Quenching of dynamic nuclear polarization by spin-orbit coupling in GaAs quantum dots.

PubMed

Nichol, John M; Harvey, Shannon P; Shulman, Michael D; Pal, Arijeet; Umansky, Vladimir; Rashba, Emmanuel I; Halperin, Bertrand I; Yacoby, Amir

2015-07-17

The central-spin problem is a widely studied model of quantum decoherence. Dynamic nuclear polarization occurs in central-spin systems when electronic angular momentum is transferred to nuclear spins and is exploited in quantum information processing for coherent spin manipulation. However, the mechanisms limiting this process remain only partially understood. Here we show that spin-orbit coupling can quench dynamic nuclear polarization in a GaAs quantum dot, because spin conservation is violated in the electron-nuclear system, despite weak spin-orbit coupling in GaAs. Using Landau-Zener sweeps to measure static and dynamic properties of the electron spin-flip probability, we observe that the size of the spin-orbit and hyperfine interactions depends on the magnitude and direction of applied magnetic field. We find that dynamic nuclear polarization is quenched when the spin-orbit contribution exceeds the hyperfine, in agreement with a theoretical model. Our results shed light on the surprisingly strong effect of spin-orbit coupling in central-spin systems.

Development of a surface isolation estimation technique suitable for application of polar orbiting satellite data

NASA Technical Reports Server (NTRS)

Davis, P. A.; Penn, L. M. (Principal Investigator)

1981-01-01

A technique is developed for the estimation of total daily insolation on the basis of data derivable from operational polar-orbiting satellites. Although surface insolation and meteorological observations are used in the development, the algorithm is constrained in application by the infrequent daytime polar-orbiter coverage.

Suomi National Polar-Orbiting Partnership Visible Infrared Imaging Radiometer Suite Polarization Sensitivity Analysis

NASA Technical Reports Server (NTRS)

Sun, Junqiang; Xiong, Xiaoxiong; Waluschka, Eugene; Wang, Menghua

2016-01-01

The Visible Infrared Imaging Radiometer Suite (VIIRS) is one of five instruments onboard the Suomi National Polar-Orbiting Partnership (SNPP) satellite that launched from Vandenberg Air Force Base, California, on October 28, 2011. It is a whiskbroom radiometer that provides +/-56.28deg scans of the Earth view. It has 22 bands, among which 14 are reflective solar bands (RSBs). The RSBs cover a wavelength range from 410 to 2250 nm. The RSBs of a remote sensor are usually sensitive to the polarization of incident light. For VIIRS, it is specified that the polarization factor should be smaller than 3% for 410 and 862 nm bands and 2.5% for other RSBs for the scan angle within +/-45deg. Several polarization sensitivity tests were performed prelaunch for SNPP VIIRS. The first few tests either had large uncertainty or were less reliable, while the last one was believed to provide the more accurate information about the polarization property of the instrument. In this paper, the measured data in the last polarization sensitivity test are analyzed, and the polarization factors and phase angles are derived from the measurements for all the RSBs. The derived polarization factors and phase angles are band, detector, and scan angle dependent. For near-infrared bands, they also depend on the half-angle mirror side. Nevertheless, the derived polarization factors are all within the specification, although the strong detector dependence of the polarization parameters was not expected. Compared to the Moderate Resolution Imaging Spectroradiometer on both Aqua and Terra satellites, the polarization effect on VIIRS RSB is much smaller.

Solar Polar ORbit Telescope (SPORT): A Potential Space Weather Mission of China

NASA Astrophysics Data System (ADS)

Liu, Y. D.; Xiong, M.; Wu, J.; Liu, H.; Zheng, J.; Li, B.; Zhang, C.; Sun, W.

2013-12-01

We describe a spacecraft mission, named Solar Polar ORbit Telescope (SPORT), which is currently under a scientific and engineering background study in China. SPORT was originally proposed in 2004 by the National Space Science Center, Chinese Academy of Sciences. It will carry a suite of remote-sensing and in-situ instruments to observe coronal mass ejections (CMEs), solar high-latitude magnetism, and the fast solar wind from a polar orbit around the Sun. It is intended to be the first mission that carries remote-sensing instruments from a high-latitude orbit around the Sun, the first mission that could image interplanetary CMEs at radio wavelengths from space, and the first mission that could measure solar high-latitude magnetism leading to eruptions and the fast solar wind. The first extended view of the polar region of the Sun and the ecliptic plane enabled by SPORT will provide a unique opportunity to study CME propagation through the inner heliosphere and solar high-latitude magnetism giving rise to eruptions and the fast solar wind.

Plan for Space Station Polar-Orbiting Platform.

DTIC Science & Technology

1985-06-01

will be accomplished through use of an Orbital Maneuvering Vehicle (OMV). Transpor- tation from the STS up to the polar platform may be accom- plished...condition of the Earth’s vegetation. Fishing fleets use the data to determine areas having a greater likelihood for a sizable catch . Maritime shippers use...rack .e. th SOtenoy thel potentall ieimtg mecanisms for mt sS/Tc- Scltass wofl senoristh folg mehnicall oving mirrfor thatd prdceThe ln-escn

3-D Imaging of Mars’ Polar Ice Caps Using Orbital Radar Data

PubMed Central

Foss, Frederick J.; Putzig, Nathaniel E.; Campbell, Bruce A.; Phillips, Roger J.

2018-01-01

Since its arrival in early 2006, various instruments aboard NASA’s Mars Reconnaissance Orbiter (MRO) have been collecting a variety of scientific and engineering data from orbit around Mars. Among these is the SHAllow RADar (SHARAD) instrument, supplied by Agenzia Spaziale Italiana (ASI) and designed for subsurface sounding in the 15–25 MHz frequency band. As of this writing, MRO has completed over 46,000 nearly polar orbits of Mars, 30% of which have included active SHARAD data collection. By 2009, a sufficient density of SHARAD coverage had been obtained over the polar regions to support 3-D processing and analysis of the data. Using tools and techniques commonly employed in terrestrial seismic data processing, we have processed subsets of the resulting collection of SHARAD observations covering the north and south polar regions as SHARAD 3-D volumes, imaging the interiors of the north and south polar ice caps known, respectively, as Planum Boreum and Planum Australe. After overcoming a series of challenges revealed during the 3-D processing and analysis, a completed Planum Boreum 3-D volume is currently being used for scientific research. Lessons learned in the northern work fed forward into our 3-D processing and analysis of the Planum Australe 3-D volume, currently under way. We discuss our experiences with these projects and present results and scientific insights stemming from these efforts. PMID:29400351

IC 5181: An S0 Galaxy with Ionized Gas on Polar Orbits

NASA Astrophysics Data System (ADS)

Pizzella, A.; Morelli, L.; Corsini, E. M.; Dalla Bontá, E.; Cesetti, M.

2014-05-01

The nearby S0 galaxy IC 5181 is studied to address the origin of the ionized gas component that orbits the galaxy on polar orbit. We perform detailed photometric and spectroscopic observations measuring the surface brightness distribution of the stars (I band), ionized gas of IC 5181 (Hα narrow band), the ionized-gas and stellar kinematics along both the major and minor axis, and the corresponding line strengths of the Lick indices. We conclude that the galaxy hosts a geometrically and kinematically decoupled component of ionized gas. It is elongated along the galaxy minor axis and in orthogonal rotation with respect to the galaxy disk. The result is suggesting that the gas component is not related to the stars having an external origin. The gas was accreted by IC 5181 on polar orbits from the surrounding environment.

Imaging interplanetary CMEs at radio frequency from solar polar orbit

NASA Astrophysics Data System (ADS)

Wu, Ji; Sun, Weiying; Zheng, Jianhua; Zhang, Cheng; Liu, Hao; Yan, Jingye; Wang, Chi; Wang, Chuanbing; Wang, Shui

2011-09-01

Coronal mass ejections (CMEs) represent a great concentration of mass and energy input into the lower corona. They have come to be recognized as the major driver of physical conditions change in the Sun-Earth system. Consequently, observations of CMEs are important for understanding and ultimately predicting space weather conditions. This paper discusses a proposed mission, the Solar Polar Orbit Radio Telescope (SPORT) mission, which will observe the propagation of interplanetary CMEs to distances of near 0.35 AU from the Sun. The orbit of SPORT is an elliptical solar polar orbit. The inclination angle between the orbit and ecliptic plane should be about 90°. The main payload on board SPORT will be an imaging radiometer working at the meter wavelength band (radio telescope), which can follow the propagation of interplanetary CMEs. The images that are obtained by the radio telescope embody the brightness temperature of the objectives. Due to the very large size required for the antenna aperture of the radio telescope, we adopt interferometric imaging technology to reduce it. Interferometric imaging technology is based on indirect spatial frequency domain measurements plus Fourier transformation. The SPORT spacecraft will also be equipped with a set of optical and in situ measurement instruments such as a EUV solar telescope, a solar wind ion instrument, an energetic particle detector, a magnetometer, a wave detector and a solar radio burst spectrometer.

Requirements and capabilities for planetary missions. Volume 2: Mars polar orbiter penetrator 1981

NASA Technical Reports Server (NTRS)

Ball, G. G.; Bird, T. H.

1976-01-01

The Mars Polar Orbiter/Penetrator 1981 mission, intended to investigate the manner in which Mars has evolved, and which surveys its geochemistry, performs climatological investigations, and attempts to determine the planet's gravitational field, was described. The spacecraft, modified from the Viking Orbiter design, carries a new remote-sensing payload and six penetrators. The penetrators are released from a 2.46-h, 1000-km sun synchronous circular orbit and interrogated daily throughout the 2-year orbital mission. X-band telemetry is used to increase data return.

The Lyman-alpha Imager onboard Solar Polar Orbit Telescope

NASA Astrophysics Data System (ADS)

Li, Baoquan; Li, Haitao; Zhou, Sizhong; Jiang, Bo

2013-12-01

Solar Polar ORbit Telescope (SPORT) was originally proposed in 2004 by the National Space Science Center, Chinese Academy of Sciences, which is currently being under background engineering study phase in China. SPORT will carry a suite of remote-sensing and in-situ instruments to observe coronal mass ejections (CMEs), solar high-latitude magnetism, and the fast solar wind from a polar orbit around the Sun. The Lyman-alpha Imager (LMI) is one of the key remotesensing instruments onboard SPORT with 45arcmin FOV, 2000mm effective focal length and 1.4arcsec/pixel spatial resolution . The size of LMI is φ150×1000mm, and the weight is less than10kg, including the 7kg telescope tube and 3kg electronic box. There are three 121.6nm filters used in the LMI optical path, so the 98% spectral purity image of 121.6nm can be achieved. The 121.6nm solar Lyman-alpha line is produced in the chromosphere and very sensitive to plasma temperature, plasma velocity and magnetism variation in the chromosphere. Solar Lyman-alpha disk image is an ideal tracker for corona magnetism variation.

Spin-orbit torque induced magnetic vortex polarity reversal utilizing spin-Hall effect

NASA Astrophysics Data System (ADS)

Li, Cheng; Cai, Li; Liu, Baojun; Yang, Xiaokuo; Cui, Huanqing; Wang, Sen; Wei, Bo

2018-05-01

We propose an effective magnetic vortex polarity reversal scheme that makes use of spin-orbit torque introduced by spin-Hall effect in heavy-metal/ferromagnet multilayers structure, which can result in subnanosecond polarity reversal without endangering the structural stability. Micromagnetic simulations are performed to investigate the spin-Hall effect driven dynamics evolution of magnetic vortex. The mechanism of magnetic vortex polarity reversal is uncovered by a quantitative analysis of exchange energy density, magnetostatic energy density, and their total energy density. The simulation results indicate that the magnetic vortex polarity is reversed through the nucleation-annihilation process of topological vortex-antivortex pair. This scheme is an attractive option for ultra-fast magnetic vortex polarity reversal, which can be used as the guidelines for the choice of polarity reversal scheme in vortex-based random access memory.

Lifetime test and heritage on orbit of coolers for space use

NASA Astrophysics Data System (ADS)

Narasaki, Katsuhiro; Tsunematsu, Shoji; Ootsuka, Kiyomi; Kanao, Kenichi; Okabayashi, Akinobu; Mitsuda, Kazuhisa; Murakami, Hiroshi; Nakagawa, Takao; Kikuchi, Kenichi; Sato, Ryota; Sugita, Hiroyuki; Sato, Youichi; Murakami, Masahide; Kobayashi, Masanori

2012-04-01

This report describes the results and operating status of ground lifetime testing and achievements on orbit of coolers for space use. Ground lifetime tests of coolers of three types were conducted to demonstrate their long life and reliability. Three single-stage Stirling coolers were tested for 89,016, 71,871 and 68,273 h from 1998, a two-stage Stirling cooler was tested for 72,906 h, and a 4-K class cooler with a two-stage Stirling cooler and a Joule-Thomson cooler was tested for over 2.5 years. After lifetime tests were completed, a few coolers were investigated to determine the cause of the cooling performance degradation. Additionally, the filled gas of the coolers was analyzed. These coolers have shown good results on orbit. Three single-stage Stirling coolers were carried on the X-ray astronomical satellite "SUZAKU" (launched in July 2005), Japanese lunar polar orbiter "KAGUYA" (launched in September 2007), and the Japanese Venus Climate Orbiter "AKATSUKI" (launched in June 2010). Two units of a two-stage Stirling cooler were carried on the infrared astronomical satellite "AKARI" launched in February 2006. A 4-K class cooler was carried on the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) aboard the Japanese Experiment Module (JEM) of the International Space Station (ISS). SMILES was launched in September 2009.

New Operational Algorithms for Particle Data from Low-Altitude Polar-Orbiting Satellites

NASA Astrophysics Data System (ADS)

Machol, J. L.; Green, J. C.; Rodriguez, J. V.; Onsager, T. G.; Denig, W. F.

2010-12-01

As part of the algorithm development effort started under the former National Polar-orbiting Operational Environmental Satellite System (NPOESS) program, the NOAA Space Weather Prediction Center (SWPC) is developing operational algorithms for the next generation of low-altitude polar-orbiting weather satellites. This presentation reviews the two new algorithms on which SWPC has focused: Energetic Ions (EI) and Auroral Energy Deposition (AED). Both algorithms take advantage of the improved performance of the Space Environment Monitor - Next (SEM-N) sensors over earlier SEM instruments flown on NOAA Polar Orbiting Environmental Satellites (POES). The EI algorithm iterates a piecewise power law fit in order to derive a differential energy flux spectrum for protons with energies from 10-250 MeV. The algorithm provides the data in physical units (MeV/cm2-s-str-keV) instead of just counts/s as was done in the past, making the data generally more useful and easier to integrate into higher level products. The AED algorithm estimates the energy flux deposited into the atmosphere by precipitating low- and medium-energy charged particles. The AED calculations include particle pitch-angle distributions, information that was not available from POES. This presentation also describes methods that we are evaluating for creating higher level products that would specify the global particle environment based on real time measurements.

Neptune Polar Orbiter with Probes

NASA Technical Reports Server (NTRS)

Bienstock, Bernard; Atkinson, David; Baines, Kevin; Mahaffy, Paul; Steffes, Paul; Atreya, Sushil; Stern, Alan; Wright, Michael; Willenberg, Harvey; Smith, David;

Medical Implications of Space Radiation Exposure Due to Low-Altitude Polar Orbits.

PubMed

Chancellor, Jeffery C; Auñon-Chancellor, Serena M; Charles, John

2018-01-01

Space radiation research has progressed rapidly in recent years, but there remain large uncertainties in predicting and extrapolating biological responses to humans. Exposure to cosmic radiation and solar particle events (SPEs) may pose a critical health risk to future spaceflight crews and can have a serious impact on all biomedical aspects of space exploration. The relatively minimal shielding of the cancelled 1960s Manned Orbiting Laboratory (MOL) program's space vehicle and the high inclination polar orbits would have left the crew susceptible to high exposures of cosmic radiation and high dose-rate SPEs that are mostly unpredictable in frequency and intensity. In this study, we have modeled the nominal and off-nominal radiation environment that a MOL-like spacecraft vehicle would be exposed to during a 30-d mission using high performance, multicore computers. Projected doses from a historically large SPE (e.g., the August 1972 solar event) have been analyzed in the context of the MOL orbit profile, providing an opportunity to study its impact to crew health and subsequent contingencies. It is reasonable to presume that future commercial, government, and military spaceflight missions in low-Earth orbit (LEO) will have vehicles with similar shielding and orbital profiles. Studying the impact of cosmic radiation to the mission's operational integrity and the health of MOL crewmembers provides an excellent surrogate and case-study for future commercial and military spaceflight missions.Chancellor JC, Auñon-Chancellor SM, Charles J. Medical implications of space radiation exposure due to low-altitude polar orbits. Aerosp Med Hum Perform. 2018; 89(1):3-8.

Polarization-insensitive PAM-4-carrying free-space orbital angular momentum (OAM) communications.

PubMed

Liu, Jun; Wang, Jian

2016-02-22

We present a simple configuration incorporating single polarization-sensitive phase-only liquid crystal spatial light modulator (SLM) to facilitate polarization-insensitive free-space optical communications employing orbital angular momentum (OAM) modes. We experimentally demonstrate several polarization-insensitive optical communication subsystems by propagating a single OAM mode, multicasting 4 and 10 OAM modes, and multiplexing 8 OAM modes, respectively. Free-space polarization-insensitive optical communication links using OAM modes that carry four-level pulse-amplitude modulation (PAM-4) signal are demonstrated in the experiment. The observed optical signal-to-noise ratio (OSNR) penalties are less than 1 dB in both polarization-insensitive N-fold OAM modes multicasting and multiple OAM modes multiplexing at a bit-error rate (BER) of 2e-3 (enhanced forward-error correction (EFEC) threshold).

Asynchronous polar V1500 Cyg: orbital, spin and beat periods

NASA Astrophysics Data System (ADS)

Pavlenko, E. P.; Mason, P. A.; Sosnovskij, A. A.; Shugarov, S. Yu; Babina, Ju V.; Antonyuk, K. A.; Andreev, M. V.; Pit, N. V.; Antonyuk, O. I.; Baklanov, A. V.

2018-06-01

The bright Nova Cygni 1975 is a rare nova on a magnetic white dwarf (WD). Later it was found to be an asynchronous polar, now called V1500 Cyg. Our multisite photometric campaign occurring 40 years post eruption covered 26-nights (2015-2017). The reflection effect from the heated donor has decreased, but still dominates the optical radiation with an amplitude ˜1m.5. The 0m.3 residual reveals cyclotron emission and ellipsoidal variations. Mean brightness modulation from night-to-night is used to measure the 9.6-d spin-orbit beat period that is due to changing accretion geometry including magnetic pole-switching of the flow. By subtracting the orbital and beat frequencies, spin-phase dependent light curves are obtained. The amplitude and profile of the WD spin light curves track the cyclotron emitting accretion regions on the WD and they vary systematically with beat phase. A weak intermittent signal at 0.137613-d is likely the spin period, which is 1.73(1) min shorter than the orbital period. The O-C diagram of light curve maxima displays phase jumps every one-half beat period, a characteristic of asynchronous polars. The first jump we interpret as pole switching between regions separated by 180°. Then the spot drifts during ˜ 0.1 beat phase before undergoing a second phase jump between spots separated by less than 180°. We trace the cooling of the still hot WD as revealed by the irradiated companion. The post nova evolution and spin-orbit asynchronism of V1500 Cyg continues to be a powerful laboratory for accretion flows onto magnetic white dwarfs.

Joint Polar Satellite System (JPSS) Micrometeoroid and Orbital Debris (MMOD) Assessment

NASA Technical Reports Server (NTRS)

Squire, Michael D.; Cooke, William J.; Williamsen, Joel; Kessler, Donald; Vesely, William E.; Hull, Scott H.; Schonberg, William; Peterson, Glenn E.; Jenkin, Alan B.; Cornford, Steven L.

2015-01-01

The Joint Polar Satellite System (JPSS) Project requested the NASA Engineering and Safety Center (NESC) conduct an independent evaluation of the Micrometeoroid and Orbital Debris (MMOD) models used in the latest JPSS MMOD risk assessment. The principal focus of the assessment was to compare Orbital Debris Engineering Model version 3 (ORDEM 3.0) with the Meteoroid and Space Debris Terrestrial Environment Reference version 2009 (MASTER-2009) and Aerospace Debris Environment Projection Tool (ADEPT) and provide recommendations to the JPSS Project regarding MMOD protection. The outcome of the NESC assessment is contained in this report.

Polar Dunes Resolved by the Mars Orbiter Laser Altimeter Gridded Topography and Pulse Widths

NASA Technical Reports Server (NTRS)

Neumann, Gregory A.

2003-01-01

The Mars Orbiter Laser Altimeter (MOLA) polar data have been refined to the extent that many features poorly imaged by Viking Orbiters are now resolved in densely gridded altimetry. Individual linear polar dunes with spacings of 0.5 km or more can be seen as well as sparsely distributed and partially mantled dunes. The refined altimetry will enable measurements of the extent and possibly volume of the north polar ergs. MOLA pulse widths have been recalibrated using inflight data, and a robust algorithm applied to solve for the surface optical impulse response. It shows the surface root-mean-square (RMS) roughness at the 75-m-diameter MOLA footprint scale, together with a geological map. While the roughness is of vital interest for landing site safety studies, a variety of geomorphological studies may also be performed. Pulse widths corrected for regional slope clearly delineate the extent of the polar dunes. The MOLA PEDR profile data have now been re-released in their entirety (Version L). The final Mission Experiment Gridded Data Records (MEGDR's) are now provided at up to 128 pixels per degree globally. Densities as high as 512 pixels per degree are available in a polar stereographic projection. A large computational effort has been expended in improving the accuracy of the MOLA altimetry themselves, both in improved orbital modeling and in after-the-fact adjustment of tracks to improve their registration at crossovers. The current release adopts the IAU2000 rotation model and cartographic frame recommended by the Mars Cartography Working Group. Adoption of the current standard will allow registration of images and profiles globally with an uncertainty of less than 100 m. The MOLA detector is still operational and is currently collecting radiometric data at 1064 nm. Seasonal images of the reflectivity of the polar caps can be generated with a resolution of about 300 m per pixel.

Polarized iridescence of the multilayered elytra of the Japanese jewel beetle, Chrysochroa fulgidissima

PubMed Central

Stavenga, Doekele G.; Wilts, Bodo D.; Leertouwer, Hein L.; Hariyama, Takahiko

2011-01-01

The elytra of the Japanese jewel beetle Chrysochroa fulgidissima are metallic green with purple stripes. Scanning electron microscopy and atomic force microscopy demonstrated that the elytral surface is approximately flat. The accordingly specular green and purple areas have, with normal illumination, 100–150 nm broad reflectance bands, peaking at about 530 and 700 nm. The bands shift progressively towards shorter wavelengths with increasing oblique illumination, and the reflection then becomes highly polarized. Transmission electron microscopy revealed that the epicuticle of the green and purple areas consists of stacks of 16 and 12 layers, respectively. Assuming gradient refractive index values of the layers between 1.6 and 1.7 and applying the classical multilayer theory allowed modelling of the measured polarization- and angle-dependent reflectance spectra. The extreme polarized iridescence exhibited by the elytra of the jewel beetle may have a function in intraspecific recognition. PMID:21282175

Aerocapture Design Study for a Titan Polar Orbiter

NASA Astrophysics Data System (ADS)

Nixon, C. A.; Kirchman, F.; Esper, J.; Folta, D.; Mashiku, A.

2016-03-01

In 2014 a team at NASA Goddard Space Flight Center (GSFC) studied the feasibility of using active aerocapture to reduce the chemical ΔV requirements for inserting a small scientific satellite into Titan polar orbit. The scientific goals of the mission would be multi-spectral imaging and active radar mapping of Titan's surface and subsurface. The study objectives were to: (i) identify and select from launch window opportunities and refine the trajectory to Titan; (ii) study the aerocapture flight path and refine the entry corridor; (iii) design a carrier spacecraft and systems architecture; (iv) develop a scientific and engineering plan for the orbital portion of the mission. Study results include: (i) a launch in October 2021 on an Atlas V vehicle, using gravity assists from Earth and Venus to arrive at Titan in January 2031; (ii) initial aerocapture via an 8-km wide entry corridor to reach an initial 350-6000 km orbit, followed by aerobraking to reach a 350-1500 km orbit, and a periapse raise maneuver to reach a final 1500 km circular orbit; (iii) a three-part spacecraft system consisting of a cruise stage, radiator module, and orbiter inside a heat shield; (iv) a 22-month mission including station keeping to prevent orbital decay due to Saturn perturbations, with 240 Gb of compressed data returned. High-level issues identified include: (i) downlink capability - realistic downlink rates preclude the desired multi- spectral, global coverage of Titan's surface; (ii) power - demise of the NASA ASRG (Advanced Stirling Radioisotope Generator) program, and limited availability at present of MMRTGs (Multi-Mission Radioisotope Generators) needed for competed outer planet missions; (iii) thermal - external radiators must be carried to remove 4 kW of waste heat from MMRTGs inside the aeroshell, requiring heat pipes that pass through the aeroshell lid, compromising shielding ability; (iv) optical navigation to reach the entry corridor; (v) the NASA requirement of continuous

Space and time aliasing structure is monthly mean polar-orbiting satellite data

NASA Technical Reports Server (NTRS)

Zeng, Lixin; Levy, Gad

1995-01-01

Monthly mean wind fields from the European Remote Sensing Satellite (ERS1) scatterometer are presented. A banded structure which resembles the satellite subtrack is clearly and consistently apparent in the isotachs as well as the u and v components of the routinely produced fields. The structure also appears in the means of data from other polar-orbiting satellites and instruments. An experiment is designed to trace the cause of the banded structure. The European Centre for Medium-Range Weather Forecast (ECMWF) gridded surface wind analyses are used as a control set. These analyses are also sampled with the ERS1 temporal-spatial samplig pattern to form a simulated scatterometer wind set. Both sets are used to create monthly averages. The banded structures appear in the monthly mean simulated data but do not appear in the control set. It is concluded that the source of the banded structure lies in the spatial and temporal sampling of the polar-orbiting satellite which results in undersampling. The problem involves multiple timescales and space scales, oversampling and under-sampling in space, aliasing in the time and space domains, and preferentially sampled variability. It is shown that commonly used spatial smoothers (or filters), while producing visually pleasing results, also significantly bias the true mean. A three-dimensional spatial-temporal interpolator is designed and used to determine the mean field. It is found to produce satisfactory monthly means from both simulated and real ERS1 data. The implications to climate studies involving polar-orbiting satellite data are discussed.

The National Polar-orbiting Operational Environmental Satellite System

NASA Astrophysics Data System (ADS)

Hoffman, C. W.; Mango, S.; Schneider, S.; Duda, J.; Haas, J.; Bloom, H.

2005-12-01

Over the last decade, the tri-agency Integrated Program Office (IPO), comprised of the National Oceanic and Atmospheric Administration (NOAA), the Department of Defense (DoD), and the National Aeronautics and Space Administration (NASA), has been managing the development of the National Polar-orbiting Operational Environmental Satellite System (NPOESS). Once operational later this decade, NPOESS will replace NOAA's Polar-orbiting Operational Environmental Satellites (POES) and DoD's Defense Meteorological Satellite Program (DMSP) systems. The IPO, through its Acquisition and Operations contractor, Northrop Grumman, will launch NPOESS spacecraft into three orbital planes to provide a single, national system capable of satisfying both civil and national security requirements for space-based, remotely sensed environmental data. With the development of NPOESS, we are evolving the existing 'weather' satellites into integrated environmental observing systems by expanding our capabilities to observe, assess, and predict the total Earth system - ocean, atmosphere, land, and the space environment. NPOESS will transform today's short-term, space-based ocean research missions into a sustained, operational ocean remote sensing observation program. Ocean measurements comprise one-fourth of the 55 user-validated requirements for geophysical measurements that will be made by NPOESS sensors. In 1997, the IPO initiated a robust sensor risk reduction effort for early development of the critical sensor suites and algorithms necessary to support NPOESS. In 2001, preliminary design efforts were completed for the last of five critical imaging/sounding instruments for NPOESS. Ocean requirements have directly and substantially 'driven' the design of three NPOESS sensors: the Visible/Infrared Imager Radiometer Suite (VIIRS); the Conical-scanning Microwave Imager/Sounder (CMIS); and the Altimeter. With these instruments, NPOESS will deliver higher resolution (spatial and temporal) and more

Correlated Observations of Epithermal Neutrons and Polar Illumination for Orbital Neutron Detectors

NASA Technical Reports Server (NTRS)

McClanahan, T. P.; Mitrofanov, I. G.; Boynton, W. V.; Chin, G.; Droege, G.; Evans, L. G.; Garvin, J.; Harshman, K.; Malakhov, A.; Livengood, T.;

Influence of quantum confinement and strain on orbital polarization of four-layer LaNiO 3 superlattices: A DFT+DMFT study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Hyowon; Millis, Andrew J.; Marianetti, Chris A.

Atomically precise superlattices involving transition metal oxides provide a unique opportunity to engineer correlated electron physics using strain (modulated by choice of substate) and quantum confinement (controlled by layer thickness). We use the combination of density functional theory and dynamical mean field theory (DFT+DMFT) to study Ni E g d-orbital polarization in strained LaNiO 3/LaAlO 3 superlattices consisting of four layers of nominally metallic NiO 2 and four layers of insulating AlO 2 separated by LaO layers. The layer-resolved orbital polarization is calculated as a function of strain and analyzed in terms of structural, quantum confinement, and correlation effects. Wemore » determined that the effect of strain is from the dependence of the results on the Ni-O bondlength ratio and the octahedral rotation angles; quantum confinement is studied by comparison to bulk calculations with similar degrees of strain; correlation effects are inferred by varying interaction parameters within our DFT+DMFT calculations. The calculated dependence of orbital polarization on strain in superlattices is qualitatively consistent with recent X-ray absorption spectroscopy and resonant reflectometry data. But, interesting differences of detail are found between theory and experiment. Under tensile strain, the two inequivalent Ni ions display orbital polarization similar to that calculated for strained bulk LaNiO 3 and observed in experiment. Compressive strain produces a larger dependence of orbital polarization on Ni position and even the inner Ni layer exhibits orbital polarization different from that calculated for strained bulk LaNiO 3.« less

Influence of quantum confinement and strain on orbital polarization of four-layer LaNiO 3 superlattices: A DFT+DMFT study

DOE PAGES

Park, Hyowon; Millis, Andrew J.; Marianetti, Chris A.

2016-06-07

Atomically precise superlattices involving transition metal oxides provide a unique opportunity to engineer correlated electron physics using strain (modulated by choice of substate) and quantum confinement (controlled by layer thickness). We use the combination of density functional theory and dynamical mean field theory (DFT+DMFT) to study Ni E g d-orbital polarization in strained LaNiO 3/LaAlO 3 superlattices consisting of four layers of nominally metallic NiO 2 and four layers of insulating AlO 2 separated by LaO layers. The layer-resolved orbital polarization is calculated as a function of strain and analyzed in terms of structural, quantum confinement, and correlation effects. Wemore » determined that the effect of strain is from the dependence of the results on the Ni-O bondlength ratio and the octahedral rotation angles; quantum confinement is studied by comparison to bulk calculations with similar degrees of strain; correlation effects are inferred by varying interaction parameters within our DFT+DMFT calculations. The calculated dependence of orbital polarization on strain in superlattices is qualitatively consistent with recent X-ray absorption spectroscopy and resonant reflectometry data. But, interesting differences of detail are found between theory and experiment. Under tensile strain, the two inequivalent Ni ions display orbital polarization similar to that calculated for strained bulk LaNiO 3 and observed in experiment. Compressive strain produces a larger dependence of orbital polarization on Ni position and even the inner Ni layer exhibits orbital polarization different from that calculated for strained bulk LaNiO 3.« less

National Polar-orbiting Operational Environmental Satellite System (NPOESS) Design and Architecture

NASA Astrophysics Data System (ADS)

Hinnant, F.

2008-12-01

The National Oceanic and Atmospheric Administration (NOAA), Department of Defense (DoD), and National Aeronautics and Space Administration (NASA) are jointly acquiring the next-generation weather and environmental satellite system - the National Polar-orbiting Operational Environmental Satellite System (NPOESS). NPOESS will replace the current Polar-orbiting Operational Environmental Satellites (POES) managed by NOAA and the Defense Meteorological Satellite Program (DMSP) managed by the DoD and will provide continuity for the NASA Earth Observing System (EOS) with the launch of the NPOESS Preparatory Project (NPP). This poster will provide an overview of the NPOESS architecture, which includes four segments. The space segment includes satellites in two orbits that carry a suite of sensors to collect meteorological, oceanographic, climatological, and solar-geophysical observations of the Earth, atmosphere, and near-Earth space environment. The NPOESS design allows centralized mission management and delivers high quality environmental products to military, civil and scientific users through a Command, Control, and Communication Segment (C3S). The data processing for NPOESS is accomplished through an Interface Data Processing Segment (IDPS)/Field Terminal Segment (FTS) that processes NPOESS satellite data to provide environmental data products to NOAA and DoD processing centers operated by the United States government as well as to remote terminal users. The Launch Support Segment completes the four segments that make up NPOESS that will enhance the connectivity between research and operations and provide critical operational and scientific environmental measurements to military, civil, and scientific users until 2026.

Aerocapture Design Study for a Titan Polar Orbiter

NASA Technical Reports Server (NTRS)

Nixon, Conor A.; Kirchman, Frank; Esper, Jaime; Folta, David; Mashiku, Alinda

2016-01-01

In 2014 a team at NASA Goddard Space Flight Center (GSFC) studied the feasibility of using active aerocapture to reduce the chemical Delta V requirements for inserting a small scientific satellite into Titan polar orbit. The scientific goals of the mission would be multi-spectral imaging and active radar mapping of Titan's surface and subsurface. The study objectives were to: (i) identify and select from launch window opportunities and refine the trajectory to Titan; (ii) study the aerocapture flight path and refine the entry corridor; (iii) design a carrier spacecraft and systems architecture; (iv) develop a scientific and engineering plan for the orbital portion of the mission. Study results include: (i) a launch in October 2021 on an Atlas V vehicle, using gravity assists from Earth and Venus to arrive at Titan in January 2031; (ii) initial aerocapture via an 8-km wide entry corridor to reach an initial 350X6000 km orbit, followed by aerobraking to reach a 350X1500 km orbit, and a periapse raise maneuver to reach a final 1500 km circular orbit; (iii) a three-part spacecraft system consisting of a cruise stage, radiator module, and orbiter inside a heat shield; (iv) a 22-month mission including station keeping to prevent orbital decay due to Saturn perturbations, with 240 Gb of compressed data returned. High-level issues identified include: (i) downlink capability - realistic downlink rates preclude the desired multi-spectral, global coverage of Titan's surface; (ii) power - demise of the NASA ASRG (Advanced Stirling Radioisotope Generator) program, and limited availability at present of MMRTGs (Multi-Mission Radioisotope Generators) needed for competed outer planet missions; (iii) thermal - external radiators must be carried to remove 4 kW of waste heat from MMRTGs inside the aeroshell, requiring heat pipes that pass through the aeroshell lid, compromising shielding ability; (iv) optical navigation to reach the entry corridor; (v) the NASA requirement of

Spin-orbit-coupled Bose-Einstein condensates of rotating polar molecules

NASA Astrophysics Data System (ADS)

Deng, Y.; You, L.; Yi, S.

2018-05-01

An experimental proposal for realizing spin-orbit (SO) coupling of pseudospin 1 in the ground manifold 1Σ (υ =0 ) of (bosonic) bialkali polar molecules is presented. The three spin components are composed of the ground rotational state and two substates from the first excited rotational level. Using hyperfine resolved Raman processes through two select excited states resonantly coupled by a microwave, an effective coupling between the spin tensor and linear momentum is realized. The properties of Bose-Einstein condensates for such SO-coupled molecules exhibiting dipolar interactions are further explored. In addition to the SO-coupling-induced stripe structures, the singly and doubly quantized vortex phases are found to appear, implicating exciting opportunities for exploring novel quantum physics using SO-coupled rotating polar molecules with dipolar interactions.

a Permanent Magnet Hall Thruster for Orbit Control of Lunar Polar Satellites

NASA Astrophysics Data System (ADS)

Ferreira, Jose Leonardo; Silva Moraes, Bruno; Soares Ferreira, Ivan; Cardozo Mour, Decio; Winter, Othon

Future moon missions devoted to lunar surface remote sensing and to many others scientific exploration topics will require more fine and higher precision orbit control. It is well known that, lunar satellites in polar orbits will suffer a high increase on the eccentricity due to the gravitational perturbation of the Earth. Without proper orbit correction the satellite life time will decrease and end up in a collision with the moon surface. It is pointed out by many authors that this effect is a natural consequence of the Lidov-Kozai resonance. In the present work, we propose a precise method of orbit eccentricity control based on the use of a low thrust Hall plasma thruster. The proposed method is based on an approach intended to keep the orbital eccentricity of the satellite at low values. A previous work on this subject was made using numerical integration considering two systems: the 3-body problem, Moon-Earth-satellite and the 4-body problem, Moon-Earth-Sun-satellite (??). In such simulation it is possible to follow the evolution of the satellite's eccentricity and find empirical expressions for the length of time needed to occur the collision with the moon. In this work, a satellite orbit eccentricity control maneuvering is proposed. It is based on working parameters of a low thrust propulsion permanent magnet Hall plasma thruster (PMHT), which is been developed at University of Brasilia, Brazil. We studied different arcs of active lunar satellite propulsion in order to be able to introduce a correction of the eccentricity at each cycle. The calculations were made considering a set of different thrust values, from 0.1N up to 0.4N which can be obtained by using the PMHT. In each calculation procedure we measured the length of eccentricity correction provided by active propulsion. From these results we obtained empirical expressions of the time needed for the corrections as a function of the initial altitude and as a function of the thrust value. 1. Winter, O. C

Joint Polar Satellite System: the United States New Generation Civilian Polar Orbiting Environmental Satellite System

NASA Astrophysics Data System (ADS)

Mandt, G.

2017-12-01

The Joint Polar Satellite System (JPSS) is the Nation's advanced series of polar-orbiting environmental satellites. JPSS represents significant technological and scientific advancements in observations used for severe weather prediction and environmental monitoring. The Suomi National Polar-orbiting Partnership (S-NPP) is providing state-of-the art atmospheric, oceanographic, and environmental data, as the first of the JPSS satellites while the second in the series, J-1, is scheduled to launch in October 2017. The JPSS baseline consists of a suite of four instruments: an advanced microwave and infrared sounders which are critical for weather forecasting; a leading-edge visible and infrared imager critical to data sparse areas such as Alaska and needed for environmental assessments such as snow/ice cover, droughts, volcanic ash, forest fires and surface temperature; and an ozone sensor primarily used for global monitoring of ozone and input to weather and climate models. The same suite of instruments that are on JPSS-1 will be on JPSS-2, 3 and 4. The JPSS-2 instruments are well into their assembly and test phases and are scheduled to be completed in 2018. The JPSS-2 spacecraft critical design review (CDR) is scheduled for 2Q 2018 with the launch in 2021. The sensors for the JPSS-3 and 4 spacecraft have been approved to enter into their acquisition phases. JPSS partnership with the US National Aeronautics and Space Agency (NASA) continues to provide a strong foundation for the program's success. JPSS also continues to maintain its important international relationships with European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and the Japan Aerospace Exploration Agency (JAXA). JPSS works closely with its user community through the Proving Ground and Risk Reduction (PGRR) Program to identify opportunities to maximize the operational application of current JPSS capabilities. The PGRR Program also helps identify and evaluate the use of JPSS

Global Geospace Science/Polar Plasma Laboratory: POLAR

NASA Technical Reports Server (NTRS)

1996-01-01

The Global Geospace Science (GGS) Project is discussed as part of the International Solar-Terrestrial Physics (ISTP) Science Initiative. The objectives of Polar Plasma Laboratory (POLAR), one of the two spacecraft to be used by the Project to fill critical gaps in the scientific understanding of solar and plasma physics, are outlined. POLAR Laboratory is described, along with POLAR instrumentation, support subsystems, and orbits. Launch vehicle and injection into orbit are also addressed.

Assessment of Terra MODIS On-Orbit Polarization Sensitivity Using Pseudoinvariant Desert Sites

NASA Technical Reports Server (NTRS)

Wu, Aisheng; Geng, Xu; Wald, Andrew; Angal, Amit; Xiong, Xiaoxiong

2017-01-01

The Moderate Resolution Imaging Spectroradiometer (MODIS) is currently flying on NASA's Earth Observing System Terra and Aqua satellites, launched in 1999 and 2002, respectively. MODIS reflective solar bands in the visible wavelength range are known to be sensitive to polarized light based on prelaunch polarization sensitivity tests. After about five years of on-orbit operations, it was discovered that the polarization sensitivity at short wavelengths had shown a noticeable increase. In this paper, we examine the impact of polarization on measured top-of-atmosphere (TOA) reflectance based on MODIS Collection-6 L1B over pseudo invariant desert sites. The standard polarization correction equation is used in combination with simulated at-sensor radiances using the second simulation of a satellite signal in the Solar Spectrum, Vector Radiative Transfer Code (6SV). We ignore the polarization contribution from the surface and a ratio approach is used for both 6SV-derived in put parameters and observed TOA reflectance. Results indicate that significant gain corrections up to 25% are required near the end of scan for the 412 and 443 nm bands. The polarization correction reduces the seasonal fluctuations in reflectance trends and mirror side ratios from 30% and 12% to 10% and 5%, respectively, for the two bands. Comparison of the effectiveness of the polarization correction with the results from the NASA Ocean Biology Processing Group shows a good agreement in the corrected reflectance trending results and their seasonal fluctuations.

Q-plates as higher order polarization controllers for orbital angular momentum modes of fiber.

PubMed

Gregg, P; Mirhosseini, M; Rubano, A; Marrucci, L; Karimi, E; Boyd, R W; Ramachandran, S

2015-04-15

We demonstrate that a |q|=1/2 plate, in conjunction with appropriate polarization optics, can selectively and switchably excite all linear combinations of the first radial mode order |l|=1 orbital angular momentum (OAM) fiber modes. This enables full mapping of free-space polarization states onto fiber vector modes, including the radially (TM) and azimuthally polarized (TE) modes. The setup requires few optical components and can yield mode purities as high as ∼30  dB. Additionally, just as a conventional fiber polarization controller creates arbitrary elliptical polarization states to counteract fiber birefringence and yield desired polarizations at the output of a single-mode fiber, q-plates disentangle degenerate state mixing effects between fiber OAM states to yield pure states, even after long-length fiber propagation. We thus demonstrate the ability to switch dynamically, potentially at ∼GHz rates, between OAM modes, or create desired linear combinations of them. We envision applications in fiber-based lasers employing vector or OAM mode outputs, as well as communications networking schemes exploiting spatial modes for higher dimensional encoding.

The National Polar-orbiting Operational Environmental Satellite System

NASA Astrophysics Data System (ADS)

Bloom, H.

The tri-agency Integrated Program Office (IPO) is responsible for managing the development of the National Polar-orbiting Operational Environmental Satellite System (NPOESS). NPOESS will replace the current military and civilian operational polar-orbiting ``weather'' satellites. The Northrop Grumman Space Technology - Raytheon team was competitively selected in 2002 as the Acquisition and Operations contractor team to develop, integrate, deploy, and operate NPOESS satellites to meet the tri-agency user requirements for NPOESS over the 10-year (2009-2018) operational life of the program. Beginning in 2009, NPOESS spacecraft will be launched into three orbital planes to provide significantly improved operational capabilities and benefits to satisfy critical civil and national security requirements for space-based, remotely sensed environmental data. With the development of NPOESS, we are evolving operational ``weather'' satellites into integrated environmental observing systems by expanding our capabilities to observe, assess, and predict the total Earth system - atmosphere, ocean, land, and the space environment. In recent years, the operational weather forecasting and climate science communities have levied more rigorous requirements on space-based observations of the Earth's system that have significantly increased demands on performance of the instruments, spacecraft, and ground systems required to deliver NPOESS data, products, and information to end users. The ``end-to-end'' system consists of: the spacecraft; instruments and sensors on the spacecraft; launch support capabilities; the command, control, communications, and data routing infrastructure; and data processing hardware and software. NPOESS will observe significantly more phenomena simultaneously from space than its operational predecessors. NPOESS is expected to deliver large volumes of more accurate measurements at higher spatial (horizontal and vertical) and temporal resolution at much higher data

Report of the Terrestrial Bodies Science Working Group. Volume 4: The moon. [lunar polar orbiter mission

NASA Technical Reports Server (NTRS)

Haskin, L. A.; Duke, M. B.; Hubbard, N.; Johnson, T. V.; Malin, M. C.; Minear, J.

1977-01-01

A rationale for furture exploration of the moon is given. Topics discussed include the objectives of the lunar polar orbiter mission, the mission profile, and general characteristics of the spacraft to be used.

The latest views of Venus as observed by the Japanese Orbiter "Akatsuki"

NASA Astrophysics Data System (ADS)

Satoh, Takehiko; Akatsuki Project Team

2016-10-01

Akatsuki, also known as the Venus Climate Orbiter (VCO) of Japan, was launched on 21 May 2010 from Tanegashima Space Center, Kagoshima, Japan. After 6 months of cruising to Venus, an attempt was made to insert Akatsuki in Venus orbit (VOI) on 7 December 2010. However, due to the clogged check valve in a pressurizing system of fuel line, the thrust to decelerate the spacecraft was not enough to allow it captured by the gravitational pull of Venus. After this failure, Akatsuki became an artificial planet around the sun with an orbital period of ~200 days. We waited for 5 earth years (or 9 Akatsuki years), and the second attempt (VOI-R1) was made on the same day, 7 December 2015. It was a great surprise to the world that a "once failed" spacecraft made a successful orbital insertion after many years of time. The orbital period around Venus is slightly shorter than 11 days, with the apoapsis altitude of ~0.37 million km.After Venus Express (VEX), which was in Venus orbit for 8 years, Akatsuki still keeps a unique position and is expected to make a great contribution to the Venus science due primarily to its orbit. In contrast to the polar orbits of Pioneer Venus or VEX, Akatsuki is in a near-equatorial plane and revolves westward, the same direction as the super rotating atmosphere. This orbit allows the spacecraft in a "partial" synchronization with the atmospheric motion when Akatsuki is near the planet. When at greater distances, the atmosphere moves faster than Akatsuki's orbital motion so the spacecraft maps the full longitude range of Venus in several days. This meteorological-satellite-like concept makes Akatsuki the most unique planetary orbiter in the history. To sense the various levels of the atmosphere, to draw 3-dimentional picture of dynamics, Akatsuki is equipped with 5 on-board cameras, UVI (283 and 365 nm wavelength), IR1 (0.90, 0.97, and 1.01 μm), IR2 (1.65, 1.735, 2.02, 2.26, and 2.32 μm), LIR (8-12 μm), and LAC (a special high-speed sensor at

The fluxgate magnetometer of the BepiColombo Mercury Planetary Orbiter

NASA Astrophysics Data System (ADS)

Glassmeier, K.-H.; Auster, H.-U.; Heyner, D.; Okrafka, K.; Carr, C.; Berghofer, G.; Anderson, B. J.; Balogh, A.; Baumjohann, W.; Cargill, P.; Christensen, U.; Delva, M.; Dougherty, M.; Fornaçon, K.-H.; Horbury, T. S.; Lucek, E. A.; Magnes, W.; Mandea, M.; Matsuoka, A.; Matsushima, M.; Motschmann, U.; Nakamura, R.; Narita, Y.; O'Brien, H.; Richter, I.; Schwingenschuh, K.; Shibuya, H.; Slavin, J. A.; Sotin, C.; Stoll, B.; Tsunakawa, H.; Vennerstrom, S.; Vogt, J.; Zhang, T.

