospace plasma environment to an interplanetary shock at approx. 0224 UT on May 28, 2008 from multiple THEMIS spacecraft observations in the magnetosheath (THEMIS B and C) and the mid-afternoon (THEMIS A) and dusk <span class="hlt">magnetosphere</span> (THEMIS D and E). The interaction of the transmitted interplanetary shock with the <span class="hlt">magnetosphere</span> has global effects. Consequently, it can affect geospace plasma significantly. After interacting with the bow shock, the interplanetary shock transmitted a fast shock and a discontinuity which propagated through the magnetosheath toward the <span class="hlt">Earth</span> at speeds of 300 km/s and 137 km/s respectively. THEMIS A observations indicate that the plasmaspheric plume changed significantly by the interplanetary shock impact. The plasmaspheric plume density increased rapidly from 10 to 100/ cubic cm in 4 min and the ion distribution changed from isotropic to strongly anisotropic distribution. Electromagnetic ion cyclotron (EMIC) waves observed by THEMIS A are most likely excited by the anisotropic ion distributions caused by the interplanetary shock impact. To our best knowledge, this is the first direct observation of the plasmaspheric plume response to an interplanetary shock's impact. THEMIS A, but not D or E, observed a plasmaspheric plume in the dayside <span class="hlt">magnetosphere</span>. Multiple spacecraft observations indicate that the dawn-side edge of the plasmaspheric plume was located between THEMIS A and D (or E).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSM41C2456G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSM41C2456G"><span>Global fully kinetic models of planetary <span class="hlt">magnetospheres</span> with iPic3D</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gonzalez, D.; Sanna, L.; Amaya, J.; Zitz, A.; Lembege, B.; Markidis, S.; Schriver, D.; Walker, R. J.; Berchem, J.; Peng, I. B.; Travnicek, P. M.; Lapenta, G.</p> <p>2016-12-01</p> <p>We report on the latest developments of our approach to model planetary <span class="hlt">magnetospheres</span>, mini <span class="hlt">magnetospheres</span> and the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span> with the fully kinetic, electromagnetic particle in cell code iPic3D. The code treats electrons and multiple species of ions as full kinetic particles. We review: 1) Why a fully kinetic model and in particular why kinetic electrons are needed for capturing some of the most important aspects of the physics processes of planetary <span class="hlt">magnetospheres</span>. 2) Why the energy conserving implicit method (ECIM) in its newest implementation [1] is the right approach to reach this goal. We consider the different electron scales and study how the new IECIM can be tuned to resolve only the electron scales of interest while averaging over the unresolved scales preserving their contribution to the evolution. 3) How with modern computing planetary <span class="hlt">magnetospheres</span>, mini <span class="hlt">magnetosphere</span> and eventually <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span> can be modeled with fully kinetic electrons. The path from petascale to exascale for iPiC3D is outlined based on the DEEP-ER project [2], using dynamic allocation of different processor architectures (Xeon and Xeon Phi) and innovative I/O technologies.Specifically results from models of Mercury are presented and compared with MESSENGER observations and with previous hybrid (fluid electrons and kinetic ions) simulations. The plasma convection around the planets includes the development of hydrodynamic instabilities at the flanks, the presence of the collisionless shocks, the magnetosheath, the magnetopause, reconnection zones, the formation of the plasma sheet and the magnetotail, and the variation of ion/electron plasma flows when crossing these frontiers. Given the full kinetic nature of our approach we focus on detailed particle dynamics and distribution at locations that can be used for comparison with satellite data. [1] Lapenta, G. (2016). Exactly Energy Conserving Implicit Moment Particle in Cell Formulation. arXiv preprint ar</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140010881','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140010881"><span>A New Standard Pulsar <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Contopoulos, Ioannis; Kalapotharakos, Constantinos; Kazanas, Demosthenes</p> <p>2014-01-01</p> <p>In view of recent efforts to probe the physical conditions in the pulsar current sheet, we revisit the standard solution that describes the main elements of the ideal force-free pulsar <span class="hlt">magnetosphere</span>. The simple physical requirement that the electric current contained in the current layer consists of the local electric charge moving outward at close to the speed of light yields a new solution for the pulsar <span class="hlt">magnetosphere</span> everywhere that is ideal force-free except in the current layer. The main elements of the new solution are as follows: (1) the pulsar spindown rate of the aligned rotator is 23% larger than that of the orthogonal vacuum rotator; (2) only 60% of the magnetic flux that crosses the light cylinder opens up to infinity; (3) the electric current closes along the other 40%, which gradually converges to the equator; (4) this transfers 40% of the total pulsar spindown energy flux in the equatorial current sheet, which is then dissipated in the acceleration of particles and in high-energy electromagnetic radiation; and (5) there is no separatrix current layer. Our solution is a minimum free-parameter solution in that the equatorial current layer is electrostatically supported against collapse and thus does not require a thermal particle population. In this respect, it is one more step toward the development of a new standard solution. We discuss the implications for intermittent pulsars and long-duration gamma-ray bursts. We conclude that the physical conditions in the equatorial current layer determine the global structure of the pulsar <span class="hlt">magnetosphere</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22348147-new-standard-pulsar-magnetosphere','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22348147-new-standard-pulsar-magnetosphere"><span>A new standard pulsar <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Contopoulos, Ioannis; Kalapotharakos, Constantinos; Kazanas, Demosthenes, E-mail: icontop@academyofathens.gr</p> <p>2014-01-20</p> <p>In view of recent efforts to probe the physical conditions in the pulsar current sheet, we revisit the standard solution that describes the main elements of the ideal force-free pulsar <span class="hlt">magnetosphere</span>. The simple physical requirement that the electric current contained in the current layer consists of the local electric charge moving outward at close to the speed of light yields a new solution for the pulsar <span class="hlt">magnetosphere</span> everywhere that is ideal force-free except in the current layer. The main elements of the new solution are as follows: (1) the pulsar spindown rate of the aligned rotator is 23% larger thanmore » that of the orthogonal vacuum rotator; (2) only 60% of the magnetic flux that crosses the light cylinder opens up to infinity; (3) the electric current closes along the other 40%, which gradually converges to the equator; (4) this transfers 40% of the total pulsar spindown energy flux in the equatorial current sheet, which is then dissipated in the acceleration of particles and in high-energy electromagnetic radiation; and (5) there is no separatrix current layer. Our solution is a minimum free-parameter solution in that the equatorial current layer is electrostatically supported against collapse and thus does not require a thermal particle population. In this respect, it is one more step toward the development of a new standard solution. We discuss the implications for intermittent pulsars and long-duration gamma-ray bursts. We conclude that the physical conditions in the equatorial current layer determine the global structure of the pulsar <span class="hlt">magnetosphere</span>.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150020825','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150020825"><span>Navigation Operations for the <span class="hlt">Magnetospheric</span> Multiscale Mission</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Long, Anne; Farahmand, Mitra; Carpenter, Russell</p> <p>2015-01-01</p> <p>The <span class="hlt">Magnetospheric</span> Multiscale (MMS) mission employs four identical spinning spacecraft flying in highly elliptical <span class="hlt">Earth</span> orbits. These spacecraft will fly in a series of tetrahedral formations with separations of less than 10 km. MMS navigation operations use onboard navigation to satisfy the mission definitive orbit and time determination requirements and in addition to minimize operations cost and complexity. The onboard navigation subsystem consists of the Navigator GPS receiver with Goddard Enhanced Onboard Navigation System (GEONS) software, and an Ultra-Stable Oscillator. The four MMS spacecraft are operated from a single Mission Operations Center, which includes a Flight Dynamics Operations Area (FDOA) that supports MMS navigation operations, as well as maneuver planning, conjunction assessment and attitude ground operations. The System Manager component of the FDOA automates routine operations processes. The GEONS Ground Support System component of the FDOA provides the tools needed to support MMS navigation operations. This paper provides an overview of the MMS mission and associated navigation requirements and constraints and discusses MMS navigation operations and the associated MMS ground system components built to support navigation-related operations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhPl...25d2303S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhPl...25d2303S"><span>Electron acoustic nonlinear structures in planetary <span class="hlt">magnetospheres</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shah, K. H.; Qureshi, M. N. S.; Masood, W.; Shah, H. A.</p> <p>2018-04-01</p> <p>In this paper, we have studied linear and nonlinear propagation of electron acoustic waves (EAWs) comprising cold and hot populations in which the ions form the neutralizing background. The hot electrons have been assumed to follow the generalized ( r , q ) distribution which has the advantage that it mimics most of the distribution functions observed in space plasmas. Interestingly, it has been found that unlike Maxwellian and kappa distributions, the electron acoustic waves admit not only rarefactive structures but also allow the formation of compressive solitary structures for generalized ( r , q ) distribution. It has been found that the flatness parameter r , tail parameter q , and the nonlinear propagation velocity u affect the propagation characteristics of nonlinear EAWs. Using the plasmas parameters, typically found in Saturn's <span class="hlt">magnetosphere</span> and the <span class="hlt">Earth</span>'s auroral region, where two populations of electrons and electron acoustic solitary waves (EASWs) have been observed, we have given an estimate of the scale lengths over which these nonlinear waves are expected to form and how the size of these structures would vary with the change in the shape of the distribution function and with the change of the plasma parameters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SSRv..192..145W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SSRv..192..145W"><span>The <span class="hlt">Earth</span>: Plasma Sources, Losses, and Transport Processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Welling, Daniel T.; André, Mats; Dandouras, Iannis; Delcourt, Dominique; Fazakerley, Andrew; Fontaine, Dominique; Foster, John; Ilie, Raluca; Kistler, Lynn; Lee, Justin H.; Liemohn, Michael W.; Slavin, James A.; Wang, Chih-Ping; Wiltberger, Michael; Yau, Andrew</p> <p>2015-10-01</p> <p>This paper reviews the state of knowledge concerning the source of <span class="hlt">magnetospheric</span> plasma at <span class="hlt">Earth</span>. Source of plasma, its acceleration and transport throughout the system, its consequences on system dynamics, and its loss are all discussed. Both observational and modeling advances since the last time this subject was covered in detail (Hultqvist et al., <span class="hlt">Magnetospheric</span> Plasma Sources and Losses, 1999) are addressed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170011155','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170011155"><span><span class="hlt">Magnetospheric</span> Multiscale Mission Navigation Performance During Apogee-Raising and Beyond</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Farahmand, Mitra; Long, Anne; Hollister, Jacob; Rose, Julie; Godine, Dominic</p> <p>2017-01-01</p> <p>The primary objective of the <span class="hlt">Magnetospheric</span> Multiscale (MMS) Mission is to study the magnetic reconnection phenomena in the <span class="hlt">Earths</span> <span class="hlt">magnetosphere</span>. The MMS mission consists of four identical spinning spacecraft with the science objectives requiring a tetrahedral formation in highly elliptical orbits. The MMS spacecraft are equipped with onboard orbit and time determination software, provided by a weak-signal Global Positioning System (GPS) Navigator receiver hosting the Goddard Enhanced Onboard Navigation System (GEONS). This paper presents the results of MMS navigation performance analysis during the Phase 2a apogee-raising campaign and Phase 2b science segment of the mission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790052163&hterms=Electromagnetic+Spectrum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DElectromagnetic%2BSpectrum','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790052163&hterms=Electromagnetic+Spectrum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DElectromagnetic%2BSpectrum"><span>Electrostatic and electromagnetic gyroharmonic emissions due to energetic electrons in <span class="hlt">magnetospheric</span> plasma</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Curtis, S. A.; Wu, C. S.</p> <p>1979-01-01</p> <p>The paper derives the growth rates and growth lengths of the electrostatic emission for spatially homogeneous and inhomogeneous energetic electrons, and numerically evaluates the growth rate and growth length spectra for several parameter sets representative of <span class="hlt">magnetospheric</span> plasmas. In addition, the growth rates are derived for the case of electromagnetic emission modeled by the ordinary mode. The numerical results of the electromagnetic and electrostatic cases are compared with observations made by satellites in the <span class="hlt">earth</span>'s <span class="hlt">magnetosphere</span>. It is concluded that the electrostatic gyroharmonic excitation is possible without the cold composition of plasma which is often postulated in the existing literature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA20754.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA20754.html"><span>Data Recorded as Juno Entered <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2016-06-30</p> <p>This chart presents data that the Waves investigation on NASA's Juno spacecraft recorded as the spacecraft crossed the bow shock just outside of Jupiter's <span class="hlt">magnetosphere</span> on June 24, 2016, while approaching Jupiter. Audio accompanies the animation, with volume and pitch correlated to the amplitude and frequency of the recorded waves. The graph is a frequency-time spectrogram with color coding to indicate wave amplitudes as a function of wave frequency (vertical axis, in hertz) and time (horizontal axis, with a total elapsed time of two hours). During the hour before Juno reached the bow shock, the Waves instrument was detecting mainly plasma oscillations just below 10,000 hertz (10 kilohertz). The frequency of these oscillations is related to the local density of electrons; the data yield an estimate of approximately one electron per cubic centimeter (about 16 per cubic inch) in this region just outside Jupiter's bow shock. The broadband burst of noise marked "Bow Shock" is the region of turbulence where the supersonic solar wind is heated and slowed by encountering the Jovian <span class="hlt">magnetosphere</span>. The shock is analogous to a sonic boom generated in <span class="hlt">Earth</span>'s atmosphere by a supersonic aircraft. The region after the shock is called the magnetosheath. The vertical bar to the right of the chart indicates the color coding of wave amplitude, in decibels (dB) above the background level detected by the Waves instrument. Each step of 10 decibels marks a tenfold increase in wave power. When Juno collected these data, the distance from the spacecraft to Jupiter was about 5.56 million miles (8.95 million kilometers), indicated on the chart as 128 times the radius of Jupiter. Jupiter's magnetic field is tilted about 10 degrees from the planet's axis of rotation. The note of 22 degrees on the chart indicates that at the time these data were recorded, the spacecraft was 22 degrees north of the magnetic-field equator. The "LT" notation is local time on Jupiter at the longitude of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1394981-warm-plasma-composition-inner-magnetosphere-during','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1394981-warm-plasma-composition-inner-magnetosphere-during"><span>The Warm Plasma Composition in the Inner <span class="hlt">Magnetosphere</span> during 2012–2015</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jahn, J. M.; Goldstein, J.; Reeves, Geoffrey D.</p> <p></p> <p>Ionospheric heavy ions play an important role in the dynamics of <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>. The greater mass and gyro radius of ionospheric oxygen differentiates its behavior from protons at the same energies. Oxygen may have an impact on tail reconnection processes, and it can at least temporarily dominate the energy content of the ring current during geomagnetic storms. At sub-keV energies, multi-species ion populations in the inner <span class="hlt">magnetosphere</span> form the warm plasma cloak, occupying the energy range between the plasmasphere and the ring current. Lastly, cold lighter ions from the mid-latitude ionosphere create the co-rotating plasmasphere whose outer regions can interactmore » with the plasma cloak, plasma sheet, ring current, and outer electron belt. Here in this paper we present a statistical view of warm, cloak-like ion populations in the inner <span class="hlt">magnetosphere</span>, contrasting in particular the warm plasma composition during quiet and active times. We study the relative abundances and absolute densities of warm plasma measured by the Van Allen Probes, whose two spacecraft cover the inner <span class="hlt">magnetosphere</span> from plasmaspheric altitudes close to <span class="hlt">Earth</span> to just inside geostationary orbit. We observe that warm (>30 eV) oxygen is most abundant closer to the plasmasphere boundary whereas warm hydrogen dominates closer to geostationary orbit. Warm helium is usually a minor constituent, but shows a noticeable enhancement in the near-<span class="hlt">Earth</span> dusk sector.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1394981-warm-plasma-composition-inner-magnetosphere-during','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1394981-warm-plasma-composition-inner-magnetosphere-during"><span>The Warm Plasma Composition in the Inner <span class="hlt">Magnetosphere</span> during 2012–2015</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Jahn, J. M.; Goldstein, J.; Reeves, Geoffrey D.; ...</p> <p>2017-09-11</p> <p>Ionospheric heavy ions play an important role in the dynamics of <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>. The greater mass and gyro radius of ionospheric oxygen differentiates its behavior from protons at the same energies. Oxygen may have an impact on tail reconnection processes, and it can at least temporarily dominate the energy content of the ring current during geomagnetic storms. At sub-keV energies, multi-species ion populations in the inner <span class="hlt">magnetosphere</span> form the warm plasma cloak, occupying the energy range between the plasmasphere and the ring current. Lastly, cold lighter ions from the mid-latitude ionosphere create the co-rotating plasmasphere whose outer regions can interactmore » with the plasma cloak, plasma sheet, ring current, and outer electron belt. Here in this paper we present a statistical view of warm, cloak-like ion populations in the inner <span class="hlt">magnetosphere</span>, contrasting in particular the warm plasma composition during quiet and active times. We study the relative abundances and absolute densities of warm plasma measured by the Van Allen Probes, whose two spacecraft cover the inner <span class="hlt">magnetosphere</span> from plasmaspheric altitudes close to <span class="hlt">Earth</span> to just inside geostationary orbit. We observe that warm (>30 eV) oxygen is most abundant closer to the plasmasphere boundary whereas warm hydrogen dominates closer to geostationary orbit. Warm helium is usually a minor constituent, but shows a noticeable enhancement in the near-<span class="hlt">Earth</span> dusk sector.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhDT........90G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhDT........90G"><span><span class="hlt">Magnetosphere</span>-ionosphere coupling during active aurora</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grubbs, Guy, II</p> <p></p> <p>In this work, processes which couple the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span> and ionosphere are examined using observations of aurora from ground-based imaging, in situ electron measurements, and electron transport modeling. The coupling of these regions relies heavily on the energy transport between the two and the ionospheric conductances, which regulate the location and magnitude of the transport. The combination of the datasets described are used to derive the conductances and electron energy populations at the upper boundary of the ionosphere. These values are constrained using error analysis of the observation and measurement techniques and made available to the global <span class="hlt">magnetosphere</span> modeling community for inclusion as boundary conditions at the <span class="hlt">magnetosphere</span> and ionosphere coupling region. A comparative study of the active aurora and incident electron distributions was conducted using ground-based measurements and in-situ sounding rocket data. Three narrow-field (47 degree field-of-view) electron-multiplying charge-coupled device (EMCCD) imagers were located at Venetie, AK which took high spatio-temporal resolution measurements of the aurora using different wavelength filters (427.8 nm, 557.7 nm, and 844.6 nm). The measured emission line ratios were combined with atmospheric modeling in order to predict the total electron energy flux and characteristic electron energy incident on the atmosphere. These predictions were compared with in-situ measurements made by the Ground-to-Rocket Electrodynamics-Electrons Correlative Experiment (GREECE) sounding rocket launched in early 2014. The GREECE particle instruments were modeled using a ray-tracing program, SIMION, in order to predict the instrument responses for different incident particles. Each instrument model was compared with data taken in the lab in order to compare and update the models appropriately. A rocket emulation system was constructed for lab testing prior to and during instrument integration into the rocket and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011atp..prop..178T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011atp..prop..178T"><span>Massive-Star <span class="hlt">Magnetospheres</span>: Now in 3-D!</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Townsend, Richard</p> <p></p> <p> prototyped. Simulation data from these codes will be used to synthesize observables, suitable for comparison with datasets from ground- and space-based facilities. Project results will be disseminated in the form of journal papers, presentations, data and visualizations, to facilitate the broad communication of our results. In addition, we will release the project codes under an open- source license, to encourage other groups' involvement in modeling massive-star <span class="hlt">magnetospheres</span>. Through furthering our insights into these <span class="hlt">magnetospheres</span>, the project is congruous with NASA's Strategic Goal 2, 'Expand scientific understanding of the <span class="hlt">Earth</span> and the universe in which we live'. By making testable predictions of X-ray emission and UV line profiles, it is naturally synergistic with observational studies of magnetic massive stars using NASA's ROSAT, Chandra, IUE and FUSE missions. By exploring magnetic braking, it will have a direct impact on theoretical predictions of collapsar yields, and thereby help drive forward the analysis and interpretation of gamma-ray burst observations by NASA's Swift and Fermi missions. And, through its general contribution toward understanding the lifecycle of massive stars, the project will complement the past, present and future investments in studying these stars using NASA's other space-based observatories.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EPSC....8..402S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EPSC....8..402S"><span>MESSENGER Observations of Extreme Space Weather in Mercury's <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Slavin, J. A.</p> <p>2013-09-01</p> <p>Increasing activity on the Sun is allowing MESSENGER to make its first observations of Mercury's <span class="hlt">magnetosphere</span> under extreme solar wind conditions. At <span class="hlt">Earth</span> interplanetary shock waves and coronal mass ejections produce severe "space weather" in the form of large geomagnetic storms that affect telecommunications, space systems, and ground-based power grids. In the case of Mercury the primary effect of extreme space weather in on the degree to which this it's weak global magnetic field can shield the planet from the solar wind. Direct impact of the solar wind on the surface of airless bodies like Mercury results in space weathering of the regolith and the sputtering of atomic species like sodium and calcium to high altitudes where they contribute to a tenuous, but highly dynamic exosphere. MESSENGER observations indicate that during extreme interplanetary conditions the solar wind plasma gains access to the surface of Mercury through three main regions: 1. The <span class="hlt">magnetospheric</span> cusps, which fill with energized solar wind and planetary ions; 2. The subsolar magnetopause, which is compressed and eroded by reconnection to very low altitudes where the natural gyro-motion of solar wind protons may result in their impact on the surface; 3. The magnetotail where hot plasma sheet ions rapidly convect sunward to impact the surface on the nightside of Mercury. The possible implications of these new MESSENGER observations for our ability to predict space weather at <span class="hlt">Earth</span> and other planets will be described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012APS..DPPCP8049N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012APS..DPPCP8049N"><span><span class="hlt">Magnetospheric</span> Reconnection in Modified Current-Sheet Equilibria</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Newman, D. L.; Goldman, M. V.; Lapenta, G.; Markidis, S.</p> <p>2012-10-01</p> <p>Particle simulations of magnetic reconnection in <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span> are frequently initialized with a current-carrying Harris equilibrium superposed on a current-free uniform background plasma. The Harris equilibrium satisfies local charge neutrality, but requires that the sheet current be dominated by the hotter species -- often the ions in <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>. This constraint is not necessarily consistent with observations. A modified kinetic equilibrium that relaxes this constraint on the currents was proposed by Yamada et al. [Phys. Plasmas., 7, 1781 (2000)] with no background population. These modified equilibria were characterized by an asymptotic converging or diverging electrostatic field normal to the current sheet. By reintroducing the background plasma, we have developed new families of equilibria where the asymptotic fields are suppressed by Debye shielding. Because the electrostatic potential profiles of these new equilibria contain wells and/or barriers capable of spatially isolating different populations of electrons and/or ions, these solutions can be further generalized to include classes of asymmetric kinetic equilibria. Examples of both symmetric and asymmetric equilibria will be presented. The dynamical evolution of these equilibria, when perturbed, will be further explored by means of implicit 2D PIC reconnection simulations, including comparisons with simulations employing standard Harris-equilibrium initializations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20100032909&hterms=lime&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dlime','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20100032909&hterms=lime&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dlime"><span>Saturation of the Electric Field Transmitted to the <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lyatsky, Wladislaw; Khazanov, George V.; Slavin, James A.</p> <p>2010-01-01</p> <p>We reexamined the processes leading to saturation of the electric field, transmitted into the <span class="hlt">Earth</span>'s ionosphere from the solar wind, incorporating features of the coupled system previously ignored. We took into account that the electric field is transmitted into the ionosphere through a region of open field lines, and that the ionospheric conductivity in the polar cap and auroral zone may be different. Penetration of the electric field into the <span class="hlt">magnetosphere</span> is linked with the generation of the Alfven wave, going out from the ionosphere into the solar wind and being coupled with the field-aligned currents at the boundary of the open field limes. The electric field of the outgoing Alfven wave reduces the original electric field and provides the saturation effect in the electric field and currents during strong geomagnetic disturbances, associated with increasing ionospheric conductivity. The electric field and field-aligned currents of this Alfven wave are dependent on the ionospheric and solar wind parameters and may significantly affect the electric field and field-aligned currents, generated in the polar ionosphere. Estimating the magnitude of the saturation effect in the electric field and field-aligned currents allows us to improve the correlation between solar wind parameters and resulting disturbances in the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017SSRv..212.1221E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017SSRv..212.1221E"><span>The Scientific Foundations of Forecasting <span class="hlt">Magnetospheric</span> Space Weather</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eastwood, J. P.; Nakamura, R.; Turc, L.; Mejnertsen, L.; Hesse, M.</p> <p>2017-11-01</p> <p>The <span class="hlt">magnetosphere</span> is the lens through which solar space weather phenomena are focused and directed towards the <span class="hlt">Earth</span>. In particular, the non-linear interaction of the solar wind with the <span class="hlt">Earth</span>'s magnetic field leads to the formation of highly inhomogenous electrical currents in the ionosphere which can ultimately result in damage to and problems with the operation of power distribution networks. Since electric power is the fundamental cornerstone of modern life, the interruption of power is the primary pathway by which space weather has impact on human activity and technology. Consequently, in the context of space weather, it is the ability to predict geomagnetic activity that is of key importance. This is usually stated in terms of geomagnetic storms, but we argue that in fact it is the substorm phenomenon which contains the crucial physics, and therefore prediction of substorm occurrence, severity and duration, either within the context of a longer-lasting geomagnetic storm, but potentially also as an isolated event, is of critical importance. Here we review the physics of the <span class="hlt">magnetosphere</span> in the frame of space weather forecasting, focusing on recent results, current understanding, and an assessment of probable future developments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830026222','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830026222"><span>Nonlinear longitudinal resonance interaction of energetic charged particles and VLF waves in the <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tkalcevic, S.</p> <p>1982-01-01</p> <p>The longitudinal resonance of waves and energetic electrons in the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>, and the possible role this resonance may play in generating various <span class="hlt">magnetospheric</span> phenomena are studied. The derivation of time-averaged nonlinear equations of motion for energetic particles longitudinally resonant with a whistler mode wave propagating with nonzero wave normal is considered. It is shown that the wave magnetic forces can be neglected at lower particle pitch angles, while they become equal to or larger than the wave electric forces for alpha 20 deg. The time-averaged equations of motion were used in test particle simulation which were done for a wide range of wave amplitudes, wave normals, particle pitch angles, particle parallel velocities, and in an inhomogeneous medium such as the <span class="hlt">magnetosphere</span>. It was found that there are two classes of particles, trapped and untrapped, and that the scattering and energy exchange for those two groups exhibit significantly different behavior.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSA43B2653F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSA43B2653F"><span>Coupling of the <span class="hlt">Magnetosphere</span>-Ionosphere/Thermosphere and Oxygen Outflow-- MIT Mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fu, S.</p> <p>2017-12-01</p> <p>The goal of the MIT mission is to understand the coupling of the <span class="hlt">magnetosphere</span> and ionosphere from the prospective of particles. It will focus on the outflow of the ionosphere particles (mainly oxygen ions) from the <span class="hlt">Earth</span>, including the acceleration mechanisms of oxygen ions and their relative importance in different regions, the importance of these ions while transferred into the <span class="hlt">magnetosphere</span> and the roles they played in <span class="hlt">magnetosphere</span> activities. A constellation of four satellites orbiting at three elliptical orbits will provide the unique opportunities to observed there ions at three different altitude with temporal changes of the flux of these particles and the magnetic field environments. The conceptual design of the spacecraft and a summary of the payload will be presented. The MIT mission was selected as one of the five candidates for the upcoming mission plan in China.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AIPC.1953n0137P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AIPC.1953n0137P"><span>Oblique propagating electromagnetic ion - Cyclotron instability with A.C. field in outer <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pandey, R. S.; Singh, Vikrant; Rani, Anju; Varughese, George; Singh, K. M.</p> <p>2018-05-01</p> <p>In the present paper Oblique propagating electromagnetic ion-cyclotron wave has been analyzed for anisotropic multi ion plasma (H+, He+, O+ ions) in <span class="hlt">earth</span> <span class="hlt">magnetosphere</span> for the Dione shell of L=7 i.e., the outer radiation belt of the <span class="hlt">magnetosphere</span> for Loss-cone distribution function with a spectral index j in the presence of A.C. electric field. Detail for particle trajectories and dispersion relation has been derived by using the method of characteristic solution on the basis of wave particle interaction and transformation of energy. Results for the growth rate have been calculated numerically for various parameters and have been compared for different ions present in <span class="hlt">magnetosphere</span>. It has been found that for studying the wave over wider spectrum, anisotropy for different values of j should be taken. The effect of frequency of A.C. electric field and angle which propagation vector make with magnetic field, on growth rate has been explained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM41C2493P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM41C2493P"><span>Identification of the different magnetic field contributions during a geomagnetic storm in <span class="hlt">magnetosphere</span> and at ground.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Piersanti, M.; Alberti, T.; Vecchio, A.; Lepreti, F.; Villante, U.; Carbone, V.; De Michelis, P.</p> <p>2015-12-01</p> <p>Geomagnetic storms (GS) are global geomagnetic disturbances that result from the interaction between magnetized plasma that propagates from the Sun and plasma and magnetic fields in the near-<span class="hlt">Earth</span> space plasma environment. The Dst (Disturbance Storm Time) global Ring Current index is still taken to be the definitive representation for geomagnetic storm and is used widely by researcher. Recent in situ measurements by satellites passing through the ring-current region (i.e. Van Allen probes) and computations with <span class="hlt">magnetospheric</span> field models showed that there are many other field contributions on the geomagnetic storming time variations at middle and low latitudes. Appling the Empirical Mode Decomposition [Huang et al., 1998] to <span class="hlt">magnetospheric</span> and ground observations, we detect the different magnetic field contributions during a GS and introduce the concepts of modulated baseline and fluctuations of the geomagnetic field. This allows to define local geomagnetic indices that can be used in discriminating the ionospheric from <span class="hlt">magnetospheric</span> origin contribution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090006653','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090006653"><span>Pair-Starved Pulsar <span class="hlt">Magnetospheres</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Muslimov, Alex G.; Harding, Alice K.