2010-01-01

The magnetometer (MAG) on the Mercury Planetary Orbiter (MPO) of the joint European-Japanese BepiColombo mission to planet Mercury is a low-noise, tri-axial, dual-sensor, digital fluxgate instrument with its sensors mounted on a 2.8-m-long boom. The primary MPO/MAG science objectives are to determine the spatial and temporal structure of the magnetic field in the Hermean system, in particular the structure and origin of the intrinsic magnetic field of Mercury. MPO/MAG has a dynamic measurement range of ±2000nT with a resolution of 2 pT during operation along the near-polar orbit of the MPO spacecraft around Mercury. MPO/MAG is designed to provide measurements with rates between 0.5 and 128 vectors/s. In cooperation with its sister magnetometer instrument, MMO/MGF on board the BepiColombo Mercury Magnetospheric Orbiter (MMO), MPO/MAG will be able to distinguish between temporal and spatial magnetic field variations in the magnetically closely coupled Hermean system.

Martian Polar Impact Craters: A Preliminary Assessment Using Mars Orbiter Laser Altimeter (MOLA)

NASA Technical Reports Server (NTRS)

Sakimoto, S. E. H.; Garvin, J. B.

1999-01-01

Our knowledge of the age of the layered polar deposits and their activity in the volatile cycling and climate history of Mars is based to a large extent on their apparent ages as determined from crater counts. Interpretation of the polar stratigraphy (in terms of climate change) is complicated by reported differences in the ages of the northern and southern layered deposits. The north polar residual ice deposits are thought to be relatively young, based on the reported lack of any fresh impact craters in Viking Orbiter Images. Herkenhoff et al., report no craters at all on the North polar layered deposits or ice cap, and placed an upper bound on the surface age (or, alternatively, the vertical resurfacing rate) of 100 thousand years to 10 million years, suggesting that the north polar region is an active resurfacing site. In contrast, the southern polar region was found to have at least 15 impact craters in the layered deposits and cap. Plaut et al, concluded that the surface was less than or = 120 million years old. This reported age difference factor of 100 to 1000 increases complexity in climate and volatile modeling. Recent MOLA results for the topography of the northern polar cap document a handful or more of possible craters, which could result in revised age or resurfacing estimates for the northern cap. This study is a preliminary look at putative craters in both polar caps. Additional information is contained in the original extended abstract.

Cloud and Aerosol Measurements from the GLAS Polar Orbiting Lidar: First Year Results

NASA Technical Reports Server (NTRS)

Spinhirne, J. D.; Palm, S. P.; Hlavka, D. L.; Hart, W. D.; Mahesh, A.; Welton, E. J.

2004-01-01

The Geoscience Laser Altimeter System (GLAS) launched in 2003 is the first polar orbiting satellite lidar. The instrument was designed for high performance observations of the distribution and optical scattering cross sections of clouds and aerosol. GLAS is approaching six months of on orbit data operation. These data from thousands of orbits illustrate the ability of space lidar to accurately and dramatically measure the height distribution of global cloud and aerosol to an unprecedented degree. There were many intended science applications of the GLAS data and significant results have already been realized. One application is the accurate height distribution and coverage of global cloud cover with one goal of defining the limitation and inaccuracies of passive retrievals. Comparison to MODIS cloud retrievals shows notable discrepancies. Initial comparisons to NOAA 14&15 satellite cloud retrievals show basic similarity in overall cloud coverage, but important differences in height distribution. Because of the especially poor performance of passive cloud retrievals in polar regions, and partly because of high orbit track densities, the GLAS measurements are by far the most accurate measurement of Arctic and Antarctica cloud cover from space to date. Global aerosol height profiling is a fundamentally new measurement from space with multiple applications. A most important aerosol application is providing input to global aerosol generation and transport models. Another is improved measurement of aerosol optical depth. Oceanic surface energy flux derivation from PBL and LCL height measurements is another application of GLAS data that is being pursued. A special area of work for GLAS data is the correction and application of multiple scattering effects. Stretching of surface return pulses in excess of 40 m from cloud propagation effects and other interesting multiple scattering phenomena have been observed. As an EOS project instrument, GLAS data products are openly

Orbital Engineering in Nickelate Heterostructures Driven by Anisotropic Oxygen Hybridization rather than Orbital Energy Levels

NASA Astrophysics Data System (ADS)

Fabbris, G.; Meyers, D.; Okamoto, J.; Pelliciari, J.; Disa, A. S.; Huang, Y.; Chen, Z.-Y.; Wu, W. B.; Chen, C. T.; Ismail-Beigi, S.; Ahn, C. H.; Walker, F. J.; Huang, D. J.; Schmitt, T.; Dean, M. P. M.

2016-09-01

Resonant inelastic x-ray scattering is used to investigate the electronic origin of orbital polarization in nickelate heterostructures taking LaTiO3-LaNiO3-3 ×(LaA l O3) , a system with exceptionally large polarization, as a model system. We find that heterostructuring generates only minor changes in the Ni 3 d orbital energy levels, contradicting the often-invoked picture in which changes in orbital energy levels generate orbital polarization. Instead, O K -edge x-ray absorption spectroscopy demonstrates that orbital polarization is caused by an anisotropic reconstruction of the oxygen ligand hole states. This provides an explanation for the limited success of theoretical predictions based on tuning orbital energy levels and implies that future theories should focus on anisotropic hybridization as the most effective means to drive large changes in electronic structure and realize novel emergent phenomena.

Out-of-plane spin polarization of edge currents in Chern insulator with Rashba spin-orbit interaction

NASA Astrophysics Data System (ADS)

Chen, Tsung-Wei; Hsiao, Chin-Lun; Hu, Chong-Der

2016-07-01

We investigate the change in the non-zero Chern number and out-of-plane spin polarization of the edge currents in a honeycomb lattice with the Haldane-Rashba interaction. This interaction breaks the time-reversal symmetry due to the Haldane phase caused by a current loop at the site-I and site-II atoms, and also accounts for the Rashba-type spin-orbit interaction. The Rashba spin-orbit interaction increases the number of Dirac points and the band-touching phenomenon can be generated by tuning the on-site potential in the non-zero Haldane phase. By using the Pontryagin winding number and numerical Berry curvature methods, we find that the Chern number pattern is {+2, -1, 0} and {-2, +1, 0} for the positive and negative Haldane phase, respectively. A non-zero Chern number is called a Chern-insulating phase. We discovered that changes in both the Haldane phase and on-site potential leads to a change in the orientation of the bulk spin polarization of site-I and site-II atoms. Interestingly, in a ribbon with a zigzag edge, which naturally has site-I atoms at one outer edge and site-II atoms at the opposite outer edge, the spin polarization of the edge states approximately obeys the properties of bulk spin polarization regardless of the change in the Chern number. In addition, even when the Chern number changes from  +2 to  -1 (or  -2 to  +1), by tuning the strength of the on-site potential, the sign of the spin polarization of the edge states persists. This approximate bulk-edge correspondence of the spin polarization in the Haldane-Rashba system would play an important role in spintronics, because it enables us to control the orientation of the spin polarization in a single Chern-insulating phase.

Out-of-plane spin polarization of edge currents in Chern insulator with Rashba spin-orbit interaction.

PubMed

Chen, Tsung-Wei; Hsiao, Chin-Lun; Hu, Chong-Der

2016-07-13

We investigate the change in the non-zero Chern number and out-of-plane spin polarization of the edge currents in a honeycomb lattice with the Haldane-Rashba interaction. This interaction breaks the time-reversal symmetry due to the Haldane phase caused by a current loop at the site-I and site-II atoms, and also accounts for the Rashba-type spin-orbit interaction. The Rashba spin-orbit interaction increases the number of Dirac points and the band-touching phenomenon can be generated by tuning the on-site potential in the non-zero Haldane phase. By using the Pontryagin winding number and numerical Berry curvature methods, we find that the Chern number pattern is {+2, -1, 0} and {-2, +1, 0} for the positive and negative Haldane phase, respectively. A non-zero Chern number is called a Chern-insulating phase. We discovered that changes in both the Haldane phase and on-site potential leads to a change in the orientation of the bulk spin polarization of site-I and site-II atoms. Interestingly, in a ribbon with a zigzag edge, which naturally has site-I atoms at one outer edge and site-II atoms at the opposite outer edge, the spin polarization of the edge states approximately obeys the properties of bulk spin polarization regardless of the change in the Chern number. In addition, even when the Chern number changes from  +2 to  -1 (or  -2 to  +1), by tuning the strength of the on-site potential, the sign of the spin polarization of the edge states persists. This approximate bulk-edge correspondence of the spin polarization in the Haldane-Rashba system would play an important role in spintronics, because it enables us to control the orientation of the spin polarization in a single Chern-insulating phase.

attitude control design for the solar polar orbit radio telesope

NASA Astrophysics Data System (ADS)

Gao, D.; Zheng, J.

This paper studies the attitude dynamics and control of the Solar Polar Orbit Radio Telescope SPORT The SPORT which consists of one parent satellite and eight tethered satellites runs around the Sun in a polar orbit The parent satellite locates at the mass center of the constellation and tethered satellites which are tied with the parent satellite through a non-electric rope rotate around the parent satellite It is also supposed that the parent satellite and all tethered satellites are in a plane when the constellation works begin figure htbp centerline includegraphics width 3 85in height 2 38in 75271331 6a6eb71057 doc1 eps label fig1 end figure Fig 1 the SPORT constellation Firstly this paper gives the dynamic equations of the tethered satellite and the parent satellite From the dynamic characteristic of the tethered satellite we then find that the roll axis is coupled with the yaw axis The control torque of the roll axis can control the yaw angle But the control torque of the roll axis and pitch axis provided by the tether is very small it can not meet the accuracy requirement of the yaw angle In order to improve the attitude pointing accuracy of the tethered satellite a gradient pole is set in the negative orientation of the yaw axis The gradient pole can improve not only the attitude accuracy of roll angle and pitch angle but also that of the yaw angle indirectly As to the dynamic characteristic of the parent satellite the roll axis is coupled with the pitch axis due to the spinning angular velocity At the same

Latency features of SafetyNet ground systems architecture for the National Polar-orbiting Operational Environmental Satellite System (NPOESS)

NASA Astrophysics Data System (ADS)

Duda, James L.; Mulligan, Joseph; Valenti, James; Wenkel, Michael

2005-01-01

A key feature of the National Polar-orbiting Operational Environmental Satellite System (NPOESS) is the Northrop Grumman Space Technology patent-pending innovative data routing and retrieval architecture called SafetyNetTM. The SafetyNetTM ground system architecture for the National Polar-orbiting Operational Environmental Satellite System (NPOESS), combined with the Interface Data Processing Segment (IDPS), will together provide low data latency and high data availability to its customers. The NPOESS will cut the time between observation and delivery by a factor of four when compared with today's space-based weather systems, the Defense Meteorological Satellite Program (DMSP) and NOAA's Polar-orbiting Operational Environmental Satellites (POES). SafetyNetTM will be a key element of the NPOESS architecture, delivering near real-time data over commercial telecommunications networks. Scattered around the globe, the 15 unmanned ground receptors are linked by fiber-optic systems to four central data processing centers in the U. S. known as Weather Centrals. The National Environmental Satellite, Data and Information Service; Air Force Weather Agency; Fleet Numerical Meteorology and Oceanography Center, and the Naval Oceanographic Office operate the Centrals. In addition, this ground system architecture will have unused capacity attendant with an infrastructure that can accommodate additional users.

Application of polar orbiter products in weather forecasting using open source tools and open standards

NASA Astrophysics Data System (ADS)

Plieger, Maarten; de Vreede, Ernst

2015-04-01

EUMETSAT disseminates data for a number of polar satellites. At KNMI these data are not fully used for operational weather forecasting mainly because of the irregular coverage and lack of tools for handling these different types of data and products. For weather forecasting there is a lot of interest in the application of products from these polar orbiters. One of the key aspects is the high-resolution of these products, which can complement the information provided by numerical weather forecasts. Another advantage over geostationary satellites is the high coverage at higher latitudes and lack of parallax. Products like the VIIRS day-night band offer many possibilities for this application. This presentation will describe a project that aims to make available a number of products from polar satellites to the forecasting operation. The goal of the project is to enable easy and timely access to polar orbiter products and enable combined presentations of satellite imagery with model data. The system will be able to generate RGB composites (“false colour images”) for operational use. The system will be built using open source components and open standards. Pytroll components are used for data handling, reprojection and derived product generation. For interactive presentation of imagery the browser based ADAGUC WMS viewer component is used. Image generation is done by ADAGUC server components, which provide OGC WMS services. Polar satellite products are stored as true color RGBA data in the NetCDF file format, the satellite swaths are stored as regular grids with their own custom geographical projection. The ADAGUC WMS system is able to reproject, render and combine these data in a webbrowser interactively. Results and lessons learned will be presented at the conference.

Formation of the Martian Polar Layered Terrains: Quantifying Polar Water Ice and Dust Surface Deposition during Current and Past Orbital Epochs with the NASA Ames GCM

NASA Astrophysics Data System (ADS)

Emmett, Jeremy; Murphy, Jim

2016-10-01

Structural and compositional variability in the layering sequences comprising Mars' polar layered terrains (PLT's) is likely explained by orbital-forced climatic variations in the sedimentary cycles of water ice and dust from which they formed [1]. The PLT's therefore contain a direct, extensive record of the recent climate history of Mars encoded in their structure and stratigraphy, but deciphering this record requires understanding the depositional history of their dust and water ice constituents. 3D Mars atmosphere modeling enables direct simulation of atmospheric dynamics, aerosol transport and quantification of surface accumulation for a range of past and present orbital configurations. By quantifying the net yearly polar deposition rates of water ice and dust under Mars' current and past orbital configurations characteristic of the last several millions of years, and integrating these into the present with a time-stepping model, the formation history of the north and south PLT's will be investigated, further constraining their age and composition, and, if reproducible, revealing the processes responsible for prominent features and stratigraphy observed within the deposits. Simulating the formation of the deposits by quantifying net deposition rates during past orbital epochs and integrating these into the present, effectively 'rebuilding' the terrains, could aid in understanding deeper stratigraphic trends, correlating between geographically-separated deposits, explaining the presence and shapes of large-scale polar features, and correlating stratigraphy with geological time. Quantification of the magnitude and geographical distribution of surface aerosol accumulation will build on the work of previous GCM-based investigations [3]. Construction and analysis of hypothetical stratigraphic sequences in the PLT's will draw from previous climate-controlled stratigraphy methodologies [2,4], but will utilize GCM-derived net deposition rates to model orbital

The GLAS Polar Orbiting Lidar Experiment: First Year Results and Available Data

NASA Technical Reports Server (NTRS)

Spinhirne, James D.; Welton, E. Judd; Palm, Stephen P.; Hart, William D.; Hlavka, Dennis; Mahesh, Ashwin; Lancaster, Redgie S.

2004-01-01

The first polar orbiting satellite lidar instrument, the Geoscience Laser Altimeter System (GLAS), was launched in 2003 and is approaching six months of data operations. As part of the NASA Earth Observing System (EOS) project, the GLAS instrument is intended as a laser sensor fulfilling complementary requirements for several earth science disciplines including atmospheric and surface applications on the Ice, Cloud and Land Elevation Satellite. In this paper we present examples of atmospheric measurement results and explain access to data for the international science community.

Orbital Engineering in Nickelate Heterostructures Driven by Anisotropic Oxygen Hybridization rather than Orbital Energy Levels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fabbris, G.; Meyers, D.; Okamoto, J.

We used resonant inelastic x-ray scattering to investigate the electronic origin of orbital polarization in nickelate heterostructures taking LaTiO 3-LaNiO 3-3×(LaAlO 3), a system with exceptionally large polarization, as a model system. Furthermore, we find that heterostructuring generates only minor changes in the Ni 3d orbital energy levels, contradicting the often-invoked picture in which changes in orbital energy levels generate orbital polarization. Instead, O K-edge x-ray absorption spectroscopy demonstrates that orbital polarization is caused by an anisotropic reconstruction of the oxygen ligand hole states. This also provides an explanation for the limited success of theoretical predictions based on tuning orbitalmore » energy levels and implies that future theories should focus on anisotropic hybridization as the most effective means to drive large changes in electronic structure and realize novel emergent phenomena.« less

Orbital Engineering in Nickelate Heterostructures Driven by Anisotropic Oxygen Hybridization rather than Orbital Energy Levels

DOE PAGES

Fabbris, G.; Meyers, D.; Okamoto, J.; ...

2016-09-30

We used resonant inelastic x-ray scattering to investigate the electronic origin of orbital polarization in nickelate heterostructures taking LaTiO 3-LaNiO 3-3×(LaAlO 3), a system with exceptionally large polarization, as a model system. Furthermore, we find that heterostructuring generates only minor changes in the Ni 3d orbital energy levels, contradicting the often-invoked picture in which changes in orbital energy levels generate orbital polarization. Instead, O K-edge x-ray absorption spectroscopy demonstrates that orbital polarization is caused by an anisotropic reconstruction of the oxygen ligand hole states. This also provides an explanation for the limited success of theoretical predictions based on tuning orbitalmore » energy levels and implies that future theories should focus on anisotropic hybridization as the most effective means to drive large changes in electronic structure and realize novel emergent phenomena.« less

Cassini/CIRS Observations of Saturn’s Polar Vortices from Proximal Orbit Observations

NASA Astrophysics Data System (ADS)

Achterberg, Richard; Bjoraker, Gordon L.; Hesman, Brigette E.; Flasar, F. Michael

2017-10-01

The proximal orbit phase of the Cassini mission, with periapses inside the inner edge of the rings, has allowed observations of Saturn’s atmosphere with unprecedented spatial resolution. During the periapse periods on 26 April and 29 June 2017, the Composite Infrared Spectrometer (CIRS) performed scans over both the north and south poles with a spatial resolution better than 0.2° of latitude, over a factor of 4 better resolution than previous observations. A further observation of the south pole is planned on 20 Aug 2017.Previous thermal infrared observations of Saturn’s poles [1,2] showed a compact hot spot in the upper troposphere at each pole, roughly coincident with the hurricane-like polar vortex seen in visible imaging [3]. Preliminary results from the proximal orbit scans of the north pole, near summer solstice, show that in the upper troposphere, the meridional temperature gradient increases sharply at about 89°N, with the temperature increasing by ~5K between 89°N and the pole, with the temperature gradient persisting all the way to the pole within the spatial resolution of the observation. In the northern stratosphere, the polar hot spot is broader than in the troposphere, extending to ~86°N at 4 mbar, and disappearing into the general meridional gradient at 1 mbar.[1] G. S. Orton and P. A. Yanamadra-Fisher, Science 307, 696[2] L. N. Fletcher et al., Science, 319, 79[3] U. A. Dyudina et al., Icarus, 202, 240.

Integrated optical modulator manipulating the polarization and rotation handedness of Orbital Angular Momentum states.

PubMed

Mousavi, S Faezeh; Nouroozi, Rahman; Vallone, Giuseppe; Villoresi, Paolo

2017-06-19

Recent studies demonstrated that the optical channels encoded by Orbital Angular Momentum (OAM) are capable candidates for improving the next generation of communication systems. OAM states can enhance the capacity and security of high-dimensional communication channels in both classical and quantum regimes based on optical fibre and free space. Hence, fast and precise control of the beams encoded by OAM can provide their commercial applications in the compatible communication networks. Integrated optical devices are good miniaturized options to perform this issue. This paper proposes a numerically verified integrated high-frequency electro-optical modulator for manipulation of the guided modes encoded in both OAM and polarization states. The proposed modulator is designed as an electro-optically active Lithium Niobate (LN) core photonic wire with silica as its cladding in a LN on Insulator (LNOI) configuration. It consists of two successive parts; a phase shifter to reverse the rotation handedness of the input OAM state and a polarization converter to change the horizontally polarized OAM state to the vertically polarized one. It is shown that all four possible output polarization-OAM encoded states can be achieved with only 6 V and 7 V applied voltages to the electrodes in the two parts of the modulator.

Japanese Experiment Module arrival

NASA Image and Video Library

2007-03-29

The Experiment Logistics Module Pressurized Section for the Japanese Experiment Module arrives at the Space Station Processing Facility. The logistics module is one of the components of the Japanese Experiment Module or JEM, also known as Kibo, which means "hope" in Japanese. Kibo comprises six components: two research facilities -- the Pressurized Module and Exposed Facility; a Logistics Module attached to each of them; a Remote Manipulator System; and an Inter-Orbit Communication System unit. Kibo also has a scientific airlock through which experiments are transferred and exposed to the external environment of space. Kibo is Japan's first human space facility and its primary contribution to the station. Kibo will enhance the unique research capabilities of the orbiting complex by providing an additional environment in which astronauts can conduct science experiments. The various components of JEM will be assembled in space over the course of three Space Shuttle missions. The first of those three missions, STS-123, will carry the Experiment Logistics Module Pressurized Section aboard the Space Shuttle Endeavour, targeted for launch in 2007.

Japanese Experiment Module arrival

NASA Image and Video Library

2007-03-29

Inside the Space Station Processing Facility, the Experiment Logistics Module Pressurized Section for the Japanese Experiment Module is revealed after the top of the crate is removed. The logistics module is one of the components of the Japanese Experiment Module or JEM, also known as Kibo, which means "hope" in Japanese. Kibo comprises six components: two research facilities -- the Pressurized Module and Exposed Facility; a Logistics Module attached to each of them; a Remote Manipulator System; and an Inter-Orbit Communication System unit. Kibo also has a scientific airlock through which experiments are transferred and exposed to the external environment of space. Kibo is Japan's first human space facility and its primary contribution to the station. Kibo will enhance the unique research capabilities of the orbiting complex by providing an additional environment in which astronauts can conduct science experiments. The various components of JEM will be assembled in space over the course of three Space Shuttle missions. The first of those three missions, STS-123, will carry the Experiment Logistics Module Pressurized Section aboard the Space Shuttle Endeavour, targeted for launch in 2007.

Japanese Experiment Module arrival

NASA Image and Video Library

2007-03-29

The Experiment Logistics Module Pressurized Section for the Japanese Experiment Module arrives at the Space Station Processing Facility for uncrating. The logistics module is one of the components of the Japanese Experiment Module or JEM, also known as Kibo, which means "hope" in Japanese. Kibo comprises six components: two research facilities -- the Pressurized Module and Exposed Facility; a Logistics Module attached to each of them; a Remote Manipulator System; and an Inter-Orbit Communication System unit. Kibo also has a scientific airlock through which experiments are transferred and exposed to the external environment of space. Kibo is Japan's first human space facility and its primary contribution to the station. Kibo will enhance the unique research capabilities of the orbiting complex by providing an additional environment in which astronauts can conduct science experiments. The various components of JEM will be assembled in space over the course of three Space Shuttle missions. The first of those three missions, STS-123, will carry the Experiment Logistics Module Pressurized Section aboard the Space Shuttle Endeavour, targeted for launch in 2007.

Observations of the north polar region of Mars from the Mars orbiter laser altimeter.

PubMed

Zuber, M T; Smith, D E; Solomon, S C; Abshire, J B; Afzal, R S; Aharonson, O; Fishbaugh, K; Ford, P G; Frey, H V; Garvin, J B; Head, J W; Ivanov, A B; Johnson, C L; Muhleman, D O; Neumann, G A; Pettengill, G H; Phillips, R J; Sun, X; Zwally, H J; Banerdt, W B; Duxbury, T C

1998-12-11

Elevations from the Mars Orbiter Laser Altimeter (MOLA) have been used to construct a precise topographic map of the martian north polar region. The northern ice cap has a maximum elevation of 3 kilometers above its surroundings but lies within a 5-kilometer-deep hemispheric depression that is contiguous with the area into which most outflow channels emptied. Polar cap topography displays evidence of modification by ablation, flow, and wind and is consistent with a primarily H2O composition. Correlation of topography with images suggests that the cap was more spatially extensive in the past. The cap volume of 1.2 x 10(6) to 1.7 x 10(6) cubic kilometers is about half that of the Greenland ice cap. Clouds observed over the polar cap are likely composed of CO2 that condensed out of the atmosphere during northern hemisphere winter. Many clouds exhibit dynamical structure likely caused by the interaction of propagating wave fronts with surface topography.

Density functional perturbational orbital theory of spin polarization in electronic systems. II. Transition metal dimer complexes.

PubMed

Seo, Dong-Kyun

2007-11-14

We present a theoretical scheme for a semiquantitative analysis of electronic structures of magnetic transition metal dimer complexes within spin density functional theory (DFT). Based on the spin polarization perturbational orbital theory [D.-K. Seo, J. Chem. Phys. 125, 154105 (2006)], explicit spin-dependent expressions of the spin orbital energies and coefficients are derived, which allows to understand how spin orbitals form and change their energies and shapes when two magnetic sites are coupled either ferromagnetically or antiferromagnetically. Upon employment of the concept of magnetic orbitals in the active-electron approximation, a general mathematical formula is obtained for the magnetic coupling constant J from the analytical expression for the electronic energy difference between low-spin broken-symmetry and high-spin states. The origin of the potential exchange and kinetic exchange terms based on the one-electron picture is also elucidated. In addition, we provide a general account of the DFT analysis of the magnetic exchange interactions in compounds for which the active-electron approximation is not appropriate.

Joint Polar Satellite System

NASA Technical Reports Server (NTRS)

Trenkle, Timothy; Driggers, Phillip

2011-01-01

The Joint Polar Satellite System (JPSS) is a joint NOAA/NASA mission comprised of a series of polar orbiting weather and climate monitoring satellites which will fly in a sun-synchronous orbit, with a 1330 equatorial crossing time. JPSS resulted from the decision to reconstitute the National Polar-orbiting Operational Environmental Satellite System (NPOESS) into two separate programs, one to be run by the Department of Defense (DOD) and the other by NOAA. This decision was reached in early 2010, after numerous development issues caused a series of unacceptable delays in launching the NPOESS system.

All-electrical production of spin-polarized currents in carbon nanotubes: Rashba spin-orbit interaction

NASA Astrophysics Data System (ADS)

Santos, Hernán; Latgé, A.; Alvarellos, J. E.; Chico, Leonor

2016-04-01

We study the effect of the Rashba spin-orbit interaction in the quantum transport of carbon nanotubes with arbitrary chiralities. For certain spin directions, we find a strong spin-polarized electrical current that depends on the diameter of the tube, the length of the Rashba region, and on the tube chirality. Predictions for the spin-dependent conductances are presented for different families of achiral and chiral tubes. We have found that different symmetries acting on spatial and spin variables have to be considered in order to explain the relations between spin-resolved conductances in carbon nanotubes. These symmetries are more general than those employed in planar graphene systems. Our results indicate the possibility of having stable spin-polarized electrical currents in absence of external magnetic fields or magnetic impurities in carbon nanotubes.

Japanese Experiment Module arrival

NASA Image and Video Library

2007-03-29

Inside the Space Station Processing Facility, workers monitor progress as a huge crane is used to remove the top of the crate carrying the Experiment Logistics Module Pressurized Section for the Japanese Experiment Module. The logistics module is one of the components of the Japanese Experiment Module or JEM, also known as Kibo, which means "hope" in Japanese. Kibo comprises six components: two research facilities -- the Pressurized Module and Exposed Facility; a Logistics Module attached to each of them; a Remote Manipulator System; and an Inter-Orbit Communication System unit. Kibo also has a scientific airlock through which experiments are transferred and exposed to the external environment of space. Kibo is Japan's first human space facility and its primary contribution to the station. Kibo will enhance the unique research capabilities of the orbiting complex by providing an additional environment in which astronauts can conduct science experiments. The various components of JEM will be assembled in space over the course of three Space Shuttle missions. The first of those three missions, STS-123, will carry the Experiment Logistics Module Pressurized Section aboard the Space Shuttle Endeavour, targeted for launch in 2007.

Tunable ferroelectric polarization and its interplay with spin-orbit coupling in tin iodide perovskites

NASA Astrophysics Data System (ADS)

Stroppa, Alessandro; di Sante, Domenico; Barone, Paolo; Bokdam, Menno; Kresse, Georg; Franchini, Cesare; Whangbo, Myung-Hwan; Picozzi, Silvia

2014-12-01

Ferroelectricity is a potentially crucial issue in halide perovskites, breakthrough materials in photovoltaic research. Using density functional theory simulations and symmetry analysis, we show that the lead-free perovskite iodide (FA)SnI3, containing the planar formamidinium cation FA, (NH2CHNH2)+, is ferroelectric. In fact, the perpendicular arrangement of FA planes, leading to a ‘weak’ polarization, is energetically more stable than parallel arrangements of FA planes, being either antiferroelectric or ‘strong’ ferroelectric. Moreover, we show that the ‘weak’ and ‘strong’ ferroelectric states with the polar axis along different crystallographic directions are energetically competing. Therefore, at least at low temperatures, an electric field could stabilize different states with the polarization rotated by π/4, resulting in a highly tunable ferroelectricity appealing for multistate logic. Intriguingly, the relatively strong spin-orbit coupling in noncentrosymmetric (FA)SnI3 gives rise to a co-existence of Rashba and Dresselhaus effects and to a spin texture that can be induced, tuned and switched by an electric field controlling the ferroelectric state.

Japanese Next Solar Mission: SOLAR-C

NASA Astrophysics Data System (ADS)

Sakao, T.; Solar-C, W. G.

2008-09-01

We present introductory overview on the next Japanese solar mission, SOLAR-C, which has been envisaged following the success of Hinode (SOLAR-B) mission. Two plans, Plan A and Plan B, are under extensive study from science objectives as well as engineering point of view. Plan A aims to perform out-of-ecliptic observations for investigating, with helioseismic approach, internal structure and dynamo mechanisms of the Sun. It also explores polar regions where fast solar wind is believed to be originated. The baseline orbit for Plan A is a circular orbit of 1 AU distance from the Sun, with its inclination at around, or greater than, 40 degrees. Plan B pursues small-scale plasma processes and structures in the solar atmosphere which attract growing interest, following Hinode discoveries, for understanding fully dynamism and magnetic nature of the atmosphere. With Plan B, high-angular-resolution investigation of the entire solar atmosphere (from the photosphere to the corona, including their interface layers, i.e., chromosphere and transition region) is to be performed with enhanced spectroscopic and spectro-polarimetric capability as compared with Hinode, together with enhanced sensitivity towards ultra-violet wavelengths. There has been wide and evolving support for the SOLAR-C mission not only from solar physics community but also from related research areas in Japan. We request SOLAR-C to be launched in mid. 2010s. Following the highly-successful achievements of international collaboration for Yohkoh and Hinode, we strongly hope the SOLAR-C mission be realized under extensive collaboration with European and U.S. partners. Japanese SOLAR-C working group was officially approved by ISAS/JAXA in December 2007 for mission studies and promoting international collaboration. It is expected that a single mission plan is to be proposed after one year of investigation on Plan A and Plan B.

Dual-polarization and dual-mode orbital angular momentum radio vortex beam generated by using reflective metasurface

NASA Astrophysics Data System (ADS)

Yu, Shixing; Li, Long; Shi, Guangming

2016-08-01

A metasurface, which is composed of printed cross-dipole elements with different arm lengths, is designed, fabricated, and experimentally demonstrated to generate orbital angular momentum (OAM) vortex waves of dual polarizations and dual modes in the radio frequency domain simultaneously. The prototype of a practical metasurface is fabricated and measured to validate the results of theoretical analysis and design at 5.8 GHz. Numerical and experimental results verify that vortex waves with dual OAM modes and dual polarizations can be flexibly generated by using a reflective metasurface. The proposed method paves a way to generate diverse OAM vortex waves for radio frequency and microwave wireless communication applications.

Polarization singularities and orbital angular momentum sidebands from rotational symmetry broken by the Pockels effect

PubMed Central

Lu, Xiancong; Wu, Ziwen; Zhang, Wuhong; Chen, Lixiang

2014-01-01

The law of angular momentum conservation is naturally linked to the rotational symmetry of the involved system. Here we demonstrate theoretically how to break the rotational symmetry of a uniaxial crystal via the electro-optic Pockels effect. By numerical method based on asymptotic expansion, we discover the 3D structure of polarization singularities in terms of C lines and L surfaces embedded in the emerging light. We visualize the controllable dynamics evolution of polarization singularities when undergoing the Pockels effect, which behaves just like the binary fission of a prokaryotic cell, i.e., the splitting of C points and fission of L lines are animated in analogy with the cleavage of nucleus and division of cytoplasm. We reveal the connection of polarization singularity dynamics with the accompanying generation of orbital angular momentum sidebands. It is unexpected that although the total angular momentum of light is not conserved, the total topological index of C points is conserved. PMID:24784778

Polarization singularities and orbital angular momentum sidebands from rotational symmetry broken by the Pockels effect.

PubMed

Lu, Xiancong; Wu, Ziwen; Zhang, Wuhong; Chen, Lixiang

2014-05-02

The law of angular momentum conservation is naturally linked to the rotational symmetry of the involved system. Here we demonstrate theoretically how to break the rotational symmetry of a uniaxial crystal via the electro-optic Pockels effect. By numerical method based on asymptotic expansion, we discover the 3D structure of polarization singularities in terms of C lines and L surfaces embedded in the emerging light. We visualize the controllable dynamics evolution of polarization singularities when undergoing the Pockels effect, which behaves just like the binary fission of a prokaryotic cell, i.e., the splitting of C points and fission of L lines are animated in analogy with the cleavage of nucleus and division of cytoplasm. We reveal the connection of polarization singularity dynamics with the accompanying generation of orbital angular momentum sidebands. It is unexpected that although the total angular momentum of light is not conserved, the total topological index of C points is conserved.

Polarization singularities and orbital angular momentum sidebands from rotational symmetry broken by the Pockels effect

NASA Astrophysics Data System (ADS)

Lu, Xiancong; Wu, Ziwen; Zhang, Wuhong; Chen, Lixiang

2014-05-01

The law of angular momentum conservation is naturally linked to the rotational symmetry of the involved system. Here we demonstrate theoretically how to break the rotational symmetry of a uniaxial crystal via the electro-optic Pockels effect. By numerical method based on asymptotic expansion, we discover the 3D structure of polarization singularities in terms of C lines and L surfaces embedded in the emerging light. We visualize the controllable dynamics evolution of polarization singularities when undergoing the Pockels effect, which behaves just like the binary fission of a prokaryotic cell, i.e., the splitting of C points and fission of L lines are animated in analogy with the cleavage of nucleus and division of cytoplasm. We reveal the connection of polarization singularity dynamics with the accompanying generation of orbital angular momentum sidebands. It is unexpected that although the total angular momentum of light is not conserved, the total topological index of C points is conserved.

The effects of Rashba spin-orbit coupling on spin-polarized transport in hexagonal graphene nano-rings and flakes

NASA Astrophysics Data System (ADS)

Laghaei, M.; Heidari Semiromi, E.

2018-03-01

Quantum transport properties and spin polarization in hexagonal graphene nanostructures with zigzag edges and different sizes were investigated in the presence of Rashba spin-orbit interaction (RSOI). The nanostructure was considered as a channel to which two semi-infinite armchair graphene nanoribbons were coupled as input and output leads. Spin transmission and spin polarization in x, y, and z directions were calculated through applying Landauer-Buttiker formalism with tight binding model and the Green's function to the system. In these quantum structures it is shown that changing the size of system, induce and control the spin polarized currents. In short, these graphene systems are typical candidates for electrical spintronic devices as spin filtering.

Japanese Experiment Module arrival

NASA Image and Video Library

2007-03-29

Several components for delivery to the International Space Station sit in test stands inside the Space Station Processing Facility highbay. To the right, from back to front, are the Japanese Experiment Module, the Raffaello multi-purpose logistics module, and the European Space Agency's Columbus scientific research module. To the left in front is the starboard truss segment S5. Behind it is the test stand that will hold the Experiment Logistics Module Pressurized Section for the Japanese Experiment Module. The logistics module is one of the components of the Japanese Experiment Module or JEM, also known as Kibo, which means "hope" in Japanese. Kibo comprises six components: two research facilities -- the Pressurized Module and Exposed Facility; a Logistics Module attached to each of them; a Remote Manipulator System; and an Inter-Orbit Communication System unit. Kibo also has a scientific airlock through which experiments are transferred and exposed to the external environment of space. Kibo is Japan's first human space facility and its primary contribution to the station. Kibo will enhance the unique research capabilities of the orbiting complex by providing an additional environment in which astronauts can conduct science experiments. The various components of JEM will be assembled in space over the course of three Space Shuttle missions. The first of those three missions, STS-123, will carry the Experiment Logistics Module Pressurized Section aboard the Space Shuttle Endeavour, targeted for launch in 2007.

High-latitude spacecraft charging in low-Earth polar orbit

NASA Astrophysics Data System (ADS)

Frooninckx, Thomas B.

Spacecraft charging within the upper ionosphere is commonly thought to be insignificant and thus has received little attention. Recent experimental evidence has shown that electric potential differences as severe as 680 volts can develop between Defense Meteorological Satellite Program (DMSP) polar-orbiting (840 kilometers) spacecraft and their high-latitude environment. To explore space vehicle charging in this region more fully, an analysis was performed using DMSP F6, F7, F8, and F9 satellite precipitating particle and ambient plasma measurements taken during the winters of 1986-87 (solar minimum) and 1989-90 (solar maximum). An extreme solar cycle dependence was discovered as charging occurred more frequently and with greater severity during the period of solar minimum. One hundred seventy charging events ranging from -46 to 1,430 volts were identified, and satellite measurements and Time Dependent Ionospheric Model (TDIM) output were used to characterize the environments which generated and inhibited these potentials. All current sources were considered to determine the cause of the solar cycle dependence.

Large orbital polarization in a metallic square-planar nickelate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Junjie; Botana, A. S.; Freeland, J. W.

High temperature cuprate superconductivity remains a defining problem in condensed matter physics.1,2 Among myriad approaches to addressing this problem has been the study of alternative transition metal oxides3,4 with similar structures and 3d electron count that are suggested as proxies for cuprate physics. Here, we report one such alternative: the low-valent, quasi-two-dimensional trilayer nickelates, R4Ni3O8 (R=La and Pr). By combining x-ray absorption spectroscopy and density functional theory calculations, we find that these compounds exhibit a low-spin configuration and significant orbital polarization of the unoccupied eg states with pronounced dx2-y2 character near the Fermi energy. Notably, a charge-ordered stripe phase, previouslymore » reported for La4Ni3O8,5 collapses in favor of a metallic ground state when substituting La with Pr, offering entrée to a region of 3d electron count important to hole-doped high-Tc cuprates but in the absence of quenched disorder.« less

The 1997 Spring Regression of the Martian South Polar Cap: Mars Orbiter Camera Observations

USGS Publications Warehouse

James, P.B.; Cantor, B.A.; Malin, M.C.; Edgett, K.; Carr, M.H.; Danielson, G.E.; Ingersoll, A.P.; Davies, M.E.; Hartmann, W.K.; McEwen, A.S.; Soderblom, L.A.; Thomas, P.C.; Veverka, J.

2000-01-01

The Mars Orbiter cameras (MOC) on Mars Global Surveyor observed the south polar cap of Mars during its spring recession in 1997. The images acquired by the wide angle cameras reveal a pattern of recession that is qualitatively similar to that observed by Viking in 1977 but that does differ in at least two respects. The 1977 recession in the 0o to 120o longitude sector was accelerated relative to the 1997 observations after LS = 240o; the Mountains of Mitchel also detached from the main cap earlier in 1997. Comparison of the MOC images with Mars Orbiter Laser Altimeter data shows that the Mountains of Mitchel feature is controlled by local topography. Relatively dark, low albedo regions well within the boundaries of the seasonal cap were observed to have red-to-violet ratios that characterize them as frost units rather than unfrosted or partially frosted ground; this suggests the possibility of regions covered by CO2 frost having different grain sizes.

Useful lower limits to polarization contributions to intermolecular interactions using a minimal basis of localized orthogonal orbitals: theory and analysis of the water dimer.

PubMed

Azar, R Julian; Horn, Paul Richard; Sundstrom, Eric Jon; Head-Gordon, Martin

2013-02-28

The problem of describing the energy-lowering associated with polarization of interacting molecules is considered in the overlapping regime for self-consistent field wavefunctions. The existing approach of solving for absolutely localized molecular orbital (ALMO) coefficients that are block-diagonal in the fragments is shown based on formal grounds and practical calculations to often overestimate the strength of polarization effects. A new approach using a minimal basis of polarized orthogonal local MOs (polMOs) is developed as an alternative. The polMO basis is minimal in the sense that one polarization function is provided for each unpolarized orbital that is occupied; such an approach is exact in second-order perturbation theory. Based on formal grounds and practical calculations, the polMO approach is shown to underestimate the strength of polarization effects. In contrast to the ALMO method, however, the polMO approach yields results that are very stable to improvements in the underlying AO basis expansion. Combining the ALMO and polMO approaches allows an estimate of the range of energy-lowering due to polarization. Extensive numerical calculations on the water dimer using a large range of basis sets with Hartree-Fock theory and a variety of different density functionals illustrate the key considerations. Results are also presented for the polarization-dominated Na(+)CH4 complex. Implications for energy decomposition analysis of intermolecular interactions are discussed.

Spin-orbit beams for optical chirality measurement

NASA Astrophysics Data System (ADS)

Samlan, C. T.; Suna, Rashmi Ranjan; Naik, Dinesh N.; Viswanathan, Nirmal K.

2018-01-01

Accurate measurement of chirality is essential for the advancement of natural and pharmaceutical sciences. We report here a method to measure chirality using non-separable states of light with geometric phase-gradient in the circular polarization basis, which we refer to as spin-orbit beams. A modified polarization Sagnac interferometer is used to generate spin-orbit beams wherein the spin and orbital angular momentum of the input Gaussian beam are coupled. The out-of-phase interference between counter-propagating Gaussian beams with orthogonal spin states and lateral-shear or/and linear-phase difference between them results in spin-orbit beams with linear and azimuthal phase gradient. The spin-orbit beams interact efficiently with the chiral medium, inducing a measurable change in the center-of-mass of the beam, using the polarization rotation angle and hence the chirality of the medium are accurately calculated. Tunable dynamic range of measurement and flexibility to introduce large values of orbital angular momentum for the spin-orbit beam, to improve the measurement sensitivity, highlight the techniques' versatility.

Solar polar orbit radio telescope for space weather forecast

NASA Astrophysics Data System (ADS)

Wu, J.; Wang, C.; Wang, S.; Wu, J.; Sun, W.; Cai, J.; Yan, Y.

Radio emission from density plasma can be detected at low radio frequencies. An image of such plasma clouds of the entire inner interplanetary space is always a wanted input for space weather forecast and ICME propagation studies. To take such an image within the ecliptic plane may not fully explore what is happening around the Sun not only because of the blockage of the Sun, also because most of the ICMEs are propagating in the low-latitude of the Sun, near the ecliptic plane. It is then proposed to launch a solar polar orbit radio telescope to acquire high density plasma cloud images from the entire inner interplanetary space. Low radio frequency images require a large antenna aperture in space. It is, therefore, proposed to use the existing passive synthetic aperture radiometer technology to reduce mass and complicity of the deployment system of the big antenna. In order to reduce the mass of the antenna by using minimum number of elements, a zero redundant antenna element design can be used with a rotating time-shared sampling system. A preliminary assessment study shows the mission is feasible.

Extensive Radiation Shielding Analysis for Different Spacecraft Orbits

NASA Astrophysics Data System (ADS)

Çay, Yiǧit; Kaymaz, Zerefsan

2016-07-01

Radiation environment around Earth poses a great danger for spacecraft and causes immature de-orbiting or loss of the spacecraft in near Earth space environment. In this study, a student project has been designed to build a CubeSat, PolarBeeSail (PBS), with an orbit having inclination of 80°, 4 Re in perigee and 20 Re in apogee to study the polar magnetospheric environment. An extensive radiation dose analyses were carried out for PBS orbit, and integral and differential fluxes were calculated using SPENVIS tools. A shielding analysis was performed and an optimum Aluminum thickness, 3 mm, was obtained. These results for PBS were then compared for other orbits at different altitudes both for polar and equatorial orbits. For this purpose, orbital characteristics of POES-19 and GOES-15 were used. The resulting proton flux analyses, TID analyses, and further shielding studies were conducted; comparisons and recommendations were made for future design of spacecraft that will use these environments.

Use of an auxiliary basis set to describe the polarization in the fragment molecular orbital method

NASA Astrophysics Data System (ADS)

Fedorov, Dmitri G.; Kitaura, Kazuo

2014-03-01

We developed a dual basis approach within the fragment molecular orbital formalism enabling efficient and accurate use of large basis sets. The method was tested on water clusters and polypeptides and applied to perform geometry optimization of chignolin (PDB: 1UAO) in solution at the level of DFT/6-31++G∗∗, obtaining a structure in agreement with experiment (RMSD of 0.4526 Å). The polarization in polypeptides is discussed with a comparison of the α-helix and β-strand.

Electron and Ion Distributions at High Latitudes as Measured by the Air Force Polar Orbiting Satellites.

DTIC Science & Technology

1985-02-26

between the VW. full data set and the earlier determined dependencies of E on V V Kp are quite good and will not be repeated or modified here. It ""is...CHART NATIONAL BUREAU OF STANDARDS-93A AFGL-TR-85-0021 ELECTRON AND ION DISTRIBUTIONS AT HIGH LATITUDES AS MEASURED BY THE AIR FORCE POLAR ORBITING ...10. SOURCE OF FUNDING NO$. Hanscom AFB, MA 01731 PROGRAM PROJECT TASK WORK UNIT ELEMENT NO. NO. NO. NO. 61102F 2311 Gi BA 11. TITLE (Include Security

Stable low-altitude orbits around Ganymede considering a disturbing body in a circular orbit

NASA Astrophysics Data System (ADS)

Cardoso dos Santos, J.; Carvalho, J. P. S.; Vilhena de Moraes, R.

2014-10-01

Some missions are being planned to visit Ganymede like the Europa Jupiter System Mission that is a cooperation between NASA and ESA to insert the spacecraft JGO (Jupiter Ganymede Orbiter) into Ganymedes orbit. This comprehension of the dynamics of these orbits around this planetary satellite is essential for the success of this type of mission. Thus, this work aims to perform a search for low-altitude orbits around Ganymede. An emphasis is given in polar orbits and it can be useful in the planning of space missions to be conducted around, with respect to the stability of orbits of artificial satellites. The study considers orbits of artificial satellites around Ganymede under the influence of the third-body (Jupiter's gravitational attraction) and the polygenic perturbations like those due to non-uniform distribution of mass (J_2 and J_3) of the main body. A simplified dynamic model for these perturbations is used. The Lagrange planetary equations are used to describe the orbital motion of the artificial satellite. The equations of motion are developed in closed form to avoid expansions in eccentricity and inclination. The results show the argument of pericenter circulating. However, low-altitude (100 and 150 km) polar orbits are stable. Another orbital elements behaved variating with small amplitudes. Thus, such orbits are convenient to be applied to future space missions to Ganymede. Acknowledgments: FAPESP (processes n° 2011/05671-5, 2012/12539-9 and 2012/21023-6).

Family of Orbiters

NASA Technical Reports Server (NTRS)

2008-01-01

This image shows the paths of three spacecraft currently in orbit around Mars, as well as the path by which NASA's Phoenix Mars Lander will approach and land on the planet. The t-shaped crosses show where the orbiters will be when Phoenix enters the atmosphere, while the x-shaped crosses show their location at landing time.

All three orbiters, NASA's Mars Reconnaissance Orbiter, NASA's Mars Odyssey and the European Space Agency's Mars Express, will be monitoring Phoenix during the final steps of its journey to the Red Planet.

Phoenix will land just south of Mars's north polar ice cap.

The determination of the orbit of the Japanese satellite Ajisai and the GEM-T1 and GEM-T2 gravity field models

NASA Technical Reports Server (NTRS)

Sanchez, Braulio V.

1990-01-01

The Japanese Experimental Geodetic Satellite Ajisai was launched on August 12, 1986. In response to the TOPEX-POSEIDON mission requirements, the GSFC Space Geodesy Branch and its associates are producing improved models of the Earth's gravitational field. With the launch of Ajisai, precise laser data is now available which can be used to test many current gravity models. The testing of the various gravity field models show improvements of more than 70 percent in the orbital fits when using GEM-T1 and GEM-T2 relative to results obtained with the earlier GEM-10B model. The GEM-T2 orbital fits are at the 13-cm level (RMS). The results of the tests with the various versions of the GEM-T1 model indicate that the addition of satellite altimetry and surface gravity anomalies as additional data types should improve future gravity field models.

Mid-Latitude versus Polar-Latitude Transitional Impact Craters: Geometric Properties from Mars Orbiter Laser Altimeter (MOLA) Observations and Viking Images

NASA Technical Reports Server (NTRS)

Matias, A.; Garvin, J. B.; Sakimoto, S. E. H.

1998-01-01

One intriguing aspect of martian impact crater morphology is the change of crater cavity and ejecta characteristics from the mid-latitudes to the polar regions. This is thought to reflect differences in target properties such as an increasing presence of ice in the polar regions. Previous image-based efforts concerning martian crater morphology has documented some aspects of this, but has been hampered by the lack of adequate topography data. Recent Mars Orbiter Laser Altimeter (MOLA) topographic profiles provide a quantitative perspective for interpreting the detailed morphologies of martian crater cavities and ejecta morphology. This study is a preliminary effort to quantify the latitude-dependent differences in morphology with the goal of identifying target-dependent and crater modification effects from the combined of images and MOLA topography. We combine the available MOLA profiles and the corresponding Viking Mars Digital Image Mosaics (MDIMS), and high resolution Viking Orbiter images to focus on two transitional craters; one on the mid-latitudes, and one in the North Polar region. One MOLA pass (MGS Orbit 34) traverses the center of a 15.9 km diameter fresh complex crater located at 12.8degN 83.8degE on the Hesperian ridge plains unit (Hvr). Viking images, as well as MOLA data, show that this crater has well developed wall terraces and a central peak with 429 m of relative relief. Three MOLA passes have been acquired for a second impact crater, which is located at 69.5degN 41degE on the Vastitas Borealis Formation. This fresh rampart crater lacks terraces and central peak structures and it has a depth af 579 m. Correlation between images and MOLA topographic profiles allows us to construct basic facies maps of the craters. Eight main units were identified, four of which are common on both craters.

Navy Tactical Ocean Optical Products from the National Polar-orbiting Operational Environmental Satellite System (NPOESS)

NASA Astrophysics Data System (ADS)

Lyon, P. E.; Arnone, R.

2006-12-01

The Naval Research Laboratory at Stennis Space Center (NRLSSC) is preparing to produce optical products for Naval operations support from the National Polar-orbiting Operational Environmental Satellite System (NPOESS). This effort will leverage existing hardware and software systems in place at NRLSSC which are currently used to produce optical products from current sensors SeaWiFS and MODIS Aqua/Terra. This effort is part of an inter agency collaboration between NASA, NOAA, IPO, NRL and the prime contractor for NPOESS, Northrop Grumman / Raytheon. This poster presents an outline of the NRLSSC's plan for achieving the best possible optical products from NPOESS.

Creation of half-metallic f -orbital Dirac fermion with superlight elements in orbital-designed molecular lattice

NASA Astrophysics Data System (ADS)

Cui, Bin; Huang, Bing; Li, Chong; Zhang, Xiaoming; Jin, Kyung-Hwan; Zhang, Lizhi; Jiang, Wei; Liu, Desheng; Liu, Feng

2017-08-01

Magnetism in solids generally originates from the localized d or f orbitals that are hosted by heavy transition-metal elements. Here, we demonstrate a mechanism for designing a half-metallic f -orbital Dirac fermion from superlight s p elements. Combining first-principles and model calculations, we show that bare and flat-band-sandwiched (FBS) Dirac bands can be created when C20 molecules are deposited into a two-dimensional hexagonal lattice, which are composed of f -molecular orbitals (MOs) derived from s p -atomic orbitals (AOs). Furthermore, charge doping of the FBS Dirac bands induces spontaneous spin polarization, converting the system into a half-metallic Dirac state. Based on this discovery, a model of a spin field effect transistor is proposed to generate and transport 100% spin-polarized carriers. Our finding illustrates a concept to realize exotic quantum states by manipulating MOs, instead of AOs, in orbital-designed molecular crystal lattices.

No evidence for orbital loop currents in charge-ordered YBa2Cu3O6 +x from polarized neutron diffraction

NASA Astrophysics Data System (ADS)

Croft, T. P.; Blackburn, E.; Kulda, J.; Liang, Ruixing; Bonn, D. A.; Hardy, W. N.; Hayden, S. M.

2017-12-01

It has been proposed that the pseudogap state of underdoped cuprate superconductors may be due to a transition to a phase which has circulating currents within each unit cell. Here, we use polarized neutron diffraction to search for the corresponding orbital moments in two samples of underdoped YBa2Cu3O6 +x with doping levels p =0.104 and 0.123. In contrast to some other reports using polarized neutrons, but in agreement with nuclear magnetic resonance and muon spin rotation measurements, we find no evidence for the appearance of magnetic order below 300 K. Thus, our experiment suggests that such order is not an intrinsic property of high-quality cuprate superconductor single crystals. Our results provide an upper bound for a possible orbital loop moment which depends on the pattern of currents within the unit cell. For example, for the CC-θI I pattern proposed by Varma, we find that the ordered moment per current loop is less than 0.013 μB for p =0.104 .

Early On-Orbit Performance of the Visible Infrared Imaging Radiometer Suite Onboard the Suomi National Polar-Orbiting Partnership (S-NPP) Satellite

NASA Technical Reports Server (NTRS)

Cao, Changyong; DeLuccia, Frank J.; Xiong, Xiaoxiong; Wolfe, Robert; Weng, Fuzhong

2014-01-01

The Visible Infrared Imaging Radiometer Suite (VIIRS) is one of the key environmental remote-sensing instruments onboard the Suomi National Polar-Orbiting Partnership spacecraft, which was successfully launched on October 28, 2011 from the Vandenberg Air Force Base, California. Following a series of spacecraft and sensor activation operations, the VIIRS nadir door was opened on November 21, 2011. The first VIIRS image acquired signifies a new generation of operational moderate resolution-imaging capabilities following the legacy of the advanced very high-resolution radiometer series on NOAA satellites and Terra and Aqua Moderate-Resolution Imaging Spectroradiometer for NASA's Earth Observing system. VIIRS provides significant enhancements to the operational environmental monitoring and numerical weather forecasting, with 22 imaging and radiometric bands covering wavelengths from 0.41 to 12.5 microns, providing the sensor data records for 23 environmental data records including aerosol, cloud properties, fire, albedo, snow and ice, vegetation, sea surface temperature, ocean color, and nigh-time visible-light-related applications. Preliminary results from the on-orbit verification in the postlaunch check-out and intensive calibration and validation have shown that VIIRS is performing well and producing high-quality images. This paper provides an overview of the onorbit performance of VIIRS, the calibration/validation (cal/val) activities and methodologies used. It presents an assessment of the sensor initial on-orbit calibration and performance based on the efforts from the VIIRS-SDR team. Known anomalies, issues, and future calibration efforts, including the long-term monitoring, and intercalibration are also discussed.

Investigating the auroral electrojets with low altitude polar orbiting satellites

NASA Astrophysics Data System (ADS)

Moretto, T.; Olsen, N.; Ritter, P.; Lu, G.

2002-07-01

Three geomagnetic satellite missions currently provide high precision magnetic field measurements from low altitude polar orbiting spacecraft. We demonstrate how these data can be used to determine the intensity and location of the horizontal currents that flow in the ionosphere, predominantly in the auroral electrojets. First, we examine the results during a recent geomagnetic storm. The currents derived from two satellites at different altitudes are in very good agreement, which verifies good stability of the method. Further, a very high degree of correlation (correlation coefficients of 0.8 0.9) is observed between the amplitudes of the derived currents and the commonly used auroral electrojet indices based on magnetic measurements at ground. This points to the potential of defining an auroral activity index based on the satellite observations, which could be useful for space weather monitoring. A specific advantage of the satellite observations over the ground-based magnetic measurements is their coverage of the Southern Hemisphere, as well as the Northern. We utilize this in an investigation of the ionospheric currents observed in both polar regions during a period of unusually steady interplanetary magnetic field with a large negative Y-component. A pronounced asymmetry is found between the currents in the two hemispheres, which indicates real inter-hemispheric differences beyond the mirror-asymmetry between hemispheres that earlier studies have revealed. The method is also applied to another event for which the combined measurements of the three satellites provide a comprehensive view of the current systems. The analysis hereof reveals some surprising results concerning the connection between solar wind driver and the resulting ionospheric currents. Specifically, preconditioning of the magnetosphere (history of the interplanetary magnetic field) is seen to play an important role, and in the winther hemisphere, it seems to be harder to drive currents on the

Differential roles of polar orbital prefrontal cortex and parietal lobes in logical reasoning with neutral and negative emotional content.

PubMed

Eimontaite, Iveta; Goel, Vinod; Raymont, Vanessa; Krueger, Frank; Schindler, Igor; Grafman, Jordan

2018-05-14

To answer the question of how brain pathology affects reasoning about negative emotional content, we administered a disjunctive logical reasoning task involving arguments with neutral content (e.g. Either there are tigers or women in NYC, but not both; There are no tigers in NYC; There are women in NYC) and emotionally laden content (e.g. Either there are pedophiles or politicians in Texas, but not both; There are politicians in Texas; There are no pedophiles in Texas) to 92 neurological patients with focal lesions to various parts of the brain. A Voxel Lesion Symptom Mapping (VLSM) analysis identified 16 patients, all with lesions to the orbital polar prefrontal cortex (BA 10 & 11), as being selectively impaired in the emotional reasoning condition. Another 17 patients, all with lesions to the parietal cortex, were identified as being impaired in the neutral content condition. The reasoning scores of these two patient groups, along with 23 matched normal controls, underwent additional analysis to explore the effect of belief bias. This analysis revealed that the differences identified above were largely driven by trials where there was an incongruency between the believability of the conclusion and the validity of the argument (i.e. valid argument /false conclusion or invalid argument /true conclusion). Patients with lesions to polar orbital prefrontal cortex underperformed in incongruent emotional content trials and over performed in incongruent neutral content trials (compared to both normal controls and patients with parietal lobe lesions). Patients with lesions to parietal lobes underperformed normal controls (at a trend level) in neutral trials where there was a congruency between the believability of the conclusion and the validity of the argument (i.e. valid argument/true conclusion or invalid argument/false conclusion). We conclude that lesions to the polar orbital prefrontal cortex (i) prevent these patients from enjoying any emotionally induced cognitive

The Suomi National Polar-Orbiting Partnership (SNPP): Continuing NASA Research and Applications

NASA Technical Reports Server (NTRS)

Butler, James; Gleason, James; Jedlovec, Gary; Coronado, Patrick

2015-01-01

The Suomi National Polar-orbiting Partnership (SNPP) satellite was successfully launched into a polar orbit on October 28, 2011 carrying 5 remote sensing instruments designed to provide data to improve weather forecasts and to increase understanding of long-term climate change. SNPP provides operational continuity of satellite-based observations for NOAA's Polar-orbiting Operational Environmental Satellites (POES) and continues the long-term record of climate quality observations established by NASA's Earth Observing System (EOS) satellites. In the 2003 to 2011 pre-launch timeframe, NASA's SNPP Science Team assessed the adequacy of the operational Raw Data Records (RDRs), Sensor Data Records (SDRs), and Environmental Data Records (EDRs) from the SNPP instruments for use in NASA Earth Science research, examined the operational algorithms used to produce those data records, and proposed a path forward for the production of climate quality products from SNPP. In order to perform these tasks, a distributed data system, the NASA Science Data Segment (SDS), ingested RDRs, SDRs, and EDRs from the NOAA Archive and Distribution and Interface Data Processing Segments, ADS and IDPS, respectively. The SDS also obtained operational algorithms for evaluation purposes from the NOAA Government Resource for Algorithm Verification, Independent Testing and Evaluation (GRAVITE). Within the NASA SDS, five Product Evaluation and Test Elements (PEATEs) received, ingested, and stored data and performed NASA's data processing, evaluation, and analysis activities. The distributed nature of this data distribution system was established by physically housing each PEATE within one of five Climate Analysis Research Systems (CARS) located at either at a NASA or a university institution. The CARS were organized around 5 key EDRs directly in support of the following NASA Earth Science focus areas: atmospheric sounding, ocean, land, ozone, and atmospheric composition products. The PEATES provided

Integrating Polar-Orbiting Products into the Forecast Routine for Explosive Cyclogenesis and Extratropical Transition

NASA Astrophysics Data System (ADS)

Folmer, M. J.; Berndt, E.; Malloy, K.; Mazur, K.; Sienkiewicz, J. M.; Phillips, J.; Goldberg, M.

2017-12-01

The Joint Polar Satellite System (JPSS) was added to the Satellite Proving Ground for Marine, Precipitation, and Satellite Analysis in late 2012, just in time to introduce forecasters to the very high-resolution imagery available from the Suomi-National Polar Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) instrument when observing and forecasting Hurricane Sandy (2012). Since that time, more polar products have been introduced to the forecast routines at the National Weather Service (NWS) Ocean Prediction Center (OPC), Weather Prediction Center (WPC), Tropical Analysis and Forecast Branch (TAFB) of the National Hurricane Center (NHC), and the Satellite Analysis Branch (SAB) of the National Environmental Satellite, Data, and Information Service (NESDIS). These new data sets have led to research projects at the OPC and TAFB that have specifically been looking into the early identification of stratospheric intrusions that lead to explosive cyclogenesis or extratropical transition of tropical cyclones. Currently NOAA Unique CrIS/ATMS Processing System (NUCAPS) temperature and moisture soundings are available in AWIPS-II as a point-based display. Traditionally soundings are used to anticipate and forecast severe convection, however unique and valuable information can be gained from soundings for other forecasting applications, such as extratropical transition, especially in data sparse regions. Additional research has been conducted to look at how JPSS CrIS/ATMS NUCAPS soundings might help forecasters identify the pre-extratropical transition or pre-explosive cyclogenesis environments, leading to earlier diagnosis and better public advisories. CrIS/ATMS NUCAPS soundings, IASI and NUCAPS ozone products, NOAA G-IV GPS dropwindsondes, the Air Mass RGB, and single water vapor channels have been analyzed to look for the precursors to these high impact events. This presentation seeks to show some early analysis and potential uses of the polar-orbiting

Estimation of land-atmosphere energy transfer over the Tibetan Plateau by a combination use of geostationary and polar-orbiting satellite data

NASA Astrophysics Data System (ADS)

Zhong, L.; Ma, Y.

2017-12-01

Land-atmosphere energy transfer is of great importance in land-atmosphere interactions and atmospheric boundary layer processes over the Tibetan Plateau (TP). The energy fluxes have high temporal variability, especially in their diurnal cycle, which cannot be acquired by polar-orbiting satellites alone because of their low temporal resolution. Therefore, it's of great practical significance to retrieve land surface heat fluxes by a combination use of geostationary and polar orbiting satellites. In this study, a time series of the hourly LST was estimated from thermal infrared data acquired by the Chinese geostationary satellite FengYun 2C (FY-2C) over the TP. The split window algorithm (SWA) was optimized using a regression method based on the observations from the Enhanced Observing Period (CEOP) of the Asia-Australia Monsoon Project (CAMP) on the Tibetan Plateau (CAMP/Tibet) and Tibetan observation and research platform (TORP), the land surface emissivity (LSE) from the Moderate Resolution Imaging Spectroradiometer (MODIS), and the water vapor content from the National Centers for Environmental Prediction (NCEP) Climate Forecast System Reanalysis (CFSR) project. The 10-day composite hourly LST data were generated via the maximum value composite (MVC) method to reduce the cloud effects. The derived LST was validated by the field observations of CAMP/Tibet and TORP. The results show that the retrieved LST and in situ data have a very good correlation (with root mean square error (RMSE), mean bias (MB), mean absolute error (MAE) and correlation coefficient (R) values of 1.99 K, 0.83 K, 1.71 K, and 0.991, respectively). Together with other characteristic parameters derived from polar-orbiting satellites and meteorological forcing data, the energy balance budgets have been retrieved finally. The validation results showed there was a good consistency between estimation results and in-situ measurements over the TP, which prove the robustness of the proposed estimation

Integrating Satellite Measurements from Polar-orbiting instruments into Smoke Disperson Forecasts

NASA Astrophysics Data System (ADS)

Smith, N.; Pierce, R. B.; Barnet, C.; Gambacorta, A.; Davies, J. E.; Strabala, K.

2015-12-01

The IDEA-I (Infusion of Satellite Data into Environmental Applications-International) is a real-time system that currently generates trajectory-based forecasts of aerosol dispersion and stratospheric intrusions. Here we demonstrate new capabilities that use satellite measurements from the Joint Polar Satellite System (JPSS) Suomi-NPP (S-NPP) instruments (operational since 2012) in the generation of trajectory-based predictions of smoke dispersion from North American wildfires. Two such data products are used, namely the Visible Infrared Imaging Radiometer Suite (VIIRS) Aerosol Optical Depth (AOD) and the combined Cross-track Infrared Sounder (CrIS) and Advanced Technology Microwave Sounder (ATMS) NOAA-Unique CrIS-ATMS Processing System (NUCAPS) carbon monoxide (CO) retrievals. The latter is a new data product made possible by the release of full spectral-resolution CrIS measurements since December 2014. Once NUCAPS CO becomes operationally available it will be used in real-time applications such as IDEA-I along with VIIRS AOD and meteorological forecast fields to support National Weather Service (NWS) Incident Meteorologist (IMET) and air quality management decision making. By combining different measurements, the information content of the IDEA-I transport and dispersion forecast is improved within the complex terrain features that dominate the Western US and Alaska. The primary user community of smoke forecasts is the Western regions of the National Weather Service (NWS) and US Environmental Protection Agency (EPA) due to the significant impacts of wildfires in these regions. With this we demonstrate the quality of the smoke dispersion forecasts that can be achieved by integrating polar-orbiting satellite measurements with forecast models to enable on-site decision support services for fire incident management teams and other real-time air quality agencies.

Quench of paramagnetic orbital selective Mott phase and appearance of antiferromagnetic orbital selective slater phase in multiorbital correlated systems

NASA Astrophysics Data System (ADS)

Quan, Ya-Min; Liu, Da-Yong; Lin, Hai-Qing; Zou, Liang-Jian

2018-06-01

We present the modulation of magnetic order on the orbital selective Mott phases (OSMP) and the metal-insulator transitions (MIT) of multi-orbital Hubbard models by employing the rotationally invariant slave-boson methods. We show that at half filling, the well-known paramagnetic (PM) OSMP is completely covered by an antiferromagnetic (AFM) Slater insulator, and the PM Mott phase by an AFM Mott insulator when electron correlation strength varies from intermediate to strong both in two- and three-orbitals Hubbard systems. Away from half-filling, we find that a partial-polarized AFM orbital-selective Slater phase appears in the intermediate correlation regime, and an almost full-polarized AFM OSMP fully covers the paramagnetic OSMP. In addition, the ferromagnetic phase in the three-orbital case is more robust than that in the two-orbital case. These results demonstrate that the modulation of magnetic correlation to the quasiparticle spectra leads to much rich and more interesting MIT scenario in multiorbital correlated systems.

Demonstration of polarization-insensitive spatial light modulation using a single polarization-sensitive spatial light modulator.

PubMed

Liu, Jun; Wang, Jian

2015-07-06

We present a simple configuration incorporating a single polarization-sensitive phase-only liquid crystal spatial light modulator (LC-SLM) to facilitate polarization-insensitive spatial light modulation. The polarization-insensitive configuration is formed by a polarization beam splitter (PBS), a polarization-sensitive phase-only LC-SLM, a half-wave plate (HWP), and a mirror in a loop structure. We experimentally demonstrate polarization-insensitive spatial light modulations for incident linearly polarized beams with different polarization states and polarization-multiplexed beams. Polarization-insensitive spatial light modulations generating orbital angular momentum (OAM) beams are demonstrated in the experiment. The designed polarization-insensitive configuration may find promising applications in spatial light modulations accommodating diverse incident polarizations.

Bulk electron spin polarization generated by the spin Hall current

NASA Astrophysics Data System (ADS)

Korenev, V. L.

2006-07-01

It is shown that the spin Hall current generates a nonequilibrium spin polarization in the interior of crystals with reduced symmetry in a way that is drastically different from the previously well-known “equilibrium” polarization during the spin relaxation process. The steady state spin polarization value does not depend on the strength of spin-orbit interaction offering possibility to generate relatively high spin polarization even in the case of weak spin-orbit coupling.

Demonstration of polarization-insensitive spatial light modulation using a single polarization-sensitive spatial light modulator

PubMed Central

Liu, Jun; Wang, Jian

2015-01-01

We present a simple configuration incorporating a single polarization-sensitive phase-only liquid crystal spatial light modulator (LC-SLM) to facilitate polarization-insensitive spatial light modulation. The polarization-insensitive configuration is formed by a polarization beam splitter (PBS), a polarization-sensitive phase-only LC-SLM, a half-wave plate (HWP), and a mirror in a loop structure. We experimentally demonstrate polarization-insensitive spatial light modulations for incident linearly polarized beams with different polarization states and polarization-multiplexed beams. Polarization-insensitive spatial light modulations generating orbital angular momentum (OAM) beams are demonstrated in the experiment. The designed polarization-insensitive configuration may find promising applications in spatial light modulations accommodating diverse incident polarizations. PMID:26146032

Jupiter's magnetosphere and aurorae observed by the Juno spacecraft during its first polar orbits.

PubMed

Connerney, J E P; Adriani, A; Allegrini, F; Bagenal, F; Bolton, S J; Bonfond, B; Cowley, S W H; Gerard, J-C; Gladstone, G R; Grodent, D; Hospodarsky, G; Jorgensen, J L; Kurth, W S; Levin, S M; Mauk, B; McComas, D J; Mura, A; Paranicas, C; Smith, E J; Thorne, R M; Valek, P; Waite, J

2017-05-26

The Juno spacecraft acquired direct observations of the jovian magnetosphere and auroral emissions from a vantage point above the poles. Juno's capture orbit spanned the jovian magnetosphere from bow shock to the planet, providing magnetic field, charged particle, and wave phenomena context for Juno's passage over the poles and traverse of Jupiter's hazardous inner radiation belts. Juno's energetic particle and plasma detectors measured electrons precipitating in the polar regions, exciting intense aurorae, observed simultaneously by the ultraviolet and infrared imaging spectrographs. Juno transited beneath the most intense parts of the radiation belts, passed about 4000 kilometers above the cloud tops at closest approach, well inside the jovian rings, and recorded the electrical signatures of high-velocity impacts with small particles as it traversed the equator. Copyright © 2017, American Association for the Advancement of Science.

Chemical control of orbital polarization in artificially structured transition-metal oxides: La2NiXO6 (X=B,Al,Ga,In) from first principles

NASA Astrophysics Data System (ADS)

Han, M. J.; Marianetti, C. A.; Millis, A. J.

2010-10-01

The application of modern layer-by-layer growth techniques to transition-metal oxide materials raises the possibility of creating new classes of materials with rationally designed correlated electron properties. An important step toward this goal is the demonstration that electronic structure can be controlled by atomic composition. In compounds with partially occupied transition-metal d shells, one important aspect of the electronic structure is the relative occupancy of different d orbitals. Previous work has established that strain and quantum confinement can be used to influence orbital occupancy. In this paper we demonstrate a different modality for orbital control in transition-metal oxide heterostructures, using density-functional band calculations supplemented by a tight-binding analysis to show that the choice of nontransition-metal counterion X in transition-metal oxide heterostructures composed of alternating LaNiO3 and LaXO3 units strongly affects orbital occupancy, changing the magnitude and in some cases the sign of the orbital polarization.

Satellite orbits in Levi-Civita space

NASA Astrophysics Data System (ADS)

Humi, Mayer

2018-03-01

In this paper we consider satellite orbits in central force field with quadratic drag using two formalisms. The first using polar coordinates in which the satellite angular momentum plays a dominant role. The second is in Levi-Civita coordinates in which the energy plays a central role. We then merge these two formalisms by introducing polar coordinates in Levi-Civita space and derive a new equation for satellite orbits which unifies these two paradigms. In this equation energy and angular momentum appear on equal footing and thus characterize the orbit by its two invariants. Using this formalism we show that equatorial orbits around oblate spheroids can be expressed analytically in terms of Elliptic functions. In the second part of the paper we derive in Levi-Civita coordinates a linearized equation for the relative motion of two spacecrafts whose trajectories are in the same plane. We carry out also a numerical verification of these equations.

The polarization modulators based on liquid crystal variable retarders for the PHI and METIS instruments for the solar orbiter mission

NASA Astrophysics Data System (ADS)

Alvarez-Herrero, A.; García Parejo, P.; Laguna, H.; Villanueva, J.; Barandiarán, J.; Bastide, L.; Reina, M.; Royo, M.

2017-11-01

A technical development activity was carried out from 2009 to 2011 under ESA supervision to validate the Liquid Crystal Variable Retarders (LCVRs) as polarization modulators for the Solar Orbiter mission. After this, the technology achieved the Technology Readiness Level 5 (TRL5) corresponding to "Component Validation in Relevant Environment". Afterwards, additional tests and characterizations were performed in order to select the final specifications of the LCVRs cells to optimize their performances under the mission environmental conditions. The LCVRs will be used to measure the complete Stokes vector of the incoming light in PHI (The Polarimetric and Helioseismic Imager for Solar Orbiter) and the linear polarization in the case of METIS (Multi Element Telescope for Imaging and Spectroscopy). PHI is an imaging spectro-polarimeter that will acquire high resolution solar magnetograms. On the other hand, METIS is a solar coronagraph that will analyze the linear polarization for observations of the visible-light K-corona. The polarization modulators are described in this work including the optical, mechanical, thermal and electrical aspects. Both modulators will consist of two identical LCVRs with a relative azimuth orientation of 45° for PHI and parallel for the METIS modulator. In the first case, the configuration allows the analysis of the full Stockes vector with maximum polarimetric efficiencies. In the second setup, wide acceptance angles (<=+/-4°) are obtained. The polarization modulators will be thermal controlled to reach a stability better than +/-0.5°C during the measurement acquisition time (<=60s) under all the operational thermal conditions. This is required to fulfill the required polarimetric accuracy (<=10-3), because the LCVRs behavior has a dependence on temperature. The mechanical design has been conceived to minimize mass, volume and the thermal conductivity as well as the mechanical stress produced by the mounts to the cells, but taking into

Explicit polarization (X-Pol) potential using ab initio molecular orbital theory and density functional theory.

PubMed

Song, Lingchun; Han, Jaebeom; Lin, Yen-lin; Xie, Wangshen; Gao, Jiali

2009-10-29

The explicit polarization (X-Pol) method has been examined using ab initio molecular orbital theory and density functional theory. The X-Pol potential was designed to provide a novel theoretical framework for developing next-generation force fields for biomolecular simulations. Importantly, the X-Pol potential is a general method, which can be employed with any level of electronic structure theory. The present study illustrates the implementation of the X-Pol method using ab initio Hartree-Fock theory and hybrid density functional theory. The computational results are illustrated by considering a set of bimolecular complexes of small organic molecules and ions with water. The computed interaction energies and hydrogen bond geometries are in good accord with CCSD(T) calculations and B3LYP/aug-cc-pVDZ optimizations.

South Polar Cap, Summer 2000

NASA Technical Reports Server (NTRS)

2000-01-01

This is the south polar cap of Mars as it appeared to the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) on April 17, 2000. In winter and early spring, this entire scene would be covered by frost. In summer, the cap shrinks to its minimum size, as shown here. Even though it is summer, observations made by the Viking orbiters in the 1970s showed that the south polar cap remains cold enough that the polar frost (seen here as white) consists of carbon dioxide. Carbon dioxide freezes at temperatures around -125o C (-193o F). Mid-summer afternoon sunlight illuminates this scene from the upper left from about 11.2o above the horizon. Soon the cap will experience sunsets; by June 2000, this pole will be in autumn, and the area covered by frost will begin to grow. Winter will return to the south polar region in December 2000. The polar cap from left to right is about 420 km (260 mi) across.

Polarization measurements through space-to-ground atmospheric propagation paths by using a highly polarized laser source in space.

PubMed

Toyoshima, Morio; Takenaka, Hideki; Shoji, Yozo; Takayama, Yoshihisa; Koyama, Yoshisada; Kunimori, Hiroo

2009-12-07

The polarization characteristics of an artificial laser source in space were measured through space-to-ground atmospheric transmission paths. An existing Japanese laser communication satellite and optical ground station were used to measure Stokes parameters and the degree of polarization of the laser beam transmitted from the satellite. As a result, the polarization was preserved within an rms error of 1.6 degrees, and the degree of polarization was 99.4+/-4.4% through the space-to-ground atmosphere. These results contribute to the link estimation for quantum key distribution via space and provide the potential for enhancements in quantum cryptography worldwide in the future.

Cloud Coverage and Height Distribution from the GLAS Polar Orbiting Lidar: Comparison to Passive Cloud Retrievals

NASA Technical Reports Server (NTRS)

Spinhime, J. D.; Palm, S. P.; Hlavka, D. L.; Hart, W. D.; Mahesh, A.

2004-01-01

The Geoscience Laser Altimeter System (GLAS) began full on orbit operations in September 2003. A main application of the two-wavelength GLAS lidar is highly accurate detection and profiling of global cloud cover. Initial analysis indicates that cloud and aerosol layers are consistently detected on a global basis to cross-sections down to 10(exp -6) per meter. Images of the lidar data dramatically and accurately show the vertical structure of cloud and aerosol to the limit of signal attenuation. The GLAS lidar has made the most accurate measurement of global cloud coverage and height to date. In addition to the calibrated lidar signal, GLAS data products include multi level boundaries and optical depth of all transmissive layers. Processing includes a multi-variable separation of cloud and aerosol layers. An initial application of the data results is to compare monthly cloud means from several months of GLAS observations in 2003 to existing cloud climatologies from other satellite measurement. In some cases direct comparison to passive cloud retrievals is possible. A limitation of the lidar measurements is nadir only sampling. However monthly means exhibit reasonably good global statistics and coverage results, at other than polar regions, compare well with other measurements but show significant differences in height distribution. For polar regions where passive cloud retrievals are problematic and where orbit track density is greatest, the GLAS results are particularly an advance in cloud cover information. Direct comparison to MODIS retrievals show a better than 90% agreement in cloud detection for daytime, but less than 60% at night. Height retrievals are in much less agreement. GLAS is a part of the NASA EOS project and data products are thus openly available to the science community (see http://glo.gsfc.nasa.gov).

Linear analysis of the evolution of nearly polar low-mass circumbinary discs

NASA Astrophysics Data System (ADS)

Lubow, Stephen H.; Martin, Rebecca G.

2018-01-01

In a recent paper Martin & Lubow showed through simulations that an initially tilted disc around an eccentric binary can evolve to polar alignment in which the disc lies perpendicular to the binary orbital plane. We apply linear theory to show both analytically and numerically that a nearly polar aligned low-mass circumbinary disc evolves to polar alignment and determine the alignment time-scale. Significant disc evolution towards the polar state around moderately eccentric binaries can occur for typical protostellar disc parameters in less than a typical disc lifetime for binaries with orbital periods of order 100 yr or less. Resonant torques are much less effective at truncating the inner parts of circumbinary polar discs than the inner parts of coplanar discs. For polar discs, they vanish for a binary eccentricity of unity. The results agree with the simulations in showing that discs can evolve to a polar state. Circumbinary planets may then form in such discs and reside on polar orbits.

Early Assessment of VIIRS On-Orbit Calibration and Support Activities

NASA Technical Reports Server (NTRS)

Xiong, Xiaoxiong; Chiang, Kwofu; McIntire, Jeffrey; Oudrari, Hassan; Wu, Aisheng; Schwaller, Mathew; Butler, James

2012-01-01

The Suomi National Polar-orbiting Partnership (S-NPP) satellite, formally the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP), provides a bridge between current and future low-Earth orbiting weather and environmental observation satellite systems. The NASA s NPP VIIRS Characterization Support Team (VCST) is designed to assess the long term geometric and radiometric performance of the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument onboard the S-NPP spacecraft and to support NPP Science Team Principal Investigators (PI) for their independent evaluation of VIIRS Environmental Data Records (EDRs). This paper provides an overview of Suomi NPP VIIRS on-orbit calibration activities and examples of sensor initial on-orbit performance. It focuses on the radiometric calibration support activities and capabilities provided by the NASA VCST.

PALOMA:A Magnetic CV between Polars and Intermediate Polars

NASA Astrophysics Data System (ADS)

Joshi, Arti; Pandey, J. C.

Using observations made with XMM-Newton, we present temporal and spectral analysis of an intermediate polar-like object Paloma. We also interpreted Paloma as a key object for magnetic CV evolution with an orbital period right within the period gap.

Japanese MAGSAT Team

NASA Technical Reports Server (NTRS)

Fukushima, N. (Principal Investigator)

1982-01-01

CHRONINT and investigator B tapes as well as CHRONFIN data are being analyzed using a graphical display to illustrate X.Y,Z components as well as their residuals from the MGST (4/81) model. In addition to surveys of the vicinity of Japan, an aerial magnetic survey was conducted around Syowa Station in the Antarctic. Relative data collected by polar orbiting satellites are also being studied. Techniques used to separate external and internal fields from the vector data along the orbital paths; analysis of the frequency of the toroidal current in the equatorial ionosphere; investigation of the sudden storm commencement observed by MAGSAT; determination of the structure of field aligned currents associated with substorms; and calculation of the total electric current passing through the plane encircled by the MAGSAT orbit are discussed.

Cryogenic propulsion for the Titan Orbiter Polar Surveyor (TOPS) mission

NASA Astrophysics Data System (ADS)

Mustafi, S.; DeLee, C.; Francis, J.; Li, X.; McGuinness, D.; Nixon, C. A.; Purves, L.; Willis, W.; Riall, S.; Devine, M.; Hedayat, A.

2016-03-01

Liquid hydrogen (LH2) and liquid oxygen (LO2) cryogenic propellants can dramatically enhance NASA's ability to explore the solar system due to their superior specific impulse (Isp) capability. Although these cryogenic propellants can be challenging to manage and store, they allow significant mass advantages over traditional hypergolic propulsion systems and are therefore enabling for many planetary science missions. New cryogenic storage techniques such as subcooling and the use of advanced insulation and low thermal conductivity support structures will allow for the long term storage and use of cryogenic propellants for solar system exploration and hence allow NASA to deliver more payloads to targets of interest, launch on smaller and less expensive launch vehicles, or both. These new cryogenic storage technologies were implemented in a design study for the Titan Orbiter Polar Surveyor (TOPS) mission, with LH2 and LO2 as propellants, and the resulting spacecraft design was able to achieve a 43% launch mass reduction over a TOPS mission, that utilized a traditional hypergolic propulsion system with mono-methyl hydrazine (MMH) and nitrogen tetroxide (NTO) propellants. This paper describes the cryogenic propellant storage design for the TOPS mission and demonstrates how these cryogenic propellants are stored passively for a decade-long Titan mission that requires the cryogenics propellants to be stored for 8.5 years.

Mars Climate Orbiter's Investigation of the Atmosphere and Polar Caps

NASA Technical Reports Server (NTRS)

McCleese, D. J.; Moroz, V.; Schofield, T.; Taylor, F.; Zurek, R.

1999-01-01

The Mars Climate Orbiter (MCO) is now on its way to Mars. It carries an atmospheric sounder whose observations will provide a continuous, global data set on weather and climate for a full Martian year. This paper describes the observation strategy and anticipated results from the Pressure Modulator Infrared Radiometer (PMIRR). PMIRR will measure vertical profiles of atmospheric infrared radiance in the 7 to 50 micron wavelength region extending from the surface of Mars to 80-km altitude. The observations have a vertical resolution of 5 km, or one-half the atmospheric scale height. From these radiance profiles we will retrieve profiles of atmospheric temperature, pressure, and the amounts of dust, condensates and water vapor. In addition, PMIRR will measure the radiative balance of the polar regions of Mars in an effort to better understand the short-term climate variability of the planet. The information obtained with PMIRR on MCO will be complementary to data obtained by the Thermal Emission Spectrometer (TES) and Radio Science (RS) experiments on the Mars Global Surveyor. A major emphasis of our research will be the assimilation of PMIRR data into numerical models of the Martian atmosphere. Assimilation schemes, of which several are currently in development, will permit the extension of measurements to spatial and temporal scales and to phenomena (e.g. winds) not observed directly by PMIRR.

Planning Orbiter Flights

NASA Technical Reports Server (NTRS)

Harris, H. M.; Bergam, M. J.; Kim, S. L.; Smith, E. A.

1987-01-01

Shuttle Mission Design and Operations Software (SMDOS) assists in design and operation of missions involving spacecraft in low orbits around Earth by providing orbital and graphics information. SMDOS performs following five functions: display two world and two polar maps or any user-defined window 5 degrees high in latitude by 5 degrees wide in longitude in one of eight standard projections; designate Earth sites by points or polygon shapes; plot spacecraft ground track with 1-min demarcation lines; display, by means of different colors, availability of Tracking and Data Relay Satellite to Shuttle; and calculate available times and orbits to view particular site, and corresponding look angles. SMDOS written in Laboratory Micro-systems FORTH (1979 standard)

Officials welcome the arrival of the Japanese Experiment Module

NASA Image and Video Library

2007-04-17

In the Space Station Processing Facility, NASA and Japanese Aerospace and Exploration Agency (JAXA) officials welcome the arrival of the Experiment Logistics Module Pressurized Section for the Japanese Experiment Module, or JEM, to the Kennedy Space Center. Seen here at right are JAXA representatives, including Japanese astronaut Takao Doi (center of front row), who is a crew member for mission STS-123 that will deliver the module to the space station. The new International Space Station component arrived at Kennedy March 12 to begin preparations for its future launch on mission STS-123. It will serve as an on-orbit storage area for materials, tools and supplies. It can hold up to eight experiment racks and will attach to the top of another larger pressurized module.

Tuning the interfacial charge, orbital, and spin polarization properties in La0.67Sr0.33MnO3/La1-xSrxMnO3 bilayers

NASA Astrophysics Data System (ADS)

Carreira, Santiago J.; Aguirre, Myriam H.; Briatico, Javier; Weschke, Eugen; Steren, Laura B.

2018-01-01

The possibility of controlling the interfacial properties of artificial oxide heterostructures is still attracting researchers in the field of materials engineering. Here, we used surface sensitive techniques and high-resolution transmission electron microscopy to investigate the evolution of the surface spin-polarization and lattice strains across the interfaces between La0.66Sr0.33MnO3 thin films and low-doped manganites as capping layers. We have been able to fine tune the interfacial spin-polarization by changing the capping layer thickness and composition. The spin-polarization was found to be the highest at a critical capping thickness that depends on the Sr doping. We explain the non-trivial magnetic profile by the combined effect of two mechanisms: On the one hand, the extra carriers supplied by the low-doped manganites that tend to compensate the overdoped interface, favouring locally a ferromagnetic double-exchange coupling. On the other hand, the evolution from a tensile-strained structure of the inner layers to a compressed structure at the surface that changes gradually the orbital occupation and hybridization of the 3d-Mn orbitals, being detrimental for the spin polarization. The finding of an intrinsic spin-polarization at the A-site cation observed in x-ray magnetic circular dichroism (XMCD) measurements also reveals the existence of a complex magnetic configuration at the interface, different from the magnetic phases observed at the inner layers.

Orbital engineering of nickelates in three-component heterostructures

NASA Astrophysics Data System (ADS)

Disa, Ankit; Kumah, Divine; Malashevich, Andrei; Chen, Hanghui; Ismail-Beigi, Sohrab; Walker, Fred; Ahn, Charles; Specht, Eliot; Arena, Dario

2015-03-01

The orbital configuration of complex oxides dictates the emergence of a wide range of properties, including metal-insulator transitions, interfacial magnetism, and high-temperature superconductivity. In this work, we experimentally demonstrate a novel method for achieving large and tunable orbital polarizations in nickelates. The technique is based on leveraging three-component, atomically layered superlattices to yield a combination of inversion symmetry breaking, charge transfer, and polar distortions. In the system we studied, composed of LaTiO3/LaNiO3/LaAlO3, we use synchrotron x-ray diffraction and spectroscopy to characterize these properties and show that they lead to fully broken orbital degeneracy in the nickelate layer consistent with a single-band Fermi surface. Furthermore, we show that this system is widely tunable and enables quasi-continuous orbital control unachievable by conventional strain and confinement-based approaches. This technique provides an experimentally realizable route for accessing and studying novel orbitally dependent quantum phenomena.

A structural route to tuning the orbital structure of nickelates

NASA Astrophysics Data System (ADS)

Kumah, Divine; Disa, Ankit; Malashevich, Andrei; Chen, Hanghui; Ismail-Beigi, Sohrab; Walker, Fred; Ahn, Charles

2014-03-01

The rare-earth nickelates display a range of interesting magnetic and electronic phenomena arising from the strong coupling of the atomic-scale structural properties of these systems to the charge and orbital degrees of freedom. We report on modifying the orbital polarization in nickelate based heterostructures, motivated by the goal of emulating high-Tc cuprate behavior in the nickelates. Using a combination of synchrotron diffraction structural and spectroscopic characterization and first principles theory, we show how the design of a structure that splits the relative electronic occupation of Ni d x2-y2 and Ni d 3z2-r2 orbitals, is achieved in three-component heterostructures. These structures are comprised of LaTiO3/LaNiO3/LaAlO3 and are grown using molecular beam epitaxy. The key features of the theoretically proposed structure, including an internal polar field, a electron transfer from Ti to Ni, and a orbital polarization of the Ni-eg states, are experimentally studied.

Mars Observer trajectory and orbit design

NASA Technical Reports Server (NTRS)

Beerer, Joseph G.; Roncoli, Ralph B.

1991-01-01

The Mars Observer launch, interplanetary, Mars orbit insertion, and mapping orbit designs are described. The design objective is to enable a near-maximum spacecraft mass to be placed in orbit about Mars. This is accomplished by keeping spacecraft propellant requirements to a minimum, selecting a minimum acceptable launch period, equalizing the spacecraft velocity change requirement at the beginning and end of the launch period, and constraining the orbit insertion maneuvers to be coplanar. The mapping orbit design objective is to provide the opportunity for global observation of the planet by the science instruments while facilitating the spacecraft design. This is realized with a sun-synchronous near-polar orbit whose ground-track pattern covers the planet at progressively finer resolution.

Jupiter’s magnetosphere and aurorae observed by the Juno spacecraft during its first polar orbits

NASA Astrophysics Data System (ADS)

Connerney, J. E. P.; Adriani, A.; Allegrini, F.; Bagenal, F.; Bolton, S. J.; Bonfond, B.; Cowley, S. W. H.; Gerard, J.-C.; Gladstone, G. R.; Grodent, D.; Hospodarsky, G.; Jorgensen, J. L.; Kurth, W. S.; Levin, S. M.; Mauk, B.; McComas, D. J.; Mura, A.; Paranicas, C.; Smith, E. J.; Thorne, R. M.; Valek, P.; Waite, J.

2017-05-01

The Juno spacecraft acquired direct observations of the jovian magnetosphere and auroral emissions from a vantage point above the poles. Juno’s capture orbit spanned the jovian magnetosphere from bow shock to the planet, providing magnetic field, charged particle, and wave phenomena context for Juno’s passage over the poles and traverse of Jupiter’s hazardous inner radiation belts. Juno’s energetic particle and plasma detectors measured electrons precipitating in the polar regions, exciting intense aurorae, observed simultaneously by the ultraviolet and infrared imaging spectrographs. Juno transited beneath the most intense parts of the radiation belts, passed about 4000 kilometers above the cloud tops at closest approach, well inside the jovian rings, and recorded the electrical signatures of high-velocity impacts with small particles as it traversed the equator.

Arbitrary optical wavefront shaping via spin-to-orbit coupling

NASA Astrophysics Data System (ADS)

Larocque, Hugo; Gagnon-Bischoff, Jérémie; Bouchard, Frédéric; Fickler, Robert; Upham, Jeremy; Boyd, Robert W.; Karimi, Ebrahim

2016-12-01

Converting spin angular momentum to orbital angular momentum has been shown to be a practical and efficient method for generating optical beams carrying orbital angular momentum and possessing a space-varying polarized field. Here, we present novel liquid crystal devices for tailoring the wavefront of optical beams through the Pancharatnam-Berry phase concept. We demonstrate the versatility of these devices by generating an extensive range of optical beams such as beams carrying ±200 units of orbital angular momentum along with Bessel, Airy and Ince-Gauss beams. We characterize both the phase and the polarization properties of the generated beams, confirming our devices’ performance.