</p> <p>2009-01-01</p> <p>We propose a simple analytic model for the innermost (within the light cylinder of canonical radius, approx. c/Omega) structure of open-magnetic-field lines of a rotating neutron star (NS) with relativistic outflow of charged particles (electrons/positrons) and arbitrary angle between the NS spin and magnetic axes. We present the self-consistent solution of Maxwell's equations for the magnetic field and electric current in the pair-starved regime where the density of electron-positron plasma generated above the pulsar polar cap is not sufficient to completely screen the accelerating electric field and thus establish thee E . B = 0 condition above the pair-formation front up to the very high altitudes within the light cylinder. The proposed mode1 may provide a theoretical framework for developing the refined model of the global pair-starved pulsar <span class="hlt">magnetosphere</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E1728S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E1728S"><span>The super-low frequency resonances at <span class="hlt">magnetospheric</span> boundaries versus geostationary and ionospheric data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Savin, Sergey; Surjalal Sharma, A.; Pilipenko, Viacheslav; Marcucci, Maria Federica; Nemecek, Zdenek; Safrankova, Jana; Consolini, Giuseppe; Belakhovsky, Vladimir; Kozak, Ludmila; Blecki, Jan; Kronberg, Elena</p> <p>2016-07-01</p> <p>We do a multi-point study of the influence of the lowest frequency resonances (0.02-10 mHz) at the outer <span class="hlt">magnetospheric</span> boundaries on the fluctuations inside the <span class="hlt">magnetosphere</span> and ionosphere presented. The correlations of the dynamic pressure data from CLUSTER, DOUBLE STAR, GEOTAIL, ACE/ WIND, particle data from LANL, GOES with the magnetic data from polar ionospheric stations on March 27, 2005, show that: i) the waves generated by boundary resonances and their harmonics penetrate inside the <span class="hlt">magnetosphere</span> and reach the ionosphere; ii) correlations between the dynamic pressure fluctuations at the <span class="hlt">magnetospheric</span> boundaries and <span class="hlt">magnetospheric</span>/ ionospheric disturbances, including indices such as AE and SYM-H, can exceed 80%; iii) the new resonance frequencies are lower by an order of magnitude compared with our previous studies, which are as low as 0.02 mHz. Furthermore, such resonances are characteristic also for the night-side geostationary/ionospheric data and for the middle tail, i.e., they are global <span class="hlt">magnetospheric</span> features. Analysis of different types of correlations yields the unexpected result that in ~48% of the cases with pronounced maximum in the correlation function the geostationary/ ionospheric response is seen before the magnetosheath (MSH) response. We propose that some global <span class="hlt">magnetospheric</span> resonances (e.g. membrane bow shock surface (0.2-0.5 mHz) and/or magnetopause (0.5-0.9 mHz) modes along with the cavity MHS/ cusp (3-10 mHz) and <span class="hlt">magnetospheric</span> global modes (0.02-0.09mHz)) can account for the data presented. The multiple jets at the sampled MSH locations can be a consequence of the resonances, while an initial disturbance (e.g. through the interplanetary shocks, Hot Flow Anomalies, foreshock irregularities etc., were not observed by particular spacecraft in MSH because they were localized in the plane perpendicular to the Sun-<span class="hlt">Earth</span> line. So, in the explorations of the solar wind - <span class="hlt">magnetosphere</span> interactions one should take into account these</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120007923','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120007923"><span>Towards a Realistic Pulsar <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kalapotharakos, Constantinos; Kazanas, Demosthenes; Harding, Alice; Contopoulos, Ioannis</p> <p>2012-01-01</p> <p>We present the magnetic and electric field structures as well as the currents ami charge densities of pulsar magnetospberes which do not obey the ideal condition, E(raised dot) B = O. Since the acceleration of particles and the production of radiation requires the presence of an electric field component parallel to the magnetic field, E(sub ll) the structure of non-Ideal pulsar <span class="hlt">magnetospheres</span> is intimately related to the production of pulsar radiation. Therefore, knowledge of the structure of non-Ideal pulsar maglletospheres is important because their comparison (including models for t he production of radiation) with observations will delineate the physics and the parameters underlying the pulsar radiation problem. We implement a variety of prescriptions that support nonzero values for E(sub ll) and explore their effects on the structure of the resulting <span class="hlt">magnetospheres</span>. We produce families of solutions that span the entire range between the vacuum and the (ideal) Force-Free Electrodynamic solutions. We also compute the amount of dissipation as a fraction of the Poynting flux for pulsars of different angles between the rotation and magnetic axes and conclude that tltis is at most 20-40% (depending on t he non-ideal prescription) in the aligned rotator and 10% in the perpendicular one. We present also the limiting solutions with the property J = pc and discuss their possible implicatioll on the determination of the "on/ off" states of the intermittent pulsars. Finally, we find that solutions with values of J greater than those needed to null E(sub ll) locally produce oscillations, potentially observable in the data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980017492','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980017492"><span>Electric Propulsion Options for a <span class="hlt">Magnetospheric</span> Mapping Mission</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oleson, Steven; Russell, Chris; Hack, Kurt; Riehl, John</p> <p>1998-01-01</p> <p>The Twin Electric <span class="hlt">Magnetospheric</span> Probes Exploring on Spiral Trajectories mission concept was proposed as a Middle Explorer class mission. A pre-phase-A design was developed which utilizes the advantages of electric propulsion for <span class="hlt">Earth</span> scientific spacecraft use. This paper presents propulsion system analyses performed for the proposal. The proposed mission required two spacecraft to explore near circular orbits 0.1 to 15 <span class="hlt">Earth</span> radii in both high and low inclination orbits. Since the use of chemical propulsion would require launch vehicles outside the Middle Explorer class a reduction in launch mass was sought using ion, Hall, and arcjet electric propulsion system. Xenon ion technology proved to be the best propulsion option for the mission requirements requiring only two Pegasus XL launchers. The Hall thruster provided an alternative solution but required two larger, Taurus launch vehicles. Arcjet thrusters did not allow for significant launch vehicle reduction in the Middle Explorer class.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930007347','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930007347"><span>Inferences Concerning the <span class="hlt">Magnetospheric</span> Source Region for Auroral Breakup</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lyons, L. R.</p> <p>1992-01-01</p> <p>It is argued that the <span class="hlt">magnetospheric</span> source region for auroral arc breakup and substorm initiation is along boundary plasma sheet (BPS) magnetic field lines. This source region lies beyond a distinct central plasma sheet (CPS) region and sufficiently far from the <span class="hlt">Earth</span> that energetic ion motion violates the guiding center approximation (i.e., is chaotic). The source region is not constrained to any particular range of distances from the <span class="hlt">Earth</span>, and substorm initiation may be possible over a wide range of distances from near synchronous orbit to the distant tail. It is also argued that the layer of low-energy electrons and velocity dispersed ion beams observed at low altitudes on Aureol 3 is not a different region from the region of auroral arcs. Both comprise the BPS. The two regions occasionally appear distinct at low altitudes because of the effects of arc field-aligned potential drops on precipitating particles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EOSTr..83Q...2S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EOSTr..83Q...2S"><span>New clues about <span class="hlt">magnetosphere</span> noise and black aurora</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Showstack, Randy</p> <p></p> <p>The noise sounds vaguely as if it emanates from the high-pitched chatter of tropical birds or wetted fingers rubbing along musical glasses. However, the auroral kilometric radiation (AKR)—a radio wave of about 540-550 kilohertz just below the AM radio band—emanates from <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span> 11,000-13,000 kilometers above the <span class="hlt">Earth</span>'s northern lights.Some researchers had proposed this as the likely origin for the noise three decades ago. However, scientists at the AGU Fall Meeting, held in San Francisco, California, said that new measurements made by instruments onboard the four spacecraft of the European Space Agency's (ESA) Cluster mission have confirmed this theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/22069220-perturbations-ionosphere-magnetosphere-coupling-powerful-vlf-emissions-from-ground-based-transmitters','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/22069220-perturbations-ionosphere-magnetosphere-coupling-powerful-vlf-emissions-from-ground-based-transmitters"><span>Perturbations of ionosphere-<span class="hlt">magnetosphere</span> coupling by powerful VLF emissions from ground-based transmitters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Belov, A. S., E-mail: alexis-belov@yandex.ru; Markov, G. A.; Ryabov, A. O.</p> <p></p> <p>The characteristics of the plasma-wave disturbances stimulated in the near-<span class="hlt">Earth</span> plasma by powerful VLF radiation from ground-based transmitters are investigated. Radio communication VLF transmitters of about 1 MW in power are shown to produce artificial plasma-wave channels (density ducts) in the near-<span class="hlt">Earth</span> space that originate in the lower ionosphere above the disturbing emission source and extend through the entire ionosphere and <span class="hlt">magnetosphere</span> of the <span class="hlt">Earth</span> along the magnetic field lines. Measurements with the onboard equipment of the DEMETER satellite have revealed that under the action of emission from the NWC transmitter, which is one of the most powerful VLF radiomore » transmitters, the generation of quasi-electrostatic (plasma) waves is observed on most of the satellite trajectory along the disturbed magnetic flux tube. This may probably be indicative of stimulated emission of a <span class="hlt">magnetospheric</span> maser.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E.554C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E.554C"><span>Evolution of Eigenmodes of the Mhd-Waveguide in the Outer <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chuiko, Daniil</p> <p></p> <p>EVOLUTION OF EIGENMODES OF THE MHD-WAVEGUIDE IN THE OUTER <span class="hlt">MAGNETOSPHERE</span> Mazur V.A., Chuiko D.A. Institute of Solar-Terrestrial Physics, Irkutsk, Russia. Geomagnetic field and plasma inhomogeneties in the outer equatorial part of the <span class="hlt">magnetosphere</span> al-lows for existence of a channel with low Alfven speeds, which spans from the nose to the far flanks of the <span class="hlt">magnetosphere</span>, in the morning as well as in the evening sectors. This channel plays a role of a waveguide for fast magnetosonic waves. When an eigenmode travels along the waveguide (i.e. in the azimuthal direction) it undergoes certain evolution. The parameters of the waveguide are changing along the way of wave’s propagation and the eigenmode “adapts” to these parameters. Conditions of the Kelvin-Helmholtz instability are changing due to the increment in the solar wind speed along the magnetopause. The conditions of the solar wind hydromagnetic waves penetration to the <span class="hlt">magnetosphere</span> are changing due to the same increment. As such, the process of the penetration turns to overreflection regime, which abruptly increases the pump level of the <span class="hlt">magnetospheric</span> waveguide. There is an Alfven resonance deep within the <span class="hlt">magnetosphere</span>, which corresponds to the propagation of the fast mode along the waveguide. Oscillation energy dissipation takes place in the vicinity of the Alfven resonance. Alfven resonance is a standing Alfven wave along the magnetic field lines, so it reaches the ionosphere and the <span class="hlt">Earth</span> surface, when the fast modes of the waveguide, localized in the low Alfven speed channel cannot be observed on <span class="hlt">Earth</span>. The evolution of the waveguide oscillation propagating from the nose to the far tail is theoretically investigated in this work with consideration of all aforementioned effects. The spatial structure var-iation character, spectral composition and amplitude along the waveguide are found.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36.1804S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36.1804S"><span>System design and instrument development for future formation-flying <span class="hlt">magnetospheric</span> satellite mission SCOPE</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saito, Y.; Fujimoto, M.; Maezawa, K.; Kojima, H.; Takashima, T.; Matsuoka, A.; Shinohara, I.; Tsuda, Y.; Higuchi, K.; Toda, T.</p> <p></p> <p>Japan Aerospace Exploration Agency JAXA is currently planning a next generation <span class="hlt">magnetosphere</span> observation mission called SCOPE cross-Scale COupling in the Plasma universE The main purpose of this mission is to investigate the dynamic behaviors of plasmas in the Terrestrial <span class="hlt">magnetosphere</span> that range over various time and spatial scales The basic idea of the SCOPE mission is to distinguish temporal and spatial variations of physical processes by putting five formation flying spacecraft into the key region of the Terrestrial <span class="hlt">magnetosphere</span> The orbit of SCOPE is a highly elliptical orbit with its apogee 30Re from the <span class="hlt">Earth</span> center SCOPE consists of one 450kg mother satellite and four 90kg daughter satellites flying 5 to 5000km apart from each other The inter-satellite link is used for telemetry command operation as well as ranging to determine the relative orbit of 5 satellites in a small distance which cannot be resolved by the ground-based orbit determination The SCOPE mission is designed such that observational studies from the new perspective that is the cross-scale coupling viewpoint are enabled The orbit is so designed that the spacecraft will visit most of the key regions in the <span class="hlt">magnetosphere</span> that is the bow shock the <span class="hlt">magnetospheric</span> boundary the inner-<span class="hlt">magnetosphere</span> and the near-<span class="hlt">Earth</span> magnetotail In order to realize the science objectives high performance Plasma Particle sensors DC AC Magnetic and Electric field sensors and Wave Particle Correlator are planned to be onboard the SCOPE satellite All the SCOPE satellites have two 5m spin-axis antenna</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..12212153J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..12212153J"><span>Mercury's Solar Wind Interaction as Characterized by <span class="hlt">Magnetospheric</span> Plasma Mantle Observations With MESSENGER</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jasinski, Jamie M.; Slavin, James A.; Raines, Jim M.; DiBraccio, Gina A.</p> <p>2017-12-01</p> <p>We analyze 94 traversals of Mercury's southern <span class="hlt">magnetospheric</span> plasma mantle using data from the MESSENGER spacecraft. The mean and median proton number densities in the mantle are 1.5 and 1.3 cm-3, respectively. For sodium number density these values are 0.004 and 0.002 cm-3. Moderately higher densities are observed on the <span class="hlt">magnetospheric</span> dusk side. The mantle supplies up to 1.5 × 108 cm-2 s-1 and 0.8 × 108 cm-2 s-1 of proton and sodium flux to the plasma sheet, respectively. We estimate the cross-electric <span class="hlt">magnetospheric</span> potential from each observation and find a mean of 19 kV (standard deviation of 16 kV) and a median of 13 kV. This is an important result as it is lower than previous estimations and shows that Mercury's <span class="hlt">magnetosphere</span> is at times not as highly driven by the solar wind as previously thought. Our values are comparable to the estimations for the ice giant planets, Uranus and Neptune, but lower than <span class="hlt">Earth</span>. The estimated potentials do have a very large range of values (1-74 kV), showing that Mercury's <span class="hlt">magnetosphere</span> is highly dynamic. A correlation of the potential is found to the interplanetary magnetic field (IMF) magnitude, supporting evidence that dayside magnetic reconnection can occur at all shear angles at Mercury. But we also see that Mercury has an <span class="hlt">Earth</span>-like <span class="hlt">magnetospheric</span> response, favoring -BZ IMF orientation. We find evidence that -BX orientations in the IMF favor the southern cusp and southern mantle. This is in agreement with telescopic observations of exospheric emission, but in disagreement with modeling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM33B2641J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM33B2641J"><span>Mercury's solar wind interaction as characterized by <span class="hlt">magnetospheric</span> plasma mantle observations with MESSENGER</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jasinski, J. M.; Slavin, J. A.; Raines, J. M.; DiBraccio, G. A.</p> <p>2017-12-01</p> <p>We analyze 94 traversals of Mercury's <span class="hlt">magnetospheric</span> plasma mantle using data from the MESSENGER spacecraft. The mean and median proton number density in the mantle are 1.5 and 1.3 cm-3, respectively. For sodium number density these values are 0.004 and 0.002 cm-3. Moderately higher densities are observed on the <span class="hlt">magnetospheric</span> dusk side. The mantle supplies up to 1.5 x 108 cm-2 s-1 and 0.8 x 108cm-2 s-1 of proton and sodium flux to the plasma sheet, respectively. We estimate the cross-electric <span class="hlt">magnetospheric</span> potential from each observation and find a mean of 19 kV (standard deviation of 16 kV) and a median of 13 kV. This is an important result as it is lower than previous estimations and shows that Mercury's <span class="hlt">magnetosphere</span> is at times not as highly driven by the solar wind as previously thought. Our values are comparable to the estimations for the ice giant planets, Uranus and Neptune, but lower than <span class="hlt">Earth</span>. The estimated potentials do have a very large range of values (1 - 74 kV), showing that Mercury's <span class="hlt">magnetosphere</span> is highly dynamic. A correlation of the potential is found to the interplanetary magnetic field (IMF) magnitude, supporting evidence that dayside magnetic reconnection can occur at all shear angles at Mercury. But we also see that Mercury has an <span class="hlt">Earth</span>-like <span class="hlt">magnetospheric</span> response, favoring -BZ IMF orientation. We find evidence that -BX orientations in the IMF favor the southern cusp and southern mantle. This is in agreement with telescopic observations of exospheric emission, but in disagreement with modeling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMGP51B..01S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMGP51B..01S"><span>Magnetic effects of <span class="hlt">magnetospheric</span> currents at ground and in low orbit</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stolle, C.; Willer, A.; Finlay, C. C.; Olsen, N.</p> <p>2012-12-01</p> <p>Since the advent of high precision vector magnetic field observations from satellites in low orbit it has been recognized that <span class="hlt">magnetospheric</span> currents contribute by about 20nT to the geomagnetic field even during quiet times (when Dst=0nT) (Langel et al., 1980). Comparing spherical harmonic models of the <span class="hlt">magnetospheric</span> field derived from ground observations with satellite data shows a similar offset. A robust linear fit between these two quantities reveals a slope of about 0.9, indicating that only 90% of the <span class="hlt">magnetospheric</span> field as monitored on ground is seen by satellites. The intercept of ~20nT is found to diminish with reducing solar activity (as was previously noted by Lühr & Maus, 2010), while the slope is hardly affected. There have been several suggestions for the origin of this systematic difference between ground and space based observations of <span class="hlt">magnetospheric</span> fields. We compare magnetic residuals of selected observatories with those of CHAMP satellite observations at times of conjunctions, separating the data pairs by criteria including local time and longitude, season, solar and magnetic activity. Obtaining rough estimates of the ionospheric conductivity in this way, we are able to discuss possible ionospheric sources for the observed intercept. Consideration of appropriate ordering in local time, also enables us to test for possible contributions from field aligned currents connecting the ionosphere and the <span class="hlt">magnetosphere</span>. Langel RA, Mead GD, Lancaster ER, Estes RH, Fabiano EB. 1980. Initial geomagnetic field model from Magsat vector data. Geophys. Res. Lett. 7:793-96 Lühr H, Maus S. 2010. Solar cycle dependence of quiet-time <span class="hlt">magnetospheric</span> currents and a model of their near-<span class="hlt">Earth</span> magnetic fields. <span class="hlt">Earth</span> Planets Space 62:843-48</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050169213','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050169213"><span>Energetic Electron Transport in the Inner <span class="hlt">Magnetosphere</span> During Geomagnetic Storms and Substorms</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>McKenzie, D. L.; Anderson, P. C.</p> <p>2005-01-01</p> <p>We propose to examine the relationship of geomagnetic storms and substorms and the transport of energetic particles in the inner <span class="hlt">magnetosphere</span> using measurements of the auroral X-ray emissions by PIXIE. PIXIE provides a global view of the auroral oval for the extended periods of time required to study stormtime phenomena. Its unique energy response and global view allow separation of stormtime particle transport driven by strong <span class="hlt">magnetospheric</span> electric fields from substorm particle transport driven by magnetic-field dipolarization and subsequent particle injection. The relative importance of substorms in releasing stored <span class="hlt">magnetospheric</span> energy during storms and injecting particles into the inner <span class="hlt">magnetosphere</span> and the ring current is currently hotly debated. The distribution of particles in the inner <span class="hlt">magnetosphere</span> is often inferred from measurements of the precipitating auroral particles. Thus, the global distributions of the characteristics of energetic precipitating particles during storms and substorms are extremely important inputs to any description or model of the geospace environment and the Sun-<span class="hlt">Earth</span> connection. We propose to use PIXIE observations and modeling of the transport of energetic electrons to examine the relationship between storms and substorms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170002768&hterms=energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Denergy','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170002768&hterms=energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Denergy"><span>Ionosphere-<span class="hlt">Magnetosphere</span> Energy Interplay in the Regions of Diffuse Aurora</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Khazanov, G. V.; Glocer, A.; Sibeck, D. G.; Tripathi, A. K.; Detweiler, L.G.; Avanov, L. A.; Singhal, R. P.</p> <p>2016-01-01</p> <p>Both electron cyclotron harmonic (ECH) waves and whistler mode chorus waves resonate with electrons of the <span class="hlt">Earths</span> plasma sheet in the energy range from tens of eV to several keV and produce the electron diffuse aurora at ionospheric altitudes. Interaction of these superthermal electrons with the neutral atmosphere leads to the production of secondary electrons (E500600 eV) and, as a result, leads to the activation of lower energy superthermal electron spectra that can escape back to the <span class="hlt">magnetosphere</span> and contribute to the thermal electron energy deposition processes in the <span class="hlt">magnetospheric</span> plasma. The ECH and whistler mode chorus waves, however, can also interact with the secondary electrons that are coming from both of the magnetically conjugated ionospheres after they have been produced by initially precipitated high-energy electrons that came from the plasma sheet. After their degradation and subsequent reflection in magnetically conjugate atmospheric regions, both the secondary electrons and the precipitating electrons with high (E600 eV) initial energies will travel back through the loss cone, become trapped in the <span class="hlt">magnetosphere</span>, and redistribute the energy content of the <span class="hlt">magnetosphere</span>-ionosphere system. Thus, scattering of the secondary electrons by ECH and whistler mode chorus waves leads to an increase of the fraction of superthermal electron energy deposited into the core <span class="hlt">magnetospheric</span> plasma.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JGRA..123.2745B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JGRA..123.2745B"><span>ULF Wave Activity in the <span class="hlt">Magnetosphere</span>: Resolving Solar Wind Interdependencies to Identify Driving Mechanisms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bentley, S. N.; Watt, C. E. J.; Owens, M. J.; Rae, I. J.</p> <p>2018-04-01</p> <p>Ultralow frequency (ULF) waves in the <span class="hlt">magnetosphere</span> are involved in the energization and transport of radiation belt particles and are strongly driven by the external solar wind. However, the interdependency of solar wind parameters and the variety of solar wind-<span class="hlt">magnetosphere</span> coupling processes make it difficult to distinguish the effect of individual processes and to predict <span class="hlt">magnetospheric</span> wave power using solar wind properties. We examine 15 years of dayside ground-based measurements at a single representative frequency (2.5 mHz) and a single magnetic latitude (corresponding to L ˜ 6.6RE). We determine the relative contribution to ULF wave power from instantaneous nonderived solar wind parameters, accounting for their interdependencies. The most influential parameters for ground-based ULF wave power are solar wind speed vsw, southward interplanetary magnetic field component Bz<0, and summed power in number density perturbations δNp. Together, the subordinate parameters Bz and δNp still account for significant amounts of power. We suggest that these three parameters correspond to driving by the Kelvin-Helmholtz instability, formation, and/or propagation of flux transfer events and density perturbations from solar wind structures sweeping past the <span class="hlt">Earth</span>. We anticipate that this new parameter reduction will aid comparisons of ULF generation mechanisms between <span class="hlt">magnetospheric</span> sectors and will enable more sophisticated empirical models predicting <span class="hlt">magnetospheric</span> ULF power using external solar wind driving parameters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMGP51B3744L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMGP51B3744L"><span>Detection of the <span class="hlt">Magnetospheric</span> Emissions from Extrasolar Planets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lazio, J.</p> <p>2014-12-01</p> <p>Planetary-scale magnetic fields are a window to a planet's interior and provide shielding of the planet's atmosphere. The <span class="hlt">Earth</span>, Mercury, Ganymede, and the giant planets of the solar system all contain internal dynamo currents that generate planetary-scale magnetic fields. These internal dynamo currents arise from differential rotation, convection, compositional dynamics, or a combination of these. If coupled to an energy source, such as the incident kinetic or magnetic energy from the solar wind, a planet's magnetic field can produce electron cyclotron masers in its magnetic polar regions. The most well known example of this process is the Jovian decametric emission, but all of the giant planets and the <span class="hlt">Earth</span> contain similar electron cyclotron masers within their <span class="hlt">magnetospheres</span>. Extrapolated to extrasolar planets, the remote detection of the magnetic field of an extrasolar planet would provide a means of obtaining constraints on the thermal state, composition, and dynamics of its interior as well as improved understanding of the basic planetary dynamo process. The <span class="hlt">magnetospheric</span> emissions from solar system planets and the discovery of extrasolar planets have motivated both theoretical and observational work on <span class="hlt">magnetospheric</span> emissions from extrasolar planets. Stimulated by these advances, the W.M. Keck Institute for Space Studies hosted a workshop entitled "Planetary Magnetic Fields: Planetary Interiors and Habitability." I summarize the current observational status of searches for <span class="hlt">magnetospheric</span> emissions from extrasolar planets, based on observations from a number of ground-based radio telescopes, and future prospects for ground-based studies. Using the solar system planetary magnetic fields as a guide, future space-based missions will be required to study planets with magnetic field strengths lower than that of Jupiter. I summarize mission concepts identified in the KISS workshop, with a focus on the detection of planetary electron cyclotron maser emission. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1402591-kinetic-alfven-waves-particle-response-associated-shock-induced-global-ulf-perturbation-terrestrial-magnetosphere','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1402591-kinetic-alfven-waves-particle-response-associated-shock-induced-global-ulf-perturbation-terrestrial-magnetosphere"><span>Kinetic Alfvén waves and particle response associated with a shock-induced, global ULF perturbation of the terrestrial <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Malaspina, David M.; Claudepierre, Seth G.; Takahashi, Kazue; ...</p> <p>2015-11-14</p> <p>On 2 October 2013, the arrival of an interplanetary shock compressed the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span> and triggered a global ULF (ultra low frequency) oscillation. Furthermore, the Van Allen Probe B spacecraft observed this large-amplitude ULF wave in situ with both magnetic and electric field data. Broadband waves up to approximately 100 Hz were observed in conjunction with, and modulated by, this ULF wave. Detailed analysis of fields and particle data reveals that these broadband waves are Doppler-shifted kinetic Alfvén waves. This event then suggests that <span class="hlt">magnetospheric</span> compression by interplanetary shocks can induce abrupt generation of kinetic Alfvén waves over large portionsmore » of the inner <span class="hlt">magnetosphere</span>, potentially driving previously unconsidered wave-particle interactions throughout the inner <span class="hlt">magnetosphere</span> during the initial response of the <span class="hlt">magnetosphere</span> to shock impacts.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870052840&hterms=GERD&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DGERD','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870052840&hterms=GERD&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DGERD"><span><span class="hlt">Magnetospheric</span> equilibrium configurations and slow adiabatic convection</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Voigt, Gerd-Hannes</p> <p>1986-01-01</p> <p>This review paper demonstrates how the magnetohydrostatic equilibrium (MHE) theory can be used to describe the large-scale magnetic field configuration of the <span class="hlt">magnetosphere</span> and its time evolution under the influence of <span class="hlt">magnetospheric</span> convection. The equilibrium problem is reviewed, and levels of B-field modelling are examined for vacuum models, quasi-static equilibrium models, and MHD models. Results from two-dimensional MHE theory as they apply to the Grad-Shafranov equation, linear equilibria, the asymptotic theory, <span class="hlt">magnetospheric</span> convection and the substorm mechanism, and plasma anisotropies are addressed. Results from three-dimensional MHE theory are considered as they apply to an intermediate analytical <span class="hlt">magnetospheric</span> model, magnetotail configurations, and magnetopause boundary conditions and the influence of the IMF.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19073464','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19073464"><span>Interaction of Titan's ionosphere with Saturn's <span class="hlt">magnetosphere</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Coates, Andrew J</p> <p>2009-02-28</p> <p>Titan is the only Moon in the Solar System with a significant permanent atmosphere. Within this nitrogen-methane atmosphere, an ionosphere forms. Titan has no significant magnetic dipole moment, and is usually located inside Saturn's <span class="hlt">magnetosphere</span>. Atmospheric particles are ionized both by sunlight and by particles from Saturn's <span class="hlt">magnetosphere</span>, mainly electrons, which reach the top of the atmosphere. So far, the Cassini spacecraft has made over 45 close flybys of Titan, allowing measurements in the ionosphere and the surrounding <span class="hlt">magnetosphere</span> under different conditions. Here we review how Titan's ionosphere and Saturn's <span class="hlt">magnetosphere</span> interact, using measurements from Cassini low-energy particle detectors. In particular, we discuss ionization processes and ionospheric photoelectrons, including their effect on ion escape from the ionosphere. We also discuss one of the unexpected discoveries in Titan's ionosphere, the existence of extremely heavy negative ions up to 10000amu at 950km altitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986GeoRL..13..423I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986GeoRL..13..423I"><span>The sodium exosphere and <span class="hlt">magnetosphere</span> of Mercury</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ip, W.-H.</p> <p>1986-05-01</p> <p>Following the recent optical discovery of intense sodium D-line emission from Mercury, the scenario of an extended exosphere of sodium and other metallic atoms is explored. It is shown that the strong effect of solar radiation pressure acceleration would permit the escape of Na atoms from Mercury's surface even if they are ejected at a velocity lower than the surface escape velocity. Fast photoionization of the Na atoms is effective in limiting the tailward extension of the sodium exosphere, however. The subsequent loss of the photoions to the <span class="hlt">magnetosphere</span> could be a significant source of the <span class="hlt">magnetospheric</span> plasma. The recirculation of the <span class="hlt">magnetospheric</span> charged particles to the planetary surface could also play an important role in maintaining an extended sodium exosphere as well as a <span class="hlt">magnetosphere</span> of sputtered metallic ions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26462435','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26462435"><span>Lunar biological effects and the <span class="hlt">magnetosphere</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bevington, Michael</p> <p>2015-12-01</p> <p>The debate about how far the Moon causes biological effects has continued for two millennia. Pliny the Elder argued for lunar power "penetrating all things", including plants, fish, animals and humans. He also linked the Moon with tides, confirmed mathematically by Newton. A review of modern studies of biological effects, especially from plants and animals, confirms the pervasive nature of this lunar force. However calculations from physics and other arguments refute the supposed mechanisms of gravity and light. Recent space exploration allows a new approach with evidence of electromagnetic fields associated with the <span class="hlt">Earth</span>'s magnetotail at full moon during the night, and similar, but more limited, effects from the Moon's wake on the <span class="hlt">magnetosphere</span> at new moon during the day. The disturbance of the magnetotail is perhaps shown by measurements of electric fields of up to 16V/m compared with the usual <1V/m, suggesting the possibility of weak biological effects on some sensitive organisms. Similar intensities found in sferics, geomagnetic storms, aurora disturbance, sensations of a 'presence' and pre-seismic electromagnetic radiation are known to affect animals and 10-20% of the human population. There is now evidence for mechanisms such as calcium flux, melatonin disruption, magnetite and cryptochromes. Both environmental and receptor variations explain confounding factors and inconsistencies in the evidence. Electromagnetic effects might also account for some evolutionary changes. Further research on lunar biological effects, such as acute myocardial infarction, could help the development of strategies to reduce adverse effects for people sensitive to geomagnetic disturbance. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017sf2a.conf....3L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017sf2a.conf....3L"><span>First results from the <span class="hlt">Magnetospheric</span> Multiscale mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lavraud, B.</p> <p>2017-12-01</p> <p>Since its launch in March 2015, NASA's <span class="hlt">Magnetospheric</span> Multiscale mission (MMS) provides a wealth of unprecedented high resolution measurements of space plasma properties and dynamics in the near-<span class="hlt">Earth</span> environment. MMS was designed in the first place to study the fundamental process of collision-less magnetic reconnection. The two first results reviewed here pertain to this topic and highlight how the extremely high resolution MMS data (electrons, in particular, with full three dimensional measurements at 30 ms in burst mode) have permitted to tackle electron dynamics in unprecedented details. The first result demonstrates how electrons become demagnetized and scattered near the magnetic reconnection X line as a result of increased magnetic field curvature, together with a decrease in its magnitude. The second result demonstrates that electrons form crescent-shaped, agyrotropic distribution functions very near the X line, suggestive of the existence of a perpendicular current aligned with the local electric field and consistent with the energy conversion expected in magnetic reconnection (such that J\\cdot E > 0). Aside from magnetic reconnection, we show how MMS contributes to topics such as wave properties and their interaction with particles. Thanks again to extremely high resolution measurements, the lossless and periodical energy exchange between wave electromagnetic fields and particles, as expected in the case of kinetic Alfvén waves, was confirmed. Although not discussed, MMS has the potential to solve many other outstanding issues in collision-less plasma physics, for example regarding shock or turbulence acceleration, with obvious broader impacts in astrophysics in general.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850016298&hterms=convection+currents&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dconvection%2Bcurrents','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850016298&hterms=convection+currents&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dconvection%2Bcurrents"><span>Ionosphere-<span class="hlt">magnetosphere</span> coupling and convection</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wolf, R. A.; Spiro, R. W.</p> <p>1984-01-01</p> <p>The following international <span class="hlt">Magnetospheric</span> Study quantitative models of observed ionosphere-<span class="hlt">magnetosphere</span> events are reviewed: (1) a theoretical model of convection; (2) algorithms for deducing ionospheric current and electric-field patterns from sets of ground magnetograms and ionospheric conductivity information; and (3) empirical models of ionospheric conductances and polar cap potential drop. Research into magnetic-field-aligned electric fields is reviewed, particularly magnetic-mirror effects and double layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSM31E..07T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSM31E..07T"><span>Plasma Sources and <span class="hlt">Magnetospheric</span> Consequences at Saturn</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thomsen, M. F.</p> <p>2012-12-01</p> <p>Saturn's <span class="hlt">magnetospheric</span> dynamics are dominated by two facts: 1) the planet rotates very rapidly (~10-hour period); and 2) the moon Enceladus, only 500 km in diameter, orbits Saturn at a distance of 4 Rs. This tiny moon produces jets of water through cracks in its icy surface, filling a large water-product torus of neutral gas that surrounds Saturn near Enceladus' orbit. Through photoionization and electron-impact ionization, the torus forms the dominant source of Saturn's <span class="hlt">magnetospheric</span> plasma. This inside-out loading of plasma, combined with the rapid rotation of the magnetic field, leads to outward transport through a nearly continuous process of discrete flux-tube interchange. The magnetic flux that returns to the inner <span class="hlt">magnetosphere</span> during interchange events brings with it hotter, more-tenuous plasma from the outer <span class="hlt">magnetosphere</span>. When dense, relatively cold plasma from the inner <span class="hlt">magnetosphere</span> flows outward in the tail region, the magnetic field is often not strong enough to confine it, and magnetic reconnection allows the plasma to break off in plasmoids that escape the <span class="hlt">magnetospheric</span> system. This complicated ballet of production, transport, and loss is carried on continuously. In this talk we will investigate its temporal variability, on both short and long timescales.