Catalystlike effect of orbital angular momentum on the conversion of transverse to three-dimensional spin states within tightly focused radially polarized beams

NASA Astrophysics Data System (ADS)

Han, Lei; Liu, Sheng; Li, Peng; Zhang, Yi; Cheng, Huachao; Zhao, Jianlin

2018-05-01

We report on the catalystlike effect of orbital angular momentum (OAM) on local spin-state conversion within the tightly focused radially polarized beams associated with optical spin-orbit interaction. It is theoretically demonstrated that the incident OAM can lead to a conversion of purely transverse spin state to a three-dimensional spin state on the focal plane. This conversion can be conveniently manipulated by altering the sign and value of the OAM. By comparing the total OAM and spin angular momentum (SAM) on the incident plane to those on the focal plane, it is indicated that the incident OAM have no participation in the angular momentum intertransfer, and just play a role as a catalyst of local SAM conversion. Such an effect of OAM sheds new light on the optical spin-orbit interaction in tight-focusing processes. The resultant three-dimensional spin states may provide more degrees of freedom in optical manipulation and spin-dependent directive coupling.

Polar Landforms

NASA Technical Reports Server (NTRS)

2005-01-01

10 August 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows eroded remnants of carbon dioxide ice in the south polar residual cap of Mars. The scarps that outline each small mesa have retreated about 3 meters (10 feet) per Mars year since MGS began orbiting the red planet in 1997.

Location near: 87.0oS, 31.9oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

South Polar Cap

NASA Technical Reports Server (NTRS)

2005-01-01

8 December 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows landforms created by sublimation processes on the south polar residual cap of Mars. The bulk of the ice in the south polar residual cap is frozen carbon dioxide.

Location near: 86.6oS, 342.2oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

Lunar Dust Monitor for the orbiter of the next Japanese lunar mission SELENE2

NASA Astrophysics Data System (ADS)

Hirai, Takayuki; Sasaki, Sho; Ohashi, Hideo; Kobayashi, Masanori; Fujii, Masayuki; Shibata, Hiromi; Iwai, Takeo; Nogami, Ken-Ichi; Kimura, Hiroshi; Nakamura, Maki

2010-05-01

The next Japanese lunar mission SELENE2, after a successful mission Kaguya (a project named SELENE), is planned to launch in mid 2010 and to consists of a lander, a rover, and an orbiter, as a transmitting satellite to the earth [1]. A dust particle detector is proposed to be onboard the orbiter that is planned to be in operation for one year or more. Dust particles around the Moon include interplanetary dust, beta-meteoroids, interstellar dust, and possibly lunar dust that originate from the subsurface materials of the Moon. It is considered that several tens of thousands of tons of dust particles per year fall onto the Moon and supply materials to its surface layer. "Inflow" and "outflow" dust particles are very important for understanding material compositions of lunar surface. In past missions, dust detectors onboard the Hiten and Nozomi (Hiten-MDC and Nozomi-MDC) measured the flues of dust particles in the lunar orbit [2, 3]. These observations by Hiten- and Nozomi-MDCs created a small dataset of statistics of dust particles excluding earth-orbiting dust once in a week, because the dust detectors had small sensitive areas, 0.01 m2 and 0.014 m^2, respectively. The Lunar Dust EXperiment (LDEX) is designed to map a spatial and temporal variability of the dust size and density distributions in the lunar environment and will be onboard LADEE, which will be launched in 2012 [4]. LDEX will observe the lunar environment for 90 days in a nominal case or for a maximum of 9 months. It has a sensor area of 0.01 m2 at 50 km altitude. For a quantitative study of circumlunar dust, we propose a dust monitoring device with a large aperture size and a large sensor area, called the lunar dust monitor (LDM). The LDM is an impact ionization detector with dimensions 25 cm × 25 cm × 30 cm, and it has a large target (gold-plated Al) of 400 cm^2, to which a high voltage of +500 V is applied. The LDM also has two meshed grids parallel to the target. The grids are 90% transparent: the

Direct measurement of discrete valley and orbital quantum numbers in bilayer graphene.

PubMed

Hunt, B M; Li, J I A; Zibrov, A A; Wang, L; Taniguchi, T; Watanabe, K; Hone, J; Dean, C R; Zaletel, M; Ashoori, R C; Young, A F

2017-10-16

The high magnetic field electronic structure of bilayer graphene is enhanced by the spin, valley isospin, and an accidental orbital degeneracy, leading to a complex phase diagram of broken symmetry states. Here, we present a technique for measuring the layer-resolved charge density, from which we directly determine the valley and orbital polarization within the zero energy Landau level. Layer polarization evolves in discrete steps across 32 electric field-tuned phase transitions between states of different valley, spin, and orbital order, including previously unobserved orbitally polarized states stabilized by skew interlayer hopping. We fit our data to a model that captures both single-particle and interaction-induced anisotropies, providing a complete picture of this correlated electron system. The resulting roadmap to symmetry breaking paves the way for deterministic engineering of fractional quantum Hall states, while our layer-resolved technique is readily extendable to other two-dimensional materials where layer polarization maps to the valley or spin quantum numbers.The phase diagram of bilayer graphene at high magnetic fields has been an outstanding question, with orders possibly between multiple internal quantum degrees of freedom. Here, Hunt et al. report the measurement of the valley and orbital order, allowing them to directly reconstruct the phase diagram.

The disturbing function for polar Centaurs and transneptunian objects

NASA Astrophysics Data System (ADS)

Namouni, F.; Morais, M. H. M.

2017-10-01

The classical disturbing function of the three-body problem is based on an expansion of the gravitational interaction in the vicinity of nearly coplanar orbits. Consequently, it is not suitable for the identification and study of resonances of the Centaurs and transneptunian objects on nearly polar orbits with the Solar system planets. Here, we provide a series expansion algorithm of the gravitational interaction in the vicinity of polar orbits and produce explicitly the disturbing function to fourth order in eccentricity and inclination cosine. The properties of the polar series differ significantly from those of the classical disturbing function: the polar series can model any resonance, as the expansion order is not related to the resonance order. The powers of eccentricity and inclination of the force amplitude of a p:q resonance do not depend on the value of the resonance order |p - q| but only on its parity. Thus, all even resonance order eccentricity amplitudes are ∝e2 and odd ones ∝e to lowest order in eccentricity e. With the new findings on the structure of the polar disturbing function and the possible resonant critical arguments, we illustrate the dynamics of the polar resonances 1:3, 3:1, 2:9 and 7:9 where transneptunian object 471325 could currently be locked.

Sentinel-5: the new generation European operational atmospheric chemistry mission in polar orbit

NASA Astrophysics Data System (ADS)

Pérez Albiñana, Abelardo; Erdmann, Matthias; Wright, Norrie; Martin, Didier; Melf, Markus; Bartsch, Peter; Seefelder, Wolfgang

2017-08-01

Sentinel-5 is an Earth Observation instrument to be flown on the Metop Second Generation (Metop-SG) satellites with the fundamental objective of monitoring atmospheric composition from polar orbit. The Sentinel-5 instrument consists of five spectrometers to measure the solar spectral radiance backscattered by the earth atmosphere in five bands within the UV (270nm) to SWIR (2385nm) spectral range. Data provided by Sentinel-5 will allow obtaining the distribution of important atmospheric constituents such as ozone, on a global daily basis and at a finer spatial resolution than its precursor instruments on the first generation of Metop satellites. The launch of the first Metop-SG satellite is foreseen for 2021. The Sentinel-5 instrument is being developed by Airbus DS under contract to the European Space Agency. The Sentinel-5 mission is part of the Space Component of the Copernicus programme, a joint initiative by ESA, EUMETSAT and the European Commission. The Preliminary Design Review (PDR) for the Sentinel-5 development was successfully completed in 2015. This paper provides a description of the Sentinel-5 instrument design and data calibration.

North Polar Cap

NASA Technical Reports Server (NTRS)

2004-01-01

7 September 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a 1.4 m/pixel (5 ft/pixel) view of a typical martian north polar ice cap texture. The surface is pitted and rough at the scale of several meters. The north polar residual cap of Mars consists mainly of water ice, while the south polar residual cap is mostly carbon dioxide. This picture is located near 85.2oN, 283.2oW. The image covers an area approximately 1 km wide by 1.4 km high (0.62 by 0.87 miles). Sunlight illuminates this scene from the lower left.

Orbit-induced localized spin angular momentum in strong focusing of optical vectorial vortex beams

NASA Astrophysics Data System (ADS)

Li, Manman; Cai, Yanan; Yan, Shaohui; Liang, Yansheng; Zhang, Peng; Yao, Baoli

2018-05-01

Light beams may carry optical spin or orbital angular momentum, or both. The spin and orbital parts manifest themselves by the ellipticity of the state of polarization and the vortex structure of phase of light beams, separately. Optical spin and orbit interaction, arising from the interaction between the polarization and the spatial structure of light beams, has attracted enormous interest recently. The optical spin-to-orbital angular momentum conversion under strong focusing is well known, while the converse process, orbital-to-spin conversion, has not been reported so far. In this paper, we predict in theory that the orbital angular momentum can induce a localized spin angular momentum in strong focusing of a spin-free azimuthal polarization vortex beam. This localized longitudinal spin of the focused field can drive the trapped particle to spin around its own axis. This investigation provides a new degree of freedom for spinning particles by using a vortex phase, which may have considerable potentials in optical spin and orbit interaction, light-beam shaping, or optical manipulation.

The Eccentric Behavior of Nearly Frozen Orbits

NASA Technical Reports Server (NTRS)

Sweetser, Theodore H.; Vincent, Mark A.

2013-01-01

Frozen orbits are orbits which have only short-period changes in their mean eccentricity and argument of periapse, so that they basically keep a fixed orientation within their plane of motion. Nearly frozen orbits are those whose eccentricity and argument of periapse have values close to those of a frozen orbit. We call them "nearly" frozen because their eccentricity vector (a vector whose polar coordinates are eccentricity and argument of periapse) will stay within a bounded distance from the frozen orbit eccentricity vector, circulating around it over time. For highly inclined orbits around the Earth, this distance is effectively constant over time. Furthermore, frozen orbit eccentricity values are low enough that these orbits are essentially eccentric (i.e., off center) circles, so that nearly frozen orbits around Earth are bounded above and below by frozen orbits.

South Polar Layers

NASA Image and Video Library

2016-08-25

Southern hemisphere spring has arrived at the south polar cap. The ice layers that make up the cap are easily seen in this image from NASA 2001 Mars Odyssey spacecraft. Southern hemisphere spring has arrived at the south polar cap. The ice layers that make up the cap are easily seen in this VIS image. Orbit Number: 64531 Latitude: -86.6334 Longitude: 97.7916 Instrument: VIS Captured: 2016-07-01 06:55 http://photojournal.jpl.nasa.gov/catalog/PIA20972

A Dual Polarization, Active, Microstrip Antenna for an Orbital Imaging Radar System Operating at L-Band

NASA Technical Reports Server (NTRS)

Kelly, Kenneth C.; Huang, John

1999-01-01

A highly successful Earth orbiting synthetic antenna aperture radar (SAR) system, known as the SIR-C mission, was carried into orbit in 1994 on a U.S. Shuttle (Space Transportation System) mission. The radar system was mounted in the cargo bay with no need to fold, or in any other way reduce the size of the antennas for launch. Weight and size were not limited for the L-Band, C-Band, and X-Band radar systems of the SIR-C radar imaging mission; the set of antennas weighed 10,500 kg, the L-Band antenna having the major share of the weight. This paper treats designing an L-Band antenna functionally similar to that used for SIR-C, but at a fraction of the cost and at a weight in the order of 250 kg. Further, the antenna must be folded to fit into the small payload shroud of low cost booster rocket systems. Over 31 square meters of antenna area is required. This low weight, foldable, electronic scanning antenna is for the proposed LightSAR radar system which is to be placed in Earth orbit on a small, dedicated space craft at the lowest possible cost for an efficient L-Band radar imaging system. This LightSAR spacecraft radar is to be continuously available for at least five operational years, and have the ability to map or repeat-map any area on earth within a few days of any request. A microstrip patch array, with microstrip transmission lines heavily employed in the aperture and in the corporate feed network, was chosen as the low cost approach for this active dual-polarization, 80 MHz (6.4%) bandwidth antenna design.

A Dual Polarization, Active, Microstrip Antenna for an Orbital Imaging Radar System Operating at L-Band

NASA Technical Reports Server (NTRS)

Kelly, Kenneth C.; Huang, John

2000-01-01

A highly successful Earth orbiting synthetic antenna aperture radar (SAR) system, known as the SIR-C mission, was carried into orbit in 1994 on a U.S. Shuttle (Space Transportation System) mission. The radar system was mounted in the cargo bay with no need to fold, or in any other way reduce the size of the antennas for launch. Weight and size were not limited for the L-Band, C-Band, and X-Band radar systems of the SIR-C radar imaging mission; the set of antennas weighed 10,500 kg, the L-Band antenna having the major share of the weight. This paper treats designing an L-Band antenna functionally similar to that used for SIR-C, but at a fraction of the cost and at a weight in the order of 250 kg. Further, the antenna must be folded to fit into the small payload shroud of low cost booster rocket systems. Over 31 square meters of antenna area is required. This low weight, foldable, electronic scanning antenna is for the proposed LightSAR radar system which is to be placed in Earth orbit on a small, dedicated space craft at the lowest possible cost for an efficient L- Band radar imaging system. This LightSAR spacecraft radar is to be continuously available for at least five operational years, and have the ability to map or repeat-map any area on earth within a few days of any request. A microstrip patch array, with microstrip transmission lines heavily employed in the aperture and in the corporate feed network, was chosen as the low cost approach for this active dual-polarization, 80 MHz (6.4%) bandwidth antenna design.

Polar Stratigraphy

NASA Technical Reports Server (NTRS)

1999-01-01

These three images were taken on three different orbits over the north polar cap in April 1999. Each shows a different part of the same ice-free trough. The left and right images are separated by a distance of more than 100 kilometers (62 miles). Note the similar layers in each image.

Colorful Polar Layered Deposits

NASA Image and Video Library

2016-03-23

The North Polar layered deposits provide a record of recent climate changes on Mars as seen by NASA Mars Reconnaissance Orbiter spacecraft. Color variations between layers are due to differences in composition of the dust.

Polar Winds

NASA Image and Video Library

2018-04-05

This VIS image shows 'streamers' of clouds created by katabatic winds at the north polar cap. Katabatic winds are created by cold air sinking at the pole and then speeding along the ice surface towards the edge of the polar cap. When the winds enter troughs the wind regime changes from laminar flow to choatic and clouds of ice particles and/or dust are visible. This wind activity peaks at the start of northern hemisphere summer. Orbit Number: 53942 Latitude: 86.8433 Longitude: 99.3149 Instrument: VIS Captured: 2014-02-10 10:50 https://photojournal.jpl.nasa.gov/catalog/PIA22362

Implementation Options For the Solar System Exploration Survey's "Jupiter Polar Orbiter with Probes" Mission

NASA Astrophysics Data System (ADS)

Spilker, T. R.

2002-09-01

In July of this year the National Academy of Science released a draft of its report, "New Frontiers in the Solar System: An Integrated Exploration Strategy," briefly describing the current state of solar system planetary science and the most important science objectives for the next decade (2003-2013). It includes a prioritized list of five mission concepts that might be flown as part of NASA's fledgling New Frontiers Program; each "concept" is more a list of science or measurement objectives than a full mission concept, since it does not specify implementation details in most cases. Number three on that list is the "Jupiter Polar Orbiter with Probes" ("JPOP") mission. This mission concept combines the strengths of previously described or proposed Jupiter missions into a single mission, and gains from the synergies of some of the newly-combined investigations. The primary science objectives are: 1. Determine if Jupiter has a central core 2. Determine the deep abundance of water (and other volatiles) 3. Measure Jupiter's deep winds 4. Determine the structure of Jupiter's dynamo magnetic field 5. Sample in situ Jupiter's polar magnetosphere This paper examines some of the implementation options for a JPOP mission, and gives relative advantages and disadvantages. Given the New Frontier Program's maximum cost to NASA of \\650M, plus an approx. \\120M cap on international contributions, implementing the full range of JPOP science objectives in a single New Frontiers mission may be challenging. This work was performed at the Jet Propulsion Laboratory / California Institute of Technology, under contract with the National Aeronautics and Space Administration.

Auroral x-ray imaging from high- and low-Earth orbit

DOE Office of Scientific and Technical Information (OSTI.GOV)

McKenzie, D.L.; Gorney, D.J.; Imhof, W.L.

Observations of bremsstrahlung x rays emitted by energetic electrons impacting the Earth's atmosphere can be used for remotely sensing the morphology, intensity, and energy spectra of electron precipitation from the magnetosphere. The utility of the technique is derived from the broad energy range of observable x rays (2 to > 100 KeV), the simple emission process, the large x-ray mean free path in the atmosphere, and negligible background. Two auroral x-ray imagers, developed for future spaceflights, are discussed. The Polar Ionospheric X-Ray Imaging Experiment is scheduled for launch on the NASA International Solar-Terrestrial Physics/Global Geospace Science program POLAR satellite inmore » 1994. The POLAR orbit, with an apogee and perigee of 9 and 1.8 R[sub e] (Earth radii), respectively, affords the opportunity to image the aurora from a high altitude above the north pole continuously for several hours. The Magnetospheric Atmospheric X-Ray Imaging Experiment (MAXIE) was launched aboard the NOAA-I satellite on August 8, 1993. The 800-km polar orbit passes over both the northern and southern auroral zones every 101 min. MAXIE will be capable of obtaining multiple images of the same auroral region during a single satellite orbit. The experimental approaches used to exploit these very different orbits for remote sensing of the Earth's auroral zones are emphasized.« less

Polar Textures

NASA Image and Video Library

2016-09-21

This VIS image shows part of the South Polar cap. In this region the surface has numerous circular depressions, which give the appearance of a slice of swiss cheese. Orbit Number: 64848 Latitude: -86.7725 Longitude: 355.096 Instrument: VIS Captured: 2016-07-27 09:35 http://photojournal.jpl.nasa.gov/catalog/PIA20993

South Polar Layers

NASA Technical Reports Server (NTRS)

2003-01-01

MGS MOC Release No. MOC2-516, 17 October 2003

This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows eroded, stair-stepped layers in the south polar region of Mars. These layers have been considered, for the past three decades, to consist of a mixture of dust and ice. The Mars Polar Lander (MPL) mission was designed to test this hypothesis. However, sadly, MPL was lost during descent in December 1999. This exposure of south polar layered material is located near 86.3oS, 187.7oW. The image covers an area 3 km (1.9 mi) wide and is illuminated by sunlight from the upper left.

Accumulation and erosion of Mars' south polar layered deposits.

PubMed

Seu, Roberto; Phillips, Roger J; Alberti, Giovanni; Biccari, Daniela; Bonaventura, Francesco; Bortone, Marco; Calabrese, Diego; Campbell, Bruce A; Cartacci, Marco; Carter, Lynn M; Catallo, Claudio; Croce, Anna; Croci, Renato; Cutigni, Marco; Di Placido, Antonio; Dinardo, Salvatore; Federico, Costanzo; Flamini, Enrico; Fois, Franco; Frigeri, Alessandro; Fuga, Oreste; Giacomoni, Emanuele; Gim, Yonggyu; Guelfi, Mauro; Holt, John W; Kofman, Wlodek; Leuschen, Carlton J; Marinangeli, Lucia; Marras, Paolo; Masdea, Arturo; Mattei, Stefania; Mecozzi, Riccardo; Milkovich, Sarah M; Morlupi, Antonio; Mouginot, Jérémie; Orosei, Roberto; Papa, Claudio; Paternò, Tobia; Persi del Marmo, Paolo; Pettinelli, Elena; Pica, Giulia; Picardi, Giovanni; Plaut, Jeffrey J; Provenziani, Marco; Putzig, Nathaniel E; Russo, Federica; Safaeinili, Ali; Salzillo, Giuseppe; Santovito, Maria Rosaria; Smrekar, Suzanne E; Tattarletti, Barbara; Vicari, Danilo

2007-09-21

Mars' polar regions are covered with ice-rich layered deposits that potentially contain a record of climate variations. The sounding radar SHARAD on the Mars Reconnaissance Orbiter mapped detailed subsurface stratigraphy in the Promethei Lingula region of the south polar plateau, Planum Australe. Radar reflections interpreted as layers are correlated across adjacent orbits and are continuous for up to 150 kilometers along spacecraft orbital tracks. The reflectors are often separated into discrete reflector sequences, and strong echoes are seen as deep as 1 kilometer. In some cases, the sequences are dipping with respect to each other, suggesting an interdepositional period of erosion. In Australe Sulci, layers are exhumed, indicating recent erosion.

PALOMA: A Magnetic CV between Polars and Intermediate Polars

NASA Astrophysics Data System (ADS)

Joshi, Arti; Pandey, J. C.; Singh, K. P.; Agrawal, P. C.

2016-10-01

We present analyses of archival X-ray data obtained from the XMM-Newton satellite and optical photometric data obtained from 1 m class telescopes of ARIES, Nainital of a magnetic cataclysmic variable (MCV) Paloma. Two persistent periods at 156 ± 1 minutes and 130 ± 1 minutes are present in the X-ray data, which we interpret as the orbital and spin periods, respectively. These periods are similar to those obtained from the previous as well as new optical photometric observations. The soft-X-ray excess seen in the X-ray spectrum of Paloma and the averaged X-ray spectra are well fitted by two-temperature plasma models with temperatures of {0.10}-0.01+0.02 and {13.0}-0.5+0.5 keV with an Fe Kα line and an absorbing column density of 4.6 × 1022 cm-2. This material partially covers 60 ± 2% of the X-ray source. We also present the orbital and spin-phase-resolved spectroscopy of Paloma in the 0.3{--}10.0 {keV} energy band and find that the X-ray spectral parameters show orbital and spin-phase dependencies. New results obtained from optical and X-ray studies of Paloma indicate that it belongs to a class of a few magnetic CVs that seem to have the characteristics of both the polars and the intermediate polars.

Lunar Reconnaissance Orbiter Camera (LROC) instrument overview

USGS Publications Warehouse

Robinson, M.S.; Brylow, S.M.; Tschimmel, M.; Humm, D.; Lawrence, S.J.; Thomas, P.C.; Denevi, B.W.; Bowman-Cisneros, E.; Zerr, J.; Ravine, M.A.; Caplinger, M.A.; Ghaemi, F.T.; Schaffner, J.A.; Malin, M.C.; Mahanti, P.; Bartels, A.; Anderson, J.; Tran, T.N.; Eliason, E.M.; McEwen, A.S.; Turtle, E.; Jolliff, B.L.; Hiesinger, H.

2010-01-01

The Lunar Reconnaissance Orbiter Camera (LROC) Wide Angle Camera (WAC) and Narrow Angle Cameras (NACs) are on the NASA Lunar Reconnaissance Orbiter (LRO). The WAC is a 7-color push-frame camera (100 and 400 m/pixel visible and UV, respectively), while the two NACs are monochrome narrow-angle linescan imagers (0.5 m/pixel). The primary mission of LRO is to obtain measurements of the Moon that will enable future lunar human exploration. The overarching goals of the LROC investigation include landing site identification and certification, mapping of permanently polar shadowed and sunlit regions, meter-scale mapping of polar regions, global multispectral imaging, a global morphology base map, characterization of regolith properties, and determination of current impact hazards.

Extreme Spacecraft Charging in Polar Low Earth Orbit

NASA Technical Reports Server (NTRS)

Colson, Andrew D.; Minow, Joseph I.; NeergaardParker, Linda

2012-01-01

Spacecraft in low altitude, high inclination (including sun-synchronous) orbits are widely used for remote sensing of the Earth's land surface and oceans, monitoring weather and climate, communications, scientific studies of the upper atmosphere and ionosphere, and a variety of other scientific, commercial, and military applications. These systems episodically charge to frame potentials in the kilovolt range when exposed to space weather environments characterized by a high flux of energetic (10 s kilovolt) electrons in regions of low background plasma density which is similar in some ways to the space weather conditions in geostationary orbit responsible for spacecraft charging to kilovolt levels. We first review the physics of space environment interactions with spacecraft materials that control auroral charging rates and the anticipated maximum potentials that should be observed on spacecraft surfaces during disturbed space weather conditions. We then describe how the theoretical values compare to the observational history of extreme charging in auroral environments. Finally, a set of extreme DMSP charging events are described varying in maximum negative frame potential from 0.6 kV to 2 kV, focusing on the characteristics of the charging events that are of importance both to the space system designer and to spacecraft operators. The goal of the presentation is to bridge the gap between scientific studies of auroral charging and the need for engineering teams to understand how space weather impacts both spacecraft design and operations for vehicles on orbital trajectories that traverse auroral charging environments.

Modulation of spatial spin polarization at organic spinterface by side groups

NASA Astrophysics Data System (ADS)

Qiu, Shuai; Zhang, Zhao; Miao, Yuan-yuan; Zhang, Guang-ping; Ren, Jun-feng; Wang, Chuan-kui; Hu, Gui-chao

2018-01-01

Spin polarization at benzene/Ni organic/ferromagnetic interface is investigated by applying different substituting side groups. Based on first-principle calculations, it is demonstrated that the spin polarization of the states may be tuned in magnitude and sign by the side groups, which depends on the type of side groups as well as their position in the aromatic ring. Especially, a spatial spin polarization modulation is realized at the surface with the utilization of electron donating group sbnd NH2 or electron accepting group sbnd NO2. The analysis of projected density of states onto the pz orbital of carbon atoms indicates that the side group reduces the structural symmetry of the molecule and changes the pz orbital of carbon atom at different position, which further modifies the pz-d orbital hybridization as well as the spin transfer between the molecule and the ferromagnet. This work indicates a feasible way to modulate the spatial spin polarization at organic spinterface by side groups, which deserves to be measured by spin-polarized scanning tunneling microscopy.

Solar Polar Imager: Observing Coronal Transients from a New Perspective (Invited)

NASA Astrophysics Data System (ADS)

Liewer, P. C.

2013-12-01

The heliophysics community has long recognized the need for a mission to observe the Sun and corona from a polar perspective. One mission concept, the Solar Polar Imager (SPI), has been studied extensively (Liewer et al in NASA Space Science Vision Missions, 2008). In this concept, a solar sail is used to place a spacecraft in a circular 0.48-AU heliocentric orbit with an inclination of ~75 degrees. This orbit enables crucial observations not possible from lower latitude perspectives. Magnetograph and Doppler observations from a polar vantage point would revolutionize our understanding of the mechanism of solar activity cycles, polar magnetic field reversals, the internal structure and dynamics of the Sun and its atmosphere. The rapid 4-month polar orbit combined with both in situ and remote sensing instrumentation further enables unprecedented studies of the physical connection between the Sun, the solar wind, and solar energetic particles. From the polar perspective, white light imagers could be used to track CMEs and predict their arrival at Earth (as demonstrated by STEREO). SPI is also well suited to study the relative roles of CME-driven shock versus flare-associated processes in solar energetic particle acceleration. With the circular 0.48 AU orbit, solar energetic particles could be more easily traced to their sources and their variation with latitude can be studied at a constant radius. This talk will discuss the science objectives, instrumentation and mission design for the SPI mission.

Determination of the spin orbit coupling and crystal field splitting in wurtzite InP by polarization resolved photoluminescence

NASA Astrophysics Data System (ADS)

Chauvin, Nicolas; Mavel, Amaury; Jaffal, Ali; Patriarche, Gilles; Gendry, Michel

2018-02-01

Excitation photoluminescence spectroscopy is usually used to extract the crystal field splitting (ΔCR) and spin orbit coupling (ΔSO) parameters of wurtzite (Wz) InP nanowires (NWs). However, the equations expressing the valence band splitting are symmetric with respect to these two parameters, and a choice ΔCR > ΔSO or ΔCR < ΔSO has to be taken into account in order to assign the numerical values. To solve this issue, polarization resolved micro-photoluminescence was performed on vertically aligned and untapered Wz InP NWs grown on silicon. The experimental results combined with a theoretical model and finite difference time domain calculations allow us to conclude that ΔCR > ΔSO in Wz InP.

Discovery of highly spin-polarized conducting surface states in the strong spin-orbit coupling semiconductor Sb2Se3

NASA Astrophysics Data System (ADS)

Das, Shekhar; Sirohi, Anshu; Kumar Gupta, Gaurav; Kamboj, Suman; Vasdev, Aastha; Gayen, Sirshendu; Guptasarma, Prasenjit; Das, Tanmoy; Sheet, Goutam

2018-06-01

Majority of the A2B3 -type chalcogenide systems with strong spin-orbit coupling (SOC), such as Bi2Se3,Bi2Te3 , and Sb2Te3 , etc., are topological insulators. One important exception is Sb2Se3 where a topological nontrivial phase was argued to be possible under ambient conditions, but such a phase could be detected to exist only under pressure. In this paper, we show that Sb2Se3 like Bi2Se3 displays a generation of highly spin-polarized current under mesoscopic superconducting point contacts as measured by point-contact Andreev reflection spectroscopy. In addition, we observe a large negative and anisotropic magnetoresistance of the mesoscopic metallic point contacts formed on Sb2Se3 . Our band-structure calculations confirm the trivial nature of Sb2Se3 crystals and reveal two trivial surface states one of which shows large spin splitting due to Rashba-type SOC. The observed high spin polarization and related phenomena in Sb2Se3 can be attributed to this spin splitting.

Implanting Strong Spin-Orbit Coupling at Magnetoelectric Interfaces

DTIC Science & Technology

2017-12-19

one is polar. Because the broken inversion symmetry in the polar structure is driven by a combination of the Sr-Ca cation mismatch and the octahedral...ME coefficient without breaking the inversion symmetry manifest a large boost of the ME effect with strong spin-orbit coupling. Results on the polar... inversion center. These peaks are absent in the nonpolar structure and appear here due to the A-site ordering and the resulting inversion symmetry

South Polar Variety

NASA Technical Reports Server (NTRS)

2005-01-01

28 July 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a view of linear troughs and mesas formed in the frozen carbon dioxide of the martian south polar residual cap. This image, obtained in May 2005, is a reminder that not all of the south polar cap landscapes resemble 'swiss cheese.'

Location near: 86.7oS, 24.8oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

The small satellite NINA-MITA to study galactic and solar cosmic rays in low-altitude polar orbit

NASA Astrophysics Data System (ADS)

Furano, G.; Bidoli, V.; Casolino, M.; de Pascale, M. P.; Iannucci, A.; Morselli, A.; Picozza, P.; Reali, E.; Sparvoli, R.; Bakaldin, A.; Galper, A.; Koldashov, M.; Korotkov, M.; Leonov, A.; Mikhailov, V.; Murashov, A.; Voronov, S.; Mazzenga, G.; Ricci, M.; Castellini, G.; Barbiellini, M.; Boezio, M.; Bonvicini, V.; Cirami, R.; Vacchi, A.; Zampa, N.; Ambriola, M.; Bellotti, R.; Cafagna, F.; Ciacio, F.; Circella, M.; de Marzo, C.; Adriani, O.; Papini, P.; Piccardi, S.; Spillantini, P.

The satellite MITA, carrying on board the scientific payload NINA-2, was launched on July the 15th, 2000 from the cosmodrome of Plesetsk (Russia) with a Cosmos-3M rocket. The satellite and the payload are currently operating within nominal parameters. NINA-2 is the first scientific payload for the technological flight of the Italian small satellite MITA. The detector used in this mission is identical to the one already flying on the Russian satellite Resurs-O1 n.4 in a 840-km sun-synchronous orbit, but makes use of the extensive computer and telemetry capabilities of MITA bus to improve the active data acquisition time. NINA physics objectives are to study cosmic nuclei from hydrogen to iron in the energy range between 10 MeV/n and 1 GeV/n during the years 2000-2003, that is the solar maximum period. The device is capable of charge identification up to iron with isotope sensitivity up to oxigen. The 87.3 degrees, 460 km altitude polar orbit allows investigations of cosmic rays of solar and galactic origin, so to study long and short term solar transient phenomena, and the study of the trapped radiation at higher geomagnetic cutoff.

Towards Onboard Orbital Tracking of Seasonal Polar Volatiles on Mars

NASA Technical Reports Server (NTRS)

Wagstaff, Kiri L.; Castano, Rebecca; Chien, Steve; Ivanov, anton B.; Titus, Timothy N.

2005-01-01

Current conditions on Mars support both a residual polar cap, composed mainly of water ice, and a seasonal cap, composed of CO2, which appears and disappears each winter. Kieffer and Titus characterized the recession of the seasonal south polar cap using an arctangent curve fit based on data from the Thermal Emission Spectrometer on Mars Global Surveyor [1]. They also found significant interannual deviations, at the regional scale, in the recession rate [2]. Further observations will enable the refinement of our models of polar cap evolution in both hemispheres. We have developed the Bimodal Image Temperature (BIT) Histogram Analysis method for the automated detection and tracking of the seasonal polar ice caps on Mars. It is specifically tailored for possible use onboard a spacecraft. We have evaluated BIT on uncalibrated data collected by the Thermal Emission Imaging System (THEMIS) instrument [3] on the Mars Odyssey spacecraft. In this paper, we focus on the northern seasonal cap, but our approach is directly applicable to the future analysis of the southern seasonal ice cap as well.

Official portrait of STS-65 IML-2 Japanese Payload Specialist Chiaki Mukai

NASA Technical Reports Server (NTRS)

1993-01-01

Official portrait of STS-65 International Microgravity Laboratory 2 (IML-2) Japanese Payload Specialist Chiaki Mukai. Mukai represents the National Space Development Agency (NASDA) of Japan and will conduct experiments aboard Columbia, Orbiter Vehicle (OV) 102, inside the IML-2 spacelab module.

South Polar Texture

NASA Image and Video Library

2016-08-26

This VIS image of the south polar cap shows a surface with hundreds of circular depressions. This texture similar in appearance to swiss cheese. Orbit Number: 64535 Latitude: -86.8715 Longitude: 354.786 Instrument: VIS Captured: 2016-07-01 14:50 http://photojournal.jpl.nasa.gov/catalog/PIA20974

Extreme Spacecraft Charging in Polar Low Earth Orbit

NASA Technical Reports Server (NTRS)

Colson, Andrew D.; Minow, Joseph I.; Parker, L. Neergaard

2012-01-01

Spacecraft in low altitude, high inclination (including sun -synchronous) orbits are widely used for remote sensing of the Earth fs land surface and oceans, monitoring weather and climate, communications, scientific studies of the upper atmosphere and ionosphere, and a variety of other scientific, commercial, and military applications. These systems episodically charge to frame potentials in the kilovolt range when exposed to space weather environments characterized by a high flux of energetic (approx.10 fs kilovolt) electrons in regions of low background plasma density. Auroral charging conditions are similar in some ways to the space weather conditions in geostationary orbit responsible for spacecraft charging to kilovolt levels. We first review the physics of space environment interactions with spacecraft materials that control auroral charging rates and the anticipated maximum potentials that should be observed on spacecraft surfaces during disturbed space weather conditions. We then describe how the theoretical values compare to the observational history of extreme charging in auroral environments. Finally, a set of extreme DMSP charging events are described varying in maximum negative frame potential from approx.0.6 kV to approx.2 kV, focusing on the characteristics of the charging events that are of importance both to the space system designer and to spacecraft operators. The goal of the presentation is to bridge the gap between scientific studies of auroral charging and the need for engineering teams to understand how space weather impacts both spacecraft design and operations for vehicles on orbital trajectories that traverse auroral charging environments.

Tunable anisotropic anomalous Nernst effect and orbital magnetization in Floquet Weyl semimetals

NASA Astrophysics Data System (ADS)

Niu, Zhi Ping; Wu, Xueshi

2018-03-01

Weyl semimetals and nodal line semimetals display a host of novel properties. Floquet Weyl semimetals with tunable Weyl points can be obtained from nodal line semimetals under the circularly polarized off-resonant light. Here we theoretically investigate the anomalous Nernst effect and orbital magnetization in Floquet Weyl semimetals. Due to the anisotropy of the band structure in Floquet Weyl semimetals, highly anisotropic Berry phase mediated anomalous Nernst effect and orbital magnetization in the absence of magnetic field are observed, indicating orientation-dependent applications in the design of nanodevices. The amplitude and sign of anomalous Nernst coefficient and orbital magnetization can be tuned by the light direction, amplitude and polarization. The effect of the chemical potential on anomalous Nernst coefficient and orbital magnetization is also discussed. The light-modulated anomalous Nernst effect and orbital magnetization make Floquet Weyl semimetals potential candidates for thermoelectric devices.

Mars South Polar Cap "Fingerprint" Terrain

NASA Image and Video Library

2000-04-24

This picture is illuminated by sunlight from the upper left. Some portions of the martian south polar residual cap have long, somewhat curved troughs instead of circular pits. These appear to form in a layer of material that may be different than that in which "swiss cheese" circles and pits form, and none of these features has any analog in the north polar cap or elsewhere on Mars. This picture shows the "fingerprint" terrain as a series of long, narrow depressions considered to have formed by collapse and widening by sublimation of ice. Unlike the north polar cap, the south polar region stays cold enough in summer to retain frozen carbon dioxide. Viking Orbiter observations during the late 1970s showed that very little water vapor comes off the south polar cap during summer, indicating that any frozen water that might be there remains solid throughout the year. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image was obtained in early southern spring on August 4, 1999. It shows an area 3 x 5 kilometers (1.9 x 3.1 miles) at a resolution of about 7.3 meters (24 ft) per pixel. Located near 86.0°S, 53.9°W. http://photojournal.jpl.nasa.gov/catalog/PIA02373

Optical memory effect from polarized Laguerre-Gaussian light beam in light-scattering turbid media

NASA Astrophysics Data System (ADS)

Shumyatsky, Pavel; Milione, Giovanni; Alfano, Robert R.

2014-06-01

Propagation effects of polarized Laguerre-Gaussian light with different orbital angular momentum (L) in turbid media are described. The optical memory effect in scattering media consisting of small and large size (compared to the wavelength) scatterers is investigated for scattered polarized light. Imaging using polarized laser modes with a varying orbital strength L-parameter was performed. The backscattered image quality (contrast) was enhanced by more than an order of magnitude using circularly polarized light when the concentration of scatterers was close to invisibility of the object.

Spin-polarized surface resonances accompanying topological surface state formation

DOE PAGES

Jozwiak, Chris; Sobota, Jonathan A.; Gotlieb, Kenneth; ...

2016-10-14

Topological insulators host spin-polarized surface states born out of the energetic inversion of bulk bands driven by the spin-orbit interaction. Here we discover previously unidentified consequences of band-inversion on the surface electronic structure of the topological insulator Bi 2Se 3. By performing simultaneous spin, time, and angle-resolved photoemission spectroscopy, we map the spin-polarized unoccupied electronic structure and identify a surface resonance which is distinct from the topological surface state, yet shares a similar spin-orbital texture with opposite orientation. Its momentum dependence and spin texture imply an intimate connection with the topological surface state. Calculations show these two distinct states canmore » emerge from trivial Rashba-like states that change topology through the spin-orbit-induced band inversion. As a result, this work thus provides a compelling view of the coevolution of surface states through a topological phase transition, enabled by the unique capability of directly measuring the spin-polarized unoccupied band structure.« less

Spin-polarized surface resonances accompanying topological surface state formation

PubMed Central

Jozwiak, Chris; Sobota, Jonathan A.; Gotlieb, Kenneth; Kemper, Alexander F.; Rotundu, Costel R.; Birgeneau, Robert J.; Hussain, Zahid; Lee, Dung-Hai; Shen, Zhi-Xun; Lanzara, Alessandra

2016-01-01

Topological insulators host spin-polarized surface states born out of the energetic inversion of bulk bands driven by the spin-orbit interaction. Here we discover previously unidentified consequences of band-inversion on the surface electronic structure of the topological insulator Bi2Se3. By performing simultaneous spin, time, and angle-resolved photoemission spectroscopy, we map the spin-polarized unoccupied electronic structure and identify a surface resonance which is distinct from the topological surface state, yet shares a similar spin-orbital texture with opposite orientation. Its momentum dependence and spin texture imply an intimate connection with the topological surface state. Calculations show these two distinct states can emerge from trivial Rashba-like states that change topology through the spin-orbit-induced band inversion. This work thus provides a compelling view of the coevolution of surface states through a topological phase transition, enabled by the unique capability of directly measuring the spin-polarized unoccupied band structure. PMID:27739428

South Polar Scarps

NASA Technical Reports Server (NTRS)

2003-01-01

MGS MOC Release No. MOC2-438, 31 July 2003

The terrain of the south polar residual ice cap, made up mostly of frozen carbon dioxide, has come to be known by many as 'swiss cheese terrain,' because many areas of the cap resemble slices of swiss cheese. However, not all of the south polar cap looks like a tasty lunch food. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a series of curving scarps formed by erosion and sublimation of carbon dioxide from the south polar cap. This area is located near 86.3oS, 51.2oW. The image is illuminated by sunlight from the upper left; the area is about 1.5 km (0.9 mi) wide.

Officials welcome the arrival of the Japanese Experiment Module

NASA Image and Video Library

2007-04-17

In the Space Station Processing Facility, Scott Higginbotham, payload manager for the International Space Station, discusses the Experiment Logistics Module Pressurized Section for the Japanese Experiment Module (JEM), with Dr. Hidetaka Tanaka, the JEM Project Team resident manager at KSC for the Japanese Aerospace and Exploration Agency (JAXA). Earlier, NASA and JAXA officials welcomed the arrival of the module. The new International Space Station component arrived at Kennedy March 12 to begin preparations for its future launch on mission STS-123. It will serve as an on-orbit storage area for materials, tools and supplies. It can hold up to eight experiment racks and will attach to the top of another larger pressurized module.

Concepts for a geostationary-like polar mission

NASA Astrophysics Data System (ADS)

Macdonald, Malcolm; Anderson, Pamela; Carrea, Laura; Dobke, Benjamin; Embury, Owen; Merchant, Chris; Bensi, Paolo

2014-10-01

An evidence-led scientific case for development of a space-based polar remote sensing platform at geostationary-like (GEO-like) altitudes is developed through methods including a data user survey. Whilst a GEO platform provides a nearstatic perspective, multiple platforms are required to provide circumferential coverage. Systems for achieving GEO-like polar observation likewise require multiple platforms however the perspective is non-stationery. A key choice is between designs that provide complete polar view from a single platform at any given instant, and designs where this is obtained by compositing partial views from multiple sensors. Users foresee an increased challenge in extracting geophysical information from composite images and consider the use of non-composited images advantageous. Users also find the placement of apogee over the pole to be preferable to the alternative scenarios. Thus, a clear majority of data users find the "Taranis" orbit concept to be better than a critical inclination orbit, due to the improved perspective offered. The geophysical products that would benefit from a GEO-like polar platform are mainly estimated from radiances in the visible/near infrared and thermal parts of the electromagnetic spectrum, which is consistent with currently proven technologies from GEO. Based on the survey results, needs analysis, and current technology proven from GEO, scientific and observation requirements are developed along with two instrument concepts with eight and four channels, based on Flexible Combined Imager heritage. It is found that an operational system could, mostly likely, be deployed from an Ariane 5 ES to a 16-hour orbit, while a proof-of-concept system could be deployed from a Soyuz launch to the same orbit.

Different Polar Metabolites and Protein Profiles between High- and Low-Quality Japanese Ginjo Sake

PubMed Central

Takahashi, Kei; Kohno, Hiromi

2016-01-01

Japanese ginjo sake is a premium refined sake characterized by a pleasant fruity apple-like flavor and a sophisticated taste. Because of technical difficulties inherent in brewing ginjo sake, off-flavors sometimes occur. However, the metabolites responsible for off-flavors as well as those present or absent in higher quality ginjo sake remain uncertain. Here, the relationship between 202 polar chemical compounds in sake identified using capillary electrophoresis coupled with time-of-flight mass spectrometry and its organoleptic properties, such as quality and off-flavor, was examined. First, we found that some off-flavored sakes contained higher total amounts of metabolites than other sake samples. The results also identified that levels of 2-oxoglutaric acid and fumaric acid, metabolites in the tricarboxylic acid cycle, were highly but oppositely correlated with ginjo sake quality. Similarly, pyridoxine and pyridoxamine, co-enzymes for amino transferase, were also highly but oppositely correlated with ginjo sake quality. Additionally, pyruvic acid levels were associated with good quality as well. Compounds involved in the methionine salvage cycle, oxidative glutathione derivatives, and amino acid catabolites were correlated with low quality. Among off-flavors, an inharmonious bitter taste appeared attributable to polyamines. Furthermore, protein analysis displayed that a diversity of protein components and yeast protein (triosephosphate isomerase, TPI) leakage was linked to the overall metabolite intensity in ginjo sake. This research provides insight into the relationship between sake components and organoleptic properties. PMID:26939054

The polar thermosphere of Venus

NASA Astrophysics Data System (ADS)

Mueller-Wodarg, Ingo; Rosenblatt, Pascal; Bruinsma, Sean; Yelle, Roger; Svedhem, Håkan; Forbes, Jeffrey M.; Withers, Paul; Keating Sci. Gerald, Sr.; Lopez-Valverde, Miguel Angel

The thermosphere of Venus has been extensively observed in-situ primarily by the Pioneer Venus Orbiter, but those measurements concentrated on the low latitude regions. Until recently, no in-situ observations were made of the polar thermosphere of Venus, and reference atmospheres such as the VTS3 and VIRA models relied on solar zenith angle trends inferred at low latitudes in order to extrapolate to polar latitudes. The Venus Express Atmospheric Drag Experiment (VExADE) carries out accurate orbital tracking in order to infer for the first time ever the densities in Venus' polar thermosphere near 180 km altitude at solar minimum. During 3 recent tracking campaigns we obtained density measurements that allow us to compare actual densities in those regions with those predicted by the reference atmosphere models. We constructed a hydrostatic diffusive equilibrium at-mosphere model that interpolates between the Venus Express remote sensing measurements in the upper mesosphere and lower thermosphere region and the in-situ drag measurements by VExADE. This paper will present and discuss our latest findings.

SCIAMACHY’s View of the Polar Atmosphere

USGS Publications Warehouse

Gottwald, M.; Krieg, E.; von Savigny, C.; Noël, S.; Reichl, A.; Bovensmann, H.; Burrows, J.P.

2007-01-01

The instrument SCIAMACHY onboard the European ENVISAT mission provides unique capabilities for deriving atmospheric geophysical parameters. Since its launch in early 2002 it has operated successfully in orbit. Due to ENVISAT’s high inclination orbit the polar regions are monitored continuously. We report here results about the status of the polar atmosphere in the past 5 years with special emphasis on the southern hemisphere. This part of the atmosphere is considered to be highly sensitive to anthropogenic impacts on the Earth system and thus to climate change. The acquired data permit retrieving information on the Earth’s atmosphere from troposphere up to the mesosphere

Electronic ferroelectricity induced by charge and orbital orderings.

PubMed

Yamauchi, Kunihiko; Barone, Paolo

2014-03-12

After the revival of the magnetoelectric effect which took place in the early 2000s, the interest in multiferroic materials displaying simultaneous presence of spontaneous long-range magnetic and dipolar order has motivated an exponential growth of research activity, from both the experimental and theoretical perspectives. Within this context, and relying also on the rigorous formulation of macroscopic polarization as provided by the Berry-phase approach, it has been possible to identify new microscopic mechanisms responsible for the appearance of ferroelectricity. In particular, it has been realized that electronic spin, charge and orbital degrees of freedom may be responsible for the breaking of the space-inversion symmetry, a necessary condition for the appearance of electric polarization, even in centrosymmetric crystal structures. In view of its immediate potential application in magnetoelectric-based devices, many efforts have been made to understand how magnetic orderings may lead to ferroelectric polarization, and to identify candidate materials. On the other hand, the role of charge and orbital degrees of freedom, which have received much less attention, has been predicted to be non-negligible in several cases. Here, we review recent theoretical advances in the field of so-called electronic ferroelectricity, focusing on the possible mechanisms by which charge- and/or orbital-ordering effects may cause the appearance of macroscopic polarization. Generally, a naive distinction can be drawn between materials displaying almost localized electrons and those characterized by a strong covalent character and delocalized electrons. As for the latter, an intuitive understanding of basic mechanisms is provided in the framework of tight-binding model Hamiltonians, which are used to shed light on unusual charge/orbital effects in half-doped manganites, whereas the case of magnetite will be thoroughly discussed in light of recent progress pointing to an electronic

Stationkeeping for the Lunar Reconnaissance Orbiter (LRO)

NASA Technical Reports Server (NTRS)

Beckman, Mark; Lamb, Rivers

2007-01-01

The Lunar Reconnaissance Orbiter (LRO) is scheduled to launch in 2008 as the first mission under NASA's Vision for Space Exploration. Following several weeks in a quasi-frozen commissioning orbit, LRO will fly in a 50 km mean altitude lunar polar orbit. During the one year mission duration, the orbital dynamics of a low lunar orbit force LRO to perform periodic sets of stationkeeping maneuvers. This paper explores the characteristics of low lunar orbits and explains how the LRO stationkeeping plan is designed to accommodate the dynamics in such an orbit. The stationkeeping algorithm used for LRO must meet five mission constraints. These five constraints are to maintain ground station contact during maneuvers, to control the altitude variation of the orbit, to distribute periselene equally between northern and southern hemispheres, to match eccentricity at the beginning and the end of the sidereal period, and to minimize stationkeeping deltaV. This paper addresses how the maneuver plan for LRO is designed to meet all of the above constraints.

Japanese Competitiveness and Japanese Management.

ERIC Educational Resources Information Center

Minabe, Shigeo

1986-01-01

Analyzes and compares Japanese and American industrial policy and labor practices. Proposes that certain aspects of the Japanese system be adapted by American businesses for purpose of increasing international competitiveness. Proposes specific actions and plans for both the Japanese and American systems. (ML)

The METOP-A Orbit Acquisition Strategy and its LEOP Operational Experience

NASA Technical Reports Server (NTRS)

Merz, K.; Serrano, M. A. Martin; Kuijper, D.; Matatoros, M. A. Garcia

2007-01-01

Europe's first polar-orbiting weather satellite, METOPA, was launched by a Soyuz launcher from Baikonur Cosmodrome on the 19th of October of 2006. The routine operations of METOP-A are conducted by EUMETSAT (European Organization for Exploitation of Meteorological Satellites) in the frame of the European Polar System mission (EPS). The METOP-A Launch and Early Orbit Phase (LEOP) operations have been performed by ESA/ESOC. The Flight Dynamics Orbit Determination and Control team (OD&C) at ESOC was in charge of correcting the S/C orbit as delivered by the launcher in such a way that EUMETSAT would be able to acquire the reference orbit with a drift-stop manoeuvre approximately two weeks after a LEOP of 3 days and Hand-Over to the EUMETSAT Control Centre (EUMETSAT-CC) in Darmstadt, Germany. The various strict constraints and the short amount of time available for ESOC operations made this task challenging. Several strategies were prepared before launch and analysed during LEOP based on the achieved injection orbit. This paper presents the different manoeuvre strategies investigated and finally applied to acquire the operational orbit, reporting as well the details of its execution and final achieved state.

A study of the cleft region using synoptic ionospheric plasma data obtained by the polar orbiting satellites Aeros-B and Isis-2

NASA Technical Reports Server (NTRS)

Kist, R.; Klumpar, D.

1980-01-01

The concentrations of O(+) and NO(+) in the dayside high-latitude cleft region of the ionosphere are investigated based on synoptic particle and plasma measurements obtained by the polar orbiting Aeros-B and Isis-2 satellites. At a time when the orbital planes of the satellites are almost at right angles to each other, three maxima in ion temperature are observed, with two of them accompanied by an increased electron temperature and electron density irregularities, and the density of the molecular ions NO(+) and O2(+) is found to increase at the expense of O(+) density. Results are discussed in terms of a theory relating perpendicular electric fields to oxygen atom reaction rates. Systematic analysis of the Aeros data base reveals 14 additional instances of O(+) to NO(+) conversion, with a large variety of forms and structures reflecting the complex structure and dynamics of the high-latitude dayside ionosphere.

Spin-orbit scattering visualized in quasiparticle interference

NASA Astrophysics Data System (ADS)

Kohsaka, Y.; Machida, T.; Iwaya, K.; Kanou, M.; Hanaguri, T.; Sasagawa, T.

2017-03-01

In the presence of spin-orbit coupling, electron scattering off impurities depends on both spin and orbital angular momentum of electrons—spin-orbit scattering. Although some transport properties are subject to spin-orbit scattering, experimental techniques directly accessible to this effect are limited. Here we show that a signature of spin-orbit scattering manifests itself in quasiparticle interference (QPI) imaged by spectroscopic-imaging scanning tunneling microscopy. The experimental data of a polar semiconductor BiTeI are well reproduced by numerical simulations with the T -matrix formalism that include not only scalar scattering normally adopted but also spin-orbit scattering stronger than scalar scattering. To accelerate the simulations, we extend the standard efficient method of QPI calculation for momentum-independent scattering to be applicable even for spin-orbit scattering. We further identify a selection rule that makes spin-orbit scattering visible in the QPI pattern. These results demonstrate that spin-orbit scattering can exert predominant influence on QPI patterns and thus suggest that QPI measurement is available to detect spin-orbit scattering.

A Survey of Exoplanetary Spin-Orbit Angles

NASA Astrophysics Data System (ADS)

Winn, Josh

2010-02-01

Are the orbits of exoplanets aligned with the spin axes of their parent stars? One might expect a close alignment, but some of the proposed migration mechanisms predict otherwise. Indeed at least 4 planets with strongly tilted orbits are now known, including the first case of a retrograde or polar orbit. This raises the questions of how commonly misalignments occur, and which types of planets have them. We request 10 half-nights with Keck/HIRES spread over 2010A and 2010B, to measure spin-orbit angles for 9 exoplanets spanning a range of masses, periods, and eccentricities. Our measurement is based on the Rossiter-McLaughlin effect: the anomalous Doppler shift observed during planetary transits.

A Survey of Exoplanetary Spin-Orbit Angles

NASA Astrophysics Data System (ADS)

Winn, Josh

2010-08-01

Are the orbits of exoplanets aligned with the spin axes of their parent stars? One might expect a close alignment, but some of the proposed migration mechanisms predict otherwise. Indeed at least 4 planets with strongly tilted orbits are now known, including the first case of a retrograde or polar orbit. This raises the questions of how commonly misalignments occur, and which types of planets have them. We request 4 half-nights with Keck/HIRES spread over the 2010B semester, to measure spin-orbit angles for 4 exoplanets spanning a range of masses, periods, and eccentricities. Our measurement is based on the Rossiter-McLaughlin effect: the anomalous Doppler shift observed during planetary transits.

Polar Textures

NASA Image and Video Library

2016-10-04

This VIS image of the South Polar cap shows several different surface textures. It appears that the circular depressions (which look like swiss cheese) alter with time, appearing to lose the circular shape as the intervening walls of ice are removed. Orbit Number: 65187 Latitude: -87.0386 Longitude: 276.053 Instrument: VIS Captured: 2016-08-24 07:47 http://photojournal.jpl.nasa.gov/catalog/PIA21003

[Magnetic resonance imaging findings on the eyelids of Japanese cadavers for anatomical studies and a comparative examination of their histological pictures].

PubMed

Ide, Atsushi; Wakimasu, Koichi; Shiba, Tomoko; Kodama, Junichi; Shirasawa, Nobuyuki

2009-12-01

To clarify ambiguous areas in interpreting MR images of Japanese eyelids, a histological examination was conducted on cadavers after the MRI for a comparative evaluation. Orbital sections including the unilateral upper and lower palpebrae of two Japanese cadavers (an 87-year-old woman and a 49-year-old man) were examined. Following MRI, the specimens of the same cadavers were examined histologically for a comparative evaluation. In both cadavers, a high signal intensity area with a hazy appearance unlike the orbital fat--fibroadipose tissue rich with connective tissue--was recognized between the orbicularis muscle and orbital septum. The same high signal intensity area that appeared to encase the posterior section of the descending orbital fat was also composed of fibroadipose tissue. Because of the presence of this intervening fibroadipose tissue, the posterior surface of the orbicularis muscle and the orbital septum could not come into contact with each other. Although limited to only two subjects, the current observation proved that fibroadipose tissue exists not only in the superficial layer of the orbital fat but that it further descends to surround the lowest portion of the orbital fat. As already reported, it was mainly the fibroadipose tissue, but not the orbital fat, that descends into the palpebral space.

Current-induced spin polarization in InGaAs and GaAs epilayers with varying doping densities

NASA Astrophysics Data System (ADS)

Luengo-Kovac, M.; Huang, S.; Del Gaudio, D.; Occena, J.; Goldman, R. S.; Raimondi, R.; Sih, V.

2017-11-01

The current-induced spin polarization and momentum-dependent spin-orbit field were measured in InxGa1 -xAs epilayers with varying indium concentrations and silicon doping densities. Samples with higher indium concentrations and carrier concentrations and lower mobilities were found to have larger electrical spin generation efficiencies. Furthermore, current-induced spin polarization was detected in GaAs epilayers despite the absence of measurable spin-orbit fields, indicating that the extrinsic contributions to the spin-polarization mechanism must be considered. Theoretical calculations based on a model that includes extrinsic contributions to the spin dephasing and the spin Hall effect, in addition to the intrinsic Rashba and Dresselhaus spin-orbit coupling, are found to reproduce the experimental finding that the crystal direction with the smaller net spin-orbit field has larger electrical spin generation efficiency and are used to predict how sample parameters affect the magnitude of the current-induced spin polarization.

Polestitters: Using Solar Sails for Constant Real-time Sensing of Earth's Polar Regions

NASA Astrophysics Data System (ADS)

Mulligan, P.; Diedrich, B. L.; Barnes, N.; Derbes, B.

2012-12-01

NASA has funded the Sunjammer mission - a near term demonstration of solar sail technology (2014/15). Sunjammer has the potential to demonstrate stationkeeping out of Earth's orbital plane. This is a first step in achieving "polesitter" orbits with year-round, real-time visibility of Earth's polar regions. Potential applications for such missions are illustrated. Solar sails have long been a concept for spacecraft propulsion that works by exchanging momentum with sunlight reflected by large, lightweight, mirrored sails. In addition to enabling propellantless propulsion throughout the solar system and beyond, their continuous thrust enables artificial Lagrange orbits (ALOs), some of which can be called "polesitter" orbits, with 24-hour, year-round visibility of Earth's polar regions. Several potential Earth remote sensing applications have been identified that address the limited temporal and spatial coverage from traditional polar and geostationary satellites. The Galileo spacecraft during its 1990 Earth flyby acquired imagery and radiometer data similar to the view from a polesitter. The Galileo imagery was used to derive aerosols and cloud variations used in atmospheric motion vector (AMV) derivations. Composites of satellite imagery over the South Pole is routinely used to derive atmospheric motion vectors like those performed regularly from geostationary satellites. The JAXA IKAROS mission flew a 14x14m solar sail past Venus in 2010. Sunjammer will demonstrate a state of the art 38x38m solar sail from Earth to an artificial Lagrange orbit located sunward and north of the sun-Earth L1 point. Traditional spacecraft can orbit naturally occurring Lagrange equilibrium points between the sun and Earth. The low, continuous thrust of solar sails can change where these points occur, creating new orbits with a variety of potential applications including polar remote sensing, space weather monitoring, and polar communications. This figure illustrates a selection of

Dimensional crossover of effective orbital dynamics in polar distorted He 3 -A : Transitions to antispacetime

NASA Astrophysics Data System (ADS)

Nissinen, J.; Volovik, G. E.

2018-01-01

Topologically protected superfluid phases of He 3 allow one to simulate many important aspects of relativistic quantum field theories and quantum gravity in condensed matter. Here we discuss a topological Lifshitz transition of the effective quantum vacuum in which the determinant of the tetrad field changes sign through a crossing to a vacuum state with a degenerate fermionic metric. Such a transition is realized in polar distorted superfluid He 3 -A in terms of the effective tetrad fields emerging in the vicinity of the superfluid gap nodes: the tetrads of the Weyl points in the chiral A-phase of He 3 and the degenerate tetrad in the vicinity of a Dirac nodal line in the polar phase of He 3 . The continuous phase transition from the A -phase to the polar phase, i.e., the transition from the Weyl nodes to the Dirac nodal line and back, allows one to follow the behavior of the fermionic and bosonic effective actions when the sign of the tetrad determinant changes, and the effective chiral spacetime transforms to antichiral "anti-spacetime." This condensed matter realization demonstrates that while the original fermionic action is analytic across the transition, the effective action for the orbital degrees of freedom (pseudo-EM) fields and gravity have nonanalytic behavior. In particular, the action for the pseudo-EM field in the vacuum with Weyl fermions (A-phase) contains the modulus of the tetrad determinant. In the vacuum with the degenerate metric (polar phase) the nodal line is effectively a family of 2 +1 d Dirac fermion patches, which leads to a non-analytic (B2-E2)3/4 QED action in the vicinity of the Dirac line.

QSAT: The Satellite for Polar Plasma Observation

NASA Astrophysics Data System (ADS)

Tsuruda, Yoshihiro; Fujimoto, Akiko; Kurahara, Naomi; Hanada, Toshiya; Yumoto, Kiyohumi; Cho, Mengu

2009-04-01

This paper introduces QSAT, the satellite for polar plasma observation. The QSAT project began in 2006 as an initiative by graduate students of Kyushu University, and has the potential to contribute greatly to IHY (International Heliophysical Year) by showing to the world the beauty, importance, and relevance of space science. The primary objectives of the QSAT mission are (1) to investigate plasma physics in the Earth’s aurora zone in order to better understand spacecraft charging, and (2) to conduct a comparison of the field-aligned current observed in orbit with ground-based observations. The QSAT project can provide education and research opportunities for students in an activity combining space sciences and satellite engineering. The QSAT satellite is designed to be launched in a piggyback fashion with the Japanese launch vehicle H-IIA. The spacecraft bus is being developed at the Department of Aeronautics and Astronautics of Kyushu University with collaboration of Fukuoka Institute of Technology. Regarding the payload instruments, the Space Environment Research Center of Kyushu University is developing the magnetometers, whereas the Laboratory of Spacecraft Environment Interaction Engineering of Kyushu Institute of Technology is developing the plasma probes. We aim to be ready for launch in 2009 or later.

Weights assessment for orbit-on-demand vehicles

NASA Technical Reports Server (NTRS)

Macconochie, I. O.; Martin, J. A.; Breiner, C. A.; Cerro, J. A.

1985-01-01

Future manned, reusable earth-to-orbit vehicles may be required to reach orbit within hours or even minutes of a mission decision. A study has been conducted to consider vehicles with such a capability. In the initial phase of the study, 11 vehicles were sized for deployment of 5000 lbs to a polar orbit. From this matrix, two of the most promising concepts were resized for a modified mission and payload. A key feature of the study was the use of consistent mass estimating techniques for a broad range of concepts, allowing direct comparisons of sizes and weights.

Limb Correction of Polar-Orbiting Imagery for the Improved Interpretation of RGB Composites

NASA Technical Reports Server (NTRS)

Jedlovec, Gary J.; Elmer, Nicholas

2016-01-01

Red-Green-Blue (RGB) composite imagery combines information from several spectral channels into one image to aid in the operational analysis of atmospheric processes. However, infrared channels are adversely affected by the limb effect, the result of an increase in optical path length of the absorbing atmosphere between the satellite and the earth as viewing zenith angle increases. This paper reviews a newly developed technique to quickly correct for limb effects in both clear and cloudy regions using latitudinally and seasonally varying limb correction coefficients for real-time applications. These limb correction coefficients account for the increase in optical path length in order to produce limb-corrected RGB composites. The improved utility of a limb-corrected Air Mass RGB composite from the application of this approach is demonstrated using Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) imagery. However, the limb correction can be applied to any polar-orbiting sensor infrared channels, provided the proper limb correction coefficients are calculated. Corrected RGB composites provide multiple advantages over uncorrected RGB composites, including increased confidence in the interpretation of RGB features, improved situational awareness for operational forecasters, and the ability to use RGB composites from multiple sensors jointly to increase the temporal frequency of observations.

Japanese H-IIA rocket

NASA Image and Video Library

2013-11-14

The Japanese H-IIA rocket will be launching the GPM Core Observatory into orbit in 2014. Credit: JAXA The Global Precipitation Measurement (GPM) mission is an international partnership co-led by NASA and the Japan Aerospace Exploration Agency (JAXA) that will provide next-generation global observations of precipitation from space. GPM will study global rain, snow and ice to better understand our climate, weather, and hydrometeorological processes. As of Novermber 2013 the GPM Core Observatory is in the final stages of testing at NASA Goddard Space Flight Center. The satellite will be flown to Japan in the fall of 2013 and launched into orbit on an HII-A rocket in early 2014. For more on the GPM mission, visit gpm.gsfc.nasa.gov/. 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

Cryogenic implications of orbit selection of the Space Infrared Telescope Facility (SIRTF)

NASA Technical Reports Server (NTRS)

Lee, J. H.; Brooks, W. F.; Maa, S.

1986-01-01

An investigation has been conducted to determine how the choice of orbit for NASA's prospective Space IR Telescope Facility (SIRTF), between polar (99-deg) and low inclination (28.5-deg) alternatives, will affect the performance of the all-superfluid He-cooled IR optics employed. While the dewar design met both the service life and 200-micron background-limited performance criteria in the case of the polar orbit mission, the alternative orbit allowed the background-limited criteria to be met only 50 percent of the time. It is accordingly recommended that the 200-micron background-limited observations be made only for a limited portion of the mission, while meeting the 100-micron limit at all times.

Design of the Recovery Trajectory for JAXA Venus Orbiter Akatsuki

NASA Astrophysics Data System (ADS)

Campagnola, Stefano; Kawakatsu, Yasuhiro

2015-12-01

Akatsuki ("dawn" in Japanese) is the JAXA Venus orbiter that was scheduled to enter orbit around Venus on Dec. 7 th , 2010. Following the failure of the main engine during the orbit insertion maneuver, the spacecraft escaped Venus on a 200-day orbit around the Sun, only to return in early 2017. This paper presents the design and implementation of the recovery trajectory, which involves perihelion maneuvers to re-encounter Venus in late 2015. Relying only on the onboard propellant, the trajectory rescued the mission by (1) anticipating the beginning of the science phase within the nominal lifetime of the spacecraft, and (2) halving the Δ v requirements for the orbit insertion maneuver. Several trajectories are designed with an innovative use of a technique called non-tangent V-Infinity Leveraging Transfers (VILTs). Candidate solutions are then recomputed in higher fidelity models, and one solution is finally selected for its low Δv requirements and for programmatic reasons. The results of the perihelion maneuver campaign are also presented.

Aerosol and Cloud Observations and Data Products by the GLAS Polar Orbiting Lidar Instrument

NASA Technical Reports Server (NTRS)

Spinhirne, J. D.; Palm, S. P.; Hlavka, D. L.; Hart, W. D.; Mahesh, A.; Welton, E. J.

2005-01-01

The Geoscience Laser Altimeter System (GLAS) launched in 2003 is the first polar orbiting satellite lidar. The instrument was designed for high performance observations of the distribution and optical scattering cross sections of clouds and aerosol. The backscatter lidar operates at two wavelengths, 532 and 1064 nm. Both receiver channels meet and exceed their design goals, and beginning with a two month period through October and November 2003, an excellent global lidar data set now exists. The data products for atmospheric observations include the calibrated, attenuated backscatter cross section for cloud and aerosol; height detection for multiple cloud layers; planetary boundary layer height; cirrus and aerosol optical depth and the height distribution of aerosol and cloud scattering cross section profiles. The data sets are now in open release through the NASA data distribution system. The initial results on global statistics for cloud and aerosol distribution has been produced and in some cases compared to other satellite observations. The sensitivity of the cloud measurements is such that the 70% global cloud coverage result should be the most accurate to date. Results on the global distribution of aerosol are the first that produce the true height distribution for model inter-comparison.

Effects of Orbital Evolution on Lunar Ice Stability

NASA Astrophysics Data System (ADS)

Siegler, M. A.; Bills, B. G.; Paige, D. A.

2010-12-01

Permanently shadowed regions of the Moon have complex thermal histories that influence their ability to act as traps for water ice. Though many areas are now cold enough that surface water ice would be stable from sublimation losses for billions of years, this has not always been the case. Here we examine the effects of the long term orbital and rotational evolution of the Moon on polar thermal history, volatile stability and mobility. Using data from the Diviner Lunar Radiometer, aboard the Lunar Reconnaissance Orbiter, we validate models of the current temperature in the lunar polar region. This model includes the effects of topography, scattering, re-radiation, and regolith thermal properties. Then, integrating the effects of tidal torques backward from the present, we reconstruct past orbital and rotational states and use them as input to the thermal model to estimate the thermal environment of the distant lunar past. The rate of tidal evolution of the lunar orbit is quite uncertain, thus use orbital semimajor axis as independent variable, rather than time, in the reconstruction. The orbital integration results in a high obliquity period which occurred when the Moon was at about half its present distance from the Earth. This period, which caused half a year of direct sunlight on the polar region, is due to a transition between two Cassini States, spin-orbit configurations resulting from internal dissipation within the Moon. Since this event, the tilt of the Moon (with respect to the ecliptic) has slowly decreased to the current 1.54 degree. Prior to this transition, due to the relatively small Earth-Moon distance, large amplitude variations in the inclination of the orbital plain were also important. We examine the stability of polar volatiles in response to the evolving lunar orbit, and apply simple models to describe when in the Moon’s history supplied volatiles would have been most likely to be buried by thermal diffusion. When temperatures are much below

Polar Textures

NASA Image and Video Library

2017-06-08

This VIS image of the south pole was taken at the end of summer. Frost will soon start to form as the season transitions into fall. Fall in the southern hemisphere means spring in the northern, so the north polar cap is just starting to thaw. Orbit Number: 67893 Latitude: -87.0251 Longitude: 275.679 Instrument: VIS Captured: 2017-04-04 06:19 https://photojournal.jpl.nasa.gov/catalog/PIA21679

Stationkeeping for the Lunar Reconnaissance Orbiter (LRO)

NASA Technical Reports Server (NTRS)

Beckman, Mark; Lamb, Rivers

2007-01-01

The Lunar Reconnaissance Orbiter (LRO) is scheduled to launch in 2008 as the first mission under NASA's Vision for Space Exploration. Follo wing several weeks in a quasi-frozen commissioning orbit, LRO will fl y in a 50 km mean altitude lunar polar orbit. During the one year mis sion duration, the orbital dynamics of a low lunar orbit force LRO to perform periodic sets of stationkeeping maneuvers. This paper explor es the characteristics of low lunar orbits and explains how the LRO s tationkeeping plan is designed to accommodate the dynamics in such an orbit. The stationkeeping algorithm used for LRO must meet five miss ion constraints. These five constraints are to maintain ground statio n contact during maneuvers, to control the altitude variation of the orbit, to distribute periselene equally between northern and southern hemispheres, to match eccentricity at the beginning and the end of the sidereal period, and to minimize stationkeeping (Delta)V. This pape r addresses how the maneuver plan for LRO is designed to meet all of the above constraints.

Mission Design for the Lunar Reconnaissance Orbiter

NASA Technical Reports Server (NTRS)

Beckman, Mark

2007-01-01

The Lunar Reconnaissance Orbiter (LRO) will be the first mission under NASA's Vision for Space Exploration. LRO will fly in a low 50 km mean altitude lunar polar orbit. LRO will utilize a direct minimum energy lunar transfer and have a launch window of three days every two weeks. The launch window is defined by lunar orbit beta angle at times of extreme lighting conditions. This paper will define the LRO launch window and the science and engineering constraints that drive it. After lunar orbit insertion, LRO will be placed into a commissioning orbit for up to 60 days. This commissioning orbit will be a low altitude quasi-frozen orbit that minimizes stationkeeping costs during commissioning phase. LRO will use a repeating stationkeeping cycle with a pair of maneuvers every lunar sidereal period. The stationkeeping algorithm will bound LRO altitude, maintain ground station contact during maneuvers, and equally distribute periselene between northern and southern hemispheres. Orbit determination for LRO will be at the 50 m level with updated lunar gravity models. This paper will address the quasi-frozen orbit design, stationkeeping algorithms and low lunar orbit determination.

Summary of the Results from the Lunar Orbiter Laser Altimeter after Seven Years in Lunar Orbit

NASA Technical Reports Server (NTRS)

Smith, David E.; Zuber, Maria T.; Neumann, Gregory A.; Mazarico, Erwan; Lemoine, Frank G.; Head, James W., III; Lucey, Paul G.; Aharonson, Oded; Robinson, Mark S.; Sun, Xiaoli;

A Study into the Method of Precise Orbit Determination of a HEO Orbiter by GPS and Accelerometer

NASA Technical Reports Server (NTRS)

Ikenaga, Toshinori; Hashida, Yoshi; Unwin, Martin

2007-01-01

In the present day, orbit determination by Global Positioning System (GPS) is not unusual. Especially for low-cost small satellites, position determination by an on-board GPS receiver provides a cheap, reliable and precise method. However, the original purpose of GPS is for ground users, so the transmissions from all of the GPS satellites are directed toward the Earth s surface. Hence there are some restrictions for users above the GPS constellation to detect those signals. On the other hand, a desire for precise orbit determination for users in orbits higher than GPS constellation exists. For example, the next Japanese Very Long Baseline Interferometry (VLBI) mission "ASTRO-G" is trying to determine its orbit in an accuracy of a few centimeters at apogee. The use of GPS is essential for such ultra accurate orbit determination. This study aims to construct a method for precise orbit determination for such high orbit users, especially in High Elliptical Orbits (HEOs). There are several approaches for this objective. In this study, a hybrid method with GPS and an accelerometer is chosen. Basically, while the position cannot be determined by an on-board GPS receiver or other Range and Range Rate (RARR) method, all we can do to estimate the user satellite s position is to propagate the orbit along with the force model, which is not perfectly correct. However if it has an accelerometer (ACC), the coefficients of the air drag and the solar radiation pressure applied to the user satellite can be updated and then the propagation along with the "updated" force model can improve the fitting accuracy of the user satellite s orbit. In this study, it is assumed to use an accelerometer available in the present market. The effects by a bias error of an accelerometer will also be discussed in this paper.

Antisymmetric Spin-Orbit Coupling in a d-p Model on a Zigzag Chain

DOE PAGES

Sugita, Yusuke; Hayami, Satoru; Motome, Yukitoshi

2015-12-29

In this paper, we theoretically investigate how an antisymmetric spin-orbit coupling emerges in electrons moving on lattice structures which are centrosymmetric but break the spatial inversion symme- try at atomic positions. We construct an effective d-p model on the simplest lattice structure, a zigzag chain of edge-sharing octahedra, with taking into account the crystalline electric field, the spin-orbit coupling, and on-site and inter-site d-p hybridizations. We show that an effective antisymmetric spin-orbit coupling arises in the sublattice-dependent form, which results in a hidden spin polarization in the band structure. Finally, we explicitly derive the effective antisymmetric spin-orbit coupling for dmore » electrons, which not only explains the hidden spin polarization but also indicates how to enhance it.« less

Antisymmetric Spin-Orbit Coupling in a d-p Model on a Zigzag Chain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sugita, Yusuke; Hayami, Satoru; Motome, Yukitoshi

In this paper, we theoretically investigate how an antisymmetric spin-orbit coupling emerges in electrons moving on lattice structures which are centrosymmetric but break the spatial inversion symme- try at atomic positions. We construct an effective d-p model on the simplest lattice structure, a zigzag chain of edge-sharing octahedra, with taking into account the crystalline electric field, the spin-orbit coupling, and on-site and inter-site d-p hybridizations. We show that an effective antisymmetric spin-orbit coupling arises in the sublattice-dependent form, which results in a hidden spin polarization in the band structure. Finally, we explicitly derive the effective antisymmetric spin-orbit coupling for dmore » electrons, which not only explains the hidden spin polarization but also indicates how to enhance it.« less

Terahertz radiation by subpicosecond spin-polarized photocurrent originating from Dirac electrons in a Rashba-type polar semiconductor

NASA Astrophysics Data System (ADS)

Kinoshita, Yuto; Kida, Noriaki; Miyamoto, Tatsuya; Kanou, Manabu; Sasagawa, Takao; Okamoto, Hiroshi

2018-04-01

The spin-splitting energy bands induced by the relativistic spin-orbit interaction in solids provide a new opportunity to manipulate the spin-polarized electrons on the subpicosecond timescale. Here, we report one such example in a bulk Rashba-type polar semiconductor BiTeBr. Strong terahertz electromagnetic waves are emitted after the resonant excitation of the interband transition between the Rashba-type spin-splitting energy bands with a femtosecond laser pulse circularly polarized. The phase of the emitted terahertz waves is reversed by switching the circular polarization. This suggests that the observed terahertz radiation originates from the subpicosecond spin-polarized photocurrents, which are generated by the asymmetric depopulation of the Dirac state. Our result provides a way for the current-induced terahertz radiation and its phase control by the circular polarization of incident light without external electric fields.

Extreme Ultraviolet Fractional Orbital Angular Momentum Beams from High Harmonic Generation

PubMed Central

Turpin, Alex; Rego, Laura; Picón, Antonio; San Román, Julio; Hernández-García, Carlos

2017-01-01

We investigate theoretically the generation of extreme-ultraviolet (EUV) beams carrying fractional orbital angular momentum. To this end, we drive high-order harmonic generation with infrared conical refraction (CR) beams. We show that the high-order harmonic beams emitted in the EUV/soft x-ray regime preserve the characteristic signatures of the driving beam, namely ringlike transverse intensity profile and CR-like polarization distribution. As a result, through orbital and spin angular momentum conservation, harmonic beams are emitted with fractional orbital angular momentum, and they can be synthesized into structured attosecond helical beams –or “structured attosecond light springs”– with rotating linear polarization along the azimuth. Our proposal overcomes the state of the art limitations for the generation of light beams far from the visible domain carrying non-integer orbital angular momentum and could be applied in fields such as diffraction imaging, EUV lithography, particle trapping, and super-resolution imaging. PMID:28281655

South Polar Cap

NASA Technical Reports Server (NTRS)

2005-01-01

17 March 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows mesas and pits formed by sublimation of carbon dioxide of the south polar cap.

Location near: 85.8oS, 351.5oW Image width: 2 km (1.2 mi) Illumination from: upper left Season: Southern Summer

The Formal Pragmatics of Non-at-Issue Intensification in English and Japanese

ERIC Educational Resources Information Center

Taniguchi, Ai

2017-01-01

This dissertation concerns the formal pragmatics of constructions in English and Japanese that are perceptively intensificative in their discourse function in some way. In particular I examine polarity emphasis (verum focus), exclamatives, and acts of notification and surprise in language using a compositional version of Farkas and Bruce (2010)'s…

Effects of strain on ferroelectric polarization and magnetism in orthorhombic HoMnO3

NASA Astrophysics Data System (ADS)

Iuşan, Diana; Yamauchi, Kunihiko; Barone, Paolo; Sanyal, Biplab; Eriksson, Olle; Profeta, Gianni; Picozzi, Silvia

2013-01-01

We explore how the ferroelectric polarization of antiferromagnetic E-type orthorhombic HoMnO3 can be increased, by investigating the effects of in-plane strain on both the magnetic properties and the ferroelectric polarization, using combined density functional theory calculations and a model Hamiltonian technique. Our results show that the net polarization is strongly enhanced under compressive strain, due to an increase of the elec-tronic contribution to the polarization. In contrast, the ionic contribution is found to decrease. We identify the electron-lattice coupling, due to Jahn-Teller (JT) distortions, and its response to strain, to be responsible for the observed behavior. The JT-induced orbital ordering of occupied Mn-eg1 electrons in alternating 3x2-r23y2-r2 orbital states in the unstrained structure, changes under in-plane compressive strain to a mixture with x2-z2y2-z2 states. The asymmetric hopping of eg electrons between Mn ions along zigzag spin chains (typical of the AFM-E spin configuration) is therefore enhanced under strain, explaining the large value of the polarization. Using a degenerate double-exchange model including electron-phonon interaction, we reproduce the change in the orbital ordering pattern. In this picture, the orbital ordering change is related to a change of the Berry phase of the eg electrons. This causes an increase of the electronic contribution to the polarization.

Orbital-ordering-driven multiferroicity and magnetoelectric coupling in GeV₄S₈.

PubMed

Singh, Kiran; Simon, Charles; Cannuccia, Elena; Lepetit, Marie-Bernadette; Corraze, Benoit; Janod, Etienne; Cario, Laurent

2014-09-26

We report here the discovery of multiferroicity and large magnetoelectric coupling in the type I orbital order system GeV₄S₈. Our study demonstrates that this clustered compound displays a para-ferroelectric transition at 32 K. This transition originates from an orbital ordering which reorganizes the charge within the transition metal clusters. Below the antiferromagnetic transition at 17 K, the application of a magnetic field significantly affects the ferroelectric polarization, revealing thus a large magnetoelectric coupling. Our study suggests that the application of a magnetic field induces a metamagnetic transition which significantly affects the ferroelectric polarization thanks to an exchange striction phenomenon.

Officials welcome the arrival of the Japanese Experiment Module

NASA Image and Video Library

2007-04-17

In the Space Station Processing Facility, astronaut Takao Doi (left) and Commander Dominic Gorie pose in front of the Experiment Logistics Module Pressurized Section for the Japanese Experiment Module, or JEM, that recently arrived at Kennedy. Doi and Gorie are crew members for mission STS-123 that will deliver the logistics module to the International Space Station. Earlier, NASA and Japanese Aerospace and Exploration Agency (JAXA) officials welcomed the arrival of the module. The new International Space Station component arrived at Kennedy March 12 to begin preparations for its future launch on mission STS-123. It will serve as an on-orbit storage area for materials, tools and supplies. It can hold up to eight experiment racks and will attach to the top of another larger pressurized module.

Evidence for a new geomagnetic reversal from lava flows in Idaho: discussion of short polarity reversals in the Brunhes and late Matuyama Polarity Chrons

USGS Publications Warehouse

Champion, D.E.; Lanphere, M.A.; Kuntz, M.A.

1988-01-01

K-Ar ages and paleomagnetic data for basalt samples from a new core hole (site E) at the Idaho National Engineering Laboratory (INEL) indicate that the age of the reversed polarity event recorded in Snake River Plain lavas is older than 465 ?? 50 ka (1000 years before present) reported previously by Champion et al. (1981). A review of data documenting short reversal records from volcanic and sedimentary rocks shows that there is evidence for eight polarity subchrons in the Brunhes and two besides the Jaramillo in the late Matuyama. These 10 short subchrons begin to indicate the many short events that Cox (1968) hypothesized must exist if polarity interval lengths have a Poisson distribution. The mean sustained polarity interval length since late Matuyama Chron time is 90 000 years. The similarity of this number with the 105-year period of the Earth's orbital eccentricity suggests anew that linkage between geomagnetic, paleoclimatic, and possible underlying Earth orbital parameters should be evaluated. -from Authors

WARC and CCIR support for spectrum-orbit planning

NASA Technical Reports Server (NTRS)

Sawitz, P. H.

1980-01-01

Papers prepared for the use of the U.S. delegation to the 1979 World Administrative Radio Conference; papers contributed to the National CCIR study groups on broadcasting satellites and spectrum-orbit utilization; responses to specific requests for technical analyses and evaluations; and papers presented at technical conferences on related topics are presented. Nonlinear optimization methods for finding optimum positions of satellites in the fixed satellite service; the effects of geography on the use of the geostationary orbit; intercontinental orbit sharing; traffic coordination in interfering satellites operating in the fixed satellite service; and domestic fixed and broadcasting satellite systems are covered. A possible channel orbit plan for broadcasting satellite service in the U.S. and Canada; polarization for broadcasting satellite systems; and the communication capacity of the geostationary satellite orbit are also examined.

Lunar Reconnaissance Orbiter

NASA Astrophysics Data System (ADS)

Morgan, T.; Chin, G.

2007-08-01

NASA's Lunar Reconnaissance Orbiter (LRO) plans to launch in October 2008 with a companion secondary impactor mission, LCROSS, as the inaugural missions for the Exploration System Mission Directorate. LRO is a pathfinder whose objective is to obtain the needed information to prepare for eventual human return to the Moon. LRO will undertake at least one baseline year of operation with additional extended mission phase sponsored by NASA's Science Mission Directorate. LRO will employ six individual instruments to produce accurate maps and high-resolution images of future landing sites, to assess potential lunar resources, and to characterize the radiation environment. LRO will also test the feasibility of one advanced technology demonstration package. The LRO payload includes: Lunar Orbiter Laser Altimeter (LOLA) which will determine the global topography of the lunar surface at high resolution, measure landing site slopes, surface roughness, and search for possible polar surface ice in shadowed regions; Lunar Reconnaissance Orbiter Camera (LROC) which will acquire targeted narrow angle images of the lunar surface capable of resolving meter-scale features to support landing site selection, as well as wide-angle images to characterize polar illumination conditions and to identify potential resources; Lunar Exploration Neutron Detector (LEND) which will map the flux of neutrons from the lunar surface to search for evidence of water ice, and will provide space radiation environment measurements that may be useful for future human exploration; Diviner Lunar Radiometer Experiment (DLRE) which will chart the temperature of the entire lunar surface at approximately 300 meter horizontal resolution to identify cold-traps and potential ice deposits; Lyman-Alpha Mapping Project (LAMP) which will map the entire lunar surface in the far ultraviolet. LAMP will search for surface ice and frost in the polar regions and provide images of permanently shadowed regions illuminated only

Multi-Orbital contributions in High Harmonic Generation

NASA Astrophysics Data System (ADS)

Guehr, Markus

2009-05-01

The high harmonic spectrum generated from atoms or molecules in a strong laser field contains information about the electronic structure of the generation medium. In the high harmonic generation (HHG) process, a free electron wave packet tunnel-ionizes from the molecular orbital in a strong laser field. After being accelerated by the laser electric field, the free electron wave packet coherently recombines to the orbital from which is was initially ionized, thereby emitting the harmonic spectrum. Interferences between the free electron wave packet and the molecular orbital will shape the spectrum in a characteristic way. These interferences have been used to tomographically image the highest occupied molecular orbital (HOMO) of N2 [1]. Molecular electronic states energetically below the HOMO should contribute to laser-driven high harmonic generation (HHG), but this behavior has not been observed previously. We have observed evidence of HHG from multiple orbitals in aligned N2 [2]. The tunneling ionization (and therefore the harmonic generation) is most efficient if the orbital has a large extension in the direction of the harmonic generation polarization. The HOMO with its σg symmetry therefore dominates the harmonic spectrum if the molecular axis is parallel to the harmonic generation polarization, the lower bound πu HOMO-1 dominates in the perpendicular case. The HOMO contributions appear as a regular plateau with a cutoff in the HHG spectrum. In contrast, the HOMO-1 signal is strongly peaked in the cutoff region. We explain this by semi-classical simulations of the recombination process that show constructive interferences between the HOMO-1 and the recombining wave packet in the cutoff region. The ability to monitor several orbitals opens the route to imaging coherent superpositions of electronic orbitals. [1] J. Itatani et al., Nature 432, 867 (2004)[2] B. K. McFarland, J. P. Farrell, P. H. Bucksbaum and M. Gühr, Science 322, 1232 (2008)

Polar Crater Deposits as a Probe for Ancient Climate Change on Mars

NASA Astrophysics Data System (ADS)

Armstrong, John

2006-10-01

Dynamical studies of the Martian orbit suggest a planet that has undergone extreme orbital change. How has this affected the planet's climate? Is there a record of this orbit-induced climate change written in the geology that is expressed on the surface? If so, such a record would provide insight into Mars' climate history, and shed light on the types of habitats for life that may have existed in the past. We are exploring how the current seasonal polar caps interact with polar craters in an effort to identify modification that can be linked to the proximity of the polar cap. Ice deposits within the craters are evident in both thermal spectra and imagery from Mars orbiters. We have linked these ice deposits to morphological deposits that can be identified in other craters that are further from the pole. These deposits may act as a probe of the variations suggested by orbital calculations, as well as provide an indicator of the extent of the sub-surface ice table. We will present preliminary results from a sample of northern craters, and explain how this can be extended to southern craters, and possibly mid-latitude craters, in an effort to understand more fully the martian climate through time.

The influence of orbit selection on the accuracy of the Stanford Relativity gyroscope experiment

NASA Technical Reports Server (NTRS)

Vassar, R.; Everitt, C. W. F.; Vanpatten, R. A.; Breakwell, J. V.

1980-01-01

This paper discusses an error analysis for the Stanford Relativity experiment, designed to measure the precession of a gyroscope's spin-axis predicted by general relativity. Measurements will be made of the spin-axis orientations of 4 superconducting spherical gyroscopes carried by an earth-satellite. Two relativistic precessions are predicted: a 'geodetic' precession associated with the satellite's orbital motion and a 'motional' precession due to the earth's rotation. Using a Kalman filter covariance analysis with a realistic error model we have computed the error in determining the relativistic precession rates. Studies show that a slightly off-polar orbit is better than a polar orbit for determining the 'motional' drift.

Four Mars Years of South Polar Changes

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] [figure removed for brevity, see original site] View in 1999View in 2001View in 2003View in 2005

One of the most profound discoveries that would not have been possible if NASA's Mars Global Surveyor mission had not been extended beyond its primary mission of one Mars year (687 Earth days) is that of dramatic changes that take place in the south polar residual ice cap each martian year. To make this discovery, the Mars Orbiter Camera on the spacecraft had to be employed during a second Mars year to repeat images of sites on the south polar cap that had been imaged during the primary mission.

The initial discovery was made in 2001, when the camera team repeated images of portions of the south polar cap that had already been imaged in 1999. The goal of these images was to obtain stereo views, which would allow investigators to see the topography of the cap in three dimensions and to measure the thickness of the polar ice layers.

It was not possible to produce the desired 3-D views. To the team's surprise, the landforms of the south polar cap had changed.

The south polar residual cap -- that is, the portion of the ice cap that remains bright and retains ice throughout the southern summer season -- was seen in 1997 and 1999 images to have a complex terrain of broad, relatively flat mesas, small buttes, and many pits and troughs. Pits are generally circular and in some areas visually resemble a stack of thin slices of Swiss cheese. Very early in the Mars Global Surveyor mission, the Mars Orbiter Camera team speculated that these landforms must be carved into frozen carbon dioxide, because they look so unfamiliar and because Viking orbiter infrared measurements indicated that the south polar cap is cold enough consist of frozen carbon dioxide, even in summer.

The observations made by Mars Orbiter Camera in 2001, during the first part of the extended mission, showed that the scarps and pit walls of

Long-Term Cryogenic Propellant Storage for the Titan Orbiter Polar Surveyor (TOPS) Mission

NASA Technical Reports Server (NTRS)

Mustafi, Shuvo; Francis, John; Li, Xiaoyi; DeLee, Hudson; Purves, Lloyd; Willis, Dewey; Nixon, Conor; Mcguinness, Dan; Riall, Sara; Devine, Matt;

Polar Cap Pits

NASA Technical Reports Server (NTRS)

2005-01-01

17 August 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows kidney bean-shaped pits, and other pits, formed by erosion in a landscape of frozen carbon dioxide. This images shows one of about a dozen different patterns that are common in various locations across the martian south polar residual cap, an area that has been receiving intense scrutiny by the MGS MOC this year, because it is visible on every orbit and in daylight for most of 2005.

Location near: 86.9oS, 6.9oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

Mesoscopic Rings with Spin-Orbit Interactions

ERIC Educational Resources Information Center

Berche, Bertrand; Chatelain, Christophe; Medina, Ernesto

2010-01-01

A didactic description of charge and spin equilibrium currents on mesoscopic rings in the presence of spin-orbit interaction is presented. Emphasis is made on the non-trivial construction of the correct Hamiltonian in polar coordinates, the calculation of eigenvalues and eigenfunctions and the symmetries of the ground-state properties. Spin…

Geometric phase due to orbit-orbit interaction: rotating LP11 modes in a two-mode fiber

NASA Astrophysics Data System (ADS)

Pradeep Chakravarthy, T.; Naik, Dinesh N.; Viswanathan, Nirmal K.

2017-10-01

Accumulation of geometric phase due to non-coplanar propagation of higher-order modes in an optical fiber is experimentally demonstrated. Vertically-polarized LP11 fiber mode, excited in a horizontally-held, torsion-free, step-index, two-mode optical fiber, rotates due to asymmetry in the propagating k-vectors, arising due to off-centered beam location at the fiber input. Perceiving the process as due to rotation of the fiber about the off-axis launch position, the orbital Berry phase accumulation upon scanning the launch position in a closed-loop around the fiber axis manifests as rotational Doppler effect, a consequence of orbit-orbit interaction. The anticipated phase accumulation as a function of the input launch position, observed through interferometry is connected to the mode rotation angle, quantified using the autocorrelation method.

STS-33 Commander Gregory displays Japanese student banner on OV-103's middeck

NASA Technical Reports Server (NTRS)

1989-01-01

STS-33 Commander Frederick D. Gregory displays banner drawn and signed by Japanese students on Discovery's, Orbiter Vehicle (OV) 103's, middeck. Gregory's right foot is positioned under the open airlock hatch. Behind him is the port side wall. Gregory wears shorts and a United States Air Force Academy (USAFA) t-shirt.