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA00624.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA00624.html"><span>Coronal Hole Facing <span class="hlt">Earth</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2018-05-08</p> <p>An extensive equatorial coronal hole has rotated so that it is now facing <span class="hlt">Earth</span> (May 2-4, 2018). The dark coronal hole extends about halfway across the solar disk. It was observed in a wavelength of extreme ultraviolet light. This magnetically open area is streaming solar wind (i.e., a stream of charged particles released from the sun) into space. When <span class="hlt">Earth</span> enters a solar wind stream and the stream interacts with our <span class="hlt">magnetosphere</span>, we often experience nice displays of aurora. Videos are available at https://photojournal.jpl.nasa.gov/catalog/PIA00624</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA00577.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA00577.html"><span>Coronal Hole Facing <span class="hlt">Earth</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2018-05-15</p> <p>An extensive equatorial coronal hole has rotated so that it is now facing <span class="hlt">Earth</span> (May 2-4, 2018). The dark coronal hole extends about halfway across the solar disk. It was observed in a wavelength of extreme ultraviolet light. This magnetically open area is streaming solar wind (i.e., a stream of charged particles released from the sun) into space. When <span class="hlt">Earth</span> enters a solar wind stream and the stream interacts with our <span class="hlt">magnetosphere</span>, we often experience nice displays of aurora. https://photojournal.jpl.nasa.gov/catalog/PIA00577</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM43D..02O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM43D..02O"><span>Propagation of Dipolarization Signatures Observed by the Van Allen Probes in the Inner <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ohtani, S.; Motoba, T.; Gkioulidou, M.; Takahashi, K.; Kletzing, C.</p> <p>2017-12-01</p> <p>Dipolarization, the change of the local magnetic field from a stretched to a more dipolar configuration, is one of the most fundamental processes of <span class="hlt">magnetospheric</span> physics. It is especially critical for the dynamics of the inner <span class="hlt">magnetosphere</span>. The associated electric field accelerates ions and electrons and transports them closer to <span class="hlt">Earth</span>. Such injected ions intensify the ring current, and electrons constitute the seed population of the radiation belt. Those ions and electrons may also excite various waves that play important roles in the enhancement and loss of the radiation belt electrons. Despite such critical consequences, the general characteristics of dipolarization in the inner <span class="hlt">magnetosphere</span> still remain to be understood. The Van Allen Probes mission, which consists of two probes that orbit through the equatorial region of the inner <span class="hlt">magnetosphere</span>, provides an ideal opportunity to examine dipolarization signatures in the core of the ring current. In the present study we investigate the spatial expansion of the dipolarization region by examining the correlation and time delay of dipolarization signatures observed by the two probes. Whereas in general it requires three-point measurements to deduce the propagation of a signal on a certain plane, we statically examined the observed time delays and found that dipolarization signatures tend to propagate radially inward as well as away from midnight. In this paper we address the propagation of dipolarization signatures quantitatively and compare with the propagation velocities reported previously based on observations made farther away from <span class="hlt">Earth</span>. We also discuss how often and under what conditions the dipolarization region expands.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSM51E2525D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSM51E2525D"><span>Interactions Between Energetic Electrons and Realistic Whistler Mode Waves in the Jovian <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Soria-Santacruz Pich, M.; Drozdov, A.; Menietti, J. D.; Garrett, H. B.; Kellerman, A. C.; Shprits, Y. Y.</p> <p>2016-12-01</p> <p>The radiation belts of Jupiter are the most intense of all the planets in the solar system. Their source is not well understood but they are believed to be the result of inward radial transport beyond the orbit of Io. In the case of <span class="hlt">Earth</span>, the radiation belts are the result of local acceleration and radial diffusion from whistler waves, and it has been suggested that this type of acceleration may also be significant in the <span class="hlt">magnetosphere</span> of Jupiter. Multiple diffusion codes have been developed to study the dynamics of the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span> and characterize the interaction between relativistic electrons and whistler waves; in the present paper we adapt one of these codes, the two-dimensional version of the Versatile Electron Radiation Belt (VERB) computer code, to the case of the Jovian <span class="hlt">magnetosphere</span>. We use realistic parameters to determine the importance of whistler emissions in the acceleration and loss of electrons in the Jovian <span class="hlt">magnetosphere</span>. More specifically, we use an extensive wave survey from the Galileo spacecraft and initial conditions derived from the Galileo Interim Radiation Electron Model version 2 (GIRE2) to estimate the pitch angle and energy diffusion of the electron population due to lower and upper band whistlers as a function of latitude and radial distance from the planet, and we calculate the decay rates that result from this interaction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000048256','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000048256"><span>The <span class="hlt">Magnetospheric</span> Multiscale Mission...Resolving Fundamental Processes in Space Plasmas</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Curtis, S.</p> <p>1999-01-01</p> <p>The <span class="hlt">Magnetospheric</span> Multiscale (MMS) mission is a multiple-spacecraft Solar-Terrestrial Probe designed to study the microphysics of magnetic reconnection, charged particle acceleration, and turbulence in key boundary regions of <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>. These three processes, which control the flow of energy, mass, and momentum within and across plasma boundaries, occur throughout the universe and are fundamental to our understanding of astrophysical and solar system plasmas. Only in <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>, however, are they readily accessible for sustained study through in-situ measurement. MMS will employ five co-orbiting spacecraft identically instrumented to measure electric and magnetic fields, plasmas, and energetic particles. The initial parameters of the individual spacecraft orbits will be designed so that the spacecraft formation will evolve into a three-dimensional configuration near apogee, allowing MMS to differentiate between spatial and temporal effects and to determine the three dimensional geometry of plasma, field, and current structures. In order to sample all of the <span class="hlt">magnetospheric</span> boundary regions, MMS will employ a unique four-phase orbital strategy involving carefully sequenced changes in the local time and radial distance of apogee and, in the third phase, a change in orbit inclination from 10 degrees to 90 degrees. The nominal mission operational lifetime is two years. Launch is currently scheduled for 2006.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SSRv..187..181L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SSRv..187..181L"><span>Magnetic Reconnection and Associated Transient Phenomena Within the <span class="hlt">Magnetospheres</span> of Jupiter and Saturn</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Louarn, Philippe; Andre, Nicolas; Jackman, Caitriona M.; Kasahara, Satoshi; Kronberg, Elena A.; Vogt, Marissa F.</p> <p>2015-04-01</p> <p>We review in situ observations made in Jupiter and Saturn's <span class="hlt">magnetosphere</span> that illustrate the possible roles of magnetic reconnection in rapidly-rotating <span class="hlt">magnetospheres</span>. In the <span class="hlt">Earth</span>'s solar wind-driven <span class="hlt">magnetosphere</span>, the <span class="hlt">magnetospheric</span> convection is classically described as a cycle of dayside opening and tail closing reconnection (the Dungey cycle). For the rapidly-rotating Jovian and Kronian <span class="hlt">magnetospheres</span>, heavily populated by internal plasma sources, the classical concept (the Vasyliunas cycle) is that the magnetic reconnection plays a key role in the final stage of the radial plasma transport across the disk. By cutting and closing flux tubes that have been elongated by the rotational stress, the reconnection process would lead to the formation of plasmoids that propagate down the tail, contributing to the final evacuation of the internally produced plasma and allowing the return of the magnetic flux toward the planet. This process has been studied by inspecting possible `local' signatures of the reconnection, as magnetic field reversals, plasma flow anisotropies, energetic particle bursts, and more global consequences on the <span class="hlt">magnetospheric</span> activity. The investigations made at Jupiter support the concept of an `average' X-line, extended in the dawn/dusk direction and located at 90-120 Jovian radius (RJ) on the night side. The existence of a similar average X-line has not yet been established at Saturn, perhaps by lack of statistics. Both at Jupiter and Saturn, the reconfiguration signatures are consistent with <span class="hlt">magnetospheric</span> dipolarizations and formation of plasmoids and flux ropes. In several cases, the reconfigurations also appear to be closely associated with large scale activations of the <span class="hlt">magnetosphere</span>, seen from the radio and auroral emissions. Nevertheless, the statistical study also suggests that the reconnection events and the associated plasmoids are not frequent enough to explain a plasma evacuation that matches the mass input rate from the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998cee..workE..47K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998cee..workE..47K"><span>Space weather: Why are <span class="hlt">magnetospheric</span> physicists interested in solar explosive phenomena</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koskinen, H. E. J.; Pulkkinen, T. I.</p> <p></p> <p>That solar activity drives <span class="hlt">magnetospheric</span> dynamics has for a long time been the basis of solar-terrestrial physics. Numerous statistical studies correlating sunspots, 10.7 cm radiation, solar flares, etc., with various <span class="hlt">magnetospheric</span> and geomagnetic parameters have been performed. However, in studies of <span class="hlt">magnetospheric</span> dynamics the role of the Sun has often remained in the background and only the actual solar wind impinging the <span class="hlt">magnetosphere</span> has gained most of the attention. During the last few years a new applied field of solar-terrestrial physics, space weather, has emerged. The term refers to variable particle and field conditions in our space environment, which may be hazardous to space-borne or ground-based technological systems and can endanger human life and health. When the modern society is becoming increasingly dependent on space technology, the need for better modelling and also forecasting of space weather becomes urgent. While for post analysis of <span class="hlt">magnetospheric</span> phenomena it is quite sufficient to include observations from the <span class="hlt">magnetospheric</span> boundaries out to L1 where SOHO is located, these observations do not provide enough lead-time to run space weather forecasting models and to distribute the forecasts to potential customers. For such purposes we need improved physical understanding and models to predict which active processes on the Sun will impact the <span class="hlt">magnetosphere</span> and what their expected consequences are. An important change of view on the role of the Sun as the origin of <span class="hlt">magnetospheric</span> disturbances has taken place during last 10--20 years. For a long time, the solar flares were thought to be the most geoeffective solar phenomena. Now the attention has shifted much more towards coronal mass ejections and the SOHO coronal observations seem to have turned the epoch irreversibly. However, we are not yet ready to make reliable perdictions of the terrestrial environment based on CME observations. From the space weather viewpoint, the key questions are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730023998','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730023998"><span>The <span class="hlt">magnetospheric</span> structure of pulsars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Roberts, D. H.</p> <p>1973-01-01</p> <p>A model of pulsar <span class="hlt">magnetospheres</span> is described which has evolved inductively from the work of Sturrock, where the radiation is produced near the surface of a neutron star. Some of the theoretical ideas of others, particularly those of Sturrock, are discussed. The braking index n and period-pulse-width distribution of pulsars are first reinvestigated by relaxing the conventional assumption that R sub Y = R sub L, where R sub Y is the radius of the neutral points marking the transition from closed to open magnetic field lines, and R sub L is the radius of the light cylinder. This is replaced by the parameterization R sub Y = R sub * (1- eta )power R sub L (eta), where R sub * is the neutron star radius. If the ratio frequency radiation is created near the surface and beamed along open field lines, it is found that a good fit to the period-pulse-width distribution can be obtained for eta in the range 0.5 = or eta = or 0.7. The relation n = 1 + 2 eta then gives n = 2.2 + or - 0.2, which is in good agreement with the values measured for the Crab pulsar.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM33C2677C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM33C2677C"><span>Plasma circulation in Jupiter's <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chané, E.</p> <p>2017-12-01</p> <p>We are using our three-dimensional global MHD model of Jupiter's <span class="hlt">magnetosphere</span> to study the plasma circulation in the magnetodisk. We show that the Iogenic plasma does not travel outward axisymmetrically but rather forms a long spiral arm of high density corotating with the planet. This leads to periodic phenomena in the magnetodisk: for instance, every rotation period, a region of high density is rapidly moving outward on the pre-noon sector. This leads to shearing motions that generate field aligned currents and periodically affect the main oval in this sector.We will also show how the interplanetary magnetic field influences the position of the magnetodisk in our simulations, displacing the current sheet above and below the equatorial plan. We will discuss how this is affecting the depleted flux-tubes returning from the night-side after unloading most of their plasma in the magnetotail (Vasyliunas cycle) and see how they can then move above or below the magnetodisk when arriving at dawn and then reconnect with the interplanetary magnetic field on the day-side.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA170506','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA170506"><span>Acceleration Processes in the <span class="hlt">Earth</span>’s <span class="hlt">Magnetosphere</span>.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1985-05-17</p> <p>R.L . , C.T. Russel I, and M.P . Auhry, Satcl Iik t li-, of mir(I T - spheric substorm (, Aiqu,,t 15, Itoh , 9. Ptinnm o ln ical r nde I of - storms...physics of auroral field lines, Nobel Symposium, Kiruna, Sweden, 1982. 2) T. Sato, Numerical study of magnetic reconnection mechanisms, AGU, Philadelphia</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850008417','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850008417"><span>Polar rain: Solar coronal electrons in the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fairfield, D. H.; Scudder, J. D.</p> <p>1984-01-01</p> <p>Low energy electron measurements collected by ISEE 1 reveal the frequent presence of field-aligned fluxes of few hundred eV electrons in he geomagnetic tail lobes. In the northern tail lobe these electrons are most prominent when the interplanetary magnetic field is directed away from the Sun. This characteristic helps identify the electrons as polar rain electrons. By mapping the tail lobe velocity distribution function into the solar wind, previous suggestions that the polar rain is indeed of solar wind origin and is due to the access of electrons to the magnetotail lobe were confirmed. It was demonstrated that the moe energetic component of the polar rain is composed of electrons from the solar wind strahl - a field-aligned component of the solar wind which is difficult to measure but which is thought to be caused by the collisionless transit of hundred eV electrons from the inner solar corona to 1 AU.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990031964&hterms=monographs&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmonographs','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990031964&hterms=monographs&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmonographs"><span>Large-Scale Dynamics of the <span class="hlt">Magnetospheric</span> Boundary: Comparisons between Global MHD Simulation Results and ISTP Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Berchem, J.; Raeder, J.; Ashour-Abdalla, M.; Frank, L. A.; Paterson, W. R.; Ackerson, K. L.; Kokubun, S.; Yamamoto, T.; Lepping, R. P.</p> <p>1998-01-01</p> <p>Understanding the large-scale dynamics of the <span class="hlt">magnetospheric</span> boundary is an important step towards achieving the ISTP mission's broad objective of assessing the global transport of plasma and energy through the geospace environment. Our approach is based on three-dimensional global magnetohydrodynamic (MHD) simulations of the solar wind-<span class="hlt">magnetosphere</span>- ionosphere system, and consists of using interplanetary magnetic field (IMF) and plasma parameters measured by solar wind monitors upstream of the bow shock as input to the simulations for predicting the large-scale dynamics of the <span class="hlt">magnetospheric</span> boundary. The validity of these predictions is tested by comparing local data streams with time series measured by downstream spacecraft crossing the <span class="hlt">magnetospheric</span> boundary. In this paper, we review results from several case studies which confirm that our MHD model reproduces very well the large-scale motion of the <span class="hlt">magnetospheric</span> boundary. The first case illustrates the complexity of the magnetic field topology that can occur at the dayside <span class="hlt">magnetospheric</span> boundary for periods of northward IMF with strong Bx and By components. The second comparison reviewed combines dynamic and topological aspects in an investigation of the evolution of the distant tail at 200 R(sub E) from the <span class="hlt">Earth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990063838&hterms=monographs&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmonographs','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990063838&hterms=monographs&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmonographs"><span>Origins and Transport of Ions during <span class="hlt">Magnetospheric</span> Substorms</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ashour-Abdalla, Maha; El-Alaoui, Mostafa; Peroomian, Vahe; Raeder, Joachim; Walker, Ray J.; Frank, L. A.; Paterson, W. R.</p> <p>1999-01-01</p> <p>We investigate the origins and the transport of ions observed in the near-<span class="hlt">Earth</span> plasma sheet during the growth and expansion phases of a <span class="hlt">magnetospheric</span> substorm that occurred on November 24, 1996. Ions observed at Geotail were traced backward in time in time-dependent magnetic and electric fields to determine their origins and the acceleration mechanisms responsible for their energization. Results from this investigation indicate that, during the growth phase of the substorm, most of the ions reaching Geotail had origins in the low latitude boundary layer (LLBL) and had alread@, entered the <span class="hlt">magnetosphere</span> when the growth phase began. Late in the growth phase and in the expansion phase a higher proportion of the ions reaching Geotail had their origin in the plasma mantle. Indeed, during the expansion phase more than 90% of the ions seen by Geotail were from the mantle. The ions were accelerated enroute to the spacecraft; however, most of the ions' energy gain was achieved by non-adiabatic acceleration while crossing the equatorial current sheet just prior to their detection by Geotail. In general, the plasma mantle from both southern and northern hemispheres supplied non-adiabatic ions to Geotail, whereas the LLBL supplied mostly adiabatic ions to the distributions measured by the spacecraft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..DPPB11011S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..DPPB11011S"><span>X-ray observations from RT-1 <span class="hlt">magnetospheric</span> plasmas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sugata, Tetsuya; Masaki Nishiura Collaboration; Zensho Yoshida Collaboration; Naoki Kenmochi Collaboration; Shotaro Katsura Collaboration; Kaori Nakamura Collaboration</p> <p>2017-10-01</p> <p>Planetary <span class="hlt">magnetospheres</span> like <span class="hlt">Earth</span> and Jupiter realize stable confinement of high beta plasma. The RT-1 device produces a laboratory <span class="hlt">magnetosphere</span> by using a levitated superconducting coil for dipole magnetic fields and 8.2 GHz electromagnetic wave for plasma production (ne 1017m-3) and electron heating. In the recent experiments, the RT-1 device has achieved the local beta that exceeds 1. It is considered that the high energy component of electrons contributes to the beta value. Therefore, Si(Li) detectors measured the X-ray spectra from the peripheral plasmas in the range from a few keV to a few ten keV. The density of a few keV component and a few ten keV component are comparable and a few ten keV component dominates the majority of the high beta value that is operated up to 0.8. We found that 150 keV component of electrons exists near the outer of the levitated dipole magnet by using a CdTe detector.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140010795','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140010795"><span>Launch Window Analysis for the <span class="hlt">Magnetospheric</span> Multiscale Mission</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Williams, Trevor W.</p> <p>2012-01-01</p> <p>The NASA <span class="hlt">Magnetospheric</span> Multiscale (MMS) mission will fly four spinning spacecraft in formation in highly elliptical orbits to study the <span class="hlt">magnetosphere</span> of the <span class="hlt">Earth</span>. This paper describes the development of an MMS launch window tool that uses the orbitaveraged Variation of Parameter equations as the basis for a semi-analytic quantification of the dominant oblateness and lunisolar perturbation effects on the MMS orbit. This approach, coupled with a geometric interpretation of all of the MMS science and engineering constraints, allows a scan of 180(sup 2) = 32,400 different (RAAN, AOP) pairs to be carried out for a specified launch day in less than 10 s on a typical modern laptop. The resulting plot indicates the regions in (RAAN, AOP) space where each constraint is satisfied or violated: their intersection gives, in an easily interpreted graphical manner, the final solution space for the day considered. This tool, SWM76, is now used to provide launch conditions to the full fidelity (but far slower) MMS simulation code: very good agreement has been observed between the two methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950053324&hterms=dropout&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Ddropout','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950053324&hterms=dropout&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Ddropout"><span>Neptune's inner <span class="hlt">magnetosphere</span> and aurora: Energetic particle constraints</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mauk, B. H.; Krimigis, S. M.; Acuna, M. H.</p> <p>1994-01-01</p> <p>A dramatic and peculiar dropout of greater than 500-keV ions (but not electrons) was observed within Neptune's inner <span class="hlt">magnetosphere</span> near 2 R(sub N) as the Voyager 2 spacecraft approached the planet. Unlike a number of other energetic particle features this feature could not be accounted for by known material bodies in the context of the most utilized magnetic field models (neither the offset tilted dipole models nor the spehrical harmonic model 'O8'). However, the configuration of Neptune's inner <span class="hlt">magnetosphere</span> is highly uncertain. By applying a novel technique, utilizing energetic particle measurements, to constrain the magnetic field configuration of the inner regions, we show that appeals to unobserved materials within Neptune's system are unnecessary, and that the ion dropout feature was, in all likelihood, the result of ion interactions with maximum L excursions of the ring 1989N1R. The constraints also favor the se of the M2 magnetic field model (Selesnick, 1992) over the previous models. An electron feature was probably absent because the electron interactions with the ring occurred substantially before the ion interactions (about 2 hours for the electrons versus a few minutes for the ions). Pitch-angle scattering apparently eliminated the electron signature. Minimum scattering rates determined based on this premise yield enough electron precipitation power to explain the brightest component of Neptune's aurora. We propose that this bright component is analogous to the <span class="hlt">Earth</span>'s diffuse aurora.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM21C..07R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM21C..07R"><span>Dependence of Subsolar Magnetopause on Solar Wind Properties using the <span class="hlt">Magnetosphere</span> Multiscale Mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Russell, C. T.; Zhao, C.; Qi, Y.; Lai, H.; Strangeway, R. J.; Paterson, W. R.; Giles, B. L.; Baumjohann, W.; Torbert, R. B.; Burch, J.</p> <p>2017-12-01</p> <p>The nature of the solar wind interaction with the <span class="hlt">Earth</span>'s magnetic field depends on the balance between magnetic and plasma forces at the magnetopause. This balance is controlled by the magnetosonic Mach number of the bow shock standing in front of the <span class="hlt">magnetosphere</span>. We have used measurements of the solar wind obtained in the near <span class="hlt">Earth</span> solar wind to calculate this Mach number whenever MMS was near the magnetopause and in the subsolar region. In particular, we examine two intervals of magnetopause encounters when the solar wind Mach number was close to 2.0, one when the IMF was nearly due southward and one when it was due northward. The due southward magnetic field produced a rapidly oscillating boundary. The northward magnetic field produced a much more stable boundary but with a hot low density boundary layer between the <span class="hlt">magnetospheric</span> and magnetosheath plasmas. These magnetopause crossings are quite different than those studied earlier under high solar wind Mach number conditions.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSM21A2452S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSM21A2452S"><span>An Investigation of Hall Currents Associated with Tripolar Magnetic Fields During <span class="hlt">Magnetospheric</span> Kelvin Helmholtz Waves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sturner, A. P.; Eriksson, S.; Newman, D. L.; Lapenta, G.; Gershman, D. J.; Plaschke, F.; Ergun, R.; Wilder, F. D.; Torbert, R. B.; Giles, B. L.; Strangeway, R. J.; Russell, C. T.; Burch, J. L.</p> <p>2016-12-01</p> <p>Kinetic simulations and observations of magnetic reconnection suggest the Hall term of Ohm's Law is necessary for understanding fast reconnection in the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>. During high (>1) guide field plasma conditions in the solar wind and in <span class="hlt">Earth</span>'s magnetopause, tripolar variations in the guide magnetic field are often observed during current sheet crossings, and have been linked to reconnection Hall magnetic fields. Two proposed mechanisms for these tripolar variations are the presence of multiple nearby X-lines and magnetic island coalescence. We present results of an investigation into the structure of the electron currents supporting tripolar guide magnetic field variations during Kelvin-Helmholtz wave current sheet crossings using the <span class="hlt">Magnetosphere</span> Multiscale (MMS) Mission, and compare with bipolar magnetic field structures and with kinetic simulations to understand how these tripolar structures may be used as tracers for magnetic islands.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM13B2366B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM13B2366B"><span>Ion exhaust distributions and reconnection location with <span class="hlt">Magnetospheric</span> Multiscale and global MHD test particles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Broll, J. M.; Fuselier, S. A.; Trattner, K. J.; Steven, P. M.; Burch, J. L.; Giles, B. L.</p> <p>2017-12-01</p> <p>Magnetic reconnection at <span class="hlt">Earth</span>'s dayside magnetopause is an essential process in <span class="hlt">magnetospheric</span> physics. Under southward IMF conditions, reconnection occurs along a thin ribbon across the dayside magnetopause. The location of this ribbon has been studied extensively in terms of global optimization of quantities like reconnecting field energy or magnetic shear, but with expected errors of 1-2 <span class="hlt">Earth</span> radii these global models give limited context for cases where an observation is near the reconnection line. Building on previous results, which established the cutoff contour method for locating reconnection using in-situ velocity measurements, we examine the effects of MHD-scale waves on reconnection exhaust distributions. We use a test particle exhaust distribution propagated through a globamagnetohydrodynamics model fields and compare with <span class="hlt">Magnetospheric</span> Multiscale observations of reconnection exhaust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17734359','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17734359"><span>Jupiter's Magnetic Field. <span class="hlt">Magnetosphere</span>, and Interaction with the Solar Wind: Pioneer 11.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Smith, E J; Davis, L; Jones, D E; Coleman, P J; Colburn, D S; Dyal, P; Sonett, C P</p> <p>1975-05-02</p> <p>The Pioneer 11 vector helium magnetometer provided precise, contititious measurements of the magnetic fields in interplanetary space, inside Jupiter's <span class="hlt">magnetosphere</span>, and in the near vicinity of Jupiter. As with the Pioneer 10 data, evidence was seen of the dynanmic interaction of Jupiter with the solar wind which leads to a variety of phenomena (bow shock, upstream waves, nonlinear magnetosheath impulses) and to changes in the dimension of the dayside <span class="hlt">magnetosphere</span> by as much as a factor of 2. The <span class="hlt">magnetosphere</span> clearly appears to be blunt, not disk-shaped, with a well-defined outer boundary. In the outer <span class="hlt">magnetosphere</span>, the magnetic field is irregular but exhibits a persistent southward component indicative of a closed <span class="hlt">magnetosphere</span>. The data contain the first clear evidence in the dayside <span class="hlt">magnetosphere</span> of the current sheet, apparently associated with centrifugal forces, that was a donminatnt feature of the outbound Pionieer 10 data. A modest westward spiraling of the field was again evident inbound but not outbound at higher latitudes and nearer the Sun-Jupiter direction. Measurements near periapsis, which were nearer the planet and provide better latitude and longitude coverage than Pioneer 10, have revealed a 5 percent discrepancy with the Pioneer 10 offset dipole mnodel (D(2)). A revised offset dipole (6-parameter fit) is presented as well as the results of a spherical harmonic analysis (23 parameters) consisting of an interior dipole, quadrupole, and octopole and an external dipole and quadrupole. The dipole moment and the composite field appear moderately larger than inferred from Pioneer 10. Maximum surface fields of 14 and 11 gauss in the northern and southern hemispheres are inferred. Jupiter's planetary field is found to be slightly more irregular than that of <span class="hlt">Earth</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMSA31C..05L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSA31C..05L"><span>Multi-fluid simulations of the coupled solar wind-<span class="hlt">magnetosphere</span>-ionsphere system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lyon, J.</p> <p>2011-12-01</p> <p>This paper will review recent work done with the multi-fluid version of the Lyon-Fedder-Mobarry (MF-LFM) global MHD simulation code. We will concentrate on O+ outflow from the ionosphere and its importance for <span class="hlt">magnetosphere</span>-ionosphere (MI) coupling and also the importance of ionospheric conditions in determining the outflow. While the predominant method of coupling between the <span class="hlt">magnetosphere</span> and ionosphere is electrodynamic, it has become apparent the mass flows from the ionosphere into the <span class="hlt">magnetosphere</span> can have profound effects on both systems. The earliest models to attempt to incorporate this effect used very crude clouds of plasma near the <span class="hlt">Earth</span>. The earliest MF-LFM results showed that depending on the details of the outflow - where, how much, how fast - very different <span class="hlt">magnetospheric</span> responses could be found. Two approaches to causally driven models for the outflow have been developed for use in global simulations, the Polar Wind Outflow Model (PWOM), started at the Univ. of Michigan, and the model used by Bill Lotko and co-workers at Dartmouth. We will give a quick review of this model which is based on the empirical relation between outflow fluence and Poynting flux discovered by Strangeway. An additional factor used in this model is the precipitating flux of electrons, which is presumed to correlate with the scale height of the upwelling ions. parameters such as outflow speed and density are constrained by the total fluence. The effects of the outflow depend on the speed. Slower outflow tends to land in the inner <span class="hlt">magnetosphere</span> increasing the strength of the ring current. Higher speed flow out in the tail. Using this model, simulations have shown that solar wind dynamic pressure has a profound effect on the amount of fluence. The most striking result has been the simulation of <span class="hlt">magnetospheric</span> sawtooth events. We will discuss future directions for this research, emphasizing the need for better physical models for the outflow process and its coupling to the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM41D2510C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM41D2510C"><span>Penetration of Large Scale Electric Field to Inner <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, S. H.; Fok, M. C. H.; Sibeck, D. G.; Wygant, J. R.; Spence, H. E.; Larsen, B.; Reeves, G. D.; Funsten, H. O.</p> <p>2015-12-01</p> <p>The direct penetration of large scale global electric field to the inner <span class="hlt">magnetosphere</span> is a critical element in controlling how the background thermal plasma populates within the radiation belts. These plasma populations provide the source of particles and free energy needed for the generation and growth of various plasma waves that, at critical points of resonances in time and phase space, can scatter or energize radiation belt particles to regulate the flux level of the relativistic electrons in the system. At high geomagnetic activity levels, the distribution of large scale electric fields serves as an important indicator of how prevalence of strong wave-particle interactions extend over local times and radial distances. To understand the complex relationship between the global electric fields and thermal plasmas, particularly due to the ionospheric dynamo and the <span class="hlt">magnetospheric</span> convection effects, and their relations to the geomagnetic activities, we analyze the electric field and cold plasma measurements from Van Allen Probes over more than two years period and simulate a geomagnetic storm event using Coupled Inner <span class="hlt">Magnetosphere</span>-Ionosphere Model (CIMI). Our statistical analysis of the measurements from Van Allan Probes and CIMI simulations of the March 17, 2013 storm event indicate that: (1) Global dawn-dusk electric field can penetrate the inner <span class="hlt">magnetosphere</span> inside the inner belt below L~2. (2) Stronger convections occurred in the dusk and midnight sectors than those in the noon and dawn sectors. (3) Strong convections at multiple locations exist at all activity levels but more complex at higher activity levels. (4) At the high activity levels, strongest convections occur in the midnight sectors at larger distances from the <span class="hlt">Earth</span> and in the dusk sector at closer distances. (5) Two plasma populations of distinct ion temperature isotropies divided at L-Shell ~2, indicating distinct heating mechanisms between inner and outer radiation belts. (6) CIMI</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM21B..01K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM21B..01K"><span>Observations of Heavy Ions in the <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kistler, L. M.</p> <p>2017-12-01</p> <p>There are two sources for the hot ions in the <span class="hlt">magnetosphere</span>: the solar wind and the ionosphere. The solar wind is predominantly protons, with about 4% He++ and less than 1% other high charge state heavy ions. The ionospheric outflow is also predominantly H+, but can contain a significant fraction of heavy ions including O+, N+, He+, O++, and molecular ions (NO+, N2+, O2+). The ionospheric outflow composition varies significantly both with geomagnetic activity and with solar EUV. The variability in the contribution of the two sources, the variability in the ionospheric source itself, and the transport paths of the different species are all important in determining the ion composition at a given location in the <span class="hlt">magnetosphere</span>. In addition to the source variations, loss processes within the <span class="hlt">magnetosphere</span> can be mass dependent, changing the composition. In particular, charge exchange is strongly species dependent, and can lead to heavy ion dominance at some energies in the inner <span class="hlt">magnetosphere</span>. In this talk we will review the current state of our understanding of the composition of the <span class="hlt">magnetosphere</span> and the processes that determine it.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMNG31A1840F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMNG31A1840F"><span>Non-Gaussian Multi-resolution Modeling of <span class="hlt">Magnetosphere</span>-Ionosphere Coupling Processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fan, M.; Paul, D.; Lee, T. C. M.; Matsuo, T.</p> <p>2016-12-01</p> <p>The most dynamic coupling between the <span class="hlt">magnetosphere</span> and ionosphere occurs in the <span class="hlt">Earth</span>'s polar atmosphere. Our objective is to model scale-dependent stochastic characteristics of high-latitude ionospheric electric fields that originate from solar wind <span class="hlt">magnetosphere</span>-ionosphere interactions. The <span class="hlt">Earth</span>'s high-latitude ionospheric electric field exhibits considerable variability, with increasing non-Gaussian characteristics at decreasing spatio-temporal scales. Accurately representing the underlying stochastic physical process through random field modeling is crucial not only for scientific understanding of the energy, momentum and mass exchanges between the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span> and ionosphere, but also for modern technological systems including telecommunication, navigation, positioning and satellite tracking. While a lot of efforts have been made to characterize the large-scale variability of the electric field in the context of Gaussian processes, no attempt has been made so far to model the small-scale non-Gaussian stochastic process observed in the high-latitude ionosphere. We construct a novel random field model using spherical needlets as building blocks. The double localization of spherical needlets in both spatial and frequency domains enables the model to capture the non-Gaussian and multi-resolutional characteristics of the small-scale variability. The estimation procedure is computationally feasible due to the utilization of an adaptive Gibbs sampler. We apply the proposed methodology to the computational simulation output from the Lyon-Fedder-Mobarry (LFM) global magnetohydrodynamics (MHD) <span class="hlt">magnetosphere</span> model. Our non-Gaussian multi-resolution model results in characterizing significantly more energy associated with the small-scale ionospheric electric field variability in comparison to Gaussian models. By accurately representing unaccounted-for additional energy and momentum sources to the <span class="hlt">Earth</span>'s upper atmosphere, our novel random field modeling</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950057068&hterms=barium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbarium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950057068&hterms=barium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbarium"><span>Dynamics of the CRRES barium releases in the <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fuselier, S. A.; Mende, S. B.; Geller, S. P.; Miller, M.; Hoffman, R. A.; Wygant, J. R.; Pongratz, M.; Meredith, N. P.; Anderson, R. R.</p> <p>1994-01-01</p> <p>The Combined Release and Radiation Effects Satellite (CRRES) G-2, G-3, and G-4 ionized and neutral barium cloud positions are triangulated from ground-based optical data. From the time history of the ionized cloud motion perpendicular to the magnetic field, the late time coupling of the ionized cloud with the collisionless ambient plasma in the <span class="hlt">magnetosphere</span> is investigated for each of the releases. The coupling of the ionized clouds with the ambient medium is quantitatively consistent with predictions from theory in that the coupling time increases with increasing distance from the <span class="hlt">Earth</span>. Quantitative comparison with simple theory for the couping time also yields reasonable agreement. Other effects not predicted by the theory are discussed in the context of the observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960014066','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960014066"><span><span class="hlt">Magnetospheric</span> filter effect for Pc 3 Alfven mode waves</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zhang, X.; Comfort, R. H.; Gallagher, D. L.; Green, J. L.; Musielak, Z. E.; Moore, T. E.</p> <p>1995-01-01</p> <p>We present a ray-tracing study of the propagation of Pc 3 Alfven mode waves originating at the dayside magnetopause. This study reveals interesting features of <span class="hlt">magnetospheric</span> filter effect for these waves. Pc 3 Alfven mode waves cannot penetrate to low <span class="hlt">Earth</span> altitudes unless the wave frequency is below approximately 30 mHz. Configurations of the dispersion curves and the refractive index show that the gyroresonance and pseudo-cutoff introduced by the heavy ion O(+) block the waves. When the O(+) concentration is removed from the plasma composition, the barriers caused by the O(+) no longer exist, and waves with much higher frequencies than 30 mHz can penetrate to low altitudes. The result that the 30 mHz or lower frequency Alfven waves can be guided to low altitudes agrees with ground-based power spectrum observation at high altitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960003151','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960003151"><span><span class="hlt">Magnetospheric</span> filter effect for Pc 3 Alfven mode waves</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zhang, X.; Comfort, R. H.; Gallagher, D. L.; Green, J. L.; Musielak, Z. E.; Moore, T. E.</p> <p>1994-01-01</p> <p>We present a ray-tracing study of the propagation of Pc 3 Alfven mode waves originating at the dayside magnetopause. This study reveals interesting features of a <span class="hlt">magnetospheric</span> filter effect for these waves. Pc 3 Alfven mode waves cannot penetrate to low <span class="hlt">Earth</span> altitudes unless the wave frequency is below approximately 30 mHz. Configurations of the dispersion curves and the refractive index show that the gyroresonance and pseudo-cutoff introduced by the heavy ion O(+) block the waves. When the O(+) concentration is removed from the plasma composition, the barriers caused by the O(+) no longer exist, and waves with much higher frequencies than 30 mHz can penetrate to low altitudes. The result that the 30 mHz or lower frequency Alfven waves can be guided to low altitudes agrees with ground-based power spectrum observations at high latitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM33C2689V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM33C2689V"><span>Identifying Cassini's <span class="hlt">Magnetospheric</span> Location Using <span class="hlt">Magnetospheric</span> Imaging Instrument (MIMI) Data and Machine Learning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vandegriff, J. D.; Smith, G. L.; Edenbaum, H.; Peachey, J. M.; Mitchell, D. G.</p> <p>2017-12-01</p> <p>We analyzed data from Cassini's <span class="hlt">Magnetospheric</span> Imaging Instrument (MIMI) and Magnetometer (MAG) and attempted to identify the region of Saturn's <span class="hlt">magnetosphere</span> that Cassini was in at a given time using machine learning. MIMI data are from the Charge-Energy-Mass Spectrometer (CHEMS) instrument and the Low-Energy <span class="hlt">Magnetospheric</span> Measurement System (LEMMS). We trained on data where the region is known based on a previous analysis of Cassini Plasma Spectrometer (CAPS) plasma data. Three <span class="hlt">magnetospheric</span> regions are considered: <span class="hlt">Magnetosphere</span>, Magnetosheath, and Solar Wind. MIMI particle intensities, magnetic field values, and spacecraft position are used as input attributes, and the output is the CAPS-based region, which is available from 2004 to 2012. We then use the trained classifier to identify Cassini's <span class="hlt">magnetospheric</span> regions for times after 2012, when CAPS data is no longer available. Training accuracy is evaluated by testing the classifier performance on a time range of known regions that the classifier has never seen. Preliminary results indicate a 68% accuracy on such test data. Other techniques are being tested that may increase this performance. We present the data and algorithms used, and will describe the latest results, including the <span class="hlt">magnetospheric</span> regions post-2012 identified by the algorithm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880026613&hterms=creep+omega&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dcreep%2Bomega','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880026613&hterms=creep+omega&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dcreep%2Bomega"><span>Outer <span class="hlt">magnetospheric</span> fluctuations and pulsar timing noise</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cheng, K. S.</p> <p>1987-01-01</p> <p>The Cheng, Ho, and Ruderman (1986) outer-<span class="hlt">magnetosphere</span> gap model was used to investigate the stability of Crab-type outer <span class="hlt">magnetosphere</span> gaps for pulsars having the parameter (Omega-square B) similar to that of the Crab pulsar. The Lamb, Pines, and Shaham (1978) fluctuating <span class="hlt">magnetosphere</span> noise model was applied to the Crab pulsar to examine the type of the equation of state that best describes the structure of the neutron star. The noise model was also applied to other pulsars, and the theoretical results were compared with observational data. The results of the comparison are consistent with the stiff equation of state, as suggested by the vortex creep model of the neutron star interior. The timing-noise observations also contribute to the evidence for the existence of superfluid in the core of the neutron star.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820061326&hterms=1076&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D%2526%25231076','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820061326&hterms=1076&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3D%2526%25231076"><span>Charged particle periodicity in the Saturnian <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Carbary, J. F.; Krimigis, S. M.</p> <p>1982-01-01</p> <p>The present investigation is concerned with the first definitive evidence for charged particle modulations near the magnetic rotation period at Saturn. This periodicity is apparent in the ratios (and spectra) of low energy charged particles in the Saturnian <span class="hlt">magnetosphere</span>. Most of the data presented were taken during the Voyager 2 outbound portion of the Saturn encounter. During this time the spacecraft was at high latitudes (approximately 30 deg) in the southern hemisphere of the Saturnian <span class="hlt">magnetosphere</span>. The probe's trajectory was approximately along the dawn meridian at an essentially constant local time. The observation that the charged particle modulation is consistent with the Saturn Kilometric Radiation (SKR) period provides a basic input for the resolution of a puzzle which has existed ever since the discovery of the SKR modulation. The charged particle periodicity identified suggests that a basic asymmetry must exist in the Saturnian <span class="hlt">magnetosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930013496','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930013496"><span>Inner <span class="hlt">Magnetosphere</span> Imager (IMI) instrument heritage</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilson, G. R.</p> <p>1993-01-01</p> <p>This report documents the heritage of instrument concepts under consideration for the Inner <span class="hlt">Magnetosphere</span> Imager (IMI) mission. The proposed IMI will obtain the first simultaneous images of the component regions of the inner <span class="hlt">magnetosphere</span> and will enable scientists to relate these global images to internal and external influences as well as local observations. To obtain simultaneous images of component regions of the inner <span class="hlt">magnetosphere</span>, measurements will be made of: (1) the ring current and inner plasma sheet using energetic neutral atoms; (2) the plasmasphere using extreme ultraviolet; (3) the electron and proton auroras using far ultraviolet and x rays; and (4) the geocorona using FUV. Instrument concepts that show heritage and traceability to those that will be required to meet the IMI measurement objectives are described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......230P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......230P"><span>A Dynamic Coupled <span class="hlt">Magnetosphere</span>-Ionosphere-Ring Current Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pembroke, Asher</p> <p></p> <p>In this thesis we describe a coupled model of <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span> that consists of the Lyon-Fedder-Mobarry (LFM) global magnetohydrodynamics (MHD) simulation, the MIX ionosphere solver and the Rice Convection Model (RCM). We report some results of the coupled model using idealized inputs and model parameters. The algorithmic and physical components of the model are described, including the transfer of magnetic field information and plasma boundary conditions to the RCM and the return of ring current plasma properties to the LFM. Crucial aspects of the coupling include the restriction of RCM to regions where field-line averaged plasma-beta ¡=1, the use of a plasmasphere model, and the MIX ionosphere model. Compared to stand-alone MHD, the coupled model produces a substantial increase in ring current pressure and reduction of the magnetic field near the <span class="hlt">Earth</span>. In the ionosphere, stronger region-1 and region-2 Birkeland currents are seen in the coupled model but with no significant change in the cross polar cap potential drop, while the region-2 currents shielded the low-latitude convection potential. In addition, oscillations in the magnetic field are produced at geosynchronous orbit with the coupled code. The diagnostics of entropy and mass content indicate that these oscillations are associated with low-entropy flow channels moving in from the tail and may be related to bursty bulk flows and bubbles seen in observations. As with most complex numerical models, there is the ongoing challenge of untangling numerical artifacts and physics, and we find that while there is still much room for improvement, the results presented here are encouraging. Finally, we introduce several new methods for <span class="hlt">magnetospheric</span> visualization and analysis, including a fluid-spatial volume for RCM and a field-aligned analysis mesh for the LFM. The latter allows us to construct novel visualizations of flux tubes, drift surfaces, topological boundaries, and bursty-bulk flows.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011P%26SS...59..606S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011P%26SS...59..606S"><span>ROY—A multiscale <span class="hlt">magnetospheric</span> mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Savin, S.; Zelenyi, L.; Amata, E.; Budaev, V.; Buechner, J.; Blecki, J.; Balikhin, M.; Klimov, S.; Korepanov, V. E.; Kozak, L.; Kudryashov, V.; Kunitsyn, V.; Lezhen, L.; Milovanov, A. V.; Nemecek, Z.; Nesterov, I.; Novikov, D.; Panov, E.; Rauch, J. L.; Rothkaehl, H.; Romanov, S.; Safrankova, J.; Skalsky, A.; Veselov, M.</p> <p>2011-05-01</p> <p>The scientific rationale of the ROY multi-satellite mission addresses multiscale investigations of plasma processes in the key <span class="hlt">magnetospheric</span> regions with strong plasma gradients, turbulence and magnetic field annihilation in the range from electron inertial length to MHD scales. The main scientific aims of ROY mission include explorations of: turbulence on a non-uniform background as a keystone for transport processes; structures and jets in plasma flows associated with anomalously large concentration of kinetic energy; their impact on the energy balance and boundary formation; transport barriers: plasma separation and mixing, Alfvenic collapse of magnetic field lines and turbulent dissipation of kinetic energy; self-organized versus forced reconnection of magnetic field lines; collisionless shocks, plasma discontinuities and associated particle acceleration processes. In the case of autonomous operation, 4 mobile spacecrafts of about 200 kg mass with 60 kg payload equipped with electro-reactive plasma engines will provide 3D measurements at the scales of 100-10000 km and simultaneous 1D measurements at the scales 10-1000 km. The latter smaller scales will be scanned with the use of radio-tomography (phase-shift density measurements within the cone composed of 1 emitting and 3 receiving spacecrafts). We also discuss different opportunities for extra measurement points inside the ROY mission for simultaneous measurements at up to 3 scales for the common international fleet. Combined influence of intermittent turbulence and reconnection on the geomagnetic tail and on the nonlinear dynamics of boundary layers will be explored in situ with fast techniques including particle devices under development, providing plasma moments down to 30 ms resolution. We propose different options for joint measurements in conjunction with the SCOPE and other missions: simultaneous sampling of low- and high-latitudes magnetopause, bow shock and geomagnetic tail at the same local time</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17783834','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17783834"><span>Low-Energy Charged Particles in Saturn's <span class="hlt">Magnetosphere</span>: Results from Voyager 1.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Krimigis, S M; Armstrong, T P; Axford, W I; Bostrom, C O; Gloeckler, G; Keath, E P; Lanzerotti, L J; Carbary, J F; Hamilton, D C; Roelof, E C</p> <p>1981-04-10</p> <p>The low-energy charged particle instrument on Voyager 1 measured low-energy electrons and ions (energies >/= 26 and >/= 40 kiloelectron volts, respectively) in Saturn's <span class="hlt">magnetosphere</span>. The first-order ion anisotropies on the dayside are generally in the corotation direction with the amplitude decreasing with decreasing distance to the planet. The ion pitch-angle distributions generally peak at 90 degrees , whereas the electron distributions tend to have field-aligned bidirectional maxima outside the L shell of Rhea. A large decrease in particle fluxes is seen near the L shell of Titan, while selective particle absorption (least affecting the lowest energy ions) is observed at the L shells of Rhea, Dione, and Tethys. The phase space density of ions with values of the first invariant in the range approximately 300 to 1000 million electron volts per gauss is consistent with a source in the outer <span class="hlt">magnetosphere</span>. The ion population at higher energies (>/= 200 kiloelectron volts per nucleon) consists primarily of protons, molecular hydrogen, and helium. Spectra of all ion species exhibit an energy cutoff at energies >/= 2 million electron volts. The proton-to-helium ratio at equal energy per nucleon is larger (up to approximately 5 x 10(3)) than seen in other <span class="hlt">magnetospheres</span> and is consistent with a local (nonsolar wind) proton source. In contrast to the <span class="hlt">magnetospheres</span> of Jupiter and <span class="hlt">Earth</span>, there are no lobe regions essentially devoid of particles in Saturn's nighttime <span class="hlt">magnetosphere</span>. Electron pitch-angle distributions are generally bidirectional andfield-aligned, indicating closed field lines at high latitudes. Ions in this region are generally moving toward Saturn, while in the magnetosheath they exhibit strong antisunward streaming which is inconsistent with purely convective flows. Fluxes of <span class="hlt">magnetospheric</span> ions downstream from the bow shock are present over distances >/= 200 Saturn radii from the planet. Novel features identified in the Saturnian <span class="hlt">magnetosphere</span> include a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH43C..01K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH43C..01K"><span>The kappa Distribution as Tool in Investigating Hot Plasmas in the <span class="hlt">Magnetospheres</span> of Outer Planets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krimigis, S. M.; Carbary, J. F.</p> <p>2014-12-01</p> <p>The first use of a Maxwellian distribution with a high-energy tail (a κ-function) was made by Olbert (1968) and applied by Vasyliunas (1968) in analyzing electron data. The k-function combines aspects of both Maxwellian and power law forms to provide a reasonably complete description of particle density, temperature, pressure and convection velocity, all of which are key parameters of <span class="hlt">magnetospheric</span> physics. Krimigis et al (1979) used it to describe flowing plasma ions in Jupiter's <span class="hlt">magnetosphere</span> measured by Voyager 1, and obtained temperatures in the range of 20 to 35 keV. Sarris et al (1981) used the κ-function to describe plasmas in <span class="hlt">Earth</span>'s distant plasma sheet. The κ-function, in various formulations and names (e. g., γ-thermal distribution, Krimigis and Roelof, 1983) has been used routinely to parametrize hot, flowing plasmas in the <span class="hlt">magnetospheres</span> of the outer planets, with typical kT ~ 10 to 50 keV. Using angular measurements, it has been possible to obtain pitch angle distributions and convective flow directions in sufficient detail for computations of temperatures and densities of hot particle pressures. These 'hot' pressures typically dominate the cold plasma pressures in the high beta (β > 1) <span class="hlt">magnetospheres</span> of Jupiter and Saturn, but are of less importance in the relatively empty (β < 1) <span class="hlt">magnetospheres</span> of Uranus and Neptune. Thus, the κ-function represents an effective tool in analyzing plasma behavior in planetary <span class="hlt">magnetospheres</span>, but it is not applicable in all plasma environments. References Olbert, S., in Physics of the <span class="hlt">Magnetosphere</span>, (Carovillano, McClay, Radoski, Eds), Springer-Verlag, New York, p. 641-659, 1968 Vasyliunas, V., J. Geophys. Res., 73(9), 2839-2884, 1968 Krimigis, S. M., et al, Science 204, 998-1003, 1979 Sarris, E., et al, Geophys. Res. Lett. 8, 349-352, 1981 Krimigis, S. M., and E. C. Roelof, Physics of the Jovian <span class="hlt">Magnetosphere</span>, edited by A. J. Dessler, 106-156, Cambridge University Press, New York, 1983</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19760018050','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19760018050"><span>Planetary <span class="hlt">magnetospheres</span>: A comparative view</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dessler, A. J.</p> <p>1976-01-01</p> <p>There are eight large bodies in the solar system about which definite statements regarding the existence or nonexistence of a magnetic field of internal origin can now be made. Of these bodies (Sun, Mercury, Venus, <span class="hlt">Earth</span>, Mars, Jupiter, Saturn, and the <span class="hlt">Earth</span>'s Moon), only Venus and the Moon have negligible surface magnetic fields. By negligible is meant that the magnetic fields are so weak that they do not sensibly perturb the local solar wind. The other bodies provide an interesting zoo of magnetic field configurations and attendant charged particle behavior. Six of these bodies have magnetic fields, and two do not. Furthermore, of those which have magnetic fields, it appears that only that of Mars is ineffective in accelerating charged particles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA206252','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA206252"><span>Particle Simulations of <span class="hlt">Magnetospheric</span> Plasmas</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1989-03-14</p> <p>scale vortices. 2 2. Beam Instability in the Foreshock As an application of the simulation method used in the proposed research (Broadband...electrostatic noise), the beam instability in the foreshock has been investigated. Electrons backstreaming into the <span class="hlt">Earth</span>’s foreshock generate waves near the...narrowband waves near the foreshock boundary may be between 0.9wp and 0.98wpe, rather than being above w., as previously believed. 3 3. Whistler Mode</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA216256','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA216256"><span>Particle Simulations in <span class="hlt">Magnetospheric</span> Plasmas</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1989-12-18</p> <p>Foreshock As an application of the simulation method used in the proposed research (Broadband electrostatic noise), the beam instability in the... foreshock has been investigated. Electrons backstreaming into the <span class="hlt">Earth</span>’s foreshock generate waves near the plasma frequency by the beam instability. Two...results and numerical solutions of the dispersion equation indicate that the center frequency of the intense narrowband waves near the foreshock boundary</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA474765','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA474765"><span>Excitation of the <span class="hlt">Magnetospheric</span> Cavity</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2007-06-16</p> <p>gyrofrequency of 880 kHz at the ground at the equator, and uses a diffusive equilibrium model [ Angerami and Thomas, 1964] to calculate charged particle...significantly damped [Smith and Angerami , 1968; Edgar, 1976; Gurnett and Inan, 1988], resonantly interacting with, and pitch angle scattering...2429, 1999. Angerami , J. J., and J. O. Thomas, Studies of planetary Atmospheres, 1, The distribution of electrons and ions in the <span class="hlt">Earth</span>’s</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AdSpR..38..263R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AdSpR..38..263R"><span>The <span class="hlt">magnetospheric</span> and ionospheric response to a very strong interplanetary shock and coronal mass ejection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ridley, A. J.; De Zeeuw, D. L.; Manchester, W. B.; Hansen, K. C.</p> <p>2006-01-01</p> <p>We present results from a coupled <span class="hlt">magnetospheric</span> and ionospheric simulation of a very strong solar wind shock and coronal mass ejection (CME). The solar wind drivers that are used for this simulation were output from the Sun-to-<span class="hlt">Earth</span> MHD simulation of the Carrington-like CME reported in Manchester et al. [Manchester IV, W., Ridley, A., Gombosi, T., De Zeeuw, D. Modeling the Sun-<span class="hlt">Earth</span> propagation of a very fast cme. Adv. Space Res. 38 (this issue), 2006]. We use the University of Michigan's BATS-R-US MHD code to model the global <span class="hlt">magnetosphere</span> and coupled height integrated ionosphere. As the interplanetary shock swept over the <span class="hlt">magnetosphere</span>, a wave is observed to propagate through the system. This is evident both in the <span class="hlt">magnetosphere</span> and ionosphere. On the dayside, the <span class="hlt">magnetospheric</span> bowshock is shown to bifurcate. The inner shock is pushed close to the inner boundary, where it "bounces" and propagates back outwards to meet the outer bowshock, which is propagating inwards. The inward and outward motion of the bowshocks can be observed propagating down the flanks of the <span class="hlt">magnetosphere</span>. In the ionosphere, the wave is manifested as two pairs of field-aligned currents moving antisunward. The first pair is opposite of the normal region-1 current system, while the second pair is in the same sense as the normal region-1 system. The ionospheric potential shows a behavior consistent with the field-aligned current pattern, given the strong gradient in the conductance from the dayside to the nightside. As the magnetic cloud flows over the system, the entire magnetopause boundary is observed to move inside of geosynchronous orbit (6.6 Re). At the time of the most extreme solar wind conditions, the magnetopause boundary encounters the inner edge of the <span class="hlt">magnetospheric</span> simulation domain. During the magnetic cloud, the ionospheric cross-polar cap potential is shown to match the Siscoe et al. [Siscoe, G.L., Erickson, G., Sonnerup, B., Maynard, N., Schoendorf, J., Siebert, K., Weimer</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970023024','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970023024"><span>On the Azimuthal Variation of Core Plasma in the Equatorial <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gallagher, D. L.; Craven, P. D.; Comfort, R. H.; Moore, T. E.</p> <p>1995-01-01</p> <p>Previous results of plasmapause position surveys have been synthesized into a description of the underlying global distribution of plasmasphere-like or core plasma densities unique to a steady state <span class="hlt">magnetosphere</span>. Under these steady conditions, the boundary between high- and low-density regions is taken to represent the boundary between diurnal near-corotation and large-scale circulation streamlines that traverse the entire <span class="hlt">magnetosphere</span>. Results indicate a boundary that has a pronounced bulge in the dusk sector that is rotated westward and markedly reduced in size at increased levels of geomagnetic activity (and presumably <span class="hlt">magnetospheric</span> convection). The derived profile is empirical confirmation of an underlying 'tear drop' distribution of core plasma, which is valid only for prolonged steady conditions and is somewhat different from that associated with the simple superposition of sunward flow and corotation, both in its detailed shape and in its varying orientation. Variation away from the tear drop profile suggests that <span class="hlt">magnetospheric</span> circulation departs from a uniform flow field, having a radial dependence with respect to the <span class="hlt">Earth</span> that is qualitatively consistent with electrostatic shielding of the convection electric field and which is rotated westward at increased levels of geophysical activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM33C2679S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM33C2679S"><span>Influence of the solar wind and IMF on Jupiter's <span class="hlt">magnetosphere</span>: Results from global MHD simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sarkango, Y.; Jia, X.; Toth, G.; Hansen, K. C.</p> <p>2017-12-01</p> <p>Due to its large size, rapid rotation and presence of substantial internal plasma sources, Jupiter's <span class="hlt">magnetosphere</span> is fundamentally different from that of the <span class="hlt">Earth</span>. How and to what extent do the external factors, such as the solar wind and interplanetary magnetic field (IMF), influence the internally-driven <span class="hlt">magnetosphere</span> is an open question. In this work, we solve the 3D semi-relativistic magnetohydrodynamic (MHD) equations using a well-established code, BATSRUS, to model the Jovian <span class="hlt">magnetosphere</span> and study its interaction with the solar wind. Our global model adopts a non-uniform mesh covering the region from 200 RJ upstream to 1800 RJ downstream with the inner boundary placed at a radial distance of 2.5 RJ. The Io plasma torus centered around 6 RJ is generated in our model through appropriate mass-loading terms added to the set of MHD equations. We perform systematic numerical experiments in which we vary the upstream solar wind properties to investigate the impact of solar wind events, such as interplanetary shock and IMF rotation, on the global <span class="hlt">magnetosphere</span>. From our simulations, we extract the location of the magnetopause boundary, the bow shock and the open-closed field line boundary (OCB), and determine their dependence on the solar wind properties and the IMF orientation. For validation, we compare our simulation results, such as density, temperature and magnetic field, to published empirical models based on in-situ measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950005535','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950005535"><span>Inner <span class="hlt">Magnetosphere</span> Imager (IMI) solar terrestrial probe class mission preliminary design study report</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hermann, M.; Johnson, L.</p> <p>1994-01-01</p> <p>For three decades, <span class="hlt">magnetospheric</span> field and plasma measurements have been made by diverse instruments flown on spacecraft in many different orbits, widely separated in space and time, and under various solar and <span class="hlt">magnetospheric</span> conditions. Scientists have used this information to piece together an intricate, yet incomplete view of the <span class="hlt">magnetosphere</span>. A simultaneous global view, using various light wavelengths and energetic neutral atoms, could reveal exciting new data and help explain complex <span class="hlt">magnetospheric</span> processes, thus providing us with a clear picture of this region of space. The George C. Marshall Space Flight Center (MSFC) is responsible for defining the IMI mission which will study this region of space. NASA's Space Physics Division of the Office of Space Science placed the IMI third in its queue of Solar Terrestrial Probe missions for launch in the 1990's. A core instrument complement of three images (with the potential addition of one or more mission enhancing instruments) will fly in an elliptical, polar <span class="hlt">earth</span> orbit with an apogee of 44,600 km and a perigee of 4,800 km. This paper will address the mission objectives, spacecraft design consideration, interim results of the MSFC concept definition study, and future plans.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AdSpR..59.2255W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AdSpR..59.2255W"><span>Investigation of the radiation properties of <span class="hlt">magnetospheric</span> ELF waves induced by modulated ionospheric heating</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Feng; Ni, Binbin; Zhao, Zhengyu; Zhao, Shufan; Zhao, Guangxin; Wang, Min</p> <p>2017-05-01</p> <p>Electromagnetic extremely low frequency (ELF) waves play an important role in modulating the <span class="hlt">Earth</span>'s radiation belt electron dynamics. High-frequency (HF) modulated heating of the ionosphere acts as a viable means to generate artificial ELF waves. The artificial ELF waves can reside in two different plasma regions in geo-space by propagating in the ionosphere and penetrating into the <span class="hlt">magnetosphere</span>. As a consequence, the entire trajectory of ELF wave propagation should be considered to carefully analyze the wave radiation properties resulting from modulated ionospheric heating. We adopt a model of full wave solution to evaluate the Poynting vector of the ELF radiation field in the ionosphere, which can reflect the propagation characteristics of the radiated ELF waves along the background magnetic field and provide the initial condition of waves for ray tracing in the <span class="hlt">magnetosphere</span>. The results indicate that the induced ELF wave energy forms a collimated beam and the center of the ELF radiation shifts obviously with respect to the ambient magnetic field with the radiation power inversely proportional to the wave frequency. The intensity of ELF wave radiation also shows a weak correlation with the size of the radiation source or its geographical location. Furthermore, the combination of ELF propagation in the ionosphere and <span class="hlt">magnetosphere</span> is proposed on basis of the characteristics of the ELF radiation field from the upper ionospheric boundary and ray tracing simulations are implemented to reasonably calculate <span class="hlt">magnetospheric</span> ray paths of ELF waves induced by modulated ionospheric heating.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM43A2300R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM43A2300R"><span>Inner <span class="hlt">Magnetosphere</span> Modeling at the CCMC: Ring Current, Radiation Belt and Magnetic Field Mapping</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rastaetter, L.; Mendoza, A. M.; Chulaki, A.; Kuznetsova, M. M.; Zheng, Y.</p> <p>2013-12-01</p> <p>Modeling of the inner <span class="hlt">magnetosphere</span> has entered center stage with the launch of the Van Allen Probes (RBSP) in 2012. The Community Coordinated Modeling Center (CCMC) has drastically improved its offerings of inner <span class="hlt">magnetosphere</span> models that cover energetic particles in the <span class="hlt">Earth</span>'s ring current and radiation belts. Models added to the CCMC include the stand-alone Comprehensive Inner <span class="hlt">Magnetosphere</span>-Ionosphere (CIMI) model by M.C. Fok, the Rice Convection Model (RCM) by R. Wolf and S. Sazykin and numerous versions of the Tsyganenko magnetic field model (T89, T96, T01quiet, TS05). These models join the LANL* model by Y. Yu hat was offered for instant run earlier in the year. In addition to these stand-alone models, the Comprehensive Ring Current Model (CRCM) by M.C. Fok and N. Buzulukova joined as a component of the Space Weather Modeling Framework (SWMF) in the <span class="hlt">magnetosphere</span> model run-on-request category. We present modeling results of the ring current and radiation belt models and demonstrate tracking of satellites such as RBSP. Calculations using the magnetic field models include mappings to the magnetic equator or to minimum-B positions and the determination of foot points in the ionosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790046450&hterms=Electromagnetic+Spectrum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DElectromagnetic%2BSpectrum','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790046450&hterms=Electromagnetic+Spectrum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DElectromagnetic%2BSpectrum"><span>Electromagnetic and electrostatic emissions at the cusp-<span class="hlt">magnetosphere</span> interface during substorms</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Curtis, S. A.; Fairfield, D. H.; Wu, C. S.</p> <p>1979-01-01</p> <p>Strongly peaked electrostatic emissions near 10.0 kHz and electromagnetic emissions near 0.56 kHz have been observed by the VLF wave detector on board Imp 6 on crossings from the <span class="hlt">earth</span>'s <span class="hlt">magnetosphere</span> into the polar cusp during the occurrence of large <span class="hlt">magnetospheric</span> substorms. The electrostatic emissions were observed to be closely confined to the cusp-<span class="hlt">magnetosphere</span> interface. The electromagnetic emissions were of somewhat broader spatial extent and were seen on higher-latitude field lines within the cusp. Using these plasma wave observations and additional information provided by plasma, magnetometer and particle measurements made simultaneously on Imp 6, theories are constructed to explain each of the two classes of emission. The electromagnetic waves are modeled as whistlers, and the electrostatic waves as electron-cyclotron harmonics. The resulting growth rates predict power spectra similar to those observed for both emission classes. The electrostatic waves may play a significant role via enhanced diffusion in the relaxation of the sharp substorm time cusp-<span class="hlt">magnetosphere</span> boundary to a more diffuse quiet time boundary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830061197&hterms=activity+Physics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dactivity%2BPhysics','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830061197&hterms=activity+Physics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dactivity%2BPhysics"><span>An ISEE 3 high time resolution study of interplanetary parameter correlations with <span class="hlt">magnetospheric</span> activity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Baker, D. N.; Zwickl, R. D.; Bame, S. J.; Hones, E. W., Jr.; Tsurutani, B. T.; Smith, E. J.; Akasofu, S.-I.</p> <p>1983-01-01</p> <p>The coupling between the solar wind and the geomagnetic disturbances was examined using data from the ISEE-3 spacecraft at an <span class="hlt">earth</span>-sun libration point and ground-based data. One minute data were used to avoid aliasing in determining the internal <span class="hlt">magnetospheric</span> response to solar wind conditions. Attention was given to the cross-correlations between the geomagnetic index (AE), the total energy dissipation rate (UT), and the solar wind parameters, as well as the spatial and temporal scales on which the <span class="hlt">magnetosphere</span> reacts to the solar wind conditions. It was considered necessary to characterize the physics of the solar wind-<span class="hlt">magnetosphere</span> coupling in order to define the requirements for a spacecraft like the ISEE-3 that could be used as a real time monitoring system for predicting storms and substorms. The correlations among all but one parameter were lower during disturbance intervals; UT was highly correlated with all parameters during the disturbed times. An intrinsic 25-40 min delay was detected between interplanetary activity and <span class="hlt">magnetospheric</span> response in quite times, diminishing to no more than 15 min during disturbed times.