Polar Polygons

NASA Technical Reports Server (NTRS)

2005-01-01

13 February 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows polygons formed in ice-rich material in the north polar region of Mars. The bright surfaces in this image are covered by a thin water ice frost.

Location near: 79.8oN, 344.8oW Image width: 1.5 km (1.9 mi) Illumination from: lower left Season: Northern Summer

Lunar true polar wander inferred from polar hydrogen.

PubMed

Siegler, M A; Miller, R S; Keane, J T; Laneuville, M; Paige, D A; Matsuyama, I; Lawrence, D J; Crotts, A; Poston, M J

2016-03-24

The earliest dynamic and thermal history of the Moon is not well understood. The hydrogen content of deposits near the lunar poles may yield insight into this history, because these deposits (which are probably composed of water ice) survive only if they remain in permanent shadow. If the orientation of the Moon has changed, then the locations of the shadowed regions will also have changed. The polar hydrogen deposits have been mapped by orbiting neutron spectrometers, and their observed spatial distribution does not match the expected distribution of water ice inferred from present-day lunar temperatures. This finding is in contrast to the distribution of volatiles observed in similar thermal environments at Mercury's poles. Here we show that polar hydrogen preserves evidence that the spin axis of the Moon has shifted: the hydrogen deposits are antipodal and displaced equally from each pole along opposite longitudes. From the direction and magnitude of the inferred reorientation, and from analysis of the moments of inertia of the Moon, we hypothesize that this change in the spin axis, known as true polar wander, was caused by a low-density thermal anomaly beneath the Procellarum region. Radiogenic heating within this region resulted in the bulk of lunar mare volcanism and altered the density structure of the Moon, changing its moments of inertia. This resulted in true polar wander consistent with the observed remnant polar hydrogen. This thermal anomaly still exists and, in part, controls the current orientation of the Moon. The Procellarum region was most geologically active early in lunar history, which implies that polar wander initiated billions of years ago and that a large portion of the measured polar hydrogen is ancient, recording early delivery of water to the inner Solar System. Our hypothesis provides an explanation for the antipodal distribution of lunar polar hydrogen, and connects polar volatiles to the geologic and geophysical evolution of the Moon

Polar Views of Planet Earth.

ERIC Educational Resources Information Center

Brochu, Michel

1983-01-01

In August, 1981, National Aeronautics and Space Administration launched Dynamics Explorer 1 into polar orbit equipped with three cameras built to view the Northern Lights. The cameras can photograph aurora borealis' faint light without being blinded by the earth's bright dayside. Photographs taken by the satellite are provided. (JN)

Japanese Experiment Module (JEM)

NASA Technical Reports Server (NTRS)

2003-01-01

The Japanese Experiment Module (JEM) pressure module is removed from its shipping crate and moved across the floor of the Space Station Processing Facility at Kennedy Space Center (KSC) to a work stand. A research laboratory, the pressurized module is the first element of the JEM, named 'Kibo' (Hope) to arrive at KSC. Japan's primary contribution to the International Space Station, the module will enhance unique research capabilities of the orbiting complex by providing an additional environment in which astronauts will conduct experiments. The JEM also includes an exposed facility or platform for space environment experiments, a robotic manipulator system, and two logistics modules. The various JEM components will be assembled in space over the course of three Shuttle missions.

Effects of finite coverage on global polarization observables in heavy ion collisions

NASA Astrophysics Data System (ADS)

Lan, Shaowei; Lin, Zi-Wei; Shi, Shusu; Sun, Xu

2018-05-01

In non-central relativistic heavy ion collisions, the created matter possesses a large initial orbital angular momentum. Particles produced in the collisions could be polarized globally in the direction of the orbital angular momentum due to spin-orbit coupling. Recently, the STAR experiment has presented polarization signals for Λ hyperons and possible spin alignment signals for ϕ mesons. Here we discuss the effects of finite coverage on these observables. The results from a multi-phase transport and a toy model both indicate that a pseudorapidity coverage narrower than | η | < ∼ 1 will generate a larger value for the extracted ϕ-meson ρ00 parameter; thus a finite coverage can lead to an artificial deviation of ρ00 from 1/3. We also show that a finite η and pT coverage affect the extracted pH parameter for Λ hyperons when the real pH value is non-zero. Therefore proper corrections are necessary to reliably quantify the global polarization with experimental observables.

Surface Ages and Resurfacing Rates of the Polar Layered Deposits on Mars

USGS Publications Warehouse

Herkenhoff, K. E.; Plaut, J.J.

2000-01-01

Interpretation of the polar stratigraphy of Mars in terms of global climate changes is complicated by the significant difference in surface ages between the north and south polar layered terrains inferred from crater statistics. We have reassessed the cratering record in both polar regions using Viking Orbiter and Mariner 9 images. No craters have been found in the north polar layered terrain, but the surface of most of the south polar layered deposits appears to have been stable for many of the orbital/axial cycles that are thought to have induced global climate changes on Mars. The inferred surface age of the south polar layered deposits (about 10 Ma) is two orders of magnitude greater than the surface age of the north polar layered deposits and residual cap (at most 100 ka). Similarly, modeled resurfacing rates are at least 20 times greater in the north than in the south. These results are consistent with the hypotheses that polar layered deposit resurfacing rates are highest in areas covered by perennial ice and that the differences in polar resurfacing rates result from the 6.4 km difference in elevation between the polar regions. Deposition on the portion of the south polar layered deposits that is not covered by the perennial ice cap may have ceased about 5 million years ago when the obliquity of Mars no longer exceeded 40??. ?? 2000 Academic Press.

Aqua Satellite Orbiting Earth Artist Concept

NASA Image and Video Library

2002-05-08

NASA Aqua satellite carries six state-of-the-art instruments in a near-polar low-Earth orbit. Aqua is seen in this artist concept orbiting Earth. The six instruments are the Atmospheric Infrared Sounder (AIRS), the Advanced Microwave Sounding Unit (AMSU-A), the Humidity Sounder for Brazil (HSB), the Advanced Microwave Scanning Radiometer for EOS (AMSR-E), the Moderate Resolution Imaging Spectroradiometer (MODIS), and Clouds and the Earth's Radiant Energy System (CERES). Each has unique characteristics and capabilities, and all six serve together to form a powerful package for Earth observations. http://photojournal.jpl.nasa.gov/catalog/PIA18156

Participation in the Mars Orbiting Laser Altimeter Experiment

NASA Technical Reports Server (NTRS)

Pettengil, Gordon H.; Ford, Peter

2004-01-01

The Mars Orbiting Laser Altimeter (MOLA) instrument [1,2] carried aboard the Mars Global Surveyor (MGS) spacecraft, has observed strong echoes from cloud tops at 1.064 microns on 61% of its orbital passes over the winter north pole (235deg L(sub S), < 315deg) and on 58% of the passes over the winter south pole (45deg < L(sub S), < 135deg). The clouds are unlikely to be composed of water ice since the vapor pressure of H2O is very low at the Martian nighttime polar temperatures measured by the Thermal Emission Spectrometer (TES) [3], and by an analysis of MGS radio occultations [4]. Dust clouds can also be ruled out since no correlation is seen between clouds and global dust storms. The virtually certain composition for the winter polar clouds is CO2 ice.

Bell’s measure and implementing quantum Fourier transform with orbital angular momentum of classical light

PubMed Central

Song, Xinbing; Sun, Yifan; Li, Pengyun; Qin, Hongwei; Zhang, Xiangdong

2015-01-01

We perform Bell’s measurement for the non-separable correlation between polarization and orbital angular momentum from the same classical vortex beam. The violation of Bell’s inequality for such a non-separable classical correlation has been demonstrated experimentally. Based on the classical vortex beam and non-quantum entanglement between the polarization and the orbital angular momentum, the Hadamard gates and conditional phase gates have been designed. Furthermore, a quantum Fourier transform has been implemented experimentally. PMID:26369424

Far side Helioseismology with Solar Orbiter

NASA Astrophysics Data System (ADS)

Appourchaux, T.; Birch, A.; Gizon, L. C.; Löptien, B.; Schou, J.; Solanki, S. K.; del Toro Iniesta, J. C.; Gandorfer, A.; Hirzberger, J.; Alvarez-Herrero, A.; Woch, J. G.; Schmidt, W.

2016-12-01

The Solar Orbiter mission, to be launched in October 2018, will carry a suite of remote sensing and in-situ instruments, including the Polarimetric and Helioseismic Imager (PHI). PHI will deliver high-cadence images of the Sun in intensity and Doppler velocity suitable for carrying out novel helioseismic studies. The orbit of the Solar Orbiter spacecraft will reach a solar latitude up to 34 degrees by the end of the extended mission and thus will enable the first local helioseismology studies of the polar regions. The full range of Earth-Sun-spacecraft angles provided by the orbit will enable helioseismology from two vantage points by combining PHI with another instrument: stereoscopic helioseismology will allow the study of the deep solar interior and a better understanding of the physics of solar oscillations in both quiet Sun and sunspots. In this paper we will review the helioseismic objectives achievable with PHI, and will also give a short status report of the development of the Flight Model of PHI.

Mechanically Reconfigurable Single-Arm Spiral Antenna Array for Generation of Broadband Circularly Polarized Orbital Angular Momentum Vortex Waves.

PubMed

Li, Long; Zhou, Xiaoxiao

2018-03-23

In this paper, a mechanically reconfigurable circular array with single-arm spiral antennas (SASAs) is designed, fabricated, and experimentally demonstrated to generate broadband circularly polarized orbital angular momentum (OAM) vortex waves in radio frequency domain. With the symmetrical and broadband properties of single-arm spiral antennas, the vortex waves with different OAM modes can be mechanically reconfigurable generated in a wide band from 3.4 GHz to 4.7 GHz. The prototype of the circular array is proposed, conducted, and fabricated to validate the theoretical analysis. The simulated and experimental results verify that different OAM modes can be effectively generated by rotating the spiral arms of single-arm spiral antennas with corresponding degrees, which greatly simplify the feeding network. The proposed method paves a reconfigurable way to generate multiple OAM vortex waves with spin angular momentum (SAM) in radio and microwave satellite communication applications.

Strong Electron Correlation in Photoionization of Spin-Orbit Doublets

NASA Astrophysics Data System (ADS)

Amusia, M. Ya.; Chernsheva, L. V.; Mnason, S. T.; Msezane, A. Z.; Radojevic, V.

2002-05-01

A new and explicitly many-body aspect of the "leveraging" of the spin-orbit interaction is demonstrated, spin-orbit activated interchannel coupling, which can significantly alter the photoionization cross section of a spin-orbit doublet. As an example, using a modified version of the Spin-Polarized Random-Phase-Approximation with Exchange methodology, a recently observed structure in the photoionization of Xe 3d(A. Kivimaki et al, Phys. Rev. A 63), 012716 (2000) has been explained both qualitatively and quantitatively. The structure is entirely due to this new spin-orbit activated interchannel coupling effect, which should be a general feature of inner-shell photoionization. This work was supported by NSF, NASA, DOE and ISTC.

Calculations of spin-polarized Goos-Hänchen displacement in magnetically confined GaAs/Al x Ga1-x As nanostructure modulated by spin-orbit couplings

NASA Astrophysics Data System (ADS)

Lu, Mao-Wang; Chen, Sai-Yan; Zhang, Gui-Lian; Huang, Xin-Hong

2018-04-01

We theoretically investigate Goos-Hänchen (GH) displacement by modelling the spin transport in an archetypal device structure—a magnetically confined GaAs/Al x Ga1-x As nanostructure modulated by spin-orbit coupling (SOC). Both Rashba and Dresselhaus SOCs are taken into account. The degree of spin-polarized GH displacement can be tuned by Rashba or Dresselhaus SOC, i.e. interfacial confining electric field or strain engineering. Based on such a semiconductor nanostructure, a controllable spatial spin splitter can be proposed for spintronics applications.

Calculations of spin-polarized Goos-Hänchen displacement in magnetically confined GaAs/Al x Ga1-x As nanostructure modulated by spin-orbit couplings.

PubMed

Lu, Mao-Wang; Chen, Sai-Yan; Zhang, Gui-Lian; Huang, Xin-Hong

2018-04-11

We theoretically investigate Goos-Hänchen (GH) displacement by modelling the spin transport in an archetypal device structure-a magnetically confined GaAs/Al x Ga 1-x As nanostructure modulated by spin-orbit coupling (SOC). Both Rashba and Dresselhaus SOCs are taken into account. The degree of spin-polarized GH displacement can be tuned by Rashba or Dresselhaus SOC, i.e. interfacial confining electric field or strain engineering. Based on such a semiconductor nanostructure, a controllable spatial spin splitter can be proposed for spintronics applications.

Electron spin polarization in realistic trajectories around the magnetic node of two counter-propagating, circularly polarized, ultra-intense lasers

NASA Astrophysics Data System (ADS)

Del Sorbo, D.; Seipt, D.; Thomas, A. G. R.; Ridgers, C. P.

2018-06-01

It has recently been suggested that two counter-propagating, circularly polarized, ultra-intense lasers can induce a strong electron spin polarization at the magnetic node of the electromagnetic field that they setup (Del Sorbo et al 2017 Phys. Rev. A 96 043407). We confirm these results by considering a more sophisticated description that integrates over realistic trajectories. The electron dynamics is weakly affected by the variation of power radiated due to the spin polarization. The degree of spin polarization differs by approximately 5% if considering electrons initially at rest or already in a circular orbit. The instability of trajectories at the magnetic node induces a spin precession associated with the electron migration that establishes an upper temporal limit to the polarization of the electron population of about one laser period.

Mars Reconnaissance Orbiter: Aerobraking Science Analysis

NASA Astrophysics Data System (ADS)

Bougher, Stephen W.; Keating, G. M.

2006-09-01

The Mars Reconnaissance Orbiter (MRO) spacecraft was launched from the Kennedy Space Center in Florida on August 12, 2005, and arrived at Mars on March 10, 2006. Aerobraking in the martian thermosphere was conducted for nearly 5-months after arrival, enabling the desired MRO mapping orbit to be achieved. The MRO aerobraking phase began in early martian northern Spring (Ls = 36) and continued through early northern Summer (Ls 110), spanning approximately 500 orbits. The MRO periapsis latitude migrated slowly poleward/southward from 70ºS latitude upon aerobraking initiation, passed over the South pole (near Ls = 77), and moved rapidly northward to equatorial latitudes at aerobraking conclusion. Upper atmosphere sampling ( 100-200 km) was achieved on the dayside (LT 1900-2000) before polar crossing, and on the nightside (LT = 0200-0300) thereafter. These seasonal and latitude conditions are similar to a subset of those experienced by MGS during its post hiatus aerobraking Phase 2. Derived mass densities, scale heights, and estimated temperatures are the primary data products generated from each aeropass. The most important discovery of MRO aerobraking concerns the sampling of the thermosphere up to 200 km, far higher than previous MGS and Odyssey Accelerometers have achieved. This sampling contributes to the characterization of the Mars exobase region, which is required to predict and interpret atmospheric escape rates. In addition, thermospheric densities at a constant altitude were observed to decrease toward the southern (winter) pole, as expected from previous MGS experience. No winter polar warming was typically observed near the South pole. Thereafter, densities were measured to increase on the nightside as periapsis moved toward the equator. In general, thermospheric variability was observed to increase in the vicinity of the polar vortex boundary ( 70-80ºS), and decreased again inside the vortex (high southern latitudes). Finally, longitude wave features

Handling Japanese without a Japanese Operating System.

ERIC Educational Resources Information Center

Hatasa, Kazumi; And Others

1992-01-01

The Macintosh HyperCard environment has become a popular platform for Japanese language courseware because of its flexibility and ease of programing. This project created Japanese bitmap font files for the JIS Levels 1 and 2, and writing XFCNs for font manipulation, Japanese kana input, and answer correction. (12 references) (Author/LB)

Creating Two-Dimensional Electron Gas in Polar/Polar Perovskite Oxide Heterostructures: First-Principles Characterization of LaAlO3/A(+)B(5+)O3.

PubMed

Wang, Yaqin; Tang, Wu; Cheng, Jianli; Behtash, Maziar; Yang, Kesong

2016-06-01

By using first-principles electronic structure calculations, we explored the possibility of producing two-dimensional electron gas (2DEG) at the polar/polar (LaO)(+)/(BO2)(+) interface in the LaAlO3/A(+)B(5+)O3 (A = Na and K, B = Nb and Ta) heterostructures (HS). Unlike the prototype polar/nonpolar LaAlO3/SrTiO3 HS system where there exists a least film thickness of four LaAlO3 unit cells to have an insulator-to-metal transition, we found that the polar/polar LaAlO3/A(+)B(5+)O3 HS systems are intrinsically conducting at their interfaces without an insulator-to-metal transition. The interfacial charge carrier densities of these polar/polar HS systems are on the order of 10(14) cm(-2), much larger than that of the LaAlO3/SrTiO3 system. This is mainly attributed to two donor layers, i.e., (LaO)(+) and (BO2)(+) (B = Nb and Ta), in the polar/polar LaAlO3/A(+)B(5+)O3 systems, while only one (LaO)(+) donor layer in the polar/nonpolar LaAlO3/SrTiO3 system. In addition, it is expected that, due to less localized Nb 4d and Ta 5d orbitals with respect to Ti 3d orbitals, these LaAlO3/A(+)B(5+)O3 HS systems can exhibit potentially higher electron mobility because of their smaller electron effective mass than that in the LaAlO3/SrTiO3 system. Our results demonstrate that the electronic reconstruction at the polar/polar interface could be an alternative way to produce superior 2DEG in the perovskite-oxide-based HS systems.

Hidden in the Neutrons: Physical Evidence for Lunar True Polar Wander

NASA Astrophysics Data System (ADS)

Keane, J. T.; Siegler, M. A.; Miller, R. S.; Laneuville, M.; Paige, D. A.; Matsuyama, I.; Lawrence, D. J.; Crotts, A.; Poston, M.

2015-12-01

Airless bodies like the Moon are time capsules of planetary and solar system evolution. Lunar polar ices, in particular, record a history of volatile delivery, orbital dynamics, and solar system chemistry. However, despite two decades of orbital geochemistry measurements, the observed abundances and spatial distribution of lunar polar volatiles (likely water ice, as inferred by epithermal neutron deficits) remain unexplained. The observed deposits do not correlate with measured surface temperatures or thermal models of ice stability and are notably asymmetric about the lunar poles, with the peak abundance offset from the present-day pole by 5°. Here we show, for the first time, that polar volatile deposits at the North and South pole are antipodal, displaced equally from each each pole along opposite longitudes. These off-polar volatiles likely represent fossilized cold-traps, formed when the moon had a different spin pole. Reorientation of the Moon from this paleopole to the present pole (i.e. true polar wander) altered the locations of cold-traps and resulted in the asymmetric, but antipodal, polar hydrogen distribution. Since true polar wander results from changes in the distribution of mass within a planet, the direction and magnitude of this wander can be used to constrain the evolution of the lunar interior. We find a causal link between this paleopole and the unique thermal evolution of the nearside Procellarum KREEP Terrane (PKT). Radiogenic heating within this province not only resulted major mare volcanism, but also altered the Moon's moments of inertia. We use a combination of analytical, and numerical 3-D thermochemical convection models to show that the evolution of the PKT naturally produces the correct direction and magnitude of polar wander (albeit early in lunar history, when the PKT was most active). This work provides a self-consistent explanation for the spatial distribution of lunar polar volatiles and opens a deeper connection to the

Proceedings of the Fourth International Conference on Mars Polar Science and Exploration

NASA Technical Reports Server (NTRS)

2006-01-01

Sessions in this conference include: Mars polar geology and glaciology; Mars and terrestrial radar investigations; Observations, nature, and evolution of the Martian seasonal polar caps; Mars' residual south polar cap; Climate change, ice core analysis, and the redistribution of volatiles on Mars; errestrial Mars analog environments; The Phoenix Scout mission and the nature of the near-polar environment; Moderated Discussion: Key Issues Regarding Phoenix Scout Mission and the nature of the near-polar environment; Panel Discussion: Key Issues in Mars Polar Science and Exploration; Mars Reconnaissance Orbiter investigations of the Martian polar regions and climate; Mars Polar Scout Mission concepts; and Panel Discussion: New perspectives on Mars polar science and exploration

Lunar Topography: Results from the Lunar Orbiter Laser Altimeter

NASA Technical Reports Server (NTRS)

Neumann, Gregory; Smith, David E.; Zuber, Maria T.; Mazarico, Erwan

2012-01-01

The Lunar Orbiter Laser Altimeter (LOLA) onboard the Lunar Reconnaissance Orbiter (LRO) has been operating nearly continuously since July 2009, accumulating over 6 billion measurements from more than 2 billion in-orbit laser shots. LRO's near-polar orbit results in very high data density in the immediate vicinity of the lunar poles, with full coverage at the equator from more than 12000 orbital tracks averaging less than 1 km in spacing at the equator. LRO has obtained a global geodetic model of the lunar topography with 50-meter horizontal and 1-m radial accuracy in a lunar center-of-mass coordinate system, with profiles of topography at 20-m horizontal resolution, and 0.1-m vertical precision. LOLA also provides measurements of reflectivity and surface roughness down to its 5-m laser spot size. With these data LOLA has measured the shape of all lunar craters 20 km and larger. In the proposed extended mission commencing late in 2012, LOLA will concentrate observations in the Southern Hemisphere, improving the density of the polar coverage to nearly 10-m pixel resolution and accuracy to better than 20 m total position error. Uses for these data include mission planning and targeting, illumination studies, geodetic control of images, as well as lunar geology and geophysics. Further improvements in geodetic accuracy are anticipated from the use of re ned gravity fields after the successful completion of the Gravity Recovery and Interior Laboratory (GRAIL) mission in 2012.

Spin and charge controlled by antisymmetric spin-orbit coupling in a triangular-triple-quantum-dot Kondo system

NASA Astrophysics Data System (ADS)

Koga, M.; Matsumoto, M.; Kusunose, H.

2018-05-01

We study a local antisymmetric spin-orbit (ASO) coupling effect on a triangular-triple-quantum-dot (TTQD) system as a theoretical proposal for a new application of the Kondo physics to nanoscale devices. The electric polarization induced by the Kondo effect is strongly correlated with the spin configurations and molecular orbital degrees of freedom in the TTQD. In particular, an abrupt sign reversal of the emergent electric polarization is associated with a quantum critical point in a magnetic field, which can also be controlled by the ASO coupling that changes the mixing weight of different orbital components in the TTQD ground state.

At the Edge of a Polar Cap

NASA Image and Video Library

2014-05-22

The deep chasm that formed on the polar cap edge is identified as an area of strong down-slope winds and has a clear connection to Mars largest dune field, Olympia Undae as observed by NASA Mars Reconnaissance Orbiter.

Current-induced spin polarization in InGaAs and GaAs epilayers with varying doping densities

DOE PAGES

Luengo-Kovac, Marta; Huang, Simon; Del Gaudio, Davide; ...

2017-11-16

Here, the current-induced spin polarization and momentum-dependent spin-orbit field were measured in In xGa 1-xAs epilayers with varying indium concentrations and silicon doping densities. Samples with higher indium concentrations and carrier concentrations and lower mobilities were found to have larger electrical spin generation efficiencies. Furthermore, current-induced spin polarization was detected in GaAs epilayers despite the absence of measurable spin-orbit fields, indicating that the extrinsic contributions to the spin-polarization mechanism must be considered. Theoretical calculations based on a model that includes extrinsic contributions to the spin dephasing and the spin Hall effect, in addition to the intrinsic Rashba and Dresselhaus spin-orbitmore » coupling, are found to reproduce the experimental finding that the crystal direction with the smaller net spin-orbit field has larger electrical spin generation efficiency and are used to predict how sample parameters affect the magnitude of the current-induced spin polarization.« less

Current-induced spin polarization in InGaAs and GaAs epilayers with varying doping densities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luengo-Kovac, Marta; Huang, Simon; Del Gaudio, Davide

Here, the current-induced spin polarization and momentum-dependent spin-orbit field were measured in In xGa 1-xAs epilayers with varying indium concentrations and silicon doping densities. Samples with higher indium concentrations and carrier concentrations and lower mobilities were found to have larger electrical spin generation efficiencies. Furthermore, current-induced spin polarization was detected in GaAs epilayers despite the absence of measurable spin-orbit fields, indicating that the extrinsic contributions to the spin-polarization mechanism must be considered. Theoretical calculations based on a model that includes extrinsic contributions to the spin dephasing and the spin Hall effect, in addition to the intrinsic Rashba and Dresselhaus spin-orbitmore » coupling, are found to reproduce the experimental finding that the crystal direction with the smaller net spin-orbit field has larger electrical spin generation efficiency and are used to predict how sample parameters affect the magnitude of the current-induced spin polarization.« less

Polarization effects in low-energy electron-CH4 elastic collisions in an exact exchange treatment

NASA Astrophysics Data System (ADS)

Jain, Ashok; Weatherford, C. A.; Thompson, D. G.; McNaughten, P.

1989-12-01

We have investigated the polarization effects in very-low-energy (below 1 eV) electron- CH4 collisions in an exact-exchange treatment. The two models of the parameter-free polarization potential are employed; one, the VpolJT potential, introduced by Jain and Thompson [J. Phys. B 15, L631 (1982)], is based on an approximate polarized-orbital method, and two, the correlation-polarization potential VpolCP, first proposed by O'Connel and Lane [Phys. Rev. A 27, 1893 (1983)], is given as a simple analytic form in terms of the charge density of the target. In this rather very low-energy region, the polarization effects play a decisive role, particularly in creating structure in the differential cross section (DCS) and producing the Ramsauer-Townsend minimum in the total cross section. Our DCS at 0.2, 0.4, and 0.6 eV are compared with recent measurements. We found that a local parameter-free approximation for the polarization potential is quite successful if it is determined under the polarized-orbital-type technique rather than based on the correlation-polarization approach.

Nongyrotropic electron orbits in collisionless magnetic reconnection

NASA Astrophysics Data System (ADS)

Zenitani, S.

2016-12-01

In order to study inner workings of magnetic reconnection, NASA has recently launched Magnetospheric MultiScale (MMS) spacecraft. It is expected to observe electron velocity distribution functions (VDFs) at high resolution in magnetotail reconnection sites in 2017. Since VDFs are outcomes of many particle orbits, it is important to understand the relation between electron orbits and VDFs. In this work, we study electron orbits and associated VDFs in the electron current layer in magnetic reconnection, by using a two-dimensional particle-in-cell (PIC) simulation. By analyzing millions of electron orbits, we discover several new orbits: (1) Figure-eight-shaped regular orbits inside the super-Alfvenic electron jet, (2) noncrossing Speiser orbits that do not cross the midplane, (3) noncrossing regular orbits on the jet flanks, and (4) nongyrotropic electrons in the downstream of the jet termination region. Properties of these orbits are organized by a theory on particle orbits (Buchner & Zelenyi 1989 JGR). The noncrossing orbits are mediated by the polarization electric field (Hall electric field E_z) near the midplane. These orbits can be understood as electrostatic extensions of the conventional theory. Properties of the super-Alfvenic electron jet are attributed to the traditional Speiser-orbit electrons. On the other hand, the noncrossing electrons are the majority in number density in the jet flanks. This raise a serious question to our present understanding of physics of collisionless magnetic reconnection, which only assumes crossing populations. We will also discuss spatial distribution of energetic electrons and observational signatures of noncrossing electrons. Reference: Zenitani & Nagai (2016), submitted to Phys. Plasmas.

Pits in Polar Cap

NASA Technical Reports Server (NTRS)

2006-01-01

This full-frame image from the High Resolution Imaging Science Experiment camera on NASA's Mars Reconnaissance Orbiter shows faults and pits in Mars' north polar residual cap that have not been previously recognized.

The faults and depressions between them are similar to features seen on Earth where the crust is being pulled apart. Such tectonic extension must have occurred very recently because the north polar residual cap is very young, as indicated by the paucity of impact craters on its surface. Alternatively, the faults and pits may be caused by collapse due to removal of material beneath the surface. The pits are aligned along the faults, either because material has drained into the subsurface along the faults or because gas has escaped from the subsurface through them.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace and Technology Corp., Boulder, Colo.

Precise Orbital and Geodetic Parameter Estimation using SLR Observations for ILRS AAC

NASA Astrophysics Data System (ADS)

Kim, Young-Rok; Park, Eunseo; Oh, Hyungjik Jay; Park, Sang-Young; Lim, Hyung-Chul; Park, Chandeok

2013-12-01

In this study, we present results of precise orbital geodetic parameter estimation using satellite laser ranging (SLR) observations for the International Laser Ranging Service (ILRS) associate analysis center (AAC). Using normal point observations of LAGEOS-1, LAGEOS-2, ETALON-1, and ETALON-2 in SLR consolidated laser ranging data format, the NASA/ GSFC GEODYN II and SOLVE software programs were utilized for precise orbit determination (POD) and finding solutions of a terrestrial reference frame (TRF) and Earth orientation parameters (EOPs). For POD, a weekly-based orbit determination strategy was employed to process SLR observations taken from 20 weeks in 2013. For solutions of TRF and EOPs, loosely constrained scheme was used to integrate POD results of four geodetic SLR satellites. The coordinates of 11 ILRS core sites were determined and daily polar motion and polar motion rates were estimated. The root mean square (RMS) value of post-fit residuals was used for orbit quality assessment, and both the stability of TRF and the precision of EOPs by external comparison were analyzed for verification of our solutions. Results of post-fit residuals show that the RMS of the orbits of LAGEOS-1 and LAGEOS-2 are 1.20 and 1.12 cm, and those of ETALON-1 and ETALON-2 are 1.02 and 1.11 cm, respectively. The stability analysis of TRF shows that the mean value of 3D stability of the coordinates of 11 ILRS core sites is 7.0 mm. An external comparison, with respect to International Earth rotation and Reference systems Service (IERS) 08 C04 results, shows that standard deviations of polar motion XP and YP are 0.754 milliarcseconds (mas) and 0.576 mas, respectively. Our results of precise orbital and geodetic parameter estimation are reasonable and help advance research at ILRS AAC.

Estimation of Biomass Burning Emissions by Fusing Fire Radiative Power Observed from Polar-orbiting and Geostationary Satellites across the Continental United States

NASA Astrophysics Data System (ADS)

Li, F.; Zhang, X.; Kondragunta, S.

2016-12-01

Trace gases and aerosols released from biomass burning significantly disturb the energy balance of the Earth and also degrade regional air quality. However, biomass burning emissions (BBE) have been poorly estimated using the traditional bottom-up approach because of the substantial uncertainties in the burned area and fuel loads. Recently, Fire Radiative Power (FRP) derived from satellite fire observations enables the estimation of BBE at multiple spatial scales in near real time. Nonetheless, it is very challenging to accurately produce reliable FRP diurnal cycles from either polar-orbiting satellites or geostationary satellites for the calculation of the temporally integrated FRP, Fire Radiative Energy (FRE). Here we reconstruct FRP diurnal cycles by fusing FRP observed from polar-orbiting and geostationary satellites and estimate BBE from 2011 to 2015 across the Continental United States. Specifically, FRP from the Geostationary Operational Environmental Satellite (GOES) is preprocessed and calibrated using the collocated and concurred observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) over Landsat TM burn scars. The climatologically diurnal FRP curves are then calculated from the calibrated GOES FRP for the 25 Bailey's ecoregions. By fitting MODIS FRP and the calibrated GOES FRP to the climatological curves, FRP diurnal cycles are further reconstructed for individual days at a 0.25-degree grid. Both FRE estimated from FRP diurnal cycles and ecoregion specified FRE combustion rates are used to estimate hourly BBE. The estimated BBE is finally evaluated using QFED and GFED4.0 inventories and emissions modeled using Landsat TM 30m burn severities and 30m fuel loading from Fuel Characteristic Classification System. The results show that BBE estimates are greatly improved by using the reconstructed FRP diurnal cycles from high temporal (GOES) and high spatial resolution (MODIS) FRP observations.

Effects of structural spin-orbit coupling in two dimensional electron and hole liquids

NASA Astrophysics Data System (ADS)

Chesi, Stefano

The recent interest in spin-dependent phenomena in semiconductor heterostructures motivates our detailed study of the structural spin-orbit coupling present in clean two-dimensional electron and hole liquids. Interesting polarization effects are produced in a system out of equilibrium, as when a finite current flows in the sample. In particular, the consequences of a lateral confinement creating a quasi one-dimensional wire are studied in detail, partially motivated by a recent experimental investigation of the point-contact transmission for two-dimensional holes. We also address the role of the electron-electron interaction in the presence of spin-orbit coupling, which has received little attention in the literature. We discuss the formulation of the Hartree-Fock approximation in the particular case of linear Rashba spin-orbit. We establish the form of the mean-field phase diagram in the homogeneous case, which shows a complex interplay between paramagnetic and ferromagnetic states. The latter can be polarized in the plane or in a transverse direction, and are characterized by a complex spin structure and nontrivial occupation. The generality of the Hartree-Fock method allows a simple treatment of the Pauli spin susceptibility, and the application to different forms of spin-orbit coupling. Correlation corrections can be obtained in an analytic form for particular asymptotic regimes. For linear Rashba spin-orbit we identified the relevance of the large spin-orbit limit, dominated by many-body effects, and explicitly treated the high density limit, in which the system is asymptotically noninteracting. As a special case, we derive a new exact formula for the polarization dependence of the ring-diagram correlation energy.

Mars South Polar Cap 'Fingerprint' Terrain

NASA Technical Reports Server (NTRS)

2000-01-01

This picture is illuminated by sunlight from the upper left.

Some portions of the martian south polar residual cap have long, somewhat curved troughs instead of circular pits. These appear to form in a layer of material that may be different than that in which 'swiss cheese' circles and pits form, and none of these features has any analog in the north polar cap or elsewhere on Mars. This picture shows the 'fingerprint' terrain as a series of long, narrow depressions considered to have formed by collapse and widening by sublimation of ice. Unlike the north polar cap, the south polar region stays cold enough in summer to retain frozen carbon dioxide. Viking Orbiter observations during the late 1970s showed that very little water vapor comes off the south polar cap during summer, indicating that any frozen water that might be there remains solid throughout the year.

This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image was obtained in early southern spring on August 4, 1999. It shows an area 3 x 5 kilometers (1.9 x 3.1 miles) at a resolution of about 7.3 meters (24 ft) per pixel. Located near 86.0oS, 53.9oW.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

Comparative DMFT study of the eg-orbital Hubbard model in thin films

NASA Astrophysics Data System (ADS)

Rüegg, Andreas; Hung, Hsiang-Hsuan; Gull, Emanuel; Fiete, Gregory A.

2014-02-01

Heterostructures of transition-metal oxides have emerged as a new route to engineer electronic systems with desired functionalities. Motivated by these developments, we study a two-orbital Hubbard model in a thin-film geometry confined along the cubic [001] direction using the dynamical mean-field theory. We contrast the results of two approximate impurity solvers (exact diagonalization and one-crossing approximation) to the results of the numerically exact continuous-time quantum Monte Carlo solver. Consistent with earlier studies, we find that the one-crossing approximation performs well in the insulating regime, while the advantage of the exact-diagonalization-based solver is more pronounced in the metallic regime. We then investigate various aspects of strongly correlated eg-orbital systems in thin-film geometries. In particular, we show how the interfacial orbital polarization dies off quickly a few layers from the interface and how the film thickness affects the location of the interaction-driven Mott transition. In addition, we explore the changes in the electronic structure with varying carrier concentration and identify large variations of the orbital polarization in the strongly correlated regime.

Cassini UVIS Observations of Saturn during the Grand Finale Orbits

NASA Astrophysics Data System (ADS)

Pryor, W. R.; Esposito, L. W.; West, R. A.; Jouchoux, A.; Radioti, A.; Grodent, D. C.; Gerard, J. C. M. C.; Gustin, J.; Lamy, L.; Badman, S. V.

2017-12-01

In 2016 and 2017, the Cassini Saturn orbiter executed a final series of high inclination, low-periapsis orbits ideal for studies of Saturn's polar regions. The Cassini Ultraviolet Imaging Spectrograph (UVIS) obtained an extensive set of auroral images, some at the highest spatial resolution obtained during Cassini's long orbital mission (2004-2017). In some cases, two or three spacecraft slews at right angles to the long slit of the spectrograph were required to cover the entire auroral region to form auroral images. We will present selected images from this set showing narrow arcs of emission, more diffuse auroral emissions, multiple auroral arcs in a single image, discrete spots of emission, small scale vortices, large-scale spiral forms, and parallel linear features that appear to cross in places like twisted wires. Some shorter features are transverse to the main auroral arcs, like barbs on a wire. UVIS observations were in some cases simultaneous with auroral observations from the Hubble Space Telescope Space Telescope Imaging Spectrograph (STIS) that will also be presented. UVIS polar images also contain spectral information suitable for studies of the auroral electron energy distribution. The long wavelength part of the UVIS polar images contains a signal from reflected sunlight containing absorption signatures of acetylene and other Saturn hydrocarbons. The hydrocarbon spatial distribution will also be examined.

A GCM Recent History of the Northern Martian Polar Layered Deposits

NASA Technical Reports Server (NTRS)

Levrard, B.; Laskar, J.; Forget, F.; Montmessin, F.

2003-01-01

The polar layered deposits are thought to contain alternate layers of water and dust in different proportions resulting from the astronomical forcing of the martian climate. In particular, longterm variations in the orbital and axial elements of Mars are presumed to generate variations of the latitudes of surface water ice stability and of the amount of water exchanged in the polar areas. At high obliquity, simplified climate models and independent general circulation simulations suggest a transfer of water ice from the north polar region to tropical areas, whereas at lower and present obliquities, water ice is expected to be stable only at the poles. If so, over obliquity cycles, water ice may be redistributed between the surface water reservoirs leading to their incremental building or disintegration depending on the rates of water transfer. If only a relative limited amount of the available water is exchanged on orbital timescales, this may provide an efficient mechanism for the formation of the observed polar deposits. Within this context, GCM simulations of the martian water cycle have been performed for various obliquities ranging from 15 degrees to 45 degrees and for a large set of initial water ice locations to determine the rate of water exchange between the surface water reservoirs as a function of the obliquity. Propagating these rates over the last 10 Ma orbital history gives a possible recent evolution of these reservoirs.

X-Ray Polarization from High Mass X-Ray Binaries

NASA Technical Reports Server (NTRS)

Kallman, T.; Dorodnitsyn, A.; Blondin, J.

2015-01-01

X-ray astronomy allows study of objects which may be associated with compact objects, i.e. neutron stars or black holes, and also may contain strong magnetic fields. Such objects are categorically non-spherical, and likely non-circular when projected on the sky. Polarization allows study of such geometric effects, and X-ray polarimetry is likely to become feasible for a significant number of sources in the future. A class of potential targets for future X-ray polarization observations is the high mass X-ray binaries (HMXBs), which consist of a compact object in orbit with an early type star. In this paper we show that X-ray polarization from HMXBs has a distinct signature which depends on the source inclination and orbital phase. The presence of the X-ray source displaced from the star creates linear polarization even if the primary wind is spherically symmetric whenever the system is viewed away from conjunction. Direct X-rays dilute this polarization whenever the X-ray source is not eclipsed; at mid-eclipse the net polarization is expected to be small or zero if the wind is circularly symmetric around the line of centers. Resonance line scattering increases the scattering fraction, often by large factors, over the energy band spanned by resonance lines. Real winds are not expected to be spherically symmetric, or circularly symmetric around the line of centers, owing to the combined effects of the compact object gravity and ionization on the wind hydrodynamics. A sample calculation shows that this creates polarization fractions ranging up to tens of percent at mid-eclipse.

An interstellar origin for Jupiter's retrograde co-orbital asteroid

NASA Astrophysics Data System (ADS)

Namouni, F.; Morais, M. H. M.

2018-06-01

Asteroid (514107) 2015 BZ509 was discovered recently in Jupiter's co-orbital region with a retrograde motion around the Sun. The known chaotic dynamics of the outer Solar system have so far precluded the identification of its origin. Here, we perform a high-resolution statistical search for stable orbits and show that asteroid (514107) 2015 BZ509 has been in its current orbital state since the formation of the Solar system. This result indicates that (514107) 2015 BZ509 was captured from the interstellar medium 4.5 billion years in the past as planet formation models cannot produce such a primordial large-inclination orbit with the planets on nearly coplanar orbits interacting with a coplanar debris disc that must produce the low-inclination small-body reservoirs of the Solar system such as the asteroid and Kuiper belts. This result also implies that more extrasolar asteroids are currently present in the Solar system on nearly polar orbits.

International solar polar mission: The vector helium magnetometer

NASA Technical Reports Server (NTRS)

1982-01-01

The functional requirements for the vector helium magnetometer (VHM) on the Solar Polar spacecraft are presented. The VHM is one of the two magnetometers on board that will measure the vector magnetic field along the Earth to Jupiter transfer trajectory, as well as in the vicinity of Jupiter and along the solar polar orbit following the Jupiter encounter. The interconnection between these two magnetometers and their shared data processing unit is illustrated.

Controllable all-fiber generation/conversion of circularly polarized orbital angular momentum beams using long period fiber gratings

NASA Astrophysics Data System (ADS)

Han, Ya; Liu, Yan-Ge; Wang, Zhi; Huang, Wei; Chen, Lei; Zhang, Hong-Wei; Yang, Kang

2018-01-01

Mode-division multiplexing (MDM) is a promising technology for increasing the data-carrying capacity of a single few-mode optical fiber. The flexible mode manipulation would be highly desired in a robust MDM network. Recently, orbital angular momentum (OAM) modes have received wide attention as a new spatial mode basis. In this paper, we firstly proposed a long period fiber grating (LPFG) system to realize mode conversions between the higher order LP core modes in four-mode fiber. Based on the proposed system, we, for the first time, demonstrate the controllable all-fiber generation and conversion of the higher order LP core modes to the first and second order circularly polarized OAM beams with all the combinations of spin and OAM. Therefore, the proposed LPFG system can be potentially used as a controllable higher order OAM beam switch and a physical layer of the translating protocol from the conventional LP modes communication to the OAM modes communication in the future mode carrier telecommunication system and light calculation protocols.

Generalized Stoner criterion and versatile spin ordering in two-dimensional spin-orbit coupled electron systems

NASA Astrophysics Data System (ADS)

Liu, Weizhe Edward; Chesi, Stefano; Webb, David; Zülicke, U.; Winkler, R.; Joynt, Robert; Culcer, Dimitrie

2017-12-01

Spin-orbit coupling is a single-particle phenomenon known to generate topological order, and electron-electron interactions cause ordered many-body phases to exist. The rich interplay of these two mechanisms is present in a broad range of materials and has been the subject of considerable ongoing research and controversy. Here we demonstrate that interacting two-dimensional electron systems with strong spin-orbit coupling exhibit a variety of time reversal symmetry breaking phases with unconventional spin alignment. We first prove that a Stoner-type criterion can be formulated for the spin polarization response to an electric field, which predicts that the spin polarization susceptibility diverges at a certain value of the electron-electron interaction strength. The divergence indicates the possibility of unconventional ferromagnetic phases even in the absence of any applied electric or magnetic field. This leads us, in the second part of this work, to study interacting Rashba spin-orbit coupled semiconductors in equilibrium in the Hartree-Fock approximation as a generic minimal model. Using classical Monte Carlo simulations, we construct the complete phase diagram of the system as a function of density and spin-orbit coupling strength. It includes both an out-of-plane spin-polarized phase and in-plane spin-polarized phases with shifted Fermi surfaces and rich spin textures, reminiscent of the Pomeranchuk instability, as well as two different Fermi-liquid phases having one and two Fermi surfaces, respectively, which are separated by a Lifshitz transition. We discuss possibilities for experimental observation and useful application of these novel phases, especially in the context of electric-field-controlled macroscopic spin polarizations.

Polar2Grid 2.0: Reprojecting Satellite Data Made Easy

NASA Astrophysics Data System (ADS)

Hoese, D.; Strabala, K.

2015-12-01

Polar-orbiting multi-band meteorological sensors such as those on the Suomi National Polar-orbiting Partnership (SNPP) satellite pose substantial challenges for taking imagery the last mile to forecast offices, scientific analysis environments, and the general public. To do this quickly and easily, the Cooperative Institute for Meteorological Satellite Studies (CIMSS) at the University of Wisconsin has created an open-source, modular application system, Polar2Grid. This bundled solution automates tools for converting various satellite products like those from VIIRS and MODIS into a variety of output formats, including GeoTIFFs, AWIPS compatible NetCDF files, and NinJo forecasting workstation compatible TIFF images. In addition to traditional visible and infrared imagery, Polar2Grid includes three perceptual enhancements for the VIIRS Day-Night Band (DNB), as well as providing the capability to create sharpened true color, sharpened false color, and user-defined RGB images. Polar2Grid performs conversions and projections in seconds on large swaths of data. Polar2Grid is currently providing VIIRS imagery over the Continental United States, as well as Alaska and Hawaii, from various Direct-Broadcast antennas to operational forecasters at the NOAA National Weather Service (NWS) offices in their AWIPS terminals, within minutes of an overpass of the Suomi NPP satellite. Three years after Polar2Grid development started, the Polar2Grid team is now releasing version 2.0 of the software; supporting more sensors, generating more products, and providing all of its features in an easy to use command line interface.

A polarized Drell-Yan experiment to probe the dynamics of the nucleon sea

DOE PAGES

Kleinjan, David W.

2015-01-01

In QCD, nucleon spin comes from the sum of the quark spin, gluon spin, and the quark and gluon orbital angular momentum, but how these different components contribute and the interplay among them is not yet understood. For instance, sea quark orbital contribution remains largely unexplored. Measurements of the Sivers function for the sea quarks will provide a probe of the sea quark orbital contribution. The upcoming E1039 experiment at Fermilab will measure the Sivers asymmetry of the sea quarks via the Drell-Yan process using a 120 GeV unpolarized proton beam directed a transversely polarized ammonia target. Lastly, we reportmore » on the status and plans of the E1039 polarized Drell-Yan experiment.« less

A polarized Drell-Yan experiment to probe the dynamics of the nucleon sea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kleinjan, David

In QCD, nucleon spin comes from the sum of the quark spin, gluon spin, and the quark and gluon orbital angular momentum, but how these different components contribute and the interplay among them is not yet understood. For instance, sea quark orbital contribution remains largely unexplored. Measurements of the Sivers function for the sea quarks will provide a probe of the sea quark orbital contribution. The upcoming E1039 experiment at Fermilab will measure the Sivers asymmetry of the sea quarks via the Drell-Yan process using a 120 GeV unpolarized proton beam directed a transversely polarized ammonia target. We report onmore » the status and plans of the E1039 polarized Drell-Yan experiment.« less

Variability of Mars' North Polar Water Ice Cap: I. Analysis of Mariner 9 and Viking Orbiter Imaging Data

USGS Publications Warehouse

Bass, Deborah S.; Herkenhoff, Kenneth; Paige, David A.