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM23A2586I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM23A2586I"><span>The contribution of inductive electric fields to particle energization in the inner <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ilie, R.; Toth, G.; Liemohn, M. W.; Chan, A. A.</p> <p>2017-12-01</p> <p>Assessing the relative contribution of potential versus inductive electric fields at the energization of the hot ion population in the inner <span class="hlt">magnetosphere</span> is only possible by thorough examination of the time varying magnetic field and current systems using global modeling of the entire system. We present here a method to calculate the inductive and potential components of electric field in the entire <span class="hlt">magnetosphere</span> region. This method is based on the Helmholtz vector decomposition of the motional electric field as calculated by the BATS-R-US model, and is subject to boundary conditions. This approach removes the need to trace independent field lines and lifts the assumption that the magnetic field lines can be treated as frozen in a stationary ionosphere. In order to quantify the relative contributions of potential and inductive electric fields at driving plasma sheet ions into the inner <span class="hlt">magnetosphere</span>, we apply this method for the March 17th, 2013 geomagnetic storm. We present here the consequences of slow continuous changes in the geomagnetic field as well as the strong tail dipolarizations on the distortion of the near-<span class="hlt">Earth</span> magnetic field and current systems. Our findings indicate that the inductive component of the electric field is comparable, and even higher at times than the potential component, suggesting that the electric field induced by the time varying magnetic field plays a crucial role in the overall particle energization in the inner <span class="hlt">magnetosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140012579','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140012579"><span>Two Dual Ion Spectrometer Flight Units of the Fast Plasma Instrument Suite (FPI) for the <span class="hlt">Magnetospheric</span> Multiscale Mission (MMS)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Adams, Mitzi</p> <p>2014-01-01</p> <p>Two Dual Ion Spectrometer flight units of the Fast Plasma Instrument Suite (FPI) for the <span class="hlt">Magnetospheric</span> Multiscale Mission (MMS) have returned to MSFC for flight testing. Anticipated to begin on June 30, tests will ensue in the Low Energy Electron and Ion Facility of the Heliophysics and Planetary Science Office (ZP13), managed by Dr. Victoria Coffey of the Natural Environments Branch of the Engineering Directorate (EV44). The MMS mission consists of four identical spacecraft, whose purpose is to study magnetic reconnection in the boundary regions of <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730007618','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730007618"><span>Methods of determining electron concentrations in the <span class="hlt">magnetosphere</span> from nose whistlers</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Park, C. G.</p> <p>1972-01-01</p> <p>Whistler propagation in the <span class="hlt">magnetosphere</span> was studied in detail to find accurate and economical means of determining the path latitude and the electron concentration along the path from whistler parameters of nose frequency and travel time at the nose. Longitudinal propagation in field aligned whistler ducts of cold plasma was assumed, and the <span class="hlt">earth</span>'s magnetic field was approximated by a centered dipole. The effects of whistler propagation in the <span class="hlt">earth</span>-ionosphere waveguide and through the conjugate ionospheres were treated as small perturbations. Several alternative methods are described so that the most economical method may be chosen depending on the desired accuracy and the availability of a computer or a calculator.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM41C2495G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM41C2495G"><span>Storm- Time Dynamics of Ring Current Protons: Implications for the Long-Term Energy Budget in the Inner <span class="hlt">Magnetosphere</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gkioulidou, M.; Ukhorskiy, A. Y.; Mitchell, D. G.; Lanzerotti, L. J.</p> <p>2015-12-01</p> <p>The ring current energy budget plays a key role in the global electrodynamics of <span class="hlt">Earth</span>'s space environment. Pressure gradients developed in the inner <span class="hlt">magnetosphere</span> can shield the near-<span class="hlt">Earth</span> region from solar wind-induced electric fields. The distortion of <span class="hlt">Earth</span>'s magnetic field due to the ring current affects the dynamics of particles contributing both to the ring current and radiation belts. Therefore, understanding the long-term evolution of the inner <span class="hlt">magnetosphere</span> energy content is essential. We have investigated the evolution of ring current proton pressure (7 - 600 keV) in the inner <span class="hlt">magnetosphere</span> based on data from the Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) instrument aboard Van Allen Probe B throughout the year 2013. We find that although the low-energy component of the protons (< 80 keV) is governed by convective timescales and is very well correlated with the Dst index, the high-energy component (>100 keV) varies on much longer timescales and shows either no or anti-correlation with the Dst index. Interestingly, the contributions of the high- and low-energy protons to the total energy content are comparable. Our results indicate that the proton dynamics, and as a consequence the total energy budget in the inner <span class="hlt">magnetosphere</span> (inside geosynchronous orbit), is not strictly controlled by storm-time timescales as those are defined by the Dst index.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMIN23B1775S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMIN23B1775S"><span>Improving Discoverability Between the <span class="hlt">Magnetosphere</span> and Ionosphere/Thermosphere Domains</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schaefer, R. K.; Morrison, D.; Potter, M.; Barnes, R. J.; Talaat, E. R.; Sarris, T.</p> <p>2016-12-01</p> <p>With the advent of the NASA <span class="hlt">Magnetospheric</span> Multiscale Mission and the Van Allen Probes we have space missions that probe the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span> and radiation belts. These missions fly at far distances from the <span class="hlt">Earth</span> in contrast to the larger number of near-<span class="hlt">Earth</span> satellites. Both of the satellites make in situ measurements. Energetic particles flow along magnetic field lines from these measurement locations down to the ionosphere/thermosphere region. Discovering other data that may be used with these satellites is a difficult and complicated process. To solve this problem we have developed a series of light-weight web services that can provide a new data search capability for the Virtual Ionosphere Thermosphere Mesosphere Observatory (VITMO). The services consist of a database of spacecraft ephemerides and instrument fields of view; an overlap calculator to find times when the fields of view of different instruments intersect; and a magnetic field line tracing service that maps in situ and ground based measurements for a number of magnetic field models and geophysical conditions. These services run in real-time when the user queries for data and allow the non-specialist user to select data that they were previously unable to locate, opening up analysis opportunities beyond the instrument teams and specialists. Each service on their own provides a useful new capability for virtual observatories; operating together they will provide a powerful new search tool. The ephemerides service is being built using the Navigation and Ancillary Information Facility (NAIF) SPICE toolkit (http://naif.jpl.nasa.gov) allowing them to be extended to support any <span class="hlt">Earth</span> orbiting satellite with the addition of the appropriate SPICE kernels. The overlap calculator uses techniques borrowed from computer graphics to identify overlapping measurements in space and time. The calculator will allow a user defined uncertainty to be selected to allow "near misses" to be found. The magnetic field</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSM51F2560C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSM51F2560C"><span>The κ Distribution in Saturn's <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carbary, J. F.</p> <p>2016-12-01</p> <p>The <span class="hlt">magnetosphere</span> of Saturn contains abundant fluxes of electrons and ions, which originate primarily from the moon Enceladus and secondarily from the planet's ionosphere and the solar wind. Electrons from 10's of eV through 100's of keV exhibit non-thermal distributions in the form of dual-κ functions having a low-energy part and a high energy part. While the ion spectra are generally described in terms of a convecting Maxwellian, a better description might be a convecting power law and/or κ distribution. From such forms, one can derive convection speeds that are less than corotation throughout the <span class="hlt">magnetosphere</span> and which decrease with increasing radial distance. The ion and electron distributions have a notable local time dependences, and the spectral characteristics change noticeably with distance from Saturn. Saturn's spectra also vary with the distinctive 10.7h "rotational" period of the planet, a fact not fully appreciated by practitioners in the field. This presentation will review Saturn's <span class="hlt">magnetosphere</span>, how the κ distribution describes its charged particle fluxes both in the "thermal" and "energetic" particle regimes, and will offer several new observations of Saturn's <span class="hlt">magnetospheric</span> spectra.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014MNRAS.441.1943W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014MNRAS.441.1943W"><span>Polarized curvature radiation in pulsar <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, P. F.; Wang, C.; Han, J. L.</p> <p>2014-07-01</p> <p>The propagation of polarized emission in pulsar <span class="hlt">magnetosphere</span> is investigated in this paper. The polarized waves are generated through curvature radiation from the relativistic particles streaming along curved magnetic field lines and corotating with the pulsar <span class="hlt">magnetosphere</span>. Within the 1/γ emission cone, the waves can be divided into two natural wave-mode components, the ordinary (O) mode and the extraordinary (X) mode, with comparable intensities. Both components propagate separately in <span class="hlt">magnetosphere</span>, and are aligned within the cone by adiabatic walking. The refraction of O mode makes the two components separated and incoherent. The detectable emission at a given height and a given rotation phase consists of incoherent X-mode and O-mode components coming from discrete emission regions. For four particle-density models in the form of uniformity, cone, core and patches, we calculate the intensities for each mode numerically within the entire pulsar beam. If the corotation of relativistic particles with <span class="hlt">magnetosphere</span> is not considered, the intensity distributions for the X-mode and O-mode components are quite similar within the pulsar beam, which causes serious depolarization. However, if the corotation of relativistic particles is considered, the intensity distributions of the two modes are very different, and the net polarization of outcoming emission should be significant. Our numerical results are compared with observations, and can naturally explain the orthogonal polarization modes of some pulsars. Strong linear polarizations of some parts of pulsar profile can be reproduced by curvature radiation and subsequent propagation effect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880006815','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880006815"><span>Nonlinear, relativistic Langmuir waves in astrophysical <span class="hlt">magnetospheres</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chian, Abraham C.-L.</p> <p>1987-01-01</p> <p>Large amplitude, electrostatic plasma waves are relevant to physical processes occurring in the astrophysical <span class="hlt">magnetospheres</span> wherein charged particles are accelerated to relativistic energies by strong waves emitted by pulsars, quasars, or radio galaxies. The nonlinear, relativistic theory of traveling Langmuir waves in a cold plasma is reviewed. The cases of streaming electron plasma, electronic plasma, and two-streams are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004cosp...35.4450L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004cosp...35.4450L"><span><span class="hlt">Magnetosphere</span>-ionosphere coupling: processes and rates</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lotko, W.</p> <p></p> <p><span class="hlt">Magnetosphere</span>-ionosphere coupling describes the interaction between the collisionless plasma of the <span class="hlt">magnetosphere</span> and the ionized and neutral collisional gases of the ionosphere and thermosphere. This coupling introduces feedback and scale interactivity in the form of a time-variable mass flux, electron energy flux and Poynting flux flowing between the two regions. Although delineation of an MI coupling region is somewhat ambiguous, at mid and high latitudes it may be considered as the region of the topside ionosphere and low-altitude <span class="hlt">magnetosphere</span> where electromagnetic energy is converted to plasma beams and heat via collisionless dissipation processes. Above this region the magnetically guided transmission of electromagnetic power from distant <span class="hlt">magnetospheric</span> dynamos encounters only weak attenuation. The ionospheric region below it is dominated by ionization processes and collisional cross-field transport and current closure. This tutorial will use observations, models and theory to characterize three major issues in MI coupling: (1) the production of plasma beams and heat in the coupling region; (2) the acceleration of ions leading to massive outflows; and (3) the length and time scale dependence of electromagnetic energy deposition at low altitude. Our success in identifying many of the key processes is offset by a lack of quantitative understanding of the factors controlling the rates of energy deposition and of the production of particle energy and mass fluxes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMSM21B2016B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSM21B2016B"><span>The magnetic geometry of Titan's induced <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bertucci, C.; Achilleos, N.; Dougherty, M. K.</p> <p>2011-12-01</p> <p>As a result of the virtual absence of an intrinsic field at Titan, an induced <span class="hlt">magnetosphere</span> is formed from the direct interaction between its atmosphere and the plasma environment. Observations at unmagnetized objects such as comets, or planets like Venus and Mars, have shown that the orientation of the magnetic field within an induced <span class="hlt">magnetosphere</span> is, on average, symmetric with respect to the plane generated by the upstream magnetic field and plasma velocity vectors. Analyses of Voyager and early Cassini magnetometer data around Titan confirm this feature. In this work, we study the efficiency of the background magnetic field-based 'draping coordinate system' (DRAP) introduced in Neubauer et al., [2006] to organize Cassini magnetometer (MAG) measurements within the induced <span class="hlt">magnetosphere</span> of Titan for all the close flybys of the Prime Mission where MAG data is available. We find that, in general, DRAP coordinates are efficient in organizing the orientation of the draped magnetic field according to the pattern expected for an induced <span class="hlt">magnetosphere</span>, suggesting that the same system could be used to spatially organize plasma measurements. Departures from this picture are likely related to non stationarity in the upstream flow, fossil fields and, induced currents within Titan's ionosphere and, probably, its interior. REFERENCES: Neubauer, F. M., et al. (2006). Titan's near magnetotail from magnetic field and electron plasma observations and modeling: Cassini flybys TA, TB, and T3. Journal of Geophysical Research, 111(A10), 1-15. doi: 10.1029/2006JA011676.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSM41E2518F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSM41E2518F"><span>Characterizing the <span class="hlt">Magnetospheric</span> State for Sawtooth Events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fung, S. F.; Tepper, J. A.; Cai, X.</p> <p>2015-12-01</p> <p><span class="hlt">Magnetospheric</span> sawtooth events, first identified in the early 1990's, are named for their characteristic appearance of multiple quasi-periodic intervals of slow decrease followed by sharp increase of proton energy fluxes in the geosynchronous region. The successive proton flux decrease-and-increase intervals have been interpreted as recurrences of stretching and dipolarization, respectively, of the nightside geomagnetic field [Reeves et al., 2003]. Due to their often-extended intervals with 2- 10 cycles, sawteeth occurrences are sometimes referred to as a <span class="hlt">magnetospheric</span> mode [Henderson et al., 2006]. Studies over the past two decades of sawtooth events (both event and statistical) have yielded a wealth of information on the conditions for the onset and occurrence of sawtooth events, but the occurrences of sawtooth events during both storm and non-storm periods suggest that we still do not fully understand the true nature of sawtooth events [Cai et al., 2011]. In this study, we investigate the characteristic <span class="hlt">magnetospheric</span> state conditions [Fung and Shao, 2008] associated with the beginning, during, and ending intervals of sawtooth events. Unlike previous studies of individual sawtooth event conditions, <span class="hlt">magnetospheric</span> state conditions consider the combinations of both <span class="hlt">magnetospheric</span> drivers (solar wind) and multiple geomagnetic responses. Our presentation will discuss the most probable conditions for a "sawtooth state" of the <span class="hlt">magnetosphere</span>. ReferencesCai, X., J.-C. Zhang, C. R. Clauer, and M. W. Liemohn (2011), Relationship between sawtooth events and magnetic storms, J. Geophys. Res., 116, A07208, doi:10.1029/2010JA016310. Fung, S. F. and X. Shao, Specification of multiple geomagnetic responses to variable solar wind and IMF input, Ann. Geophys., 26, 639-652, 2008. Henderson, M. G., et al. (2006), <span class="hlt">Magnetospheric</span> and auroral activity during the 18 April 2002 sawtooth event, J. Geophys. Res., 111, A01S90, doi:10.1029/2005JA011111. Reeves, G. D., et al. (2004), IMAGE</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910062352&hterms=1075&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2526%25231075','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910062352&hterms=1075&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2526%25231075"><span><span class="hlt">Magnetospheric</span> radio and plasma wave research - 1987-1990</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kurth, W. S.</p> <p>1991-01-01</p> <p>This review covers research performed in the area of <span class="hlt">magnetospheric</span> plasma waves and wave-particle interactions as well as <span class="hlt">magnetospheric</span> radio emissions. The report focuses on the near-completion of the discovery phase of radio and plasma wave phenomena in the planetary <span class="hlt">magnetospheres</span> with the successful completion of the Voyager 2 encounters of Neptune and Uranus. Consideration is given to the advances made in detailed studies and theoretical investigations of radio and plasma wave phenomena in the terrestrial <span class="hlt">magnetosphere</span> or in <span class="hlt">magnetospheric</span> plasmas in general.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1511656B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1511656B"><span>One ring to rule them all: storm time ring current and its influence on radiation belts, plasmasphere and global <span class="hlt">magnetosphere</span> electrodynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buzulukova, Natalia; Fok, Mei-Ching; Glocer, Alex; Moore, Thomas E.</p> <p>2013-04-01</p> <p>We report studies of the storm time ring current and its influence on the radiation belts, plasmasphere and global <span class="hlt">magnetospheric</span> dynamics. The near-<span class="hlt">Earth</span> space environment is described by multiscale physics that reflects a variety of processes and conditions that occur in <span class="hlt">magnetospheric</span> plasma. For a successful description of such a plasma, a complex solution is needed which allows multiple physics domains to be described using multiple physical models. A key population of the inner <span class="hlt">magnetosphere</span> is ring current plasma. Ring current dynamics affects magnetic and electric fields in the entire <span class="hlt">magnetosphere</span>, the distribution of cold ionospheric plasma (plasmasphere), and radiation belts particles. To study electrodynamics of the inner <span class="hlt">magnetosphere</span>, we present a MHD model (BATSRUS code) coupled with ionospheric solver for electric field and with ring current-radiation belt model (CIMI code). The model will be used as a tool to reveal details of coupling between different regions of the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>. A model validation will be also presented based on comparison with data from THEMIS, POLAR, GOES, and TWINS missions. INVITED TALK</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM33C2678F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM33C2678F"><span>A New Approach to Modeling Jupiter's <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fukazawa, K.; Katoh, Y.; Walker, R. J.; Kimura, T.; Tsuchiya, F.; Murakami, G.; Kita, H.; Tao, C.; Murata, K. T.</p> <p>2017-12-01</p> <p>The scales in planetary <span class="hlt">magnetospheres</span> range from 10s of planetary radii to kilometers. For a number of years we have studied the <span class="hlt">magnetospheres</span> of Jupiter and Saturn by using 3-dimensional magnetohydrodynamic (MHD) simulations. However, we have not been able to reach even the limits of the MHD approximation because of the large amount of computer resources required. Recently thanks to the progress in supercomputer systems, we have obtained the capability to simulate Jupiter's <span class="hlt">magnetosphere</span> with 1000 times the number of grid points used in our previous simulations. This has allowed us to combine the high resolution global simulation with a micro-scale simulation of the Jovian <span class="hlt">magnetosphere</span>. In particular we can combine a hybrid (kinetic ions and fluid electrons) simulation with the MHD simulation. In addition, the new capability enables us to run multi-parameter survey simulations of the Jupiter-solar wind system. In this study we performed a high-resolution simulation of Jovian <span class="hlt">magnetosphere</span> to connect with the hybrid simulation, and lower resolution simulations under the various solar wind conditions to compare with Hisaki and Juno observations. In the high-resolution simulation we used a regular Cartesian gird with 0.15 RJ grid spacing and placed the inner boundary at 7 RJ. From these simulation settings, we provide the magnetic field out to around 20 RJ from Jupiter as a background field for the hybrid simulation. For the first time we have been able to resolve Kelvin Helmholtz waves on the magnetopause. We have investigated solar wind dynamic pressures between 0.01 and 0.09 nPa for a number of IMF values. These simulation data are open for the registered users to download the raw data. We have compared the results of these simulations with Hisaki auroral observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120015893','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120015893"><span>Particle Acceleration in Dissipative Pulsar <span class="hlt">Magnetospheres</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kazanas, Z.; Kalapotharakos, C.; Harding, A.; Contopoulos, I.</p> <p>2012-01-01</p> <p>Pulsar <span class="hlt">magnetospheres</span> represent unipolar inductor-type electrical circuits at which an EM potential across the polar cap (due to the rotation of their magnetic field) drives currents that run in and out of the polar cap and close at infinity. An estimate ofthe magnitude of this current can be obtained by dividing the potential induced across the polar cap V approx = B(sub O) R(sub O)(Omega R(sub O)/c)(exp 2) by the impedance of free space Z approx eq 4 pi/c; the resulting polar cap current density is close to $n {GJ} c$ where $n_{GJ}$ is the Goldreich-Julian (GJ) charge density. This argument suggests that even at current densities close to the GJ one, pulsar <span class="hlt">magnetospheres</span> have a significant component of electric field $E_{parallel}$, parallel to the magnetic field, a condition necessary for particle acceleration and the production of radiation. We present the magnetic and electric field structures as well as the currents, charge densities, spin down rates and potential drops along the magnetic field lines of pulsar <span class="hlt">magnetospheres</span> which do not obey the ideal MHD condition $E cdot B = 0$. By relating the current density along the poloidal field lines to the parallel electric field via a kind of Ohm's law $J = sigma E_{parallel}$ we study the structure of these <span class="hlt">magnetospheres</span> as a function of the conductivity $sigma$. We find that for $sigma gg OmegaS the solution tends to the (ideal) Force-Free one and to the Vacuum one for $sigma 11 OmegaS. Finally, we present dissipative <span class="hlt">magnetospheric</span> solutions with spatially variable $sigma$ that supports various microphysical properties and are compatible with the observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.5626E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.5626E"><span><span class="hlt">Magnetospheric</span> Multiscale observations of large-amplitude, parallel, electrostatic waves associated with magnetic reconnection at the magnetopause</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ergun, R. E.; Holmes, J. C.; Goodrich, K. A.; Wilder, F. D.; Stawarz, J. E.; Eriksson, S.; Newman, D. L.; Schwartz, S. J.; Goldman, M. V.; Sturner, A. P.; Malaspina, D. M.; Usanova, M. E.; Torbert, R. B.; Argall, M.; Lindqvist, P.-A.; Khotyaintsev, Y.; Burch, J. L.; Strangeway, R. J.; Russell, C. T.; Pollock, C. J.; Giles, B. L.; Dorelli, J. J. C.; Avanov, L.; Hesse, M.; Chen, L. J.; Lavraud, B.; Le Contel, O.; Retino, A.; Phan, T. D.; Eastwood, J. P.; Oieroset, M.; Drake, J.; Shay, M. A.; Cassak, P. A.; Nakamura, R.; Zhou, M.; Ashour-Abdalla, M.; André, M.</p> <p>2016-06-01</p> <p>We report observations from the <span class="hlt">Magnetospheric</span> Multiscale satellites of large-amplitude, parallel, electrostatic waves associated with magnetic reconnection at the <span class="hlt">Earth</span>'s magnetopause. The observed waves have parallel electric fields (E||) with amplitudes on the order of 100 mV/m and display nonlinear characteristics that suggest a possible net E||. These waves are observed within the ion diffusion region and adjacent to (within several electron skin depths) the electron diffusion region. They are in or near the <span class="hlt">magnetosphere</span> side current layer. Simulation results support that the strong electrostatic linear and nonlinear wave activities appear to be driven by a two stream instability, which is a consequence of mixing cold (<10 eV) plasma in the <span class="hlt">magnetosphere</span> with warm (~100 eV) plasma from the magnetosheath on a freshly reconnected magnetic field line. The frequent observation of these waves suggests that cold plasma is often present near the magnetopause.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170003529&hterms=electrostatics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Delectrostatics','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170003529&hterms=electrostatics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Delectrostatics"><span><span class="hlt">Magnetospheric</span> Multiscale Observations of Large-Amplitude Parallel, Electrostatic Waves Associated with Magnetic Reconnection at the Magnetopause</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ergun, R. E.; Holmes, J. C.; Goodrich, K. A.; Wilder, F. D.; Stawarz, J. E.; Eriksson, S.; Newman, D. L.; Schwartz, S. J.; Goldman, M. V.; Sturner, A. P.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20170003529'); toggleEditAbsImage('author_20170003529_show'); toggleEditAbsImage('author_20170003529_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20170003529_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20170003529_hide"></p> <p>2016-01-01</p> <p>We report observations from the <span class="hlt">Magnetospheric</span> Multiscale satellites of large-amplitude, parallel, electrostatic waves associated with magnetic reconnection at the <span class="hlt">Earth</span>'s magnetopause. The observed waves have parallel electric fields (E(sub parallel)) with amplitudes on the order of 100 mV/m and display nonlinear characteristics that suggest a possible net E(sub parallel). These waves are observed within the ion diffusion region and adjacent to (within several electron skin depths) the electron diffusion region. They are in or near the <span class="hlt">magnetosphere</span> side current layer. Simulation results support that the strong electrostatic linear and nonlinear wave activities appear to be driven by a two stream instability, which is a consequence of mixing cold (less than 10eV) plasma in the <span class="hlt">magnetosphere</span> with warm (approximately 100eV) plasma from the magnetosheath on a freshly reconnected magnetic field line. The frequent observation of these waves suggests that cold plasma is often present near the magnetopause.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810055592&hterms=energy+consumption&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Denergy%2Bconsumption','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810055592&hterms=energy+consumption&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Denergy%2Bconsumption"><span>Energy coupling between the solar wind and the <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Akasofu, S.-I.</p> <p>1981-01-01</p> <p>A description is given of the path leading to the first approximation expression for the solar wind-<span class="hlt">magnetosphere</span> energy coupling function (epsilon), which correlates well with the total energy consumption rate (U sub T) of the <span class="hlt">magnetosphere</span>. It is shown that epsilon is the primary factor controlling the time development of <span class="hlt">magnetospheric</span> substorms and storms. The finding of this particular expression epsilon indicates how the solar wind couples its energy to the <span class="hlt">magnetosphere</span>; the solar wind and the <span class="hlt">magnetosphere</span> make up a dynamo. In fact, the power generated by the dynamo can be identified as epsilon through the use of a dimensional analysis. In addition, the finding of epsilon suggests that the <span class="hlt">magnetosphere</span> is closer to a directly driven system than to an unloading system which stores the generated energy before converting it to substorm and storm energies. The finding of epsilon and its implications is considered to have significantly advanced and improved the understanding of <span class="hlt">magnetospheric</span> processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-PIA21874.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-PIA21874.html"><span>Coronal Hole Faces <span class="hlt">Earth</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2017-08-14</p> <p>A substantial coronal hole rotated into a position where it is facing <span class="hlt">Earth</span> (Aug. 9-11, 2017). Coronal holes are areas of open magnetic field that spew out charged particles as solar wind that spreads into space. If that solar wind interacts with our own <span class="hlt">magnetosphere</span> it can generate aurora. In this view of the sun in extreme ultraviolet light, the coronal hole appears as the dark stretch near the center of the sun. It was the most distinctive feature on the sun over the past week. Movies are available at https://photojournal.jpl.nasa.gov/catalog/PIA21874</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950056440&hterms=GERD&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DGERD','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950056440&hterms=GERD&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DGERD"><span>A <span class="hlt">magnetospheric</span> magnetic field model with flexible current systems driven by independent physical parameters</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hilmer, Robert V.; Voigt, Gerd-Hannes</p> <p>1995-01-01</p> <p>A tilt-dependent magnetic field model of the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span> with variable magnetopause standoff distance is presented. Flexible analytic representations for the ring and cross-tail currents, each composed of the elements derived from the Tsyganenko and Usmanov (1982) model, are combined with the fully shielded vacuum dipole configurations of Voigt (1981). Although the current sheet does not warp in the y-z plane, changes in the shape and position of the neutral sheet with dipole tilt are consistent with both MHD equilibrium theory and observations. In addition, there is good agreement with observed Delta B profiles and the average equatorial contours of magnetic field magnitude. While the dipole field is rigorously shielded within the defined magnetopause, the ring and cross-tails currents are not similarly confined, consequently, the model's region of validity is limited to the inner <span class="hlt">magnetosphere</span>. The model depends on four independent external parameters. We present a simple but limited method of simulating several substorm related magnetic field changes associated with the disrupion of the near-<span class="hlt">Earth</span> cross-tail current sheet and collapse of the midnight magnetotail field region. This feature further facilitates the generation of magnetic field configuration time sequences useful in plasma convection simulations of real <span class="hlt">magnetospheric</span> events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSH44A..02H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSH44A..02H"><span>The scientific challenges to forecasting and nowcasting the <span class="hlt">magnetospheric</span> response to space weather (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hesse, M.; Kuznetsova, M. M.; Birn, J.; Pulkkinen, A. A.</p> <p>2013-12-01</p> <p>Space weather is different from terrestrial weather in an essential way. Terrestrial weather has benefitted from a long history of research, which has led to a deep and detailed level of understanding. In comparison, space weather is scientifically in its infancy. Many key processes in the causal chains from processes on the Sun to space weather effects in various locations in the heliosphere remain either poorly understood or not understood at all. Space weather is therefore, and will remain in the foreseeable future, primarily a research field. Extensive further research efforts are needed before we can reasonably expect the precision and fidelity of weather forecasts. For space weather within the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>, the coupling between solar wind and <span class="hlt">magnetosphere</span> is of crucial importance. While past research has provided answers, often on qualitative levels, to some of the most fundamental questions, answers to some of the latter and the ability to predict quantitatively remain elusive. This presentation will provide an overview of pertinent aspects of solar wind-<span class="hlt">magnetospheric</span> coupling, its importance for space weather near the <span class="hlt">Earth</span>, and it will analyze the state of our ability to describe and predict its efficiency. It will conclude with a discussion of research activities, which are aimed at improving our ability to quantitatively forecast coupling processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSM42C..03F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSM42C..03F"><span>The influence of the Great White Spot on the rotation of Saturn's <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fischer, G.; Gurnett, D. A.; Ye, S.; Groene, J.; Ingersoll, A. P.; Sayanagi, K. M.; Menietti, J. D.; Kurth, W. S.</p> <p>2012-12-01</p> <p>We report about an observation which suggests that Saturn's time-variable <span class="hlt">magnetospheric</span> rotation is driven by the upper atmosphere. Saturn kilometric radiation (SKR) is a powerful non-thermal radio emission from Saturn's aurora. Its modulation turned out to be a good tracer of <span class="hlt">magnetospheric</span> periodicities which are also present in the magnetic field, the charged particles, and energetic neutral atoms. SKR as well as Saturn narrowband (NB) radio emission exhibit an unexplained seasonal course with changes of the order of ~1% over the years. There have been models suggesting a magnetic cam field structure or a centrifugally driven convective instability in the equatorial plasma disc of the inner <span class="hlt">magnetosphere</span> to explain the variation in rotation. In this presentation we will show that the period of SKR as well as NB emissions has temporarily slowed down by ~1% from the end of 2010 until August 2011, disrupting the expected seasonal course of the modulation. This time period exactly coincides with the occurrence of the giant thunderstorm called Great White Spot (GWS) that emitted radio waves associated with Saturn lightning discharges from 5 December 2010 until 28 August 2011. Furthermore, the head of the GWS and the SKR from the southern hemisphere show the same period of 10.69 h over several months in the first half of 2011. This strongly suggests that <span class="hlt">magnetospheric</span> periodicities are driven by the upper atmosphere. The GWS has evidently produced large perturbations in Saturn's stratosphere most likely caused by wave heating. On <span class="hlt">Earth</span>, penetrative convection at the tropopause during severe thunderstorms is a well-known generation mechanism of gravity waves. A similar process might be at work at Saturn, and gravity waves could have transported additional power of the order of several terawatts from Saturn's troposphere to the thermosphere. This might have led to a temporal change in the global thermospheric circulation, which via field-aligned currents is linked to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AdSpR..42.1504S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AdSpR..42.1504S"><span>Real-time global MHD simulation of the solar wind interaction with the earth’s <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shimazu, H.; Kitamura, K.; Tanaka, T.; Fujita, S.; Nakamura, M. S.; Obara, T.</p> <p>2008-11-01</p> <p>We have developed a real-time global MHD (magnetohydrodynamics) simulation of the solar wind interaction with the earth’s <span class="hlt">magnetosphere</span>. By adopting the real-time solar wind parameters and interplanetary magnetic field (IMF) observed routinely by the ACE (Advanced Composition Explorer) spacecraft, responses of the <span class="hlt">magnetosphere</span> are calculated with MHD code. The simulation is carried out routinely on the super computer system at National Institute of Information and Communications Technology (NICT), Japan. The visualized images of the magnetic field lines around the <span class="hlt">earth</span>, pressure distribution on the meridian plane, and the conductivity of the polar ionosphere, can be referred to on the web site (http://www2.nict.go.jp/y/y223/simulation/realtime/). The results show that various <span class="hlt">magnetospheric</span> activities are almost reproduced qualitatively. They also give us information how geomagnetic disturbances develop in the <span class="hlt">magnetosphere</span> in relation with the ionosphere. From the viewpoint of space weather, the real-time simulation helps us to understand the whole image in the current condition of the <span class="hlt">magnetosphere</span>. To evaluate the simulation results, we compare the AE indices derived from the simulation and observations. The simulation and observation agree well for quiet days and isolated substorm cases in general.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170002781&hterms=location&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dlocation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170002781&hterms=location&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dlocation"><span>Comparison of <span class="hlt">Magnetospheric</span> Multiscale Ion Jet Signatures with Predicted Reconnection Site Locations at the Magnetopause</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Petrinec, S. M.; Burch, J. L.; Fuselier, S. A.; Gomez, R. G.; Lewis, W.; Trattner, K. J.; Ergun, R.; Mauk, B.; Pollock, C. J.; Schiff, C.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20170002781'); toggleEditAbsImage('author_20170002781_show'); toggleEditAbsImage('author_20170002781_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20170002781_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20170002781_hide"></p> <p>2016-01-01</p> <p>Magnetic reconnection at the <span class="hlt">Earths</span> magnetopause is the primary process by which solar wind plasma and energy gains access to the <span class="hlt">magnetosphere</span>. One indication that magnetic reconnection is occurring is the observation of accelerated plasma as a jet tangential to the magnetopause. The direction of ion jets along the magnetopause surface as observed by the Fast Plasma Instrument (FPI) and the Hot Plasma Composition Analyzer (HPCA) instrument on board the recently launched <span class="hlt">Magnetospheric</span> Multiscale (MMS) set of spacecraft is examined. For those cases where ion jets are clearly discerned, the direction of origin compares well statistically with the predicted location of magnetic reconnection using convected solar wind observations in conjunction with the Maximum Magnetic Shear model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA497466','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA497466"><span>Imaging Near-<span class="hlt">Earth</span> Electron Densities Using Thomson Scattering</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2009-01-15</p> <p>geocentric solar <span class="hlt">magnetospheric</span> (GSM) coordinates1. TECs were initially computed from a viewing loca- tion at the Sun-<span class="hlt">Earth</span> L1 Lagrange point2 for both...further find that an elliptical <span class="hlt">Earth</span> orbit (apogee ~30 RE) is a suitable lower- cost option for a demonstration mission. 5. SIMULATED OBSERVATIONS We</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EP%26S...67..166A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EP%26S...67..166A"><span>Problems with mapping the auroral oval and <span class="hlt">magnetospheric</span> substorms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Antonova, E. E.; Vorobjev, V. G.; Kirpichev, I. P.; Yagodkina, O. I.; Stepanova, M. V.</p> <p>2015-10-01</p> <p>Accurate mapping of the auroral oval into the equatorial plane is critical for the analysis of aurora and substorm dynamics. Comparison of ion pressure values measured at low altitudes by Defense Meteorological Satellite Program (DMSP) satellites during their crossings of the auroral oval, with plasma pressure values obtained at the equatorial plane from Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellite measurements, indicates that the main part of the auroral oval maps into the equatorial plane at distances between 6 and 12 <span class="hlt">Earth</span> radii. On the nightside, this region is generally considered to be a part of the plasma sheet. However, our studies suggest that this region could form part of the plasma ring surrounding the <span class="hlt">Earth</span>. We discuss the possibility of using the results found here to explain the ring-like shape of the auroral oval, the location of the injection boundary inside the <span class="hlt">magnetosphere</span> near the geostationary orbit, presence of quiet auroral arcs in the auroral oval despite the constantly high level of turbulence observed in the plasma sheet, and some features of the onset of substorm expansion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090032008','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090032008"><span><span class="hlt">Magnetospheric</span> Multiscale (MMS) Mission Commissioning Phase Orbit Determination Error Analysis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chung, Lauren R.; Novak, Stefan; Long, Anne; Gramling, Cheryl</p> <p>2009-01-01</p> <p>The <span class="hlt">Magnetospheric</span> MultiScale (MMS) mission commissioning phase starts in a 185 km altitude x 12 <span class="hlt">Earth</span> radii (RE) injection orbit and lasts until the Phase 1 mission orbits and orientation to the <span class="hlt">Earth</span>-Sun li ne are achieved. During a limited time period in the early part of co mmissioning, five maneuvers are performed to raise the perigee radius to 1.2 R E, with a maneuver every other apogee. The current baseline is for the Goddard Space Flight Center Flight Dynamics Facility to p rovide MMS orbit determination support during the early commissioning phase using all available two-way range and Doppler tracking from bo th the Deep Space Network and Space Network. This paper summarizes th e results from a linear covariance analysis to determine the type and amount of tracking data required to accurately estimate the spacecraf t state, plan each perigee raising maneuver, and support thruster cal ibration during this phase. The primary focus of this study is the na vigation accuracy required to plan the first and the final perigee ra ising maneuvers. Absolute and relative position and velocity error hi stories are generated for all cases and summarized in terms of the ma ximum root-sum-square consider and measurement noise error contributi ons over the definitive and predictive arcs and at discrete times inc luding the maneuver planning and execution times. Details of the meth odology, orbital characteristics, maneuver timeline, error models, and error sensitivities are provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27656099','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27656099"><span>Problems with mapping the auroral oval and <span class="hlt">magnetospheric</span> substorms.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Antonova, E E; Vorobjev, V G; Kirpichev, I P; Yagodkina, O I; Stepanova, M V</p> <p></p> <p>Accurate mapping of the auroral oval into the equatorial plane is critical for the analysis of aurora and substorm dynamics. Comparison of ion pressure values measured at low altitudes by Defense Meteorological Satellite Program (DMSP) satellites during their crossings of the auroral oval, with plasma pressure values obtained at the equatorial plane from Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellite measurements, indicates that the main part of the auroral oval maps into the equatorial plane at distances between 6 and 12 <span class="hlt">Earth</span> radii. On the nightside, this region is generally considered to be a part of the plasma sheet. However, our studies suggest that this region could form part of the plasma ring surrounding the <span class="hlt">Earth</span>. We discuss the possibility of using the results found here to explain the ring-like shape of the auroral oval, the location of the injection boundary inside the <span class="hlt">magnetosphere</span> near the geostationary orbit, presence of quiet auroral arcs in the auroral oval despite the constantly high level of turbulence observed in the plasma sheet, and some features of the onset of substorm expansion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM33B2645V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM33B2645V"><span>Analysis of Mars <span class="hlt">magnetosphere</span> structure near terminator using MAVEN measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vaisberg, O. L.; Zelenyi, L. M.; Ermakov, V.; Shuvalov, S.; Dubinin, E.; Znobischev, A.; McFadden, J. P.; Halekas, J. S.; Connerney, J. E. P.</p> <p>2017-12-01</p> <p><span class="hlt">Magnetosphere</span> of Mars first observed on Mars-2, -3 and -5 in 1970th forms from solar wind magnetic flux tubes loaded by heavy planetary ions. These flux tubes decelerate on the dayside of Mars forming magnetic barrier forming an obstacle to the supersonic solar wind. Magnetic flux tubes pick-up planetary ions while drifting around the planet and form dynamic <span class="hlt">magnetosphere</span> of Mars. Review of 100 MAVEN crossings of flank magnetic barrier and <span class="hlt">magnetosphere</span> showed a variety of their properties. <span class="hlt">Magnetosphere</span> is identified by domination of O+ and O2+ ions. The energy of these ions at the external boundary is close to the energy of ionosheath ions and decreases to the energy of ionospheric ions at the inner boundary. The number density of <span class="hlt">magnetospheric</span> ions is close to the number density of ionosheath ions and increases by 2 orders of magnitude towards the inner boundary. From varying magnetic barrier/<span class="hlt">magnetosphere</span> configurations and properties two types of were observed more frequently. First one has smooth profile of magnetic field and plasma characteristics with magnetic field increase starting in ionosheath and reaching maximal and nearly constant magnitude within <span class="hlt">magnetosphere</span>. The number density and energy of protons are smoothly decreasing through ionosheath and magnetic barrier/<span class="hlt">magnetosphere</span>. Pitch angles of planetary ions are close to 90°. Second barrier/<span class="hlt">magnetosphere</span> structure is characterized by relatively sharp transition from ionosheath to <span class="hlt">magnetosphere</span>. Magnetic field of barrier starts to increase far from <span class="hlt">magnetosphere</span> and reaches maximum value at this boundary. The energy of the protons only slightly decreases in the magnetic barrier and may increase just before this boundary. Protons number density within magnetic barrier is smaller than in upstream flow but often increases just before <span class="hlt">magnetospheric</span> boundary. Magnetic field magnitude drops within <span class="hlt">magnetosphere</span>. The number densities of O+ and O2+ ions within <span class="hlt">magnetosphere</span> strongly increase from upper</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030066033&hterms=UV+spectro&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DUV%2Bspectro','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030066033&hterms=UV+spectro&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DUV%2Bspectro"><span>Applications of High Etendue Line-Profile Spectro-Polarimetry to the Study of the Atmospheric and <span class="hlt">Magnetospheric</span> Environments of the Jovian Icy Moons</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Harris, Walter M.; Roesler, Fred L.; Jaffel, Lotfi Ben; Ballester, Gilda E.; Oliversen, Ronald J.; Morgenthaler, Jeffrey P.; Mierkiewicz, Edwin</p> <p>2003-01-01</p> <p>Electrodynamic effects play a significant, global role in the state and energization of the <span class="hlt">Earth</span>'s ionosphere/<span class="hlt">magnetosphere</span>, but even more so on Jupiter, where the auroral energy input is four orders of magnitude greater than on <span class="hlt">Earth</span>. The Jovian <span class="hlt">magnetosphere</span> is distinguished from <span class="hlt">Earth</span>'s by its rapid rotation rate and contributions from satellite atmospheres and internal plasma sources. The electrodynamic effects of these factors have a key role in the state and energization of the ionosphere-corona- plasmasphere system of the planet and its interaction with Io and the icy satellites. Several large scale interacting processes determine conditions near the icy moons beginning with their tenuous atmospheres produced from sputtering, evaporative, and tectonic/volcanic sources, extending out to exospheres that merge with ions and neutrals in the Jovian <span class="hlt">magnetosphere</span>. This dynamic environment is dependent on a complex network of <span class="hlt">magnetospheric</span> currents that act on global scales. Field aligned currents connect the satellites and the middle and tail <span class="hlt">magnetospheric</span> regions to the Jupiter's poles via flux tubes that produce as bright auroral and satellite footprint emissions in the upper atmosphere. This large scale transfer of mass, momentum, and energy (e.g. waves, currents) means that a combination of complementary diagnostics of the plasma, neutral, and and field network must be obtained near simultaneously to correctly interpret the results. This presentation discusses the applicability of UV spatial heterodyne spectroscopy (SHS) to the broad study of this system on scales from satellite surfaces to Jupiter's aurora and corona.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998JGR...10314939A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998JGR...10314939A"><span>Toward a closer integration of <span class="hlt">magnetospheric</span> research: <span class="hlt">Magnetospheric</span> currents inferred from ground-based magnetic data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Akasofu, S.-I.; Kamide, Y.</p> <p>1998-07-01</p> <p>A new approach is needed to advance <span class="hlt">magnetospheric</span> physics in the future to achieve a much closer integration than in the past among satellite-based researchers, ground-based researchers, and theorists/modelers. Specifically, we must find efficient ways to combine two-dimensional ground-based data and single points satellite-based data to infer three-dimensional aspects of <span class="hlt">magnetospheric</span> disturbances. For this particular integration purpose, we propose a new project. It is designed to determine the currents on the <span class="hlt">magnetospheric</span> equatorial plane from the ionospheric current distribution which has become available by inverting ground-based magnetic data from an extensive, systematic network of observations, combined with ground-based radar measurements of ionospheric parameters, and satellite observations of auroras, electric fields, and currents. The inversion method is based on the KRM/AMIE algorithms. In the first part of the paper, we extensively review the reliability and accuracy of the KRM and AMIE algorithms and conclude that the ionospheric quantities thus obtained are accurate enough for the next step. In the second part, the ionospheric current distribution thus obtained is projected onto the equatorial plane. This process requires a close cooperation with modelers in determining an accurate configuration of the <span class="hlt">magnetospheric</span> field lines. If we succeed in this projection, we should be able to study the changing distribution of the currents in a vast region of the <span class="hlt">magnetospheric</span> equatorial plane for extended periods with a time resolution of about 5 min. This process requires a model of the <span class="hlt">magnetosphere</span> for the different phases of the <span class="hlt">magnetospheric</span> substorm. Satellite-based observations are needed to calibrate the projection results. Agreements and disagreements thus obtained will be crucial for theoretical studies of <span class="hlt">magnetospheric</span> plasma convection and dynamics, particularly in studying substorms. Nothing is easy in these procedures. However, unless</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18599776','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18599776"><span>Mercury's <span class="hlt">magnetosphere</span> after MESSENGER's first flyby.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Slavin, James A; Acuña, Mario H; Anderson, Brian J; Baker, Daniel N; Benna, Mehdi; Gloeckler, George; Gold, Robert E; Ho, George C; Killen, Rosemary M; Korth, Haje; Krimigis, Stamatios M; McNutt, Ralph L; Nittler, Larry R; Raines, Jim M; Schriver, David; Solomon, Sean C; Starr, Richard D; Trávnícek, Pavel; Zurbuchen, Thomas H</p> <p>2008-07-04</p> <p>Observations by MESSENGER show that Mercury's <span class="hlt">magnetosphere</span> is immersed in a comet-like cloud of planetary ions. The most abundant, Na+, is broadly distributed but exhibits flux maxima in the magnetosheath, where the local plasma flow speed is high, and near the spacecraft's closest approach, where atmospheric density should peak. The magnetic field showed reconnection signatures in the form of flux transfer events, azimuthal rotations consistent with Kelvin-Helmholtz waves along the magnetopause, and extensive ultralow-frequency wave activity. Two outbound current sheet boundaries were observed, across which the magnetic field decreased in a manner suggestive of a double magnetopause. The separation of these current layers, comparable to the gyro-radius of a Na+ pickup ion entering the <span class="hlt">magnetosphere</span> after being accelerated in the magnetosheath, may indicate a planetary ion boundary layer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM33C2667Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM33C2667Y"><span><span class="hlt">Magnetosphere</span> - Ionosphere - Thermosphere (MIT) Coupling at Jupiter</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yates, J. N.; Ray, L. C.; Achilleos, N.</p> <p>2017-12-01</p> <p>Jupiter's upper atmospheric temperature is considerably higher than that predicted by Solar Extreme Ultraviolet (EUV) heating alone. Simulations incorporating <span class="hlt">magnetosphere</span>-ionosphere coupling effects into general circulation models have, to date, struggled to reproduce the observed atmospheric temperatures under simplifying assumptions such as azimuthal symmetry and a spin-aligned dipole magnetic field. Here we present the development of a full three-dimensional thermosphere model coupled in both hemispheres to an axisymmetric <span class="hlt">magnetosphere</span> model. This new coupled model is based on the two-dimensional MIT model presented in Yates et al., 2014. This coupled model is a critical step towards to the development of a fully coupled 3D MIT model. We discuss and compare the resulting thermospheric flows, energy balance and MI coupling currents to those presented in previous 2D MIT models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930040588&hterms=Open+Field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DOpen%2BField','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930040588&hterms=Open+Field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DOpen%2BField"><span>A nonsingular model of the open <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Toffoletto, F. R.; Hill, T. W.</p> <p>1993-01-01</p> <p>We present a modified version of the Toffoletto and Hill (1989) open <span class="hlt">magnetosphere</span> model that incorporates a tail-like interconection field with a discontinuity 10 represent the slow-mode expansion fan that defines the high-latitude tail magnetopause. (The interconnection field is defined as the perturbation on an initially closed <span class="hlt">magnetosphere</span> model to make it open.) The expansion fan controls the open field line region in the tail, and the intersection of the fan with the tail current sheet is, by design, the x line. The new interconnection field allows greater control of the tail field structure; in particular, it enables us to eliminate the nightside mapping singularity that occurs in previous models when the interplanetary magnetic field is nonsouthward. Also, in contrast to earlier models, the far tail x line extends farther downstream on the flanks than in the center of the tail, consistent with observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730004648','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730004648"><span>Can the ionosphere regulate <span class="hlt">magnetospheric</span> convection?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Coroniti, F. V.; Kennel, C. F.</p> <p>1972-01-01</p> <p>Following a southward shift of the interplanetary magnetic field, which implies enhanced reconnection at the nose of the <span class="hlt">magnetosphere</span>, the magnetopause shrinks from its Chapman-Ferraro equilibrium position. If the convective return of magnetic flux to the magnetopause equalled the reconnection rate, the magnetopause would not shrink. Consequently, there is a delay in the development of <span class="hlt">magnetospheric</span> convection following the onset of reconnection, which is ascribed to line tying by the polar cusp ionosphere. A simple model relates the dayside magnetopause displacement to the currents feeding the polar cap ionosphere, from which the ionospheric electric field, and consequently, the flux return rate, may be estimated as a function of magnetopause displacement. Flux conservation arguments then permit an estimate of the time scale on which convection increases, which is not inconsistent with that of the substorm growth phase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840020651','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840020651"><span>Cosmogony as an extrapolation of <span class="hlt">magnetospheric</span> research</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Alfven, H.</p> <p>1984-01-01</p> <p>A theory of the origin and evolution of the Solar System which considered electromagnetic forces and plasma effects is revised in light of information supplied by space research. In situ measurements in the <span class="hlt">magnetospheres</span> and solar wind can be extrapolated outwards in space, to interstellar clouds, and backwards in time, to the formation of the solar system. The first extrapolation leads to a revision of cloud properties essential for the early phases in the formation of stars and solar nebulae. The latter extrapolation facilitates analysis of the cosmogonic processes by extrapolation of <span class="hlt">magnetospheric</span> phenomena. Pioneer-Voyager observations of the Saturnian rings indicate that essential parts of their structure are fossils from cosmogonic times. By using detailed information from these space missions, it is possible to reconstruct events 4 to 5 billion years ago with an accuracy of a few percent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19750058676&hterms=rate+change+frequency&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Drate%2Bchange%2Bfrequency','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19750058676&hterms=rate+change+frequency&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Drate%2Bchange%2Bfrequency"><span><span class="hlt">Magnetospheric</span> chorus - Amplitude and growth rate</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burtis, W. J.; Helliwell, R. A.</p> <p>1975-01-01</p> <p>A new study of the amplitude of <span class="hlt">magnetospheric</span> chorus with 1966-1967 data from the Stanford University/Stanford Research Institute VLF receivers on Ogo 1 and Ogo 3 has confirmed the band-limited character of <span class="hlt">magnetospheric</span> chorus in general and the double-banding of near-equatorial chorus. Chorus amplitude tended to be inversely correlated with frequency, implying lower intensities at lower L values. Individual chorus emissions often showed a characteristic amplitude variation, with rise times of 10 to 300 ms, a short duration at peak amplitude, and decay times of 100 to 3000 msec. Growth was often approximately exponential, with rates from 200 to nearly 2000 dB/sec. Rate of change of frequency was found in many cases to be independent of emission amplitude, in agreement with the cyclotron feedback theory of chorus (Helliwell, 1967, 1970).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018AAS...23230304W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018AAS...23230304W"><span>Modeling Jovian <span class="hlt">Magnetospheres</span> Beyond the Solar System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Williams, Peter K. G.</p> <p>2018-06-01</p> <p>Low-frequency radio observations are believed to represent one of the few means of directly probing the magnetic fields of extrasolar planets. However, a half-century of low-frequency planetary observations within the Solar System demonstrate that detailed, physically-motivated <span class="hlt">magnetospheric</span> models are needed to properly interpret the radio data. I will present recent work in this area focusing on the current state of the art: relatively high-frequency observations of relatively massive objects, which are now understood to have <span class="hlt">magnetospheres</span> that are largely planetary in nature. I will highlight the key challenges that will arise in future space-based observations of lower-mass objects at lower frequencies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/166258-magnetospheric-lobe-geosynchronous-orbit','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/166258-magnetospheric-lobe-geosynchronous-orbit"><span>The <span class="hlt">magnetospheric</span> lobe at geosynchronous orbit</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Thomsen, M.F.; Bame, S.J.; McComas, D.J.</p> <p>1994-09-01</p> <p>On rare occasions, satellites at geosynchronous altitude enter the <span class="hlt">magnetospheric</span> lobe, characterized by extremely low ion fluxes between 1 eV and 40 keV and electron fluxes above a few hundred eV. One year of plasma observations from two simultaneously operating spacecraft at synchronous orbit is surveyed for lobe encounters. A total of 34 full encounters and 56 apparent near encounters are identified, corresponding to {approximately}0.06% of the total observation time. Unlike energetic particle (E>40 keV) dropouts studied earlier, there is a strong tendency for the lobe encounters to occur postmidnight, as late as 07 local time. The two spacecraft encountermore » the lobe with different rates and in different seasons. These occurrence properties are not simply explicable in terms of the orbital geometry in either the solar magnetic or the geocentric solar <span class="hlt">magnetospheric</span> coordinate system. A composite coordinate system which previously organized more energetic particle dropouts is somewhat more successful in organizing the lobe encounters, suggesting that solar wind distortion of the magnetic equatorial plane away from the dipole location and toward the antisolar direction may be largely responsible for these dropouts. The authors results further suggest that this distortion persists even sunward of the dawn-dusk terminator. However, a simple dawn-dusk symmetric distortion does not fully account for all the seasonal and local time asymmetries in the occurrence of the lobe encounters; thus there is probably an additional dawn-dusk asymmetry in the distorted field. The lobe encounters are strongly associated with <span class="hlt">magnetospheric</span> activity and tend to occur in association with rare magnetosheath encounters at synchronous orbit. It thus appears that the presence of the lobe at geosynchronous orbit is the result of major, probably asymmetric modifications of the <span class="hlt">magnetospheric</span> field geometry in times of strong disturbance. 19 refs., 7 figs., 1 tab.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JGRA..122.5181T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JGRA..122.5181T"><span>Energy-banded ions in Saturn's <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thomsen, M. F.; Badman, S. V.; Jackman, C. M.; Jia, X.; Kivelson, M. G.; Kurth, W. S.</p> <p>2017-05-01</p> <p>Using data from the Cassini Plasma Spectrometer ion mass spectrometer, we report the first observation of energy-banded ions at Saturn. Observed near midnight at relatively high magnetic latitudes, the banded ions are dominantly H+, and they occupy the range of energies typically associated with the thermal pickup distribution in the inner <span class="hlt">magnetosphere</span> (L < 10), but their energies decline monotonically with increasing radial distance (or time or decreasing latitude). Their pitch angle distribution suggests a source at low (or slightly southern) latitudes. The band energies, including their pitch angle dependence, are consistent with a bounce-resonant interaction between thermal H+ ions and the standing wave structure of a field line resonance. There is additional evidence in the pitch angle dependence of the band energies that the particles in each band may have a common time of flight from their most recent interaction with the wave, which may have been at slightly southern latitudes. Thus, while the particles are basically bounce resonant, their energization may be dominated by their most recent encounter with the standing wave.<abstract type="synopsis"><title type="main">Plain Language SummaryDuring an outbound passage by the Cassini spacecraft through Saturn's inner <span class="hlt">magnetosphere</span>, ion energy distributions were observed that featured discrete flux peaks at regularly spaced energies. The peaks persisted over several hours and several Saturn radii of distance away from the planet. We show that these "bands" of ions are plausibly the result of an interaction between the Saturnian plasma and standing waves that form along the <span class="hlt">magnetospheric</span> magnetic field lines. These observations are the first reported evidence that such standing waves may be present in the inner <span class="hlt">magnetosphere</span>, where they could contribute to the radial transport of Saturn's radiation belt particles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA563652','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA563652"><span>The Community-based Whole <span class="hlt">Magnetosphere</span> Model</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2011-11-15</p> <p><span class="hlt">magnetosphere</span> to the IE module. These are used to specify the aurora. • Incorporated MSIS [Hedin, 1987] and IRI [Bil- itza, 2001] as empirical models...can actually be run utilizing MSIS and IRI at every time step, so they can be coupled like an upper atmosphere module. • Coupled the multifluid...J. L., and Gallagher, D. L.: Forma - tion of density troughs embedded in the outer plas- masphere by subauroral ion drift events, J. Geophys. Res., 102</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRA..117.8310C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRA..117.8310C"><span>Terrestrial VLF transmitter injection into the <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cohen, M. B.; Inan, U. S.</p> <p>2012-08-01</p> <p>Very Low Frequency (VLF, 3-30 kHz) radio waves emitted from ground sources (transmitters and lightning) strongly impact the radiation belts, driving electron precipitation via whistler-electron gyroresonance, and contributing to the formation of the slot region. However, calculations of the global impacts of VLF waves are based on models of trans-ionospheric propagation to calculate the VLF energy reaching the <span class="hlt">magnetosphere</span>. Limited comparisons of these models to individual satellite passes have found that the models may significantly (by >20 dB) overestimate amplitudes of ground based VLF transmitters in the <span class="hlt">magnetosphere</span>. To form a much more complete empirical picture of VLF transmitter energy reaching the <span class="hlt">magnetosphere</span>, we present observations of the radiation pattern from a number of ground-based VLF transmitters by averaging six years of data from the DEMETER satellite. We divide the slice at ˜700 km altitude above a transmitter into pixels and calculate the average field for all satellite passes through each pixel. There are enough data to see 25 km features in the radiation pattern, including the modal interference of the subionospheric signal mapped upwards. Using these data, we deduce the first empirical measure of the radiated power into the <span class="hlt">magnetosphere</span> from these transmitters, for both daytime and nighttime, and at both the overhead and geomagnetically conjugate region. We find no detectable variation of signal intensity with geomagnetic conditions at low and mid latitudes (L < 2.6). We also present evidence of ionospheric heating by one VLF transmitter which modifies the trans-ionospheric absorption of signals from other transmitters passing through the heated region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19760061666&hterms=accounting+law&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Daccounting%2Blaw','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19760061666&hterms=accounting+law&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Daccounting%2Blaw"><span>Relativistic electrons and whistlers in Jupiter's <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Barbosa, D. D.; Coroniti, F. V.</p> <p>1976-01-01</p> <p>The paper examines some of the consequences of relativistic electrons in stably trapped equilibrium with parallel propagating whistlers in the inner <span class="hlt">magnetosphere</span> of Jupiter. Approximate scaling laws for the stably trapped electron flux and equilibrium wave intensity are derived, and the equatorial growth rate for whistlers is determined. It is shown that fluxes are near the stably trapped limit, which suggests that whistler intensities may be high enough to cause significant diffusion of electrons, accounting for the observed reduction of phase space densities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMSM31C..11B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMSM31C..11B"><span>Imaging <span class="hlt">Magnetospheric</span> Boundries at Ionospheric Heights</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baumgardner, J.; Nottingham, D.; Wroten, J.; Mendillo, M.</p> <p>2001-12-01</p> <p>Stable auroral red (SAR) arcs are excited by a downward heat flux within a narrow range of fluxtubes that define the plasmapause-ring current interaction region. Ambient F-region electrons near and above the peak height (300-500 km) are heated and collisionally excite atomic oxygen to the O(1D) state, thereby emitting 6300 A photons. At the same time, the diffuse aurora at 6300 A is excited by the precipitation of plasma sheet electrons into the lower thermosphere, exciting O(1D) to emit near 200 km. An all-sky imaging system operating at a sub-auroral site (e.g., at Millstone Hill) can readily record the SAR arc centroid location and the equatorial edge of the diffuse aurora in the same 6300 A image. We have analyzed 75 such cases showing where both stuctures occur in the ionosphere and then conducted field-line mapping to define the L-shell domains of origin in the equatorial plane of the inner <span class="hlt">magnetosphere</span> (L ~ 2.5 - 4). To within the measurement and mapping accuracies, both boundaries coincide, i.e., the inner edge of the plasma sheet essentially falls along the plasmapause. Since the O(1D) 6300 A emission corresponds to ~2 ev of excitation by <span class="hlt">magnetospheric</span> processes, this technique defines ELENA (Extremely Low Energetic Neutral Atom) imaging of <span class="hlt">magnetospheric</span> structures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/5460402-energetic-particle-penetrations-inner-magnetosphere','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5460402-energetic-particle-penetrations-inner-magnetosphere"><span>Energetic particle penetrations into the inner <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ejiri, M.; Hoffman, R.A.; Smith, P.H.</p> <p></p> <p>Data from Explorer 45 (S/sup 3/- A) instruments have revealed characteristics of <span class="hlt">magnetospheric</span> storm or substorm time energetic particle enhancements in the inner <span class="hlt">magnetosphere</span> (L< or approx. =5). The properties of the ion 'nose' structure in the dusk hemisphere are examined in detail. A statistical study of the local time dependence of noses places the highest probability of occurrence around 2000 MLT, but hey can be observed even near the noon meridian. It also appears that most noses are not isolated events but will appear on successive passes. A geoelectric field enhancement corresponding to a minimum value of AE ofmore » about 205 ..gamma.. seems to be required to convect the particles within the apogee of Explorer 45. The dynamical behavior of the nose characteristics observed along successive orbits is then explained quantitatively by the time-dependent convection theory in a Volland-Stern type geoelectric field (..gamma..=2). These calculations of adiabatic charged particle motions are also applied to expalin the energy spectra and dispersion in penetration distances for both electrons and ions observed in the postmidnight to morning hours. Finally, useful descriptions are given of the dispersion properties of particles penetrating the inter <span class="hlt">magnetosphere</span> at all local times as a function of time after a sudden enhancement of the geoelectric field.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018PhDT.........9T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018PhDT.........9T"><span>On Star-Planet Interaction: <span class="hlt">Magnetospheric</span> Dynamics and Atmospheric Evolution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tilley, Matthew Tilley</p> <p></p> <p>With the explosion of exoplanetary discoveries, the question of planetary habitability is at the forefront, and generates many interesting and complex questions. One of those questions: Are planetary global magnetic fields necessary for the development of complex surface organics and the development of life? Does a global field protect planetary atmospheres? What detection signatures can be gleaned from a planet or moon with a global field as opposed to one without? We have a wealth of in situ <span class="hlt">magnetospheric</span> data from <span class="hlt">Earth</span>, as well as solar system planets and their moons from several vital satellite missions, such as the Voyager missions, the Pioneer missions, Galileo, Cassini, Messenger, MAVEN, and New Horizons. Due to the distances involved, it is not tenable to send satellites to obtain data at exoplanetary bodies, so we rely on simulations and using solar system data as analog environments to help set ground truth validation for the numerical work. In this dissertation, I use a multifluid plasma model for gas giant <span class="hlt">magnetospheres</span> to predict the potential dynamical consequences and detection signatures for giant exoplanets in a warm orbit (˜0.2 AU). I discuss the dynamics of plasma loss from an exomoon injected torus, and how the total mass flux out of the system is altered by increased stellar wind forcing as a function of orbital semi-major axis. Detection signatures for such a planet, including transit depth modifications due to plasma densities and radio emissions, show promise for further detecting and characterizing future systems. I also improve the multifluid model by implementing a full treatment of pressure anisotropy at Saturn, with a focus on the dynamics and structure of the <span class="hlt">magnetosphere</span>. The improvements to the physics of the model generate more accurate system when compared to Cassini data; the anisotropic simulations show stronger current confinement of the Enceladus torus, consistent and well-structure flux interchange events, and global</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSM23C..03T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSM23C..03T"><span>Resolving the Kinetic Reconnection Length Scale in Global <span class="hlt">Magnetospheric</span> Simulations with MHD-EPIC</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Toth, G.; Chen, Y.; Cassak, P.; Jordanova, V.; Peng, B.; Markidis, S.; Gombosi, T. I.