2000-01-01

Previous studies interpreted differences in ice coverage between Mariner 9 and Viking Orbiter observations of Mars' north residual polar cap as evidence of interannual variability of ice deposition on the cap. However, these investigators did not consider the possibility that there could be significant changes in the ice coverage within the northern residual cap over the course of the summer season. Our more comprehensive analysis of Mariner 9 and Viking Orbiter imaging data shows that the appearance of the residual cap does not show large-scale variance on an interannual basis. Rather we find evidence that regions that were dark at the beginning of summer look bright by the end of summer and that this seasonal variation of the cap repeats from year to year. Our results suggest that this brightening was due to the deposition of newly formed water ice on the surface. We find that newly formed ice deposits in the summer season have the same red-to-violet band image ratios as permanently bright deposits within the residual cap. We believe the newly formed ice accumulates in a continuous layer. To constrain the minimum amount of deposited ice, we used observed albedo data in conjunction with calculations using Mie theory for single scattering and a delta-Eddington approximation of radiative transfer for multiple scattering. The brightening could have been produced by a minimum of (1) a ~35-μm-thick layer of 50-μm-sized ice particles with 10% dust or (2) a ~14-μm-thick layer of 10-μm-sized ice particles with 50% dust.

Polar Polygons

NASA Technical Reports Server (NTRS)

2005-01-01

18 August 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark-outlined polygons on a frost-covered surface in the south polar region of Mars. In summer, this surface would not be bright and the polygons would not have dark outlines--these are a product of the presence of seasonal frost.

Location near: 77.2oS, 204.8oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

Spin polarization properties of benzene/graphene with transition metals as dopants: First principles calculations

NASA Astrophysics Data System (ADS)

Yuan, X. B.; Tian, Y. L.; Zhao, X. W.; Yue, W. W.; Hu, G. C.; Ren, J. F.

2018-05-01

First principles calculations are used to study the spin polarization properties of benzene molecule adsorbed on the graphene surface which doped with transition metals including Mn, Cr, Fe, Co, and Ni. The densities of states (DOS) of the benzene molecule can be induced to be spin split at the Fermi level only when it is adsorbed on Mn-, and Cr-doped graphene. The p-orbital of the benzene molecule will interact with the d orbital of the doped atoms, which will generate new spin coupling states and lead to obvious spin polarization of the benzene molecule. The spin-polarized density distributions as well as the differential charge density distributions of the systems also suggest that Mn-doped graphene will induce bigger spin polarization than that of Cr-doped graphene. Benzene molecule could be spin-polarized when it is adsorbed on the graphene surface with transition metal dopants, which could be a new method for researching graphene-based organic spintronic devices.

Reliable retrieval of atmospheric and aquatic parameters in coastal and inland environments from polar-orbiting and geostationary platforms: challenges and opportunities

NASA Astrophysics Data System (ADS)

Stamnes, Knut; Li, Wei; Lin, Zhenyi; Fan, Yongzhen; Chen, Nan; Gatebe, Charles; Ahn, Jae-Hyun; Kim, Wonkook; Stamnes, Jakob J.

2017-04-01

Simultaneous retrieval of aerosol and surface properties by means of inverse techniques based on a coupled atmosphere-surface radiative transfer model, neural networks, and optimal estimation can yield considerable improvements in retrieval accuracy in complex aquatic environments compared with traditional methods. Remote sensing of such environments represent specific challenges due (i) the complexity of the atmosphere and water inherent optical properties, (ii) unique bidirectional dependencies of the water-leaving radiance, and (iii) the desire to do retrievals for large solar zenith and viewing angles. We will discuss (a) how challenges related to atmospheric gaseous absorption, absorbing aerosols, and turbid waters can be addressed by using a coupled atmosphere-surface radiative transfer (forward) model in the retrieval process, (b) how the need to correct for bidirectional effects can be accommodated in a systematic and reliable manner, (c) how polarization information can be utilized, (d) how the curvature of the atmosphere can be taken into account, and (e) how neural networks and optimal estimation can be used to obtain fast yet accurate retrievals. Special emphasis will be placed on how information from existing and future sensors deployed on polar-orbiting and geostationary platforms can be obtained in a reliable and accurate manner. The need to provide uncertainty assessments and error budgets will also be discussed.

Trajectory design for Saturnian Ocean Worlds orbiters using multidimensional Poincaré maps

NASA Astrophysics Data System (ADS)

Davis, Diane Craig; Phillips, Sean M.; McCarthy, Brian P.

2018-02-01

Missions based on low-energy orbits in the vicinity of planetary moons, such as Titan or Enceladus, involve significant end-to-end trajectory design challenges due to the gravitational effects of the distant larger primary. To address these challenges, the current investigation focuses on the visualization and use of multidimensional Poincaré maps to perform preliminary design of orbits with significant out-of-plane components, including orbits that provide polar coverage. Poincaré maps facilitate the identification of families of solutions to a given orbit problem and provide the ability to easily respond to changing inputs and requirements. A visual-based design process highlights a variety of trajectory options near Saturn's ocean worlds, including both moon-centered orbits and libration point orbits.

Recent Geologic Mapping Results for the Polar Regions of Mars

NASA Technical Reports Server (NTRS)

tanaka, K. L.; Kolb, E. J.

2008-01-01

The polar regions of Mars include the densest data coverage for the planet because of the polar orbits of MGS, ODY, and MEX. Because the geology of the polar plateaus has been among the most dynamic on the planet in recent geologic time, the data enable the most detailed and complex geologic investigations of any regions on Mars, superseding previous, even recent, mapping efforts [e.g., 1-3]. Geologic mapping at regional and local scales is revealing that the stratigraphy and modificational histories of polar materials by various processes are highly complex at both poles. Here, we describe some of our recent results in polar geologic mapping and how they address the geologic processes involved and implications for polar climate history.

Analysis of Envisat Orbit Maintenance Strategies to Improve/Increase Envisat ASAR Interferometry Opportunities

NASA Technical Reports Server (NTRS)

Kuijper, D.; Matatoros, Garcia

2007-01-01

The biggest and most advanced Earth Observation Satellite in-orbit, developed by the European Space Agency (ESA) and its member states, is Envisat. It was launched on March 1, 2002 by an Ariane V from French Guyana and holds a total of 10 multi-disciplinary Earth observation instruments, among which an Advanced Synthetic Aperture Radar (ASAR). The ASAR user community requested the Flight Dynamics division of the European Space Operations Centre (ESOC) to investigate how the orbit control maintenance strategy for Envisat could be changed to optimize ASAR interferometry opportunities overall and in addition support the International Polar Year 2007/2008 initiative. The Polar Regions play a pivotal role in understanding our planet and our impact on it as they are recognized as sensitive barometers of environmental change. One of the main themes of the International Polar Year 2007/2008 is therefore the study of Earth s changing ice and snow, and its impact on our planet and our lives. Naturally, ESA would like to support this very important initiative. This paper presents the investigations that have been conducted to support these requests in the best possible way. It discusses the orbit maintenance strategy that has been in place since its launch, ensuring the actual orbit to be within 1 km of a so-called reference orbit, and presents the new orbit maintenance strategy that is aimed at improving/increasing the opportunities for Envisat ASAR interferometry, while preserving the fuel on board the spacecraft. The hydrazine on-board Envisat happens to be a precious resource as only approximately 300 kg of it was available at launch, like ERS-2. The difference being however that the mass of Envisat is approximately 3.2 times that of ERS-2.

Mars Polar Cap During Transition Phase Instrument Checkout

NASA Technical Reports Server (NTRS)

2006-01-01

During the last week of September and the first week or so of October 2006, scientific instruments on NASA's Mars Reconnaissance Orbiter were turned on to acquire test information during the transition phase leading up to full science operations. The mission's primary science phase will begin the first week of November 2006, following superior conjunction. (Superior conjunction is where a planet goes behind the sun as viewed from Earth.) Since it is very difficult to communicate with a spacecraft when it is close to the sun as seen from Earth, this checkout of the instruments was crucial to being ready for the primary science phase of the mission.

Throughout the transition-phase testing, the Mars Color Imager (MARCI) acquired terminator (transition between nighttime and daytime) to terminator swaths of color images on every dayside orbit, as the spacecraft moved northward in its orbit. The south polar region was deep in winter shadow, but the north polar region was illuminated the entire Martian day. During the primary mission, such swaths will be assembled into global maps that portray the state of the Martian atmosphere -- its weather -- as seen every day and at every place at about 3 p.m. local solar time. After the transition phase completed, most of the instruments were turned off, but the Mars Climate Sounder and MARCI have been left on. Their data will be recorded and played back to Earth following the communications blackout associated with conjunction.

Combined with wide-angle image mosaics taken by the Mars Orbiter Camera on NASA's Mars Global Surveyor at 2 p.m. local solar time, the MARCI maps will be used to track motions of clouds.

This image is a composite mosaic of four polar views of Mars, taken at midnight, 6 a.m., noon, and 6 p.m. local Martian time. This is possible because during summer the sun is always shining in the polar region. It shows the mostly water-ice perennial cap (white area), sitting atop the north polar layered

Officials welcome the arrival of the Japanese Experiment Module

NASA Image and Video Library

2007-04-17

In the Space Station Processing Facility, NASA and Japanese Aerospace and Exploration Agency (JAXA) officials welcome the arrival of the Experiment Logistics Module Pressurized Section for the Japanese Experiment Module, or JEM, to the Kennedy Space Center. At the podium is Russ Romanella, director of International Space Station and Spacecraft Processing. Seated at right are Bill Parsons, director of Kennedy Space Center; Dr. Kichiro Imagawa, project manager of the JEM Development Project Team for JAXA; Melanie Saunders, associate manager of the International Space Station Program at Johnson Space Center; and Dominic Gorie, commander on mission STS-123 that will deliver the module to the space station. The new International Space Station component arrived at Kennedy March 12 to begin preparations for its future launch on mission STS-123. It will serve as an on-orbit storage area for materials, tools and supplies. It can hold up to eight experiment racks and will attach to the top of another larger pressurized module.

Officials welcome the arrival of the Japanese Experiment Module

NASA Image and Video Library

2007-04-17

In the Space Station Processing Facility, NASA and Japanese Aerospace and Exploration Agency (JAXA) officials welcome the arrival of the Experiment Logistics Module Pressurized Section for the Japanese Experiment Module, or JEM, to the Kennedy Space Center. At the podium is Bill Parsons, director of Kennedy Space Center. Seated at right are Russ Romanella, director of International Space Station and Spacecraft Processing; Dr. Kichiro Imagawa, project manager of the JEM Development Project Team for JAXA; Melanie Saunders, associate manager of the International Space Station Program at Johnson Space Center; and Dominic Gorie, commander on mission STS-123 that will deliver the module to the space station. The new International Space Station component arrived at Kennedy March 12 to begin preparations for its future launch on mission STS-123. It will serve as an on-orbit storage area for materials, tools and supplies. It can hold up to eight experiment racks and will attach to the top of another larger pressurized module.

Future VIIRS enhancements for the integrated polar-orbiting environmental satellite system

NASA Astrophysics Data System (ADS)

Puschell, Jeffery J.; Silny, John; Cook, Lacy; Kim, Eugene

2010-08-01

The Visible/Infrared Imager Radiometer Suite (VIIRS) is the next-generation imaging spectroradiometer for the future operational polar-orbiting environmental satellite system. A successful Flight Unit 1 has been delivered and integrated onto the NPP spacecraft. The flexible VIIRS architecture can be adapted and enhanced to respond to a wide range of requirements and to incorporate new technology as it becomes available. This paper reports on recent design studies to evaluate building a MW-VLWIR dispersive hyperspectral module with active cooling into the existing VIIRS architecture. Performance of a two-grating VIIRS hyperspectral module was studied across a broad trade space defined primarily by spatial sampling, spectral range, spectral sampling interval, along-track field of view and integration time. The hyperspectral module studied here provides contiguous coverage across 3.9 - 15.5 μm with a spectral sampling interval of 10 nm or better, thereby extending VIIRS spectral range to the shortwave side of the 15.5 μm CO2 band and encompassing the 6.7 μm H2O band. Spatial sampling occurs at VIIRS I-band (~0.4 km at nadir) spatial resolution with aggregation to M-band (~0.8 km) and larger pixel sizes to improve sensitivity. Radiometric sensitivity (NEdT) at a spatial resolution of ~4 km is ~0.1 K or better for a 250 K scene across a wavelength range of 4.5 μm to 15.5 μm. The large number of high spectral and spatial resolution FOVs in this instrument improves chances for retrievals of information on the physical state and composition of the atmosphere all the way to the surface in cloudy regions relative to current systems. Spectral aggregation of spatial resolution measurements to MODIS and VIIRS multispectral bands would continue legacy measurements with better sensitivity in nearly all bands. Additional work is needed to optimize spatial sampling, spectral range and spectral sampling approaches for the hyperspectral module and to further refine this powerful

Surface properties of Mars' polar layered deposits and polar landing sites

USGS Publications Warehouse

Vasavada, Ashwin R.; Williams, Jean-Pierre; Paige, David A.; Herkenhoff, Ken E.; Bridges, Nathan T.; Greeley, Ronald; Murray, Bruce C.; Bass, Deborah S.; McBride, Karen S.

2000-01-01

On December 3, 1999, the Mars Polar Lander and Mars Microprobes will land on the planet's south polar layered deposits near (76°S, 195°W) and conduct the first in situ studies of the planet's polar regions. The scientific goals of these missions address several poorly understood and globally significant issues, such as polar meteorology, the composition and volatile content of the layered deposits, the erosional state and mass balance of their surface, their possible relationship to climate cycles, and the nature of bright and dark aeolian material. Derived thermal inertias of the southern layered deposits are very low (50-100 J m-2 s-1/2 K-1), suggesting that the surface down to a depth of a few centimeters is generally fine grained or porous and free of an appreciable amount of rock or ice. The landing site region is smoother than typical cratered terrain on ∼1 km pixel-1 Viking Orbiter images but contains low-relief texture on ∼5 to 100 m pixel-1 Mariner 9 and Mars Global Surveyor images. The surface of the southern deposits is older than that of the northern deposits and appears to be modified by aeolian erosion or ablation of ground ice.

STS-47 Japanese Payload Specialist Mohri during Homestead water training

NASA Technical Reports Server (NTRS)

1990-01-01

STS-47 Endeavour, Orbiter Vehicle (OV) 105, Japanese Payload Specialist Mamoru Mohri, wearing inflated life jacket, participates in water survival training at Homestead Air Force Base, Florida. Dockside, Mohri washes the salt water from his personalized helmet (#3) after a water exercise. The three-day course was attended by the STS-47 prime and alternate payload specialists shortly after they were announced for the scheduled summer of 1992 Spacelab Japan (SLJ) mission. Mohri represents the National Space Development Agency of Japan (NASDA).

Role of spin polarization in FM/Al/FM trilayer film at low temperature

NASA Astrophysics Data System (ADS)

Lu, Ning; Webb, Richard

2014-03-01

Measurements of electronic transport in diffusive FM/normal metal/FM trilayer film are performed at temperature ranging from 2K to 300K to determine the behavior of the spin polarized current in normal metal under the influence of quantum phase coherence and spin-orbital interaction. Ten samples of Hall bar with length of 200 micron and width of 20 micron are fabricated through e-beam lithography followed by e-gun evaporation of Ni0.8Fe0.2, aluminum and Ni0.8Fe0.2 with different thickness (5nm to 45nm) in vacuum. At low temperature of 4.2K, coherent backscattering, Rashba spin-orbital interaction and spin flip scattering of conduction electrons contribute to magnetoresistance at low field. Quantitative analysis of magnetoresistance shows transition between weak localization and weak anti-localization for samples with different thickness ratio, which indicates the spin polarization actually affects the phase coherence length and spin-orbital scattering length. However, at temperature between 50K and 300K, only the spin polarization dominates the magnetoresistance.

Plasma Flowfields Around Low Earth Orbit Objects: Aerodynamics to Underpin Orbit Predictions

NASA Astrophysics Data System (ADS)

Capon, Christopher; Boyce, Russell; Brown, Melrose

2016-07-01

Interactions between orbiting bodies and the charged space environment are complex. The large variation in passive body parameters e.g. size, geometry and materials, makes the plasma-body interaction in Low Earth Orbit (LEO) a region rich in fundamental physical phenomena. The aerodynamic interaction of LEO orbiting bodies with the neutral environment constitutes the largest non-conservative force on the body. However in general, study of the LEO plasma-body interaction has not been concerned with external flow physics, but rather with the effects on surface charging. The impact of ionospheric flow physics on the forces on space debris (and active objects) is not well understood. The work presented here investigates the contribution that plasma-body interactions have on the flow structure and hence on the total atmospheric force vector experienced by a polar orbiting LEO body. This work applies a hybrid Particle-in-Cell (PIC) - Direct Simulation Monte Carlo (DSMC) code, pdFoam, to self-consistently model the electrostatic flowfield about a cylinder with a uniform, fixed surface potential. Flow conditions are representative of the mean conditions experienced by the Earth Observing Satellite (EOS) based on the International Reference Ionosphere model (IRI-86). The electron distribution function is represented by a non-linear Boltzmann electron fluid and ion gas-surface interactions are assumed to be that of a neutralising, conducting, thermally accommodating solid wall with diffuse reflections. The variation in flowfield and aerodynamic properties with surface potential at a fixed flow condition is investigated, and insight into the relative contributions of charged and neutral species to the flow physics experienced by a LEO orbiting body is provided. This in turn is intended to help improve the fidelity of physics-based orbit predictions for space debris and other near-Earth space objects.

The Mars Climate Orbiter is prepared for launch

NASA Technical Reports Server (NTRS)

1998-01-01

Technicians carefully maneuver the Mars Climate Orbiter toward its workstand in the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2). The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Boeing Delta II 7425 rocket.

The Mars Climate Orbiter is prepared for launch

NASA Technical Reports Server (NTRS)

1998-01-01

The Mars Climate Orbiter is lifted clear of the top of its container in the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2). The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Boeing Delta II 7425 rocket.

The Mars Climate Orbiter is prepared for launch

NASA Technical Reports Server (NTRS)

1998-01-01

Technicians in the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2) oversee the removal of the Mars Climate Orbiter from its container. The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Boeing Delta II 7425 rocket.

The Mars Climate Orbiter is prepared for launch

NASA Technical Reports Server (NTRS)

1998-01-01

Technicians lower the Mars Climate Orbiter onto its workstand in the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2). The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Boeing Delta II 7425 rocket.

The Mars Climate Orbiter is prepared for launch

NASA Technical Reports Server (NTRS)

1998-01-01

In the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2), the Mars Climate Orbiter (background) is moved toward the workstand being readied by technicians (foreground). The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Boeing Delta II 7425 rocket.

The Mars Climate Orbiter is prepared for launch

NASA Technical Reports Server (NTRS)

1998-01-01

Technicians check the connections on the workstand holding the Mars Climate Orbiter in the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2). The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Boeing Delta II 7425 rocket.

STS-65 Japanese Payload Specialist Mukai on OV-102's aft flight deck

NASA Technical Reports Server (NTRS)

1994-01-01

STS-65 Japanese Payload Specialist Chiaki Mukai freefloats on Columbia's, Orbiter Vehicle (OV) 102's, aft flight deck in front of overhead windows W7 and W8 while holding a cassette case with bean sprouts in her left hand. Mukai, a physician, represented Japan's National Space Development Agency (NASDA) on the two week mission in support of the International Microgravity Laboratory 2 (IML-2).

Three-dimensional radar imaging of structures and craters in the Martian polar caps.

PubMed

Putzig, Nathaniel E; Smith, Isaac B; Perry, Matthew R; Foss, Frederick J; Campbell, Bruce A; Phillips, Roger J; Seu, Roberto

2018-07-01

Over the last decade, observations acquired by the Shallow Radar (SHARAD) sounder on individual passes of the Mars Reconnaissance Orbiter have revealed the internal structure of the Martian polar caps and provided new insights into the formation of the icy layers within and their relationship to climate. However, a complete picture of the cap interiors has been hampered by interfering reflections from off-nadir surface features and signal losses associated with sloping structures and scattering. Foss et al. (2017) addressed these limitations by assembling three-dimensional data volumes of SHARAD observations from thousands of orbital passes over each polar region and applying geometric corrections simultaneously. The radar volumes provide unprecedented views of subsurface features, readily imaging structures previously inferred from time-intensive manual analysis of single-orbit data (e.g., trough-bounding surfaces, a buried chasma, and a basal unit in the north, massive carbon-dioxide ice deposits and discontinuous layered sequences in the south). Our new mapping of the carbon-dioxide deposits yields a volume of 16,500 km 3 , 11% larger than the prior estimate. In addition, the radar volumes newly reveal other structures, including what appear to be buried impact craters with no surface expression. Our first assessment of 21 apparent craters at the base of the north polar layered deposits suggests a Hesperian age for the substrate, consistent with that of the surrounding plains as determined from statistics of surface cratering rates. Planned mapping of similar features throughout both polar volumes may provide new constraints on the age of the icy layered deposits. The radar volumes also provide new topographic data between the highest latitudes observed by the Mars Orbiter Laser Altimeter and those observed by SHARAD. In general, mapping of features in these radar volumes is placing new constraints on the nature and evolution of the polar deposits and associated

South Polar Polygons

NASA Technical Reports Server (NTRS)

2005-01-01

4 July 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a polgyon-cracked surface, into which deep, somewhat kidney-bean-shaped pits have formed. These are landscapes of the martian south polar residual cap. This view was captured during May 2005.

Location near: 86.9oS, 5.1oW Image width: 1.5 km (0.9 mi) Illumination from: upper left Season Southern Spring

Artificial two-dimensional polar metal at room temperature.

PubMed

Cao, Yanwei; Wang, Zhen; Park, Se Young; Yuan, Yakun; Liu, Xiaoran; Nikitin, Sergey M; Akamatsu, Hirofumi; Kareev, M; Middey, S; Meyers, D; Thompson, P; Ryan, P J; Shafer, Padraic; N'Diaye, A; Arenholz, E; Gopalan, Venkatraman; Zhu, Yimei; Rabe, Karin M; Chakhalian, J

2018-04-18

Polar metals, commonly defined by the coexistence of polar crystal structure and metallicity, are thought to be scarce because the long-range electrostatic fields favoring the polar structure are expected to be fully screened by the conduction electrons of a metal. Moreover, reducing from three to two dimensions, it remains an open question whether a polar metal can exist. Here we report on the realization of a room temperature two-dimensional polar metal of the B-site type in tri-color (tri-layer) superlattices BaTiO 3 /SrTiO 3 /LaTiO 3 . A combination of atomic resolution scanning transmission electron microscopy with electron energy-loss spectroscopy, optical second harmonic generation, electrical transport, and first-principles calculations have revealed the microscopic mechanisms of periodic electric polarization, charge distribution, and orbital symmetry. Our results provide a route to creating all-oxide artificial non-centrosymmetric quasi-two-dimensional metals with exotic quantum states including coexisting ferroelectric, ferromagnetic, and superconducting phases.

How Well Can Aerosol Measurements from the Terra Morning Polar Orbiting Satellite Represent the Daily Aerosol Abundance and Properties?

NASA Technical Reports Server (NTRS)

Kaufman, Y. J.; Holben, B. N.; Tanre, D.; Slutzker, I.; Eck, T. F.; Smirnov, A.; Einaudi, Franco (Technical Monitor)

2000-01-01

The Terra mission, launched at the dawn of 1999, and Aqua mission to be launched soon, will possess innovative measurements of the aerosol daily spatial distribution, distinguish between dust, smoke and regional pollution and measure aerosol radiative forcing of climate. Their polar orbit gives daily global coverage, however measurements are acquired at specific time of the day. To what degree can present measurements from Terra taken between 10:00 and 11:30 AM local time, represent the daily average aerosol forcing of climate? Here we answer this question using 7 years of data from the distributed ground based 50-70 instrument Aerosol Robotic Network (AERONET) This (AERONET) half a million measurement data set shows that Terra aerosol measurements represent the daily average values within 5%. The excellent representation is found for large dust particles or small aerosol particles from Fires or regional pollution and for any range of the optical thickness, a measure of the amount of aerosol in the atmosphere.

Spitzer Space Telescope Observations of Polars

NASA Astrophysics Data System (ADS)

Howell, S. B.; Brinkworth, C.; Chun, H.; Thomas, B.; Stefaniak, L.; Hoard, D. W.

2005-12-01

We have obtained the first Spitzer Space telescope observations of short orbital period polars. Using the Infrared Array Camera (IRAC), observations have been made in four broadband filters centered at 3.6, 4.5, 5.8, and 8.0 microns of the polars V347 Pav, GG Leo, RX J0154, and EF Eri. Spectral energy distributions have been produced for all four stars and in each case indicate excess emission in the longest wavebands. We examine our observations with respect to these binaries containing late M or brown dwarf type secondaries. We discuss the implications of the observed long wavelength emission excess in terms of the presence of dust and/or other possible emission mechanisms. The impact of this finding on the evolution of polars is also presented.

Polarization Compensation of Fresnel Aberrations in Telescopes

NASA Technical Reports Server (NTRS)

Clark, Natalie; Breckenridge, James B.

2011-01-01

Large aperture space telescopes are built with low F# s to accommodate the mechanical constraints of launch vehicles and to reduce resonance frequencies of the on-orbit system. Inherent with these low F# s is Fresnel polarization which affects image quality. We present the design and modeling of a nano-structure consisting of birefringent layers to control polarization and increase contrast. Analysis shows a device that functions across a 400nm bandwidth tunable from 300nm to 1200nm. This Fresnel compensator device has a cross leakage of less than 0.001 retardance.

Full Stark control of polariton states on a spin-orbit hypersphere

NASA Astrophysics Data System (ADS)

Li, Feng; Cancellieri, E.; Buonaiuto, G.; Skolnick, M. S.; Krizhanovskii, D. N.; Whittaker, D. M.

2016-11-01

The orbital angular momentum and the polarization of light are physical quantities widely investigated for classical and quantum information processing. In this work we propose to take advantage of strong light-matter coupling, circular-symmetric confinement, and transverse-electric transverse-magnetic splitting to exploit states where these two degrees of freedom are combined. To this end we develop a model based on a spin-orbit Poincaré hypersphere. Then we consider the example of semiconductor polariton systems and demonstrate full ultrafast Stark control of spin-orbit states. Moreover, by controlling states on three different spin-orbit spheres and switching from one sphere to another we demonstrate the control of different logic bits within one single physical system.

Quantum teleportation in the spin-orbit variables of photon pairs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khoury, A. Z.; Milman, P.; Laboratoire Materiaux et Phenomenes Quantiques, CNRS UMR 7162, Universite Paris Diderot, F-75013, Paris

2011-06-15

We propose a polarization to orbital angular momentum teleportation scheme using entangled photon pairs generated by spontaneous parametric down-conversion. By making a joint detection of the polarization and angular momentum parity of a single photon, we are able to detect all the Bell states and perform, in principle, perfect teleportation from a discrete to a continuous system using minimal resources. The proposed protocol implementation demands experimental resources that are currently available in quantum optics laboratories.

Coupled ferroelectric polarization and magnetization in spinel FeCr2S4

PubMed Central

Lin, L.; Zhu, H. X.; Jiang, X. M.; Wang, K. F.; Dong, S.; Yan, Z. B.; Yang, Z. R.; Wan, J. G.; Liu, J.-M.

2014-01-01

One of the core issues for multiferroicity is the strongly coupled ferroelectric polarization and magnetization, while so far most multiferroics have antiferromagnetic order with nearly zero magnetization. Magnetic spinel compounds with ferrimagnetic order may be alternative candidates offering large magnetization when ferroelectricity can be activated simultaneously. In this work, we investigate the ferroelectricity and magnetism of spinel FeCr2S4 in which the Fe2+ sublattice and Cr3+ sublattice are coupled in antiparallel alignment. Well defined ferroelectric transitions below the Fe2+ orbital ordering termperature Too = 8.5 K are demonstrated. The ferroelectric polarization has two components. One component arises mainly from the noncollinear conical spin order associated with the spin-orbit coupling, which is thus magnetic field sensitive. The other is probably attributed to the Jahn-Teller distortion induced lattice symmetry breaking, occuring below the orbital ordering of Fe2+. Furthermore, the coupled ferroelectric polarization and magnetization in response to magnetic field are observed. The present work suggests that spinel FeCr2S4 is a multiferroic offering both ferroelectricity and ferrimagnetism with large net magnetization. PMID:25284432

Jupiter's Magnetic Field and Magnetosphere after Juno's First 8 Orbits

NASA Astrophysics Data System (ADS)

Connerney, J. E. P.; Oliversen, R. J.; Espley, J. R.; Gruesbeck, J.; Kotsiaros, S.; DiBraccio, G. A.; Joergensen, J. L.; Joergensen, P. S.; Merayo, J. M. G.; Denver, T.; Benn, M.; Bjarno, J. B.; Malinnikova Bang, A.; Bloxham, J.; Moore, K.; Bolton, S. J.; Levin, S.; Gershman, D. J.

2016-12-01

The Juno spacecraft entered polar orbit about Jupiter on July 4, 2016, embarking upon an ambitious mission to map Jupiter's magnetic and gravitational potential fields and probe its deep atmosphere, in search of clues to the planet's formation and evolution. Juno is also instrumented to conduct the first exploration of the polar magnetosphere and to acquire images and spectra of its polar auroras and atmosphere. Juno's 53.5-day orbit trajectory carries her science instruments from pole to pole in approximately 2 hours, with a closest approach to within 1.05 Rj of the center of the planet (one Rj = 71,492 km, Jupiter's equatorial radius), just a few thousand km above the clouds. Repeated periapsis passes will eventually encircle the planet with a dense net of observations equally spaced in longitude (<12° at the equator) and optimized for characterization of the Jovian dynamo. Such close passages are sensitive to small spatial scale variations in the magnetic field and therefore many such passes are required to bring the magnetic field into focus. Nevertheless, after only 8 orbits, low-degree spherical harmonics can be extracted from a partial solution to a much more complicated representation (e.g., 20 degree/order), providing the first new information about Jupiter's magnetic field in decades. Juno is equipped with two magnetometer sensor suites, located 10 and 12 m from the center of the spacecraft at the end of one of Juno's three solar panel wings. Each contains a vector fluxgate magnetometer (FGM) sensor and a pair of co-located non-magnetic star tracker camera heads, providing accurate attitude determination for the FGM sensors. We present an overview of the magnetometer observations obtained during Juno's first year in orbit in context with prior observations and those acquired by Juno's other science instruments.

Jupiter's Magnetic Field and Magnetosphere after Juno's First 8 Orbits

NASA Astrophysics Data System (ADS)

Connerney, J. E. P.; Oliversen, R. J.; Espley, J. R.; Gruesbeck, J.; Kotsiaros, S.; DiBraccio, G. A.; Joergensen, J. L.; Joergensen, P. S.; Merayo, J. M. G.; Denver, T.; Benn, M.; Bjarno, J. B.; Malinnikova Bang, A.; Bloxham, J.; Moore, K.; Bolton, S. J.; Levin, S.; Gershman, D. J.

2017-12-01

The Juno spacecraft entered polar orbit about Jupiter on July 4, 2016, embarking upon an ambitious mission to map Jupiter's magnetic and gravitational potential fields and probe its deep atmosphere, in search of clues to the planet's formation and evolution. Juno is also instrumented to conduct the first exploration of the polar magnetosphere and to acquire images and spectra of its polar auroras and atmosphere. Juno's 53.5-day orbit trajectory carries her science instruments from pole to pole in approximately 2 hours, with a closest approach to within 1.05 Rj of the center of the planet (one Rj = 71,492 km, Jupiter's equatorial radius), just a few thousand km above the clouds. Repeated periapsis passes will eventually encircle the planet with a dense net of observations equally spaced in longitude (<12° at the equator) and optimized for characterization of the Jovian dynamo. Such close passages are sensitive to small spatial scale variations in the magnetic field and therefore many such passes are required to bring the magnetic field into focus. Nevertheless, after only 8 orbits, low-degree spherical harmonics can be extracted from a partial solution to a much more complicated representation (e.g., 20 degree/order), providing the first new information about Jupiter's magnetic field in decades. Juno is equipped with two magnetometer sensor suites, located 10 and 12 m from the center of the spacecraft at the end of one of Juno's three solar panel wings. Each contains a vector fluxgate magnetometer (FGM) sensor and a pair of co-located non-magnetic star tracker camera heads, providing accurate attitude determination for the FGM sensors. We present an overview of the magnetometer observations obtained during Juno's first year in orbit in context with prior observations and those acquired by Juno's other science instruments.

On the uniqueness of the constrained space orbital variation (CSOV) technique

NASA Technical Reports Server (NTRS)

Bauschlicher, C. W., Jr.

1986-01-01

Several CSOV analyses are performed for the 1Sigma(+) state of NiCO, and it is shown that the importance of the CO sigma donation, Ni pi back donation, and interunit polarizations are virtually independent of the order of the CSOV steps, provided that the open-shell 3d sigma and 4s Ni orbitals are orthogonalized to the CO. This order of orthogonalization is consistent with the polarization of the Ni observed in the unconstrained SCF wavefunction. If instead the CO is orthogonalized to the open-shell Ni orbitals, the frozen orbital repulsion and entire CSOV analysis becomes unphysical. A comparison of the SCF and CAS SCF descriptions for the NiCO 1Sigma(+) state shows the importance of the s to d promotion and sd hybridization in reducing the repulsion and increasing the Ni to CO pi bonding. For LiF, CSOV analyses starting from both the neutral and ionic asymptotes show the bonding to be predominantly Li(+) - F(-). These examples show the uniqueness of the CSOV decomposition.

Spin-orbit proximity effect in graphene

NASA Astrophysics Data System (ADS)

Avsar, A.; Tan, J. Y.; Taychatanapat, T.; Balakrishnan, J.; Koon, G. K. W.; Yeo, Y.; Lahiri, J.; Carvalho, A.; Rodin, A. S.; O'Farrell, E. C. T.; Eda, G.; Castro Neto, A. H.; Özyilmaz, B.

2014-09-01

The development of spintronics devices relies on efficient generation of spin-polarized currents and their electric-field-controlled manipulation. While observation of exceptionally long spin relaxation lengths makes graphene an intriguing material for spintronics studies, electric field modulation of spin currents is almost impossible due to negligible intrinsic spin-orbit coupling of graphene. In this work, we create an artificial interface between monolayer graphene and few-layer semiconducting tungsten disulphide. In these devices, we observe that graphene acquires spin-orbit coupling up to 17 meV, three orders of magnitude higher than its intrinsic value, without modifying the structure of the graphene. The proximity spin-orbit coupling leads to the spin Hall effect even at room temperature, and opens the door to spin field effect transistors. We show that intrinsic defects in tungsten disulphide play an important role in this proximity effect and that graphene can act as a probe to detect defects in semiconducting surfaces.

Interpreting Radar View near Mars' North Pole, Orbit 1512

NASA Technical Reports Server (NTRS)

2006-01-01

A radargram from the Shallow Subsurface Radar instrument (SHARAD) on NASA's Mars Reconnaissance Orbiter is shown in the upper-right panel and reveals detailed structure in the polar layered deposits of the north pole of Mars (with blowups shown in the upper-left panels). The sounding radar collected the data presented here during orbit 1512 of the mission, on Nov. 22, 2006.

The horizontal scale in the radargram is distance along the ground track. It can be referenced to the ground track map shown in the lower right. The radar traversed from about 83.5 degrees to 80.5 degrees north latitude, or about 180 kilometers (110 miles). The ground track map shows elevation measured by the Mars Orbiter Laser Altimeter on NASA's Mars Global Surveyor orbiter. Green indicates low elevation; reddish-white indicates higher elevation. The traverse is from the high elevation of the plateau formed by the layers to the lowlands below.

The vertical scale on the radargram is time delay of the radar signals reflected back to Mars Reconnaissance Orbiter from the surface and subsurface. For reference, using an assumed velocity of the radar waves in the subsurface, time is converted to depth below the surface in two places: about 600 meters (2,000 feet) to the lowest of an upper series of bright reflectors and about 2,000 meters (6,500 feet) to the base of the polar layered deposits. The color scale of the radargram varies from black for weak reflections to bright yellow for strong reflections.

The lower-left panel is a image from the Mars Orbiter Camera on Mars Global Surveyor showing exposed polar layering in the walls of a canyon near the north pole. The layering is divided into a finely structured upper unit (labeled 'Upper PLD') and less-well-defined stratigraphy in the lower unit (labeled 'Lower PLD'). The radargram clearly reveals the complexity of the layering in the upper unit, additional reflections from the lower unit, and the base of the entire stack of

KENNEDY SPACE CENTER, FLA. - In the Space Station Processing Facility, technicians begin pre-assembly measurements on the Japanese Experiment Module (JEM). Developed by the Japan Aerospace Exploration Agency (JAXA), the JEM will enhance the unique research capabilities of the orbiting complex by providing an additional environment for astronauts to conduct science experiments.

NASA Image and Video Library

2003-11-05

KENNEDY SPACE CENTER, FLA. - In the Space Station Processing Facility, technicians begin pre-assembly measurements on the Japanese Experiment Module (JEM). Developed by the Japan Aerospace Exploration Agency (JAXA), the JEM will enhance the unique research capabilities of the orbiting complex by providing an additional environment for astronauts to conduct science experiments.

The CAMEO barium release - E/parallel/ fields over the polar cap

NASA Technical Reports Server (NTRS)

Heppner, J. P.; Miller, M. L.; Pongratz, M. B.; Smith, G. M.; Smith, L. L.; Mende, S. B.; Nath, N. R.

1981-01-01

Four successive thermite barium releases at an altitude of 965 km over polar cap invariant latitudes 84 to 76 deg near magnetic midnight were conducted from the orbiting second stage of the vehicle that launched Nimbus 7; the releases were made as part of the CAMEO (Chemically Active Material Ejected in Orbit) program. This was the first opportunity to observe the behavior of conventional barium release when conducted at orbital velocity in the near-earth magnetic field. The principal unexpected characteristic in the release dynamics was the high, 1.4 to 2.6 km/s, initial Ba(+) expansion velocity relative to an expected velocity of 0.9 km/s. Attention is also given to neutral cloud expansion, initial ion cloud expansion, convective motion, and the characteristics of field-aligned motion. The possibility of measuring parallel electric fields over the polar cap by observing perturbations in the motion of the visible ions is assessed.

Do American born Japanese children still grow faster than native Japanese?

PubMed

Kano, K; Chung, C S

1975-09-01

Growth patterns of Japanese schoolchildren in Hawaii, composed of 2,954 boys and 3,213 girls aged between 11 and 17, were compared with those comparable groups of Japanese schoolchildren in Japan based on the data published by the Japanese Ministry of Education. Growth characteristics studied were height, weight, and relative weight index, weight/(height). The Hawaii-Japanese boys were taller at early ages but the difference disappeared by age 16. Native Japanese girls were shorter than Hawaii-Japanese until age 13, but they overtook the latter by age 14, exceeding them in height after age 15. A similar pattern was found in weights of girls but the Hawaii-Japanese boys remained consistently heavier by 5.0 to 9.0 kg than native Japanese. The relative weight measure indicated that the Hawaii boys were more "obese" than native Japanese boys for the growth period studied; whereas the same tendency was maintained until age 15 in girls. These observations indicate a marked degree of convergence of the patterns of physical growth of the two populations, whose differences were unmistakably in favor of American born children in earlier studies. It is concluded that the convergence is due largely to the improved environmental conditions in Japan in recent years.

Aquarius Radiometer Performance: Early On-Orbit Calibration and Results

NASA Technical Reports Server (NTRS)

Piepmeier, Jeffrey R.; LeVine, David M.; Yueh, Simon H.; Wentz, Frank; Ruf, Christopher

2012-01-01

The Aquarius/SAC-D observatory was launched into a 657-km altitude, 6-PM ascending node, sun-synchronous polar orbit from Vandenberg, California, USA on June 10, 2011. The Aquarius instrument was commissioned two months after launch and began operating in mission mode August 25. The Aquarius radiometer meets all engineering requirements, exhibited initial calibration biases within expected error bars, and continues to operate well. A review of the instrument design, discussion of early on-orbit performance and calibration assessment, and investigation of an on-going calibration drift are summarized in this abstract.

Spin polarization and magnetic dichroism in photoemission from core and valence states in localized magnetic systems. IV. Core-hole polarization in resonant photoemission

NASA Astrophysics Data System (ADS)

van der Laan, Gerrit; Thole, B. T.

1995-12-01

A simple theory is presented for core-hole polarization probed by resonant photoemission in a two-steps approximation. After excitation from a core level to the valence shell, the core hole decays into two shallower core holes under emission of an electron. The nonspherical core hole and the final state selected cause a specific angle and spin distribution of the emitted electron. The experiment is characterized by the ground-state moments, the polarization of the light, and the spin and angular distribution of the emitted electron. The intensity is a sum over ground-state expectation values of tensor operators times the probability to create a polarized core hole using polarized light, times the probability for decay of such a core hole into the final state. We give general expressions for the angle- and spin-dependent intensities in various regimes of Coulomb and spin-orbit interaction: LS, LSJ, and jjJ coupling. The core-polarization analysis, which generalizes the use of sum rules in x-ray absorption spectroscopy where the integrated peak intensities give ground-state expectation values of the spin and orbital moment operators, makes it possible to measure different linear combinations of these operators. As an application the 2p3/23p3p decay in ferromagnetic nickel is calculated using Hartree-Fock values for the radial matrix elements and phase factors, and compared with experiment, the dichroism is smaller in the 3P final state but stronger in the 1D, 1S peak.

Possible experiment with two counter-orbiting drag-free satellites to obtain a new test of Einstein's general theory of relativity and improved measurements in geodesy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Patten, R.A.; Everitt, C.W.F.

1976-03-22

In 1918, Lense and Thirring calculated that a moon orbiting a rotating planet would experience a nodal dragging effect due to general relativity. We describe an experiment to measure this effect to 1% with two counter-orbiting drag-free satellites in polar earth orbit. In addition to tracking data from existing ground stations, satellite-to-satellite Doppler ranging data are taken near the poles. New geophysical information is inherent in the polar data. (AIP)

The Mars Climate Orbiter is prepared for launch

NASA Technical Reports Server (NTRS)

1998-01-01

Technicians in the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2) prepare a lifting device they will use to remove the Mars Climate Orbiter from its container (behind the workers). The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Boeing Delta II 7425 rocket.

Coulomb-free and Coulomb-distorted recolliding quantum orbits in photoelectron holography

NASA Astrophysics Data System (ADS)

Maxwell, A. S.; Figueira de Morisson Faria, C.

2018-06-01

We perform a detailed analysis of the different types of orbits in the Coulomb quantum orbit strong-field approximation (CQSFA), ranging from direct to those undergoing hard collisions. We show that some of them exhibit clear counterparts in the standard formulations of the strong-field approximation for direct and rescattered above-threshold ionization, and show that the standard orbit classification commonly used in Coulomb-corrected models is over-simplified. We identify several types of rescattered orbits, such as those responsible for the low-energy structures reported in the literature, and determine the momentum regions in which they occur. We also find formerly overlooked interference patterns caused by backscattered Coulomb-corrected orbits and assess their effect on photoelectron angular distributions. These orbits improve the agreement of photoelectron angular distributions computed with the CQSFA with the outcome of ab initio methods for high energy phtotoelectrons perpendicular to the field polarization axis.

Stereoselective Epoxidation of 4-Deoxypentenosides: A Polarized-πModel

PubMed Central

Cheng, Gang; Boulineau, Fabien P.; Liew, Siong-Tern; Shi, Qicun; Wenthold, Paul G.; Wei, Alexander

2008-01-01

The high facioselectivity in the epoxidation of 4-deoxypentenosides (4-DPs) by dimethyldioxirane (DMDO) correlates with a stereoelectronic bias in the 4-DPs’ ground-state conformations, as elucidated by polarized-π frontier molecular orbital (PPFMO) analysis. PMID:16986946

QED effects on individual atomic orbital energies

NASA Astrophysics Data System (ADS)

Kozioł, Karol; Aucar, Gustavo A.

2018-04-01

Several issues, concerning QED corrections, that are important in precise atomic calculations are presented. The leading QED corrections, self-energy and vacuum polarization, to the orbital energy for selected atoms with 30 ≤ Z ≤ 118 have been calculated. The sum of QED and Breit contributions to the orbital energy is analyzed. It has been found that for ns subshells the Breit and QED contributions are of comparative size, but for np and nd subshells the Breit contribution takes a major part of the QED+Breit sum. It has also, been found that the Breit to leading QED contributions ratio for ns subshells is almost independent of Z. The Z-dependence of QED and Breit+QED contributions per subshell is shown. The fitting coefficients may be used to estimate QED effects on inner molecular orbitals. We present results of our calculations for QED contributions to orbital energy of valence ns-subshell for group 1 and 11 atoms and discuss about the reliability of these numbers by comparing them with experimental first ionization potential data.

The Mars Climate Orbiter at Launch Complex 17A, CCAS

NASA Technical Reports Server (NTRS)

1998-01-01

At Launch Complex 17A, Cape Canaveral Air Station, workers place aside a piece of the canister surrounding the Mars Climate Orbiter. Targeted for liftoff on Dec. 10, 1998, aboard a Boeing Delta II (7425) rocket, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface.

The Mars Climate Orbiter at Launch Complex 17A, CCAS

NASA Technical Reports Server (NTRS)

1998-01-01

At Launch Complex 17A, Cape Canaveral Air Station, workers remove the canister surrounding the Mars Climate Orbiter. Targeted for liftoff on Dec. 10, 1998, aboard a Boeing Delta II (7425) rocket, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface.

Orbital debris removal and salvage system

NASA Technical Reports Server (NTRS)

1990-01-01

Four Texas A&M University projects are discussed. The first project is a design to eliminate a majority of orbital debris. The Orbital Debris and Salvage System will push the smaller particles into lower orbits where their orbits will decay at a higher rate. This will be done by momentum transfer via laser. The salvageable satellites will be delivered to the Space Station by an Orbital Transfer Vehicle. The rest of the debris will be collected by Salvage I. The second project is the design of a space based satellite system to prevent the depletion of atmospheric ozone. The focus is on ozone depletion in the Antarctic. The plan is to use an orbiting solar array system designed to transmit microwaves at a frequency of 22 GHz over the region in order to dissipate polar stratospheric clouds that form during the months beginning in August and ending in October. The third project, Project Poseidon, involves a conceptual design of a space based hurricane control system consisting of a network of 21 low-orbiting laser platforms arranged in three rings designed to heat the upper atmosphere of a developing tropical depression. Fusion power plants are proposed to provide power for the lasers. The fourth project, Project Donatello, involves a proposed Mars exploration initiative for the year 2050. The project is a conceptual design for a futuristic superfreighter that will transport large numbers of people and supplies to Mars for the construction of a full scale scientific and manufacturing complex.