</p> <p>2016-12-01</p> <p>We have recently developed a new modeling capability: the Magnetohydrodynamics with Embedded Particle-in-Cell (MHD-EPIC) algorithm with support from Los Alamos SHIELDS and NSF INSPIRE grants. We have implemented MHD-EPIC into the Space Weather Modeling Framework (SWMF) using the implicit Particle-in-Cell (iPIC3D) and the BATS-R-US extended magnetohydrodynamic codes. The MHD-EPIC model allows two-way coupled simulations in two and three dimensions with multiple embedded PIC regions. Both BATS-R-US and iPIC3D are massively parallel codes. The MHD-EPIC approach allows global <span class="hlt">magnetosphere</span> simulations with embedded kinetic simulations. For small <span class="hlt">magnetospheres</span>, like Ganymede or Mercury, we can easily resolve the ion scales around the reconnection sites. Modeling the <span class="hlt">Earth</span> <span class="hlt">magnetosphere</span> is very challenging even with our efficient MHD-EPIC model due to the large separation between the global and ion scales. On the other hand the large separation of scales may be exploited: the solution may not be sensitive to the ion inertial length as long as it is small relative to the global scales. The ion inertial length can be varied by changing the ion mass while keeping the MHD mass density, the velocity, and pressure the same for the initial and boundary conditions. Our two-dimensional MHD-EPIC simulations for the dayside reconnection region show in fact, that the overall solution is not sensitive to ion inertial length. The shape, size and frequency of flux transfer events are very similar for a wide range of ion masses. Our results mean that 3D MHD-EPIC simulations for the <span class="hlt">Earth</span> and other large <span class="hlt">magnetospheres</span> can be made computationally affordable by artificially increasing the ion mass: the required grid resolution and time step in the PIC model are proportional to the ion inertial length. Changing the ion mass by a factor of 4, for example, speeds up the PIC code by a factor of 256. In fact, this approach allowed us to perform an hour-long 3D MHD-EPIC simulations for the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730007617','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730007617"><span>The structure of the <span class="hlt">magnetosphere</span> as deduced from <span class="hlt">magnetospherically</span> reflected whistlers</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Edgar, B. C.</p> <p>1972-01-01</p> <p>Very low frequency (VLF) electromagnetic wave phenomenon called the <span class="hlt">magnetospherically</span> reflected (MR) whistler was investigated. VLF (0.3 to 12.5 kHz) data obtained from the Orbiting Geophysical Observatories 1 and 3 from October 1964 to December 1966 were used. MR whistlers are produced by the dispersive propagation of energy from atmospheric lightning through the <span class="hlt">magnetosphere</span> to the satellite along ray paths which undergo one or more reflections due to the presence of ions. The gross features of MR whistler frequency-time spectrograms are explained in terms of propagation through a <span class="hlt">magnetosphere</span> composed of thermal ions and electrons and having small density gradients across L-shells. Irregularities observed in MR spectra were interpreted in terms of propagation through field-aligned density structures. Trough and enhancement density structures were found to produce unique and easily recognizable signatures in MR spectra. Sharp cross-field density dropoff produces extra traces in MR spectrograms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1917573S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1917573S"><span>Wave particle interactions in Jupiter's <span class="hlt">magnetosphere</span>: Implications for auroral and <span class="hlt">magnetospheric</span> particle distributions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saur, Joachim; Schreiner, Anne; Barry, Mauk; Clark, George; Kollman, Peter</p> <p>2017-04-01</p> <p>We investigate the occurrence and the role of wave particle interaction processes, i.e., Landau and cyclotron damping, in Jupiter's <span class="hlt">magnetosphere</span>. Therefore we calculate kinetic length and temporal scales, which we cross-compare at various regions within Jupiter's <span class="hlt">magnetosphere</span>. Based on these scales, we investigate the roles of possible wave particle mechanisms in each region, e.g., Jupiter's plasma sheet, the auroral acceleration region and the polar ionosphere. We thereby consider that the <span class="hlt">magnetospheric</span> regions are coupled through convective transport, Alfven and other wave modes. We particularly focus on the role of kinetic Alfven waves in contributing to Jupiter's aurora. Our results will aid the interpretation of particle distribution functions measured by the JEDI instrument onboard the JUNO spacecraft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUSMSM14A..01S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUSMSM14A..01S"><span>Morphology of the Saturn <span class="hlt">Magnetospheric</span> Neutral gas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shemansky, D. E.</p> <p>2009-05-01</p> <p>Although it has been known that Saturn's <span class="hlt">magnetospheric</span> volume is filled with neutral gas, from the time of the Voyager encounters and subsequent HST observations, the Cassini Mission was essential for revealing the depth of complexity in the source processes and structure of this system. The state of the <span class="hlt">magnetosphere</span> is unique, containing a plasma environment quenched by neutral gas from the top of the atmosphere to beyond the bow shock with neutral/plasma mixing ratios in the range 100 to ˜ 3000. The dominant neutral species identified in the <span class="hlt">magnetosphere</span> by remote sensing are atomic hydrogen and oxygen, OH and H2O . Atomic hydrogen was mapped using the Voyager UVS and found to have an asymmetric distribution in local time, filling the entire <span class="hlt">magnetosphere</span>, with a broad latitudinal distribution. These observations were followed by the measurement of the OH spectrum using the HST FOS. The definition of the HST distribution was limited to a few points in the system, showing a peak near 3. Saturn radii (RS ) from system center. Atomic oxygen was detected and mapped using the Cassini UVIS system, showing orbital asymmetry and temporal variation, with a substantially broader distribution than OH. All of the observed species emissions from the <span class="hlt">magnetosphere</span> are produced by solar photon fluorescence, the ambient plasma volume being too low in density and temperature to generate measurable particle excited emission. H2O has been measured in Cassini UVIS stellar occultations at the south polar plumes at Enceladus, with a total mass injection rate that is the same order needed to maintain the oxygen population. The oxygen distribution, however, indicates that sources other than Enceladus may be contributing. Virtually all of the atomic hydrogen in the system is attributed to escape from the top of the Saturn atmosphere. The complexity of this process was graphically revealed in the Cassini UVIS system higher resolution images showing a plume of atoms in ballistic and</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790059806&hterms=application+ion+exchange&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dapplication%2Bion%2Bexchange','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790059806&hterms=application+ion+exchange&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dapplication%2Bion%2Bexchange"><span>Expected charge states of energetic ions in the <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spjeldvik, W. N.</p> <p>1979-01-01</p> <p>Major developments in <span class="hlt">magnetospheric</span> heavy ion physics during the period 1974-1977 are reviewed with emphasis on charge state aspects. Particular attention is given to the high energy component at energies above tens of keV per ion. Also considered are charge exchange processes with application to the inner <span class="hlt">magnetosphere</span>, a comparison between theory and measurements, and a survey of heavy ion and charge state observations in the outer <span class="hlt">magnetosphere</span>, magnetosheath and the surrounding space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.P43F..08R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.P43F..08R"><span>Simulation Study of Solar Wind Interaction with Mercury's <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Richer, E.; Modolo, R.; Chanteur, G. M.; Hess, S.; Mancini, M.; Leblanc, F.</p> <p>2011-12-01</p> <p>The three flybys of Mariner 10, the numerous terrestrial observations of Mercury's exosphere and the recent flybys of MESSENGER [1] have brought important information about the Hermean environment. Mercury's intrinsic magnetic field is principally dipolar and its interaction with the Solar Wind (SW) creates a small and very dynamic <span class="hlt">magnetosphere</span>. Mercury's exosphere is a highly variable [2] and complex neutral environment made of several species : H, He, O, Na, K, Ca, and Mg have already been detected [3,4]. The small number of in situ observations and the fact that the Hermean <span class="hlt">magnetospheric</span> activity is not observable from <span class="hlt">Earth</span> make simulation studies of the Hermean environment a useful tool to understand the global interaction of the SW with Mercury. This study presents simulation results from a 3-dimensional parallel multi-species hybrid model of Mercury's <span class="hlt">magnetosphere</span> interaction with the SW. The SW in this model is representative of conditions at Mercury's aphelion (0.47AU) and is composed of 95% protons and 5% alpha particles. The simulated IMF is oriented accordingly observations during the first flyby of MESSENGER on January 2008 with a cone angle of ~45°. A neutral corona of atomic hydrogen is included in this model and is partly ionized by solar photons, electron impacts and charge exchange between SW ions and neutral H. Two electron fluids with different temperature are implemented to mimic the SW and ionospheric plasma. This model is an adapted version of the 3D parallel model for the Martian environment. Planetary and SW plasmas are treated separately and the dynamic of each ion species can be investigated separately. Simulations have been performed on a grid of 190×350×350 cells with a spatial resolution of Δx~120km. Acknowledgements The authors are indebted to CNES (French space agency) for the funding of their modeling activity through its program Sun - Heliosphere - <span class="hlt">Magnetosphere</span> and to ANR (French national agency for research) for supporting</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhDT........78M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhDT........78M"><span><span class="hlt">Magnetospheric</span> Whistler Mode Raytracing with the Inclusion of Finite Electron and ion Temperature</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maxworth, Ashanthi S.</p> <p></p> <p>Whistler mode waves are a type of a low frequency (100 Hz - 30 kHz) wave, which exists only in a magnetized plasma. These waves play a major role in <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>. Due to the impact of whistler mode waves in many fields such as space weather, satellite communications and lifetime of space electronics, it is important to accurately predict the propagation path of these waves. The method used to determine the propagation path of whistler waves is called numerical raytracing. Numerical raytracing determines the power flow path of the whistler mode waves by solving a set of equations known as the Haselgrove's equations. In the majority of the previous work, raytracing was implemented assuming a cold background plasma (0 K), but the actual <span class="hlt">magnetosphere</span> is at a temperature of about 1 eV (11600 K). In this work we have modified the numerical raytracing algorithm to work at finite electron and ion temperatures. The finite temperature effects have also been introduced into the formulations for linear cyclotron resonance wave growth and Landau damping, which are the primary mechanisms for whistler mode growth and attenuation in the <span class="hlt">magnetosphere</span>. Including temperature increases the complexity of numerical raytracing, but the overall effects are mostly limited to increasing the group velocity of the waves at highly oblique wave normal angles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM42A..03G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM42A..03G"><span>Magnetic reconnection in 3D <span class="hlt">magnetosphere</span> models: magnetic separators and open flux production</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Glocer, A.; Dorelli, J.; Toth, G.; Komar, C. M.; Cassak, P.</p> <p>2014-12-01</p> <p>There are multiple competing definitions of magnetic reconnection in 3D (e.g., Hesse and Schindler [1988], Lau and Finn [1990], and Boozer [2002]). In this work we focus on separator reconnection. A magnetic separator can be understood as the 3D analogue of a 2D x line with a guide field, and is defined by the line corresponding to the intersection of the separatrix surfaces associated with the magnetic nulls. A separator in the <span class="hlt">magnetosphere</span> represents the intersection of four distinct magnetic topologies: solar wind, closed, open connected to the northern hemisphere, and open connected to the southern hemisphere. The integral of the parallel electric field along the separator defines the rate of open flux production, and is one measure of the reconnection rate. We present three methods for locating magnetic separators and apply them to 3D resistive MHD simulations of the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span> using the BATS-R-US code. The techniques for finding separators and determining the reconnection rate are insensitive to IMF clock angle and can in principle be applied to any <span class="hlt">magnetospheric</span> model. The present work examines cases of high and low resistivity, for two clock angles. We also examine the separator during Flux Transfer Events (FTEs) and Kelvin-Helmholtz instability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150007954','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150007954"><span>Challenges in Measuring External Currents Driven by the Solar Wind-<span class="hlt">Magnetosphere</span> Interaction</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Le, Guan; Slavin, James A.; Pfaff, Robert F.</p> <p>2014-01-01</p> <p>In studying the <span class="hlt">Earth</span>'s geomagnetism, it has always been a challenge to separate magnetic fields from external currents originating from the ionosphere and <span class="hlt">magnetosphere</span>. While the internal magnetic field changes very slowly in time scales of years and more, the ionospheric and <span class="hlt">magnetospheric</span> current systems driven by the solar wind -<span class="hlt">magnetosphere</span> interaction are very dynamic. They are intimately controlled by the ionospheric electrodynamics and ionospheremagnetosphere coupling. Single spacecraft observations are not able to separate their spatial and temporal variations, and thus to accurately describe their configurations. To characterize and understand the external currents, satellite observations require both good spatial and temporal resolutions. This paper reviews our observations of the external currents from two recent LEO satellite missions: Space Technology 5 (ST-5), NASA's first three-satellite constellation mission in LEO polar orbit, and Communications/Navigation Outage Forecasting System (C/NOFS), an equatorial satellite developed by US Air Force Research Laboratory. We present recommendations for future geomagnetism missions based on these observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MNRAS.tmp.1573D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MNRAS.tmp.1573D"><span>Inhibition of the electron cyclotron maser instability in the dense <span class="hlt">magnetosphere</span> of a hot Jupiter</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Daley-Yates, S.; Stevens, I. R.</p> <p>2018-06-01</p> <p>Hot Jupiter (HJ) type exoplanets are expected to produce strong radio emission in the MHz range via the Electron Cyclotron Maser Instability (ECMI). To date, no repeatable detections have been made. To explain the absence of observational results, we conduct 3D adaptive mess refinement (AMR) magnetohydrodynamic (MHD) simulations of the magnetic interactions between a solar type star and HJ using the publicly available code PLUTO. The results are used to calculate the efficiency of the ECMI at producing detectable radio emission from the planets <span class="hlt">magnetosphere</span>. We also calculate the frequency of the ECMI emission, providing an upper and lower bounds, placing it at the limits of detectability due to <span class="hlt">Earth</span>'s ionospheric cutoff of ˜10 MHz. The incident kinetic and magnetic power available to the ECMI is also determined and a flux of 0.075 mJy for an observer at 10 pc is calculated. The <span class="hlt">magnetosphere</span> is also characterized and an analysis of the bow shock which forms upstream of the planet is conducted. This shock corresponds to the thin shell model for a colliding wind system. A result consistent with a colliding wind system. The simulation results show that the ECMI process is completely inhibited by the planets expanding atmosphere, due to absorption of UV radiation form the host star. The density, velocity, temperature and magnetic field of the planetary wind are found to result in a <span class="hlt">magnetosphere</span> where the plasma frequency is raised above that due to the ECMI process making the planet undetectable at radio MHz frequencies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMSM13B1607Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMSM13B1607Y"><span>An RCM-E simulation of a steady <span class="hlt">magnetospheric</span> convection event</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, J.; Toffoletto, F.; Wolf, R.; Song, Y.</p> <p>2009-12-01</p> <p>We present simulation results of an idealized steady <span class="hlt">magnetospheric</span> convection (SMC) event using the Rice Convection Model coupled with an equilibrium magnetic field solver (RCM-E). The event is modeled by placing a plasma distribution with substantially depleted entropy parameter PV5/3 on the RCM's high latitude boundary. The calculated magnetic field shows a highly depressed configuration due to the enhanced westward current around geosynchronous orbit where the resulting partial ring current is stronger and more symmetric than in a typical substorm growth phase. The magnitude of BZ component in the mid plasma sheet is large compared to empirical magnetic field models. Contrary to some previous results, there is no deep BZ minimum in the near-<span class="hlt">Earth</span> plasma sheet. This suggests that the <span class="hlt">magnetosphere</span> could transfer into a strong adiabatic earthward convection mode without significant stretching of the plasma-sheet magnetic field, when there are flux tubes with depleted plasma content continuously entering the inner <span class="hlt">magnetosphere</span> from the mid-tail. Virtual AU/AL and Dst indices are also calculated using a synthetic magnetogram code and are compared to typical features in published observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://images.nasa.gov/#/details-GSFC_20171208_Archive_e002115.html','SCIGOVIMAGE-NASA'); return false;" href="https://images.nasa.gov/#/details-GSFC_20171208_Archive_e002115.html"><span>NASA Sun <span class="hlt">Earth</span></span></a></p> <p><a target="_blank" href="https://images.nasa.gov/">NASA Image and Video Library</a></p> <p></p> <p>2017-12-08</p> <p>CME blast and subsequent impact at <span class="hlt">Earth</span> -- This illustration shows a CME blasting off the Sun’s surface in the direction of Ea CME blast and subsequent impact at <span class="hlt">Earth</span> -- This illustration shows a CME blasting off the Sun’s surface in the direction of <span class="hlt">Earth</span>. This left portion is composed of an EIT 304 image superimposed on a LASCO C2 coronagraph. Two to four days later, the CME cloud is shown striking and beginning to be mostly deflected around the Earth’s <span class="hlt">magnetosphere</span>. The blue paths emanating from the Earth’s poles represent some of its magnetic field lines. The magnetic cloud of plasma can extend to 30 million miles wide by the time it reaches <span class="hlt">earth</span>. These storms, which occur frequently, can disrupt communications and navigational equipment, damage satellites, and even cause blackouts. (Objects in the illustration are not drawn to scale.) Credit: NASA/GSFC/SOHO/ESA To learn more go to the SOHO website: sohowww.nascom.nasa.gov/home.html To learn more about NASA's Sun <span class="hlt">Earth</span> Day go here: sunearthday.nasa.gov/2010/index.php</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSM43D..01M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSM43D..01M"><span>Cassini/MIMI Measurements in Saturn's <span class="hlt">Magnetosphere</span> and their Implications for <span class="hlt">Magnetospheric</span> Dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mitchell, D. G.</p> <p>2016-12-01</p> <p>The Cassini spacecraft has been in orbit about Saturn since early July, 2004. In less than a year, on September 15, 2017, Cassini will plunge into Saturn's atmosphere, ending what has been a highly successful and interesting mission. As befitting a Planetary Division Flagship Mission, Cassini's science payload included instrumentation designed for a multitude of science objectives, from surfaces of moons to rings to atmospheres to Saturn's vast, fast-rotating <span class="hlt">magnetosphere</span>. Saturn's <span class="hlt">magnetosphere</span> exhibits considerable variability, both from inner <span class="hlt">magnetosphere</span> to outer, and over time. Characterizing the dynamics of the <span class="hlt">magnetosphere</span> has required the full range of energetic particles (measured by the <span class="hlt">magnetospheric</span> imaging instrument, MIMI - https://saturn.jpl.nasa.gov/<span class="hlt">magnetospheric</span>-imaging-instrument/), plasma (provided by the Cassini plasma spectrometer, CAPS), gas (ion and neutral mass spectrometer, INMS), magnetic fields (Cassini magnetometer, MAG), radio and plasma waves (radio and plasma wave science, RPWS), dust (Cassini Dust Analyzer, CDA), as well as ultraviolet, visible and infrared imaging (ultraviolet imaging spectrograph, UVIS; Cassini imaging subsystem ISS; visible and infrared mapping spectrometer, VIMS; Cassini composite infrared spectrometer, CIRS) and ionospheric sounding by the Cassini radio science subsystem (RSS). It has also required the full range of orbital geometries from equatorial to high inclination and all local times, as well as the full range of solar wind conditions, seasonal sun-Saturn configurations. In this talk we focus on the contributions of the MIMI instrument suite (CHEMS, LEMMS, and INCA) to our understanding of the dynamics of Saturn's <span class="hlt">magnetosphere</span>. We will both review past work, and present recent observations from the high inclination orbits that precede the final stages of the Cassini mission, the sets of high inclination orbits that cross the equator just beyond the edge of the main ring system, and later cross between</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19760029851&hterms=amp&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Damp','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19760029851&hterms=amp&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Damp"><span>AMPS sciences objectives and philosophy. [Atmospheric, <span class="hlt">Magnetospheric</span> and Plasmas-in-Space project on Spacelab</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schmerling, E. R.</p> <p>1975-01-01</p> <p>The Space Shuttle will open a new era in the exploration of <span class="hlt">earth</span>'s near-space environment, where the weight and power capabilities of Spacelab and the ability to use man in real time add important new features. The Atmospheric, <span class="hlt">Magnetospheric</span>, and Plasmas-in-Space project (AMPS) is conceived of as a facility where flexible core instruments can be flown repeatedly to perform different observations and experiments. The twin thrusts of remote sensing of the atmosphere below 120 km and active experiments on the space plasma are the major themes. They have broader implications in increasing our understanding of plasma physics and of energy conversion processes elsewhere in the universe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20180000036','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20180000036"><span>Sensitivity of <span class="hlt">Magnetospheric</span> Multi-Scale (MMS) Mission Naviation Accuracy to Major Error Sources</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Olson, Corwin; Long, Anne; Carpenter, J. Russell</p> <p>2011-01-01</p> <p>The <span class="hlt">Magnetospheric</span> Multiscale (MMS) mission consists of four satellites flying in formation in highly elliptical orbits about the <span class="hlt">Earth</span>, with a primary objective of studying magnetic reconnection. The baseline navigation concept is independent estimation of each spacecraft state using GPS pseudorange measurements referenced to an Ultra Stable Oscillator (USO) with accelerometer measurements included during maneuvers. MMS state estimation is performed onboard each spacecraft using the Goddard Enhanced Onboard Navigation System (GEONS), which is embedded in the Navigator GPS receiver. This paper describes the sensitivity of MMS navigation performance to two major error sources: USO clock errors and thrust acceleration knowledge errors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19800031759&hterms=methods+quantitative&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmethods%2Bquantitative','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19800031759&hterms=methods+quantitative&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmethods%2Bquantitative"><span>A method of evaluating quantitative <span class="hlt">magnetospheric</span> field models by an angular parameter alpha</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sugiura, M.; Poros, D. J.</p> <p>1979-01-01</p> <p>The paper introduces an angular parameter, termed alpha, which represents the angular difference between the observed, or model, field and the internal model field. The study discusses why this parameter is chosen and demonstrates its usefulness by applying it to both observations and models. In certain areas alpha is more sensitive than delta-B (the difference between the magnitude of the observed magnetic field and that of the <span class="hlt">earth</span>'s internal field calculated from a spherical harmonic expansion) in expressing <span class="hlt">magnetospheric</span> field distortions. It is recommended to use both alpha and delta-B in comparing models with observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110008137','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110008137"><span>Sensitivity of <span class="hlt">Magnetospheric</span> Multi-Scale (MMS) Mission Navigation Accuracy to Major Error Sources</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Olson, Corwin; Long, Anne; Car[emter. Russell</p> <p>2011-01-01</p> <p>The <span class="hlt">Magnetospheric</span> Multiscale (MMS) mission consists of four satellites flying in formation in highly elliptical orbits about the <span class="hlt">Earth</span>, with a primary objective of studying magnetic reconnection. The baseline navigation concept is independent estimation of each spacecraft state using GPS pseudorange measurements referenced to an Ultra Stable Oscillator (USO) with accelerometer measurements included during maneuvers. MMS state estimation is performed onboard each spacecraft using the Goddard Enhanced Onboard Navigation System (GEONS), which is embedded in the Navigator GPS receiver. This paper describes the sensitivity of MMS navigation performance to two major error sources: USO clock errors and thrust acceleration knowledge errors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19750038692&hterms=fashion+models&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dfashion%2Bmodels','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19750038692&hterms=fashion+models&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dfashion%2Bmodels"><span>Substorm injection boundaries. [<span class="hlt">magnetospheric</span> electric field model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mcilwain, C. E.</p> <p>1974-01-01</p> <p>An improved <span class="hlt">magnetospheric</span> electric field model is used to compute the initial locations of particles injected by several substorms. Trajectories are traced from the time of their encounter with the ATS-5 satellite backwards to the onset time given by ground-based magnetometers. A spiral shaped inner boundary of injection is found which is quite similar to that found by a statistical analysis. This injection boundary is shown to move in an energy dependent fashion which can explain the soft energy spectra observed at the inner edge of the electrons plasma sheet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ascl.soft07009B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ascl.soft07009B"><span>PICsar: Particle in cell pulsar <span class="hlt">magnetosphere</span> simulator</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Belyaev, Mikhail A.</p> <p>2016-07-01</p> <p>PICsar simulates the <span class="hlt">magnetosphere</span> of an aligned axisymmetric pulsar and can be used to simulate other arbitrary electromagnetics problems in axisymmetry. Written in Fortran, this special relativistic, electromagnetic, charge conservative particle in cell code features stretchable body-fitted coordinates that follow the surface of a sphere, simplifying the application of boundary conditions in the case of the aligned pulsar; a radiation absorbing outer boundary, which allows a steady state to be set up dynamically and maintained indefinitely from transient initial conditions; and algorithms for injection of charged particles into the simulation domain. PICsar is parallelized using MPI and has been used on research problems with 1000 CPUs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT.......150L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT.......150L"><span>On plasma convection in Saturn's <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Livi, Roberto</p> <p></p> <p>We use CAPS plasma data to derive particle characteristics within Saturn's inner <span class="hlt">magnetosphere</span>. Our approach is to first develop a forward-modeling program to derive 1-dimensional (1D) isotropic plasma characteristics in Saturn's inner, equatorial <span class="hlt">magnetosphere</span> using a novel correction for the spacecraft potential and penetrating background radiation. The advantage of this fitting routine is the simultaneous modeling of plasma data and systematic errors when operating on large data sets, which greatly reduces the computation time and accurately quantifies instrument noise. The data set consists of particle measurements from the Electron Spectrometer (ELS) and the Ion Mass Spectrometer (IMS), which are part of the Cassini Plasma Spectrometer (CAPS) instrument suite onboard the Cassini spacecraft. The data is limited to peak ion flux measurements within +/-10° magnetic latitude and 3-15 geocentric equatorial radial distance (RS). Systematic errors such as spacecraft charging and penetrating background radiation are parametrized individually in the modeling and are automatically addressed during the fitting procedure. The resulting values are in turn used as cross-calibration between IMS and ELS, where we show a significant improvement in <span class="hlt">magnetospheric</span> electron densities and minor changes in the ion characteristics due to the error adjustments. Preliminary results show ion and electron densities in close agreement, consistent with charge neutrality throughout Saturn's inner <span class="hlt">magnetosphere</span> and confirming the spacecraft potential to be a common influence on IMS and ELS. Comparison of derived plasma parameters with results from previous studies using CAPS data and the Radio And Plasma Wave Science (RPWS) investigation yields good agreement. Using the derived plasma characteristics we focus on the radial transport of hot electrons. We present evidence of loss-free adiabatic transport of equatorially mirroring electrons (100 eV - 10 keV) in Saturn's <span class="hlt">magnetosphere</span> between</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EPSC...11..230S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EPSC...11..230S"><span>Saturn's <span class="hlt">Magnetospheric</span> Plasma Flow Encountered by Titan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sillanpää, I.</p> <p>2017-09-01</p> <p>Titan has been a major target of the ending Cassini mission to Saturn. 126 flybys have sampled, measured and observed a variety of Titan's features and processes from the surface features to atmospheric composition and upper atmospheric processes. Titan's interaction with the <span class="hlt">magnetospheric</span> plasma flow it is mostly embedded in is highly dependent on the characteristics of the ambient plasma. The density, velocity and even the composition of the plasma flow can have great variance from flyby to flyby. Our purpose is the present the plasma flow conditions for all over 70 flybys of which we have Cassini Plasma Spectrometer (CAPS) measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMSM41A2688N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMSM41A2688N"><span>Effects of Ionospheric Hall Polarization on <span class="hlt">Magnetospheric</span> Configurations and Dynamics in Global MHD Simulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakamizo, A.; Yoshikawa, A.; Tanaka, T.</p> <p>2017-12-01</p> <p>We investigate how the M-I coupling and boundary conditions affects the results of global simulations of the <span class="hlt">magnetosphere</span>. More specifically, we examine the effects of ionospheric Hall polarization on <span class="hlt">magnetospheric</span> convection and dynamics by using an MHD code developed by Tanaka et al. [2010]. This study is motivated by the recently proposed idea that the ionospheric convection is modified by the ionospheric polarization [Yoshikawa et al., 2013]. We perform simulations for the following pairs of Hall conductance and IMF-By; Hall conductance set by αH = 2, 3.5, 5, and uniform distribution (1.0 [S] everywhere), where RH is the ratio of Hall to Pedersen conductance, and IMF-By of positive, negative, and zero. The results are summarized as follows. (a) Large-scale structure: In the cases of uniform Hall conductance, the <span class="hlt">magnetosphere</span> is completely symmetric under the zero IMF-By. In the cases of non-uniform Hall conductance, the <span class="hlt">magnetosphere</span> shows asymmetries globally even under the zero IMF-By. Asymmetries become severe for larger αH. The results indicate that ionospheric Hall polarization is one of the important factors to determine the global structure. (b) Formation of NENL: The location becomes closer to the <span class="hlt">earth</span> and timing becomes earlier for larger RH. The difference is considered to be related to the combined effects of field lines twisting due to ionospheric Hall polarization and M-I energy/current closures. (c) Near-<span class="hlt">earth</span> convection: In the cases of non-uniform Hall conductance, an inflection structure is formed around premidnight sector on equatorial plane inside 10 RE. Considering that the region 2 FAC is not sufficiently generated in MHD models, the structure corresponds to a convection reversal often shown in the RCM. Previous studies regard the structure as the Harang Reversal in the <span class="hlt">magnetosphere</span>. In the cases of uniform Hall conductance, by contrast, such structure is not formed, indicating that the Harang Reversal may not be formed without the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37.2948S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.2948S"><span>MESSENGER observations of the response of Mercury's <span class="hlt">magnetosphere</span> to northward and southward interplanetary magnetic fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Slavin, James</p> <p></p> <p> these southward-Bz intervals. The inbound magnetopause crossing in the magnetic field measurements is consistent with a transition from the magnetosheath into the plasma sheet. Immediately following MESSENGER's entry into the <span class="hlt">magnetosphere</span>, rotational perturbations in the magnetic field similar to those seen at the <span class="hlt">Earth</span> in association with large-scale plasma sheet vortices driven by Kelvin-Helmholtz waves along the magnetotail boundary at the <span class="hlt">Earth</span> are observed. The outbound magnetopause occurred during northward IMF Bz and had the characteristics of a tangential discontinuity. These new observations have important implications for our understanding of energy transfer into Mercury's <span class="hlt">magnetosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910050764&hterms=1085&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231085','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910050764&hterms=1085&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231085"><span>Nitrogen airglow sources - Comparison of Triton, Titan, and <span class="hlt">earth</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Strobel, Darrell F.; Meier, R. R.; Summers, Michael E.; Strickland, Douglas J.</p> <p>1991-01-01</p> <p>The individual contributions of direct solar excitation, photoelectron excitation, and <span class="hlt">magnetospheric</span> electron excitation of Triton and Titan airglow observed by the Voyager Ultraviolet Spectrometer (UVS) are quantified. The principal spectral features of Triton's airglow are shown to be consistent with precipitation of <span class="hlt">magnetospheric</span> electrons with power dissipation about 500 million W. Solar excitation rates of the dominant N2 and N(+) emission features are factors of 2-7 weaker than <span class="hlt">magnetospheric</span> electron excitation. On Titan, the calculated disk center and bright limb N(+) 1085 A intensities due to solar excitation agree with observed values, while the 970 A feature is mostly N21 c5 band emission. The calculated LBH intensity by photoelectrons suggests that <span class="hlt">magnetospheric</span> electrons play a minor role in Titan's UV airglow. On <span class="hlt">earth</span>, solar/photoelectron excitation explains the observed N(+) 1085 A and LBH intensites and accounts for only 40 percent of the N(+) 916 A intensity.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001JGR...10615545H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001JGR...10615545H"><span>Relationships of models of the inner <span class="hlt">magnetosphere</span> to the Rice Convection Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heinemann, M.; Wolf, R. A.</p> <p>2001-08-01</p> <p>Ideal magnetohydrodynamics is known to be inaccurate for the <span class="hlt">Earth</span>'s inner <span class="hlt">magnetosphere</span>, where transport by gradient-curvature drift is nonnegligible compared to E×B drift. Most theoretical treatments of the inner plasma sheet and ring current, including the Rice Convection Model (RCM), treat the inner <span class="hlt">magnetospheric</span> plasma in terms of guiding center drifts. The RCM assumes that the distribution function is isotropic, but particles with different energy invariants are treated as separate guiding center fluids. However, Peymirat and Fontaine [1994] developed a two-fluid picture of the inner <span class="hlt">magnetosphere</span>, which utilizes modified forms of the conventional fluid equations, not guiding center drift equations. Heinemann [1999] argued theoretically that for inner <span class="hlt">magnetospheric</span> conditions the fluid energy equation should include a heat flux term, which, in the case of Maxwellian plasma, was derived by Braginskii [1965]. We have now reconciled the Heinemann [1999] fluid approach with the RCM. The fluid equations, including the Braginskii heat flux, can be derived by taking appropriate moments of the RCM equations for the case of the Maxwellian distribution. The physical difference between the RCM formalism and the Heinemann [1999] fluid approach is that the RCM pretends that particles suffer elastic collisions that maintain the isotropy of the distribution function but do not change particle energies. The Heinemann [1999] fluid treatment makes a different physical approximation, namely that the collisions maintain local thermal equilibrium among the ions and separately among the electrons. For some simple cases, numerical results are presented that illustrate the differences in the predictions of the two formalisms, along with those of MHD, guiding center theory, and Peymirat and Fontaine [1994].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017CosRe..55..426K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017CosRe..55..426K"><span>Plasma flow disturbances in the <span class="hlt">magnetospheric</span> plasma sheet during substorm activations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kozelova, T. V.; Kozelov, B. V.; Turyanskii, V. A.</p> <p>2017-11-01</p> <p>We have considered variations in fields and particle fluxes in the near-<span class="hlt">Earth</span> plasma sheet on the THEMIS-D satellite together with the auroral dynamics in the satellite-conjugate ionospheric part during two substorm activations on December 19, 2014 with K p = 2. The satellite was at 8.5 R E and MLT = 21.8 in the outer region of captured energetic particles with isotropic ion fluxes near the convection boundary of electrons with an energy of 10 keV. During substorm activations, the satellite recorded energetic particle injections and magnetic field oscillations with a period of 90 s. In the satellite-conjugate ionospheric part, the activations were preceded by wavelike disturbances of auroral brightness along the southern azimuthal arc. In the expansion phase of activations, large-scale vortex structures appeared in the structure of auroras. The sudden enhancements of auroral activity (brightening of arcs, auroral breakup, and appearance of NS forms) coincided with moments of local magnetic field dipolarization and an increase in the amplitude Pi2 of pulsations of the B z component of the magnetic field on the satellite. Approximately 30-50 s before these moments, the <span class="hlt">magnetosphere</span> was characterized by an increased rate of plasma flow in the radial direction, which initiated the formation of plasma vortices. The auroral activation delays relative to the times when plasma vortices appear in the <span class="hlt">magnetosphere</span> decreased with decreasing latitude of the satellite projection. The plasma vortices in the <span class="hlt">magnetosphere</span> are assumed to be responsible for the observed auroral vortex structures and the manifestation of the hybrid vortex instability (or shear flow ballooning instability) that develops in the equatorial <span class="hlt">magnetospheric</span> plane in the presence of a shear plasma flow in the region of strong pressure gradients in the Earthward direction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E1130H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E1130H"><span>Plasma Entry from Tail into the Dipolar <span class="hlt">Magnetosphere</span> During Substorms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haerendel, Gerhard</p> <p></p> <p>Plasma entering the dipolar <span class="hlt">magnetosphere</span> from the tail has to overcome the obstacle presented by the conductivity enhancements caused by the poleward arc(s). While the arcs move poleward, the plasma proceeds equatorward as testified by the existence of a westward electric field. The arcs break into smaller-scale structures and loops with a tendency of eastward growth and expansion, although the basic driving force is directed earthward/equatorward. The likely reason is that the arc-related conductivity enhancements act as flow barriers and convert normal into shear stresses. The energy derived from the release of the shear stresses and dissipated in the arcs lowers the entropy content of the flux tubes and enables their earthward progression. In addition, poleward jumps of the breakup arcs are quite common. They result from refreshments of the generator plasma by the sequential arrival of flow bursts from the near-<span class="hlt">Earth</span> neutral line. Once inside the oval, the plasma continues to move equatorward as manifested through north-south aligned auroral forms. Owing to the existence of an inner border of the oval, marked by the Region 2 currents, all flows are eventually diverted sunward.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001JASTP..63.1281L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001JASTP..63.1281L"><span>Differential drift of plasma clouds in the <span class="hlt">magnetosphere</span>: an update</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lemaire, J. F.</p> <p>2001-07-01</p> <p>First, Brice's (Journal of Geophysical Research 72 (1967) 5193) original theory for the formation of the plasmapause is recalled. Next, the motivation for writing a modification to this early theory is pointed out. The key aspects of Brice's manuscript are outlined and discussed. The mechanism of interchange driven by gravitational forces, centrifugal effects and kinetic pressure is considered in the cases when the integrated Pedersen conductivity is (i) negligibly small (as in Chandrasekhar's, Plasma Physics, University of Chicago Press, Chicago, 1960, 217 pp. and Longmire's, Elementary Plasma Physics, Wiley Interscience, New York, 1963, 296 pp., textbooks), (ii) infinitely large (as in many <span class="hlt">magnetospheric</span> convection models), or (iii) has a finite value of the order of 0.2 mho, as in the <span class="hlt">Earth</span>'s ionosphere. Updates of this theory of interchange resulting from the existence of weak double layers, from quasi-interchange, or from the effects of an additional population of energetic ring-current particles forming the extended tail of the velocity distribution function, have also been reexamined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090032013','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090032013"><span><span class="hlt">Magnetospheric</span> Multiscale Mission (MMS) Phase 2B Navigation Performance</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Scaperoth, Paige Thomas; Long, Anne; Carpenter, Russell</p> <p>2009-01-01</p> <p>The <span class="hlt">Magnetospheric</span> Multiscale (MMS) formation flying mission, which consists of four spacecraft flying in a tetrahedral formation, has challenging navigation requirements associated with determining and maintaining the relative separations required to meet the science requirements. The baseline navigation concept for MMS is for each spacecraft to independently estimate its position, velocity and clock states using GPS pseudorange data provided by the Goddard Space Flight Center-developed Navigator receiver and maneuver acceleration measurements provided by the spacecraft's attitude control subsystem. State estimation is performed onboard in real-time using the Goddard Enhanced Onboard Navigation System flight software, which is embedded in the Navigator receiver. The current concept of operations for formation maintenance consists of a sequence of two maintenance maneuvers that is performed every 2 weeks. Phase 2b of the MMS mission, in which the spacecraft are in 1.2 x 25 <span class="hlt">Earth</span> radii orbits with nominal separations at apogee ranging from 30 km to 400 km, has the most challenging navigation requirements because, during this phase, GPS signal acquisition is restricted to less than one day of the 2.8-day orbit. This paper summarizes the results from high-fidelity simulations to determine if the MMS navigation requirements can be met between and immediately following the maintenance maneuver sequence in Phase 2b.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EP%26S...64..451B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EP%26S...64..451B"><span>Possibility of <span class="hlt">magnetospheric</span> VLF response to atmospheric infrasonic waves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bespalov, P. A.; Savina, O. N.</p> <p>2012-06-01</p> <p>In this paper, we consider a model of the influence of atmospheric infrasonic waves on VLF <span class="hlt">magnetospheric</span> whistler wave excitation. This excitation occurs as a result of a succession of processes: a modulation of the plasma density by acoustic-gravity waves in the ionosphere, a reflection of the whistlers by ionosphere modulation, and a modification of whistler wave generation in the <span class="hlt">magnetospheric</span> resonator. A variation of the <span class="hlt">magnetospheric</span> resonator Q-factor has an influence on the operation of the plasma <span class="hlt">magnetospheric</span> maser, where the active substances are radiation belt particles, and the working modes are electromagnetic whistler waves. The <span class="hlt">magnetospheric</span> maser is an oscillating system which can be responsible for the excitation of self-oscillations. These self-oscillations are frequently characterized by alternating stages of accumulation and precipitation of energetic particles into the ionosphere during a pulse of whistler emissions. Numerical and analytical investigations of the response of self-oscillations to harmonic oscillations of the whistler reflection coefficient shows that even a small modulation rate can significantly change <span class="hlt">magnetospheric</span> VLF emissions. Our results can explain the causes of the modulation of energetic electron fluxes and whistler wave intensity with a time scale from 10 to 150 s in the day-side <span class="hlt">magnetosphere</span>. Such quasi-periodic VLF emissions are often observed in the sub-auroral and auroral <span class="hlt">magnetosphere</span> and have a noticeable effect on the formation of space weather phenomena.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930060116&hterms=kaufmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D40%26Ntt%3Dkaufmann','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930060116&hterms=kaufmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D40%26Ntt%3Dkaufmann"><span>Mapping and energization in the magnetotail. I - <span class="hlt">Magnetospheric</span> boundaries</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kaufmann, Richard L.; Larson, Douglas J.; Beidl, Paul; Lu, Chen</p> <p>1993-01-01</p> <p>The definition and mapping of the principal observed <span class="hlt">magnetospheric</span> boundaries between the ionospheric and the equatorial plane are considered. All field tracing is done using the Tsyganenko (1989) or T89 <span class="hlt">magnetospheric</span> model. Some of the model limitations are described. Particular attention is given to a search for signatures of the magnetotail subregions that may be observable by low- or middle-altitude satellites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017simi.conf.....G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017simi.conf.....G"><span>Ninth Workshop 'Solar Influences on the <span class="hlt">Magnetosphere</span>, Ionosphere and Atmosphere'</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Georgieva, Kayta; Kirov, Boian; Danov, Dimitar</p> <p>2017-08-01</p> <p>The 9th Workshop "Solar Influences on the <span class="hlt">Magnetosphere</span>, Ionosphere and Atmosphere" is an international forum for scientists working in the fields of: Sun and solar activity, Solar wind-<span class="hlt">magnetosphere</span>-ionosphere interactions, Solar influences on the lower atmosphere and climate, Solar effects in the biosphere, Instrumentation for space weather monitoring and Data processing and modelling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990028499','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990028499"><span>General Information: Chapman Conference on <span class="hlt">Magnetospheric</span> Current Systems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spicer, Daniel S.; Curtis, Steven</p> <p>1999-01-01</p> <p>The goal of this conference is to address recent achievements of observational, computational, theoretical, and modeling studies, and to foster communication among people working with different approaches. Electric current systems play an important role in the energetics of the <span class="hlt">magnetosphere</span>. This conference will target outstanding issues related to <span class="hlt">magnetospheric</span> current systems, placing its emphasis on interregional processes and driving mechanisms of current systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986SvPhU..29..946B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986SvPhU..29..946B"><span>REVIEWS OF TOPICAL PROBLEMS: Physics of pulsar <span class="hlt">magnetospheres</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beskin, Vasilii S.; Gurevich, Aleksandr V.; Istomin, Yakov N.</p> <p>1986-10-01</p> <p>A self-consistent model of the <span class="hlt">magnetosphere</span> of a pulsar is constructed. This model is based on a successive solution of the equations describing global properties of the <span class="hlt">magnetosphere</span> and on a comparison of the basic predictions of the developed theory and observational data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.1421K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.1421K"><span>Field and plasma periodicities in Saturn's equatorial middle <span class="hlt">magnetosphere</span>: Links between the asymmetric ring current and plasma circulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kivelson, Margaret; Southwood, David</p> <p></p> <p>Superimposed on the predominantly dipolar field of Saturn's middle <span class="hlt">magnetosphere</span> (here taken as between 5 and 10 RS) are perturbations of a few nT amplitude that vary with the SKR periodicity. Andrews and coworkers (2008) have determined that averages of the perturbations of the radial and azimuthal field components vary roughly sinusoidally and in quadrature, with the radial component leading. Thus these two components of the magnetic perturbations can be represented as an approximately uniform field rotating in the sense of Saturn's rotation (Espinosa et al., 2003). This perturbation field is referred to by Southwood and Kivelson (2007) as the cam field. Andrews et al. (2008) show that perturbation of the theta component, (theta is colatitude) is also nearly sinusoidal and in-phase with the radial perturbations. It follows that near the equator variations of the field magnitude are also in phase with the radial perturbations. Provan et al. (2009) and Khurana et al. (2009) have attributed the periodicity of the field magnitude to an asymmetric ring current. Saturn's asymmetric ring current is not fixed in local time,as it is at <span class="hlt">Earth</span>, but rotates quasi-rigidly at the SKR period. A distributed, rotating field-aligned current (FAC) system must develop between regions with an excess of or a dearth of azimuthal current but, because those FACs spread over a large spatial region, the associated current density will be smaller than the current density of the more localized cam current system. Thus, it is the electrons associated with the latter currents that are likely to drive the periodically modulated SKR signals. The ring current of the middle <span class="hlt">magnetosphere</span> is dominated by inertial currents carried by the thermal plasma (Sergis et al., 2010), but the variation of azimuthal current may arise either from density variations or variations of plasma beta. In either case, the current pattern must drive a circulation of the plasma in the middle <span class="hlt">magnetosphere</span>. [A circulating</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.9382C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.9382C"><span>Energetic heavy ion dominance in the outer <span class="hlt">magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cohen, Ian; Mitchell, Don; Mauk, Barry; Anderson, Brian; Ohtani, Shin; Kistler, Lynn; Hamilton, Doug; Turner, Drew; Blake, Bern; Fennell, Joe; Jaynes, Allison; Leonard, Trevor; Gerrard, Andy; Lanzerotti, Lou; Burch, Jim</p> <p>2017-04-01</p> <p>Despite the extensive study of ring current ion composition, little exists in the literature regarding the nature of energetic ions with energies >200 keV, especially in the outer <span class="hlt">magnetosphere</span> (r > 9 RE). In particular, information on the relative fluxes and spectral shapes of the different ion species over these energy ranges is lacking. However, new observations from the Energetic Ion Spectrometer (EIS) instruments on the <span class="hlt">Magnetospheric</span> Multiscale (MMS) spacecraft have revealed the dominance of heavy ion species (specifically oxygen and helium) at these energies in the outer <span class="hlt">magnetosphere</span>. This result is supported by prior but previously unreported observations obtained by the Geotail spacecraft, which also show that these heavy ion species are primarily dominated by multiply-charged populations from the solar wind. Using additional observations from the inner <span class="hlt">magnetosphere</span> obtained by the RBSPICE instrument on the Van Allen Probes suggest, we will investigate whether this effect is due to a preferential loss of protons in the outer <span class="hlt">magnetosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUSMIN31A..03M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUSMIN31A..03M"><span>Integrated Access to Heliospheric and <span class="hlt">Magnetospheric</span> Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Merka, J.; Szabo, A.; Narock, T. W.</p> <p>2007-05-01</p> <p>Heliospheric and <span class="hlt">magnetospheric</span> data are provided by a variety of diverse sources. For space physics scientists, knowing that such data sources exist and where they are located are only the first hurdles to overcome before they can utilize the data for research. As a solution, the NASA Heliophysics Division has established a group of virtual observatories (VOs) to provide the scientific community with integrated access to well documented data and related services. The VOs are organized by scientific discipline and yet their essential characteristic is cross-discipline data discovery and exchange. In this talk, we will demonstrate the architecture and features of two distributed data systems, the Virtual Heliospheric Observatory (VHO) and the Virtual <span class="hlt">Magnetospheric</span> Observatory at NASA Goddard Space Flight Center (VMO/G). The VHO and VMO/G are designed to share most of the components to facilitate faster development and to ease communication between the two VxOs. Since different communities are served by the two observatories, slightly, and sometimes even significantly, different terms and expectations must be accommodated and correctly processed. In our approach the interfaces are tuned for a particular community while the standard SPASE data model is employed internally. Together with other VxOs, we are also developing a standard query language for metadata exchange among the VxOs, data providers, and VxO-related services. Specific examples will be given. http:vho.nasa.gov</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20170003501&hterms=figueroa&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dfigueroa','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20170003501&hterms=figueroa&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dfigueroa"><span>Fast Plasma Investigation for <span class="hlt">Magnetospheric</span> Multiscale</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pollock, C.; Moore, T.; Coffey, V.; Dorelli J.; Giles, B.; Adrian, M.; Chandler, M.; Duncan, C.; Figueroa-Vinas, A.; Garcia, K.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20170003501'); toggleEditAbsImage('author_20170003501_show'); toggleEditAbsImage('author_20170003501_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20170003501_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20170003501_hide"></p> <p>2016-01-01</p> <p>The Fast Plasma Investigation (FPI) was developed for flight on the <span class="hlt">Magnetospheric</span> Multiscale (MMS) mission to measure the differential directional flux of <span class="hlt">magnetospheric</span> electrons and ions with unprecedented time resolution to resolve kinetic-scale plasma dynamics. This increased resolution has been accomplished by placing four dual 180-degree top hat spectrometers for electrons and four dual 180-degree top hat spectrometers for ions around the periphery of each of four MMS spacecraft. Using electrostatic field-of-view deflection, the eight spectrometers for each species together provide 4pi-sr-field-of-view with, at worst, 11.25-degree sample spacing. Energy/charge sampling is provided by swept electrostatic energy/charge selection over the range from 10 eVq to 30000 eVq. The eight dual spectrometers on each spacecraft are controlled and interrogated by a single block redundant Instrument Data Processing Unit, which in turn interfaces to the observatory's Instrument Suite Central Instrument Data processor. This paper described the design of FPI, its ground and in-flight calibration, its operational concept, and its data products.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AAS...211.2304M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AAS...211.2304M"><span>The Aurora, <span class="hlt">Magnetosphere</span>, and the IGY</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McKim Malville, J.</p> <p>2007-12-01</p> <p>This retrospective of auroral research during the IGY will be from the perspective of the auroral observers in the Antarctic from 1956-58. The IGY served as a watershed divide in our understanding of auroral physics. Prior to the IGY the role of "solar corpuscular radiation” in exciting auroral radiation was the pre-eminent research question. The mechanisms for the acceleration of solar protons and electrons had not been resolved, nor had the role of plasma instabilities been envisioned. The spectroscopic research program during the IGY was dominated by the work of Aden Meinel and Joseph W. Chamberlain at Yerkes Observatory. The dynamics of precipitating solar protons into a dilute gas was a major research focus. The changes brought about by the discoveries of the radiation belts, the solar wind, and the <span class="hlt">magnetosphere</span> resulted in a remarkable transformation and a paradigm shift in our understanding of the physics of the aurora. Antarctic observations during the IGY revealed the auroral oval, which is a signature of radiation belts distorted by the solar wind. High auroral rays could be explained by pitch angle distributions of trapped electrons. Sudden accelerations of electrons, resulting in red lower borders of aurora deep in the atmosphere, revealed the serious deficiencies of available theory. Whistlers, first detected in the Antarctic at Ellsworth Station in 1957, proved to be valuable probes of the <span class="hlt">magnetosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Icar..302..560P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Icar..302..560P"><span><span class="hlt">Magnetospheric</span> considerations for solar system ice state</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Paranicas, C.; Hibbitts, C. A.; Kollmann, P.; Ligier, N.; Hendrix, A. R.; Nordheim, T. A.; Roussos, E.; Krupp, N.; Blaney, D.; Cassidy, T. A.; Clark, G.</p> <p>2018-03-01</p> <p>The current lattice configuration of the water ice on the surfaces of the inner satellites of Jupiter and Saturn is likely shaped by many factors. But laboratory experiments have found that energetic proton irradiation can cause a transition in the structure of pure water ice from crystalline to amorphous. It is not known to what extent this process is competitive with other processes in solar system contexts. For example, surface regions that are rich in water ice may be too warm for this effect to be important, even if the energetic proton bombardment rate is very high. In this paper, we make predictions, based on particle flux levels and other considerations, about where in the <span class="hlt">magnetospheres</span> of Jupiter and Saturn the ∼MeV proton irradiation mechanism should be most relevant. Our results support the conclusions of Hansen and McCord (2004), who related relative level of radiation on the three outer Galilean satellites to the amorphous ice content within the top 1 mm of surface. We argue here that if <span class="hlt">magnetospheric</span> effects are considered more carefully, the correlation is even more compelling. Crystalline ice is by far the dominant ice state detected on the inner Saturnian satellites and, as we show here, the flux of bombarding energetic protons onto these bodies is much smaller than at the inner Jovian satellites. Therefore, the ice on the Saturnian satellites also corroborates the correlation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFMSM23A0284C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFMSM23A0284C"><span>Charged Particle Periodicities in Saturn's Outer <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carbary, J.; Mitchell, D.; Krimigis, S.; Krupp, N.</p> <p>2006-12-01</p> <p>The MIMI/LEMMS instrument on the Cassini spacecraft has measured energetic electrons in the energy range 20-300 keV within Saturn's <span class="hlt">magnetosphere</span>. In the outer <span class="hlt">magnetosphere</span> beyond about 20 RS, these electrons and their spectral index display strong variations with periods comparable to the 10.76 hour period measured by radio observations of Cassini. Inside about 20 RS, such electron variations may be present but are masked by satellite and ring effects. Electron periodicities are most easily recognized on the "night side" segments of the Cassini orbits, although they are also observed to some extent on the day side. For both day and night sides, a wavelet analysis of de-trended count rates in the 20-40 RS region reveals a mean period of 10.52 +/- 0.74 hrs for the six electron channels investigated. If constrained to the night side only, a wavelet analysis gives a mean period of 10.88 +/- 0.52 hours. These periods were obtained from several orbits of the Cassini spacecraft during the two-year period from SOI (July 2004) to the present (November 2006).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110005665','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110005665"><span>Modeling of the Convection and Interaction of Ring Current, Plasmaspheric and Plasma Sheet Plasmas in the Inner <span class="hlt">Magnetosphere</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fok, Mei-Ching; Chen, Sheng-Hsien; Buzulukova, Natalia; Glocer, Alex</p> <p>2010-01-01</p> <p>Distinctive sources of ions reside in the plasmasphere, plasmasheet, and ring current regions at discrete energies constitute the major plasma populations in the inner/middle <span class="hlt">magnetosphere</span>. They contribute to the electrodynamics of the ionosphere-<span class="hlt">magnetosphere</span> system as important carriers of the global current system, in triggering; geomagnetic storm and substorms, as well as critical components of plasma instabilities such as reconnection and Kelvin-Helmholtz instability at the <span class="hlt">magnetospheric</span> boundaries. Our preliminary analysis of in-situ measurements shoves the complexity of the plasmas pitch angle distributions at particularly the cold and warm plasmas, vary dramatically at different local times and radial distances from the <span class="hlt">Earth</span> in response to changes in solar wind condition and Dst index. Using an MHD-ring current coupled code, we model the convection and interaction of cold, warm and energetic ions of plasmaspheric, plasmasheet, and ring current origins in the inner <span class="hlt">magnetosphere</span>. We compare our simulation results with in-situ and remotely sensed measurements from recent instrumentation on Geotail, Cluster, THEMIS, and TWINS spacecraft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1212463-spatial-structure-temporal-evolution-energetic-particle-injections-inner-magnetosphere-during-july-substorm-event','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1212463-spatial-structure-temporal-evolution-energetic-particle-injections-inner-magnetosphere-during-july-substorm-event"><span>Spatial structure and temporal evolution of energetic particle injections in the inner <span class="hlt">magnetosphere</span> during the 14 July 2013 substorm event</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Gkioulidou, Matina; Ohtani, S.; Mitchell, D. G.; ...</p> <p>2015-03-20</p> <p>Recent results by the Van Allen Probes mission showed that the occurrence of energetic ion injections inside geosynchronous orbit could be very frequent throughout the main phase of a geomagnetic storm. Understanding, therefore, the formation and evolution of energetic particle injections is critical in order to quantify their effect in the inner <span class="hlt">magnetosphere</span>. We present a case study of a substorm event that occurred during a weak storm (Dst ~ –40 nT) on 14 July 2013. Van Allen Probe B, inside geosynchronous orbit, observed two energetic proton injections within 10 min, with different dipolarization signatures and duration. The first onemore » is a dispersionless, short-timescale injection pulse accompanied by a sharp dipolarization signature, while the second one is a dispersed, longer-timescale injection pulse accompanied by a gradual dipolarization signature. We combined ground magnetometer data from various stations and in situ particle and magnetic field data from multiple satellites in the inner <span class="hlt">magnetosphere</span> and near-<span class="hlt">Earth</span> plasma sheet to determine the spatial extent of these injections, their temporal evolution, and their effects in the inner <span class="hlt">magnetosphere</span>. Our results indicate that there are different spatial and temporal scales at which injections can occur in the inner <span class="hlt">magnetosphere</span> and depict the necessity of multipoint observations of both particle and magnetic field data in order to determine these scales.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100017492','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100017492"><span>GPS Navigation for the <span class="hlt">Magnetospheric</span> Multi-Scale Mission</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bamford, William; Mitchell, Jason; Southward, Michael; Baldwin, Philip; Winternitz, Luke; Heckler, Gregory; Kurichh, Rishi; Sirotzky, Steve</p> <p>2009-01-01</p> <p>In 2014. NASA is scheduled to launch the <span class="hlt">Magnetospheric</span> Multiscale Mission (MMS), a four-satellite formation designed to monitor fluctuations in the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>. This mission has two planned phases with different orbits (1? x 12Re and 1.2 x 25Re) to allow for varying science regions of interest. To minimize ground resources and to mitigate the probability of collisions between formation members, an on-board orbit determination system consisting of a Global Positioning System (GPS) receiver and crosslink transceiver was desired. Candidate sensors would be required to acquire GPS signals both below and above the constellation while spinning at three revolutions-per-minute (RPM) and exchanging state and science information among the constellation. The Intersatellite Ranging and Alarm System (IRAS), developed by Goddard Space Flight Center (GSFC) was selected to meet this challenge. IRAS leverages the eight years of development GSFC has invested in the Navigator GPS receiver and its spacecraft communication expertise, culminating in a sensor capable of absolute and relative navigation as well as intersatellite communication. The Navigator is a state-of-the-art receiver designed to acquire and track weak GPS signals down to -147dBm. This innovation allows the receiver to track both the main lobe and the much weaker side lobe signals. The Navigator's four antenna inputs and 24 tracking channels, together with customized hardware and software, allow it to seamlessly maintain visibility while rotating. Additionally, an extended Kalman filter provides autonomous, near real-time, absolute state and time estimates. The Navigator made its maiden voyage on the Space Shuttle during the Hubble Servicing Mission, and is scheduled to fly on MMS as well as the Global Precipitation Measurement Mission (GPM). Additionally, Navigator's acquisition engine will be featured in the receiver being developed for the Orion vehicle. The crosslink transceiver is a 1/4 Watt transmitter</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFMSM11A..04H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFMSM11A..04H"><span>CISM: Modeling the Sun-<span class="hlt">Earth</span> Connection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hughes, W. J.; Team, T. C.</p> <p>2003-12-01</p> <p>The Center for Integrated SpaceWeather Modeling (CISM), an NSF Science and Technology Center that is a consortium of ten institutions headed by Boston University, has as its primary goal the development of a series of ever improving versions of a comprehensive physics-based simulation model that describes the space environment from the Sun to the <span class="hlt">Earth</span>. CISM will do this by coupling existing models of components of the system. In this paper we review our progress to date and summarize our plans. We discuss results of initial coupling of MHD models of the corona and solar wind, and of a global <span class="hlt">magnetospheric</span> MHD model with a global ionosphere/thermosphere model, a radiation belt model, and a ring current particle model. Coupling the SAIC coronal MHD model and the U Colorado/SEC solar wind MHD codes allows us to track CMEs from the base of the corona to 1 AU. The results show how shocks form and develop in the heliosphere, and how the CME flattens into a pancake shape by the time it reaches <span class="hlt">earth</span>. Coupling the Lyon/Fedder/Mobarry global MHD model with the Rice Convection Model and the NCAR TIE-GCM/TING model allows full dynamic coupling between the <span class="hlt">magnetosphere</span>, the ionosphere/thermosphere, and the hot plasma in the inner <span class="hlt">magnetosphere</span>. Including the Dartmouth radiation belt model shows how the radiation belts evolve in a realistic <span class="hlt">magnetosphere</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010066718','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010066718"><span>The <span class="hlt">Magnetospheric</span> Constellation Mission. Dynamic Response and Coupling Observatory (DRACO): Understanding the Global Dynamics of the Structured Magnetotail</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2001-01-01</p> <p><span class="hlt">Magnetospheric</span> Constellation Dynamic Response and Coupling Observatory (DRACO) is the Solar Terrestrial Probe (STP) designed to understand the nonlinear dynamics, responses, and connections within the <span class="hlt">Earth</span>'s structured magnetotail, using a constellation of approximately 50 to 100 distributed vector measurement spacecraft. DRACO will reveal magnetotail processes operating within a domain extending 20 <span class="hlt">Earth</span> radii (R(sub E)) across the tail and 40 R(sub E)down the tail, on spatial and time scales accessible to global circulation models, i.e., approximately 2 R(sub E) and 10 seconds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMSM44A..03E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMSM44A..03E"><span>Cluster and THEMIS observations of the <span class="hlt">magnetosphere</span> dayside boundaries in preparation for the SMILE mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Escoubet, C. P.; Dimmock, A. P.; Walsh, B.; Sibeck, D. G.; Berchem, J.; Nykyri, K.; Turc, L.; Read, A.; Branduardi-Raymont, G.; Wang, C.; Sembay, S.; Kuntz, K. D.; Dai, L.; Li, L.; Donovan, E.; Spanswick, E.; Laakso, H. E.; Zheng, J.; Rebuffat, D.</p> <p>2016-12-01</p> <p>Solar wind <span class="hlt">Magnetosphere</span> Ionosphere Link Explorer (SMILE) is a novel self-standing mission, in collaboration between ESA and Chinese Academy of Science. Its objective is to observe the solar wind-<span class="hlt">magnetosphere</span> coupling via simultaneous in situ solar wind/magnetosheath plasma and magnetic field measurements, soft X-Ray images of the magnetosheath and polar cusps, and UV images of global auroral distributions. The observations of the cusps and magnetosheath with the X-ray imager are possible through the relatively recent discovery of solar wind charge exchange (SWCX) X-ray emission, first observed at comets, and subsequently found to occur in the vicinity of the <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span>. In preparation for the mission, we need to determine the cusp's morphology, motion and in situ properties (density, velocity, temperature) that are expected to be observed by the spacecraft. To do so, we have selected a series of cusp crossings by the Cluster spacecraft that can be used to simulate X-ray emissions across the width of the cusp for different IMF orientations. In view of the well-known cusp ion dispersions, we expect that X ray emissions peak near the equatorial boundary of the cusp for southward IMF Bz, but near the poleward boundary of the cusp for northward IMF Bz. We also employ Cluster cusp observations during storms to predict X-ray emissions to be expected for periods of high solar wind fluxes. In addition, we use THEMIS observations from January 2008 to July 2015 for moderate (nsw*vsw < 4.9x10^8 /cm^2s) and high (nsw*vsw > 4.9x10^8 /cm^2s) solar wind fluxes to investigate X-rays emitted by the magnetosheath and to determine their variation as a function of distance from the subsolar point along the Sun-<span class="hlt">Earth</span> line and along the flanks of the <span class="hlt">magnetosphere</span>. We will show that high solar wind fluxes greatly enhance soft X-ray emissions, not only because solar wind fluxes increases but also because the emission region moves deeper within the <span class="hlt">Earth</span>'s exosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996ESASP.392..277W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996ESASP.392..277W"><span>A Study of the Solar Wind-<span class="hlt">Magnetosphere</span> Coupling Using Neural Networks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Jian-Guo; Lundstedt, Henrik</p> <p>1996-12-01</p> <p>The interaction between solar wind plasma and interplanetary magnetic field (IMF) and <span class="hlt">Earth</span>'s <span class="hlt">magnetosphere</span> induces geomagnetic activity. Geomagnetic storms can cause many adverse effects on technical systems in space and on the <span class="hlt">Earth</span>. It is therefore of great significance to accurately predict geomagnetic activity so as to minimize the amount of disruption to these operational systems and to allow them to work as efficiently as possible. Dynamic neural networks are powerful in modeling the dynamics encoded in time series of data. In this study, we use partially recurrent neural networks to study the solar wind-<span class="hlt">magnetosphere</span> coupling by predicting geomagnetic storms (as measured by the Dstindex) from solar wind measurements. The solar wind, the IMF and the geomagnetic index Dst data are hourly averaged and read from the National Space Science Data Center's OMNI database. We selected these data from the period 1963 to 1992, which cover 10552h and contain storm time periods 9552h and quiet time periods 1000h. The data are then categorized into three data sets: a training set (6634h), across-validation set (1962h), and a test set (1956h). The validation set is used to determine where the training should be stopped whereas the test set is used for neural networks to get the generalization capability (the out-of-sample performance). Based on the correlation analysis between the Dst index and various solar wind parameters (including various combinations of solar wind parameters), the best coupling functions can be found from the out-of-sample performance of trained neural networks. The coupling functions found are then used to forecast geomagnetic storms one to several hours in advance. The comparisons are made on iterating the single-step prediction several times and on making a non iterated, direct prediction. Thus, we will present the best solar wind-<span class="hlt">magnetosphere</span> coupling functions and the corresponding prediction results. Interesting Links: Lund Space Weather and AI</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhDT........35P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhDT........35P"><span>Hemispheric Asymmetries of <span class="hlt">Magnetosphere</span>-Ionosphere-Thermosphere Dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p>