Oxygen Abundances in the Rings of Polar-Ring Galaxies

NASA Astrophysics Data System (ADS)

Radtke, I. R.; Eskridge, P. B.; Pogge, R. W.

2003-05-01

Polar ring galaxies (PRGs) are typically early-type (S0 or E) galaxies surrounded by rings of gas, dust, and stars orbiting nearly perpendicular to the principle plane of the host galaxy (Whitmore et al. 1990 AJ 100 1489). Given that PRGs have two separate, perpendicular axes of rotation, it is clear on dynamical grounds that PRGs are the products of merger events between two galaxies, but are observed in a state where two distinct kinematic and morphological structures are still apparent. As such, they present a unique opportunity to study merger events in systems where the debris is not confused with material from the host. Our understanding of the relative importance of polar ring systems in the overall process of galaxy evolution is confounded by our lack of knowledge regarding the typical lifetimes and evolutionary histories of polar rings. A crucial factor for understanding the formation and evolution of PRGs is information regarding the elemental abundances of the ring material. Polar rings are typically rich in {\\protectH 2} regions. Optical spectroscopy of these {\\protectH 2} regions can tell us their density, temperature, and oxygen abundance. Our earlier work (Eskridge & Pogge 1997 ApJ 486 259) revealed roughly Solar oxygen abundances for {\\protectH 2} regions in the polar ring of NGC 2685. We have extended this project, and now have spectra for six PRGs. Analysis of the data for II Zw 73 and UGC 7576 reveal the polar rings of these galaxies to have {\\protectH 2} region oxygen abundances in the range 0.3 to 0.6 Solar, substantially less than found for NGC 2685. Abundances in this range are much easier to explain with conventional models of chemical enrichment and polar ring formation. We shall present results for our full sample. Taken as a whole, this sample will provide a clear foundation for the typical chemical enrichment patterns in polar rings, and thus provide a clearer understanding of the formation and evolution of these curious objects. We

Development of the Lunar Polar Hydrogen Mapper Mission

NASA Astrophysics Data System (ADS)

Hardgrove, C.; Bell, J. F.; Starr, R.; Colaprete, A.; Drake, D.; Lazbin, I.; West, S.; Johnson, E. B.; Christian, J.; Heffern, L.; Genova, A.; Dunham, D.; Williams, B.; Nelson, D.; Puckett, S.; Babuscia, A.; Scowen, P.; Kerner, H.; Amzler, R. J.

2018-04-01

The Lunar Polar Hydrogen Mapper is a 6U CubeSat mission launching on SLS EM-1. The spacecraft will orbit at a low altitude perlune over the lunar south pole and carries a miniature neutron spectrometer to map small scale hydrogen enrichments in PSRs.

Waveform and polarization of compressional Pc 5 waves at geosynchronous orbit

NASA Astrophysics Data System (ADS)

Higuchi, Tomoyuki; Kokubun, Susumu

1988-12-01

The factors controlling the occurrence and the properties of compressional Pc 5 waves were examined by studying the statistical characteristics of compressional Pc 5 waves, using magnetic-field data obtained by GOES 2 and GOES 3 satellites during the August 1978 - August 1980 period. The compressional Pc 5 waves could be classified into the harmonic, transitional, and normal types, on the basis of the second-harmonic component in the compressional component of the magnetic field oscillation. It was found that the harmonic and the transitional waves have significant azimuthal perturbations and show right-handed polarization with respect to the local magnetic field, while most of the normal-type waves have small amplitude in the azimuthal component. The polarization properties of transverse perturbation, which may reflect the spatial inhomogeneity of the medium, are investigated.

STS-65 Japanese Payload Specialist Mukai prepares for MAIL egress training

NASA Technical Reports Server (NTRS)

1994-01-01

STS-65 Japanese Payload Specialist Chiaki Mukai, wearing launch and entry suit (LES), prepares to participate in a training session in the Johnson Space Center's (JSC's) Mockup and Integration Laboratory (MAIL) Bldg 9NE. The entire STS-65 crew was on hand for egress training and countdown rehearsals. Representing Japan's National Space Development Agency (NASDA) Mukai will join six NASA astronauts for the International Microgravity Laboratory 2 (IML-2) mission aboard the Space Shuttle Columbia, Orbiter Vehicle (OV) 102, later this year.

Toward a Unified View of the Moon's Polar Volatiles from the Lunar Reconnaissance Orbiter

NASA Astrophysics Data System (ADS)

Hayne, Paul

2016-04-01

Although the scientific basis for the possibility of water and other volatiles in the cold traps of the lunar polar regions was developed in the 1960's and '70's [1,2], only recently have the data become available to test the theories in detail. Furthermore, comparisons with other planetary bodies, particularly Mercury, have revealed surprising differences that may point to inconsistencies or holes in our understanding of the basic processes involving volatiles on airless bodies [3]. Addressing these gaps in understanding is critical to the future exploration of the Moon, for which water is an important scientific and engineering resource [4]. Launched in 2009, NASA's Lunar Reconnaissance Orbiter (LRO) has been acquiring data from lunar orbit for more than six years. All seven of the remote sensing instruments on the payload have now contributed significantly to advancing understanding of volatiles on the Moon. Here we present results from these investigations, and discuss attempts to synthesize the disparate information to create a self-consistent model for lunar volatiles. In addition to the LRO data, we must take into account results from earlier missions [5,6], ground-based telescopes [7], and sample analyses [8]. The results from these inter-comparisons show that water is likely available in useful quantities, but key additional measurements may be required to resolve remaining uncertainties. [1] Watson, K., Murray, B. C., & Brown, H. (1961), J. Geophys. Res., 66(9), 3033-3045. [2] Arnold, J. R. (1979), J. Geophys. Res. (1978-2012), 84(B10), 5659-5668. [3] Paige, D. A., Siegler, M. A., Harmon, J. K., Neumann, G. A., Mazarico, E. M., Smith, D. E., ... & Solomon, S. C. (2013), Science, 339(6117), 300-303. [4] Hayne, P. O., et al. (2014), Keck Inst. Space Studies Report. [5] Nozette, S., Lichtenberg, C. L., Spudis, P., Bonner, R., Ort, W., Malaret, E., ... & Shoemaker, E. M. (1996), Science, 274(5292), 1495-1498. [6] Pieters, C. M., Goswami, J. N., Clark, R. N

Japaneseplex: A forensic SNP assay for identification of Japanese people using Japanese-specific alleles.

PubMed

Yuasa, Isao; Akane, Atsushi; Yamamoto, Toshimichi; Matsusue, Aya; Endoh, Minoru; Nakagawa, Mayumi; Umetsu, Kazuo; Ishikawa, Takaki; Iino, Morio

2018-04-24

It is sometimes necessary to determine whether a forensic biological sample came from a Japanese person. In this study, we developed a 60-locus SNP assay designed for the differentiation of Japanese people from other East Asians using entirely and nearly Japanese-specific alleles. This multiplex assay consisted of 6 independent PCR reactions followed by single nucleotide extension. The average number and standard deviation of Japanese-specific alleles possessed by an individual were 0.81 ± 0.93 in 108 Koreans from Seoul, 8.87 ± 2.89 in 103 Japanese from Tottori, 17.20 ± 3.80 in 88 Japanese from Okinawa, and 0 in 220 Han Chinese from Wuxi and Changsha. The Koreans had 0-4 Japanese-specific alleles per individual, whereas the Japanese had 4-26 Japanese-specific alleles. Almost all Japanese were distinguished from the Koreans and other people by the factorial correspondence and principal component analyses. The Snipper program was also useful to estimate the degree of Japaneseness. The method described here was successfully applied to the differentiation of Japanese from non-Japanese people in forensic cases. This Japanese-specific SNP assay was named Japaneseplex. Copyright © 2018 Elsevier B.V. All rights reserved.

Orbital configuration in CaTiO 3 films on NdGaO 3

DOE PAGES

Cao, Yanwei; Park, Se Young; Liu, Xiaoran; ...

2016-10-13

Despite its use as a constituent layer for realization of a polar metal and interfacial conductivity, the microscopic study of electronic structure of CaTiO 3 is still very limited. Here, we epitaxially stabilized CaTiO 3 films on NdGaO 3 (110) substrates in a layer-by-layer way by pulsed laser deposition. The structural and electronic properties of the films were characterized by reflection-high-energy-electron-diffraction, X-ray diffraction, and element-specific resonant X-ray absorption spectroscopy. To reveal the orbital polarization and the crystal field splitting of the titanium 3d state, X-ray linear dichroism was carried out on CaTiO 3 films, demonstrating the orbital configuration of dmore » xz/d yz < d xy < d 3z2-r2 < d x2-y2. To further explore the origin of this configuration, we performed the first-principles density function theory calculations, which linked the orbital occupation to the on-site energy of Ti 3d orbitals. Finally, these findings can be important for understanding and designing exotic quantum states in heterostructures based on CaTiO 3.« less

Anisotropic orbital occupation and Jahn-Teller distortion of orthorhombic YMnO{sub 3} epitaxial films: A combined experimental and theoretical study on polarization-dependent x-ray absorption spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haw, Shu-Chih; Chen, Shin-Ann; National Synchrotron Radiation Research Center

2014-04-21

The b-axis oriented orthorhombic YMnO{sub 3} (o-YMnO{sub 3}) epitaxial films on a YAlO{sub 3} (010) substrate were fabricated with pulsed-laser deposition. The anisotropic orbital occupation and Jahn-Teller (JT) distortion of an o-YMnO{sub 3} film were investigated with polarization-dependent x-ray absorption spectra and configuration-interaction multiplet-cluster calculations. A significant energy difference, ∼3.8 eV, for the main white line along E//b and E//a in polarization-dependent Mn K-edge spectra of o-YMnO{sub 3} indicates an extraordinary JT distortion and significant anisotropic Mn–O bonding within the ab plane in the o-YMnO{sub 3} film. Most importantly, although the orbital occupation of 3d electrons in o-YMnO{sub 3} filmsmore » is almost the same as that in single crystalline o-DyMnO{sub 3}, the JT distortion of o-YMnO{sub 3} films is larger than that of single crystalline o-DyMnO{sub 3}, deduced from the multiplet calculations. We speculate that this JT distortion predominantly contributes to the origin of the cycloidal spin deformation in bulk o-YMnO{sub 3}, because of a suppressed nearest-neighbor superexchange interaction and an enhanced next-nearest-neighbor superexchange interaction. These complementary results provide insight into the origin of the E-type magnetic configuration of o-YMnO{sub 3}.« less

South Polar Depression

NASA Technical Reports Server (NTRS)

2005-01-01

14 August 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a circular depression and a suite of eroding mesas of carbon dioxide. These features occur in the south polar residual cap of Mars. The eroding carbon dioxide creates landforms reminiscent of 'Swiss cheese.' The circular feature might indicate the location of a filled, buried impact crater.

Location near: 86.8oS, 111.0oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

Polar Cap Retreat

NASA Technical Reports Server (NTRS)

2004-01-01

13 August 2004 This red wide angle Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a view of the retreating seasonal south polar cap in the most recent spring in late 2003. Bright areas are covered with frost, dark areas are those from which the solid carbon dioxide has sublimed away. The center of this image is located near 76.5oS, 28.2oW. The scene is large; it covers an area about 250 km (155 mi) across. The scene is illuminated by sunlight from the upper left.

Stability of orbits around planetary satellites considering a disturbing body in an elliptical orbit: Applications to Europa and Ganymede

NASA Astrophysics Data System (ADS)

Cardoso dos Santos, Josué; Carvalho, Jean Paulo; Vilhena de Moraes, Rodolpho

Europa and Ganymede are two of the four Jupiter’s moons which compose the Galilean satellite. These ones are planetary satellites of greater interest at the present moment among the scientific community. There are some missions being planned to visit them and and the Jovian system. One of them is the cooperation between NASA and ESA for the Europa Jupiter System Mission (EJSM). In this mission are planned the insertion of the spacecrafts JEO (Jupiter Europa Orbiter) and JGO (Jupiter Ganymede Orbiter) into Europa and Ganymede’s orbit. Thus, there is a great necessity for having a better comprehension of the dynamics of the orbits around this planetary satellite. This comprehension is essential for the success of this type of mission. In this context, this work aims to perform a search for low-altitude orbits around these planetary satellites. An emphasis is given in polar orbits. These orbits can be useful in the planning of aerospace activities to be conducted around this planetary satellite, with respect to the stability of orbits of artificial satellites. The study considers orbits of an artificial satellite around Europa and Ganymede under the influence of the third-body perturbation (the gravitational attraction of Jupiter) and the polygenic perturbations. These last ones occur due to forces such as the non-uniform distribution of mass (J2 and J3) of the main (central) body. A simplified dynamic model for polygenic perturbations is used. A new model for the third-body disturbance is presented considering it in an elliptical orbit. The Lagrange planetary equations, which compose a system of nonlinear differential equations, are used to describe the orbital motion of the artificial satellite around Ganymede. The equations showed here are developed in closed form to avoid expansions in inclination and eccentricity.

Defrosting Polar Dunes -- "The Snow Leopard"

NASA Image and Video Library

2000-05-16

The patterns created by dark spots on defrosting south polar dunes are often strange and beautiful. This picture, which the Mars Orbiter Camera team has dubbed, "the snow leopard," shows a dune field located at 61.5°S, 18.9°W, as it appeared on July 1, 1999. The spots are areas where dark sand has been exposed from beneath bright frost as the south polar winter cap begins to retreat. Many of the spots have a diffuse, bright ring around them this is thought to be fresh frost that was re-precipitated after being removed from the dark spot. The spots seen on defrosting polar dunes are a new phenomenon that was not observed by previous spacecraft missions to Mars. Thus, there is much about these features that remains unknown. For example, no one yet knows why the dunes become defrosted by forming small spots that grow and grow over time. No one knows for sure if the bright rings around the dark spots are actually composed of re-precipitated frost. And no one knows for sure why some dune show spots that appear to be "lined-up" (as they do in the picture shown here). This Mars Global Surveyor Mars Orbiter Camera image is illuminated from the upper left. North is toward the upper right. The scale bar indicates a distance of 200 meters (656 feet). http://photojournal.jpl.nasa.gov/catalog/PIA02301

Electrofluorescence polarity in a molecular diode

NASA Astrophysics Data System (ADS)

Petrov, E. G.; Leonov, V. A.; Shevchenko, E. V.

2017-11-01

The kinetic equations describing the transmission of an electron in the molecular compound "electrode 1-molecule-electrode 2" (1M2 system) are derived using the method of a nonequilibrium density matrix. The steady-state transmission regime is considered, for which detailed analysis of the kinetics of electrofluorescence formation in systems with symmetric and asymmetric couplings between the molecule and the electrodes is carried out. It is shown that the optically active state of the molecule is formed as a result of electron hops between the molecule and each of the electrodes, as well as due to inelastic interelectrode tunneling of the electron. The electrofluorescence power for a molecular diode (asymmetric 1M2 system) depends on the polarity of the voltage bias applied to the electrodes. The polarity is explained using a model in which the optically active part of the molecule (chromophore group) is represented by the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). Two mechanisms of the emergence of polarity are revealed. One mechanism is associated with nonidentical Stark shifts of the HOMO and LUMO levels relative to the Fermi levels of the electrodes. The second mechanism is associated with the fact that the rates of an electron hopping between HOMO (LUMO) and one of the electrodes are much higher than the rates of such a hopping with the other electrode. The conditions in which each mechanism can be implemented experimentally are indicated.

Artificial two-dimensional polar metal at room temperature

DOE PAGES

Cao, Yanwei; Wang, Zhen; Park, Se Young; ...

2018-04-18

Polar metals, commonly defined by the coexistence of polar crystal structure and metallicity, are thought to be scarce because the long-range electrostatic fields favoring the polar structure are expected to be fully screened by the conduction electrons of a metal. Moreover, reducing from three to two dimensions, it remains an open question whether a polar metal can exist. Here we report on the realization of a room temperature two-dimensional polar metal of the B-site type in tri-color (tri-layer) superlattices BaTiO 3/SrTiO 3/LaTiO 3. A combination of atomic resolution scanning transmission electron microscopy with electron energy-loss spectroscopy, optical second harmonic generation,more » electrical transport, and first-principles calculations have revealed the microscopic mechanisms of periodic electric polarization, charge distribution, and orbital symmetry. Lastly, our results provide a route to creating all-oxide artificial non-centrosymmetric quasi-two-dimensional metals with exotic quantum states including coexisting ferroelectric, ferromagnetic, and superconducting phases.« less

Artificial two-dimensional polar metal at room temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Yanwei; Wang, Zhen; Park, Se Young

Polar metals, commonly defined by the coexistence of polar crystal structure and metallicity, are thought to be scarce because the long-range electrostatic fields favoring the polar structure are expected to be fully screened by the conduction electrons of a metal. Moreover, reducing from three to two dimensions, it remains an open question whether a polar metal can exist. Here we report on the realization of a room temperature two-dimensional polar metal of the B-site type in tri-color (tri-layer) superlattices BaTiO 3/SrTiO 3/LaTiO 3. A combination of atomic resolution scanning transmission electron microscopy with electron energy-loss spectroscopy, optical second harmonic generation,more » electrical transport, and first-principles calculations have revealed the microscopic mechanisms of periodic electric polarization, charge distribution, and orbital symmetry. Lastly, our results provide a route to creating all-oxide artificial non-centrosymmetric quasi-two-dimensional metals with exotic quantum states including coexisting ferroelectric, ferromagnetic, and superconducting phases.« less

X-ray microprobe of orbital alignment in strong-field ionized atoms.

PubMed

Young, L; Arms, D A; Dufresne, E M; Dunford, R W; Ederer, D L; Höhr, C; Kanter, E P; Krässig, B; Landahl, E C; Peterson, E R; Rudati, J; Santra, R; Southworth, S H

2006-08-25

We have developed a synchrotron-based, time-resolved x-ray microprobe to investigate optical strong-field processes at intermediate intensities (10(14) - 10(15) W/cm2). This quantum-state specific probe has enabled the direct observation of orbital alignment in the residual ion produced by strong-field ionization of krypton atoms via resonant, polarized x-ray absorption. We found strong alignment to persist for a period long compared to the spin-orbit coupling time scale (6.2 fs). The observed degree of alignment can be explained by models that incorporate spin-orbit coupling. The methodology is applicable to a wide range of problems.

High-precision broad-band linear polarimetry of early-type binaries. I. Discovery of variable, phase-locked polarization in HD 48099

NASA Astrophysics Data System (ADS)

Berdyugin, A.; Piirola, V.; Sadegi, S.; Tsygankov, S.; Sakanoi, T.; Kagitani, M.; Yoneda, M.; Okano, S.; Poutanen, J.

2016-06-01

Aims: We investigate the structure of the O-type binary system HD 48099 by measuring linear polarization that arises due to light scattering process. High-precison polarimetry provides independent estimates of the orbital parameters and gives important information on the properties of the system. Methods: Linear polarization measurements of HD 48099 in the B, V and R passbands with the high-precision Dipol-2 polarimeter have been carried out. The data have been obtained with the 60 cm KVA (Observatory Roque de los Muchachos, La Palma, Spain) and T60 (Haleakala, Hawaii, USA) remotely controlled telescopes during 31 observing nights. Polarimetry in the optical wavelengths has been complemented by observations in the X-rays with the Swift space observatory. Results: Optical polarimetry revealed small intrinsic polarization in HD 48099 with ~0.1% peak to peak variation over the orbital period of 3.08 d. The variability pattern is typical for binary systems, showing strong second harmonic of the orbital period. We apply our model code for the electron scattering in the circumstellar matter to put constraints on the system geometry. A good model fit is obtained for scattering of light on a cloud produced by the colliding stellar winds. The geometry of the cloud, with a broad distribution of scattering particles away from the orbital plane, helps in constraining the (low) orbital inclination. We derive from the polarization data the inclination I = 17° ± 2° and the longitude of the ascending node Ω = 82° ± 1° of the binary orbit. The available X-ray data provide additional evidence for the existence of the colliding stellar winds in the system. Another possible source of the polarized light could be scattering from the stellar photospheres. The models with circumstellar envelopes, or matter confined to the orbital plane, do not provide good constraints on the low inclination, better than I ≤ 27°, as is already suggested by the absence of eclipses. The

[Understanding the symbolic values of Japanese onomatopoeia: comparison of Japanese and Chinese speakers].

PubMed

Haryu, Etsuko; Zhao, Lihua

2007-10-01

Do non-native speakers of the Japanese language understand the symbolic values of Japanese onomatopoeia matching a voiced/unvoiced consonant with a big/small sound made by a big/small object? In three experiments, participants who were native speakers of Japanese, Japanese-learning Chinese, or Chinese without knowledge of the Japanese language were shown two pictures. One picture was of a small object making a small sound, such as a small vase being broken, and the other was of a big object making a big sound, such as a big vase being broken. Participants were presented with two novel onomatopoetic words with voicing contrasts, e.g.,/dachan/vs./tachan/, and were told that each word corresponded to one of the two pictures. They were then asked to match the words to the corresponding pictures. Chinese without knowledge of Japanese performed only at chance level, whereas Japanese and Japanese-learning Chinese successfully matched a voiced/unvoiced consonant with a big/small object respectively. The results suggest that the key to understanding the symbolic values of voicing contrasts in Japanese onomatopoeia is some basic knowledge that is intrinsic to the Japanese language.

Dzyaloshinskii-Moriya interaction in the presence of Rashba and Dresselhaus spin-orbit coupling

NASA Astrophysics Data System (ADS)

Valizadeh, Mohammad M.; Satpathy, S.

2018-03-01

Chiral order in magnetic structures is currently an area of considerable interest and leads to skyrmion structures and domain walls with certain chirality. The chiral structure originates from the Dzyaloshinskii-Moriya interaction caused by broken inversion symmetry and the spin-orbit interaction. In addition to the Rashba or Dresselhaus interactions, there may also exist substantial spin polarization in magnetic thin films. Here, we study the exchange interaction between two localized magnetic moments in the spin-polarized electron gas with both Rashba and Dresselhaus spin-orbit interaction present. Analytical expressions are found in certain limits in addition to what is known in the literature. The stability of the Bloch and Néel domain walls in magnetic thin films is discussed in light of our results.

Improper ferroelectric polarization in a perovskite driven by intersite charge transfer and ordering

NASA Astrophysics Data System (ADS)

Chen, Wei-Tin; Wang, Chin-Wei; Wu, Hung-Cheng; Chou, Fang-Cheng; Yang, Hung-Duen; Simonov, Arkadiy; Senn, M. S.

2018-04-01

It is of great interest to design and make materials in which ferroelectric polarization is coupled to other order parameters such as lattice, magnetic, and electronic instabilities. Such materials will be invaluable in next-generation data storage devices. Recently, remarkable progress has been made in understanding improper ferroelectric coupling mechanisms that arise from lattice and magnetic instabilities. However, although theoretically predicted, a compact lattice coupling between electronic and ferroelectric (polar) instabilities has yet to be realized. Here we report detailed crystallographic studies of a perovskite HgAMn3A'Mn4BO12 that is found to exhibit a polar ground state on account of such couplings that arise from charge and orbital ordering on both the A'- and B-sites, which are themselves driven by a highly unusual MnA '-MnB intersite charge transfer. The inherent coupling of polar, charge, orbital, and hence magnetic degrees of freedom make this a system of great fundamental interest, and demonstrating ferroelectric switching in this and a host of recently reported hybrid improper ferroelectrics remains a substantial challenge.

A review of shock waves around aeroassisted orbital transfer vehicles

NASA Technical Reports Server (NTRS)

Park, C.

1986-01-01

Aeroassisted orbital transfer vehicles (AOTVs) are a proposed type of reusable spacecraft that would be used to transport cargoes from one earth-bound orbit to another. Such vehicles could be based on the proposed space station and used to transport commercial satellites from the space station to geostationary orbits or to polar orbits and return. During a mission, AOTVs would fly through earth's atmosphere, thus generating aerodynamic forces that could be used for decelerating the vehicles or changing their direction. AOTV research findings were concerned with the shock-wave-induced, high-temperature airflows that would be produced around these vehicles during atmospheric flight. Special emphasis was placed on the problems of: (1) the chemical physics of multitemperature, ionizing, nonequilibrium air flows, and (2) the dynamics of the flows in the base region of a blunt body with complex afterbody geometry.

The Mars Climate Orbiter at Launch Complex 17A, CCAS

NASA Technical Reports Server (NTRS)

1998-01-01

At Launch Complex 17A, Cape Canaveral Air Station, the Mars Climate Orbiter is free of the protective canister that surrounded it during the move to the pad. Targeted for liftoff on Dec. 10, 1998, aboard a Boeing Delta II (7425) rocket, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface.

The Mars Climate Orbiter at Launch Complex 17A, CCAS

NASA Technical Reports Server (NTRS)

1998-01-01

At Launch Complex 17A, Cape Canaveral Air Station, workers get ready to remove the last piece of the canister surrounding the Mars Climate Orbiter. Targeted for liftoff on Dec. 10, 1998, aboard a Boeing Delta II (7425) rocket, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface.

A review of shock waves around aeroassisted orbital transfer vehicles

NASA Technical Reports Server (NTRS)

Park, C.

1985-01-01

Aeroassisted orbital transfer vehicles (AOTVs) are a proposed type of reusable spacecraft that would be used to transport cargoes from one Earth-bound orbit to another. Such vehicles could be based on the proposed space station and used to transport commercial satellites from the space station to geostationary orbits or to polar orbits and return. During a mission, AOTVs would fly through Earth's atmosphere, thus generating aerodynamic forces that could be used for decelerating the vehicles or changing their direction. AOTV research findings were concerned with the shock-wave-induced, high-temperature airflows that would be produced around these vehicles during atmospheric flight. Special emphasis was placed on the problems of: (1) the chemical physics of multitemperature, ionizing, nonequilibrium air flows, and (2) the dynamics of the flows in the base region of a blunt body with complex afterbody geometry.

Generation of cylindrically polarized vector vortex beams with digital micromirror device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, Lei; Liu, Weiwei; Wang, Meng

We propose a novel technique to directly transform a linearly polarized Gaussian beam into vector-vortex beams with various spatial patterns. Full high-quality control of amplitude and phase is implemented via a Digital Micro-mirror Device (DMD) binary holography for generating Laguerre-Gaussian, Bessel-Gaussian, and helical Mathieu–Gaussian modes, while a radial polarization converter (S-waveplate) is employed to effectively convert the optical vortices into cylindrically polarized vortex beams. Additionally, the generated vector-vortex beams maintain their polarization symmetry after arbitrary polarization manipulation. Due to the high frame rates of DMD, rapid switching among a series of vector modes carrying different orbital angular momenta paves themore » way for optical microscopy, trapping, and communication.« less

Three-dimensional radar imaging of structures and craters in the Martian polar caps

NASA Astrophysics Data System (ADS)

Putzig, Nathaniel E.; Smith, Isaac B.; Perry, Matthew R.; Foss, Frederick J.; Campbell, Bruce A.; Phillips, Roger J.; Seu, Roberto

2018-07-01

Over the last decade, observations acquired by the Shallow Radar (SHARAD) sounder on individual passes of the Mars Reconnaissance Orbiter have revealed the internal structure of the Martian polar caps and provided new insights into the formation of the icy layers within and their relationship to climate. However, a complete picture of the cap interiors has been hampered by interfering reflections from off-nadir surface features and signal losses associated with sloping structures and scattering. Foss et al. (The Leading Edge 36, 43-57, 2017, https://doi.org/10.1190/tle36010043.1) addressed these limitations by assembling three-dimensional data volumes of SHARAD observations from thousands of orbital passes over each polar region and applying geometric corrections simultaneously. The radar volumes provide unprecedented views of subsurface features, readily imaging structures previously inferred from time-intensive manual analysis of single-orbit data (e.g., trough-bounding surfaces, a buried chasma, and a basal unit in the north, massive carbon-dioxide ice deposits and discontinuous layered sequences in the south). Our new mapping of the carbon-dioxide deposits yields a volume of 16,500 km3, 11% larger than the prior estimate. In addition, the radar volumes newly reveal other structures, including what appear to be buried impact craters with no surface expression. Our first assessment of 21 apparent craters at the base of the north polar layered deposits suggests a Hesperian age for the substrate, consistent with that of the surrounding plains as determined from statistics of surface cratering rates. Planned mapping of similar features throughout both polar volumes may provide new constraints on the age of the icy layered deposits. The radar volumes also provide new topographic data between the highest latitudes observed by the Mars Orbiter Laser Altimeter and those observed by SHARAD. In general, mapping of features in these radar volumes is placing new constraints

The Japanese Mind: Understanding Contemporary Japanese Culture.

ERIC Educational Resources Information Center

Davies, Roger J., Ed.; Ikeno, Osamu, Ed.

This collection of essays offers an overview of contemporary Japanese culture, and can serve as a resource for classes studying Japan. The 28 essays offer an informative, accessible look at the values, attitudes, behavior patterns, and communication styles of modern Japan from the unique perspective of the Japanese people. Filled with examples…

KENNEDY SPACE CENTER, FLA. - In the Space Station Processing Facility, a technician takes readings for pre-assembly measurements on the Japanese Experiment Module (JEM). Developed by the Japan Aerospace Exploration Agency (JAXA), the JEM will enhance the unique research capabilities of the orbiting complex by providing an additional environment for astronauts to conduct science experiments.

NASA Image and Video Library

2003-11-05

KENNEDY SPACE CENTER, FLA. - In the Space Station Processing Facility, a technician takes readings for pre-assembly measurements on the Japanese Experiment Module (JEM). Developed by the Japan Aerospace Exploration Agency (JAXA), the JEM will enhance the unique research capabilities of the orbiting complex by providing an additional environment for astronauts to conduct science experiments.

KENNEDY SPACE CENTER, FLA. - In the Space Station Processing Facility, technicians take readings for pre-assembly measurements on the Japanese Experiment Module (JEM). Developed by the Japan Aerospace Exploration Agency (JAXA), the JEM will enhance the unique research capabilities of the orbiting complex by providing an additional environment for astronauts to conduct science experiments.

NASA Image and Video Library

2003-11-05

KENNEDY SPACE CENTER, FLA. - In the Space Station Processing Facility, technicians take readings for pre-assembly measurements on the Japanese Experiment Module (JEM). Developed by the Japan Aerospace Exploration Agency (JAXA), the JEM will enhance the unique research capabilities of the orbiting complex by providing an additional environment for astronauts to conduct science experiments.

KENNEDY SPACE CENTER, FLA. - In the Space Station Processing Facility, the Japanese Experiment Module (JEM) rests on a workstand during pre-assembly measurement activities. Developed by the Japan Aerospace Exploration Agency (JAXA), the JEM will enhance the unique research capabilities of the orbiting complex by providing an additional environment for astronauts to conduct science experiments.

NASA Image and Video Library

2003-11-05

KENNEDY SPACE CENTER, FLA. - In the Space Station Processing Facility, the Japanese Experiment Module (JEM) rests on a workstand during pre-assembly measurement activities. Developed by the Japan Aerospace Exploration Agency (JAXA), the JEM will enhance the unique research capabilities of the orbiting complex by providing an additional environment for astronauts to conduct science experiments.

The polarized electron beam at ELSA

NASA Astrophysics Data System (ADS)

Hoffmann, M.; Drachenfels, W. V.; Frommberger, F.; Gowin, M.; Helbing, K.; Hillert, W.; Husmann, D.; Keil, J.; Michel, T.; Naumann, J.; Speckner, T.; Zeitler, G.

2001-06-01

The future medium energy physics program at the electron stretcher accelerator ELSA of Bonn University mainly relies on experiments using polarized electrons in the energy range from 1 to 3.2 GeV. To provide a polarized beam with high polarization and sufficient intensity a dedicated source has been developed and set into operation. To prevent depolarization during acceleration in the circular accelerators several depolarizing resonances have to be corrected for. Intrinsic resonances are compensated using two pulsed betatron tune jump quadrupoles. The influence of imperfection resonances is successfully reduced applying a dynamic closed orbit correction in combination with an empirical harmonic correction on the energy ramp. In order to minimize beam depolarization, both types of resonances and the correction techniques have been studied in detail. It turned out that the polarization in ELSA can be conserved up to 2.5 GeV and partially up to 3.2 GeV which is demonstrated by measurements using a Møller polarimeter installed in the external GDH1-beamline. .

Generation of radio vortex beams with designable polarization using anisotropic frequency selective surface

NASA Astrophysics Data System (ADS)

Yang, Jin; Zhang, Cheng; Ma, Hui Feng; Zhao, Jie; Dai, Jun Yan; Yuan, Wei; Yang, Liu Xi; Cheng, Qiang; Cui, Tie Jun

2018-05-01

We propose a strategy to convert a linearly polarized wave from a single point source to an orbital angular momentum (OAM) wave by arbitrary polarization via an anisotropic frequency selective surface (FSS) in the microwave frequency. By tailoring the geometries of FSS elements, reflection-phases in x and y polarizations are engineered and encoded independently, which allows us to design the eventual polarization state of the generated OAM vortex beam by elaborately selecting individual coding sequences for each polarization. Two types of FSSs are designed and experimentally characterized to demonstrate the capability of OAM generation with circular and linear polarizations, respectively, showing excellent performance in a wide bandwidth from 14 to 16 GHz. This method provides opportunities for polarization multiplexing in microwave OAM communication systems.

Orbital design strategy for domestic communication satellite systems.

NASA Technical Reports Server (NTRS)

Ramji, S.; Sawitz, P.

1973-01-01

Review of some of the considerations pertinent to efficient orbit utilization in the design of domestic communications satellite systems. A strategy is developed to efficiently locate a heterogeneous system of satellites within the available arc and provide room for future growth. A practical design is illustrated, using a computer simulation model, for the placement of 25 satellites within 73% of the available arc employing frequency and polarization coordination techniques. A number of widely variable factors that influence satellite spacing are examined. These factors include such critical system elements as telephony and television interference noise limits, frequency plan coordination, polarization plan coordination, ground antenna diameter, signal protection ratio, and satellite station keeping.

Interpreting Radar View near Mars' South Pole, Orbit 1360

NASA Technical Reports Server (NTRS)

2006-01-01

A radargram from the Shallow Subsurface Radar instrument (SHARAD) on NASA's Mars Reconnaissance Orbiter is shown in the upper-right panel and reveals detailed structure in the polar layered deposits of the south pole of Mars.

The sounding radar collected the data presented here during orbit 1360 of the mission, on Nov. 10, 2006.

The horizontal scale in the radargram is distance along the ground track. It can be referenced to the ground track map shown in the lower right. The radar traversed from about 74 degrees to 85 degrees south latitude, or about 650 kilometers (400 miles). The ground track map shows elevation measured by the Mars Orbiter Laser Altimeter on NASA's Mars Global Surveyor orbiter. Green indicates low elevation; reddish-white indicates higher elevation. The traverse proceeds up onto a plateau formed by the layers.

The vertical scale on the radargram is time delay of the radar signals reflected back to Mars Reconnaissance Orbiter from the surface and subsurface. For reference, using an assumed velocity of the radar waves in the subsurface, time is converted to depth below the surface at one place: about 800 meters (2,600 feet) to one of the strongest subsurface reflectors. This reflector marks the base of the polar layered deposits. The color scale varies from black for weak reflections to white for strong reflections.

The middle panel shows mapping of the major subsurface reflectors, some of which can be traced for a distance of 100 kilometers (60 miles) or more. The layering manifests the recent climate history of Mars, recorded by the deposition and removal of ice and dust.

The Shallow Subsurface Radar was provided by the Italian Space Agency (ASI). Its operations are led by the University of Rome and its data are analyzed by a joint U.S.-Italian science team. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science

Viking orbiter views of Mars

NASA Technical Reports Server (NTRS)

Carr, M. H.; Baum, W. A.; Blasius, K. R.; Briggs, G. A.; Cutts, J. A.; Duxbury, T. C.; Greeley, R.; Guest, J.; Masursky, H.; Smith, B. A.

1980-01-01

Images acquired by the Viking orbiters, beginning in 1976 are presented. The pictures represent only a small fraction of the many thousands taken, and were chosen to illustrate the diverse geology of Mars and its atmospheric phenomena. Specific topics discussed include the Viking mission and its objectives, a brief comparison of Earth and Mars, and surface features of Mars including the great equatorial canyons, channels, volcanic and deformational features, and craters. Martian moons, surface processes, polar regions, and the Martian atmosphere are also covered.

Europa Planetary Protection for Juno Jupiter Orbiter

NASA Technical Reports Server (NTRS)

Bernard, Douglas E.; Abelson, Robert D.; Johannesen, Jennie R.; Lam, Try; McAlpine, William J.; Newlin, Laura E.

2010-01-01

NASA's Juno mission launched in 2011 and will explore the Jupiter system starting in 2016. Juno's suite of instruments is designed to investigate the atmosphere, gravitational fields, magnetic fields, and auroral regions. Its low perijove polar orbit will allow it to explore portions of the Jovian environment never before visited. While the Juno mission is not orbiting or flying close to Europa or the other Galilean satellites, planetary protection requirements for avoiding the contamination of Europa have been taken into account in the Juno mission design.The science mission is designed to conclude with a deorbit burn that disposes of the spacecraft in Jupiter's atmosphere. Compliance with planetary protection requirements is verified through a set of analyses including analysis of initial bioburden, analysis of the effect of bioburden reduction due to the space and Jovian radiation environments, probabilistic risk assessment of successful deorbit, Monte-Carlo orbit propagation, and bioburden reduction in the event of impact with an icy body.

Electric field induced spin-polarized current

DOEpatents

Murakami, Shuichi; Nagaosa, Naoto; Zhang, Shoucheng

2006-05-02

A device and a method for generating an electric-field-induced spin current are disclosed. A highly spin-polarized electric current is generated using a semiconductor structure and an applied electric field across the semiconductor structure. The semiconductor structure can be a hole-doped semiconductor having finite or zero bandgap or an undoped semiconductor of zero bandgap. In one embodiment, a device for injecting spin-polarized current into a current output terminal includes a semiconductor structure including first and second electrodes, along a first axis, receiving an applied electric field and a third electrode, along a direction perpendicular to the first axis, providing the spin-polarized current. The semiconductor structure includes a semiconductor material whose spin orbit coupling energy is greater than room temperature (300 Kelvin) times the Boltzmann constant. In one embodiment, the semiconductor structure is a hole-doped semiconductor structure, such as a p-type GaAs semiconductor layer.

SeaWiFS Technical Report Series. Volume 7: Cloud screening for polar orbiting visible and infrared (IR) satellite sensors

NASA Technical Reports Server (NTRS)

Darzi, Michael; Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor)

1992-01-01

Methods for detecting and screening cloud contamination from satellite derived visible and infrared data are reviewed in this document. The methods are applicable to past, present, and future polar orbiting satellite radiometers. Such instruments include the Coastal Zone Color Scanner (CZCS), operational from 1978 through 1986; the Advanced Very High Resolution Radiometer (AVHRR); the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), scheduled for launch in August 1993; and the Moderate Resolution Imaging Spectrometer (IMODIS). Constant threshold methods are the least demanding computationally, and often provide adequate results. An improvement to these methods are the least demanding computationally, and often provide adequate results. An improvement to these methods is to determine the thresholds dynamically by adjusting them according to the areal and temporal distributions of the surrounding pixels. Spatial coherence methods set thresholds based on the expected spatial variability of the data. Other statistically derived methods and various combinations of basic methods are also reviewed. The complexity of the methods is ultimately limited by the computing resources. Finally, some criteria for evaluating cloud screening methods are discussed.

Spin-polarized currents in a two-terminal double quantum ring driven by magnetic fields and Rashba spin-orbit interaction

NASA Astrophysics Data System (ADS)

Dehghan, E.; Khoshnoud, D. Sanavi; Naeimi, A. S.

2018-06-01

Aim of this study is to investigate spin transportation in double quantum ring (DQR). We developed an array of DQR to measure the transmission coefficient and analyze the spin transportation through this system in the presence of Rashba spin-orbit interaction (RSOI) and magnetic flux estimated using S-matrix method. In this article, we compute the spin transport and spin-current characteristics numerically as functions of electron energy, angles between the leads, coupling constant of the leads, RSOI, and magnetic flux. Our results suggest that, for typical values of the magnetic flux (ϕ /ϕ0) and Rashba constant (αR), such system can demonstrates many spintronic properties. It is possible to design a new geometry of DQR by incoming electrons polarization in a way to optimize the system to work as a spin-filtering and spin-inverting nano-device with very high efficiency. The results prove that the spin current will strongly modulate with an increase in the magnetic flux and Rashba constant. Moreover it is shown that, when the lead coupling is weak, the perfect spin-inverter does not occur.

Hydrogen Distribution in the Lunar Polar Regions

NASA Technical Reports Server (NTRS)

Sanin, A. B.; Mitrofanov, I. G.; Litvak, M. L.; Bakhtin, B. N.; Bodnarik, J. G.; Boynton, W. V.; Chin, G.; Evans, L. G.; Harshmann, K.; Fedosov, F.;

Titanium magnetic polarization at the Fe/BaTiO3 interfaces: An effect of ferroelectric polarization discontinuity

NASA Astrophysics Data System (ADS)

Paul, Amitesh; Zheng, Jian-Guo; Aoki, Toshihiro

2017-10-01

The exotic magnetic phenomena and the associated functionalities have attracted extensive scientific interest in fundamental physics and cater to the purpose of the novel material search. In this article, with a combination of the electron energy-loss spectroscopy and the X-ray absorption spectroscopy, we have investigated the interfacial Fe atoms and the induced ferromagnetic moment of Ti atoms in Fe/BaTiO3 (BTO) heterostructures. The samples were grown with two different BTO thicknesses, thus resulting in two different states of distorted oxygen environments or different electrostatic potentials. We demonstrate that in these systems, the electronic and magnetic proximity effects remain coupled as the ferroelectric polar discontinuity is held responsible for an induced transfer of the interface electrons. These electrons migrate from the Fe2+ layers to the Ti(4+)-δ layers with the hybridization via O-2p oxide orbitals into Ti orbitals to screen the ferroelectric polarization. These findings, in charge neutral BaO-TiO2 and FeO layers or nonpolar/nopolar interface, essentially underline the central role of the covalent bonding in defining the spin-electronic properties.

Superconducting quantum spin-Hall systems with giant orbital g-factors

NASA Astrophysics Data System (ADS)

Hankiewicz, Ewelina; Reinthaler, Rolf; Tkachov, Grigory

Topological aspects of superconductivity in quantum spin-Hall systems (QSHSs) such as thin layers of three-dimensional topological insulators (3D Tis) or two-dimensional Tis are in the focus of current research. Here, we describe a novel superconducting quantum spin-Hall effect (quantum spin Hall system in the proximity to the s-wave superconductor and in the orbital in-plane magnetic field), which is protected against elastic backscattering by combined time-reversal and particle-hole symmetry. This effect is characterized by spin-polarized edge states, which can be manipulated in weak magnetic fields due to a giant effective orbital g-factor, allowing the generation of spin currents. The phenomenon provides a novel solution to the outstanding challenge of detecting the spin-polarization of the edge states. Here we propose the detection of the edge polarization in the three-terminal junction using unusual transport properties of superconducting quantum Hall-effect: a non-monotonic excess current and a zero-bias conductance splitting. We thank for the financial support the German Science Foundation (DFG), Grants No HA 5893/4-1 within SPP 1666, HA5893/5-2 within FOR1162 and TK60/1-1 (G.T.), as well the ENB graduate school ``Topological insulators''.

Current-induced spin polarization on metal surfaces probed by spin-polarized positron beam

PubMed Central

Zhang, H. J.; Yamamoto, S.; Fukaya, Y.; Maekawa, M.; Li, H.; Kawasuso, A.; Seki, T.; Saitoh, E.; Takanashi, K.

2014-01-01

Current-induced spin polarization (CISP) on the outermost surfaces of Au, Cu, Pt, Pd, Ta, and W nanoscaled films were studied using a spin-polarized positron beam. The Au and Cu surfaces showed no significant CISP. In contrast, the Pt, Pd, Ta, and W films exhibited large CISP (3~15% per input charge current of 105 A/cm2) and the CISP of Ta and W were opposite to those of Pt and Pd. The sign of the CISP obeys the same rule in spin Hall effect suggesting that the spin-orbit coupling is mainly responsible for the CISP. The magnitude of the CISP is explained by the Rashba-Edelstein mechanism rather than the diffusive spin Hall effect. This settles a controversy, that which of these two mechanisms dominates the large CISP on metal surfaces. PMID:24776781

Mission design concepts for repeat groundtrack orbits and application to the ICESat mission

NASA Astrophysics Data System (ADS)

Pie, Nadege

The primary objective of the NASA sponsored ICESat mission is to study the short and long term changes in the ice mass in the Greenland and Antarctica regions. The satellite was therefore placed into a frozen near-polar near-circular repeat groundtrack to ensure an adequate coverage of the polar regions while keeping the groundtrack periodic and reducing the variations in the orbital elements, and more specifically the semi-major axis of the ICESat orbit. After launch, a contingency plan had to be devised to compensate for a laser that dangerously compromised the lifetime of the ICESat mission. This new plan makes an intensive use of the ICESat subcycles, a characteristic of the repeat groundtrack orbits often over-looked. The subcycle of a repeat groundtrack orbit provide global coverage within a time shorter than the groundtrack repetition period. For a satellite with an off-nadir pointing capacity, the subcycles provide near-repeat tracks which represents added opportunity for altimetry measurement over a specific track. The ICESat subcycles were also used in a very innovative fashion to reposition the satellite within its repeat cycle via orbital maneuvers called phasing maneuver. The necessary theoretical framework is provided for the subcycle analysis and the implementation of phasing maneuvers for any future repeat orbit mission. In the perspective of performing cross-validation of missions like CryoSat using the ICESat off-nadir capacity, a study was conducted to determine the geolocations of crossovers between two different repeat groundtrack Keplerian orbits. The general analytical solution was applied to ICESat vs. several other repeat groundtrack orbit mission, including the future ICESat-II mission. ICESat's repeat groundtrack orbit was designed using a disturbing force model that includes only the Earth geopotential. Though the third body effect from the Sun and the Moon was neglected in the orbit design, it does in fact disrupt the repeatability

Mars Reconnaissance Orbiter: Aerobraking Science Discoveries using the Accelerometer

NASA Astrophysics Data System (ADS)

Keating, Gerald M.; Bougher, S. W.

2006-09-01

The Mars Reconnaissance Orbiter (MRO) spacecraft was launched from the Kennedy Space Center in Florida on August 12, 2005, and arrived at Mars on March 10, 2006. Aerobraking in the martian thermosphere was conducted for nearly 5-months after arrival, enabling the desired MRO mapping orbit to be achieved. The MRO aerobraking phase began in early martian northern Spring (Ls = 36) and continued through early northern Summer (Ls 110), spanning approximately 500 orbits. The MRO periapsis latitude migrated slowly poleward/southward from 70ºS latitude upon aerobraking initiation, passed over the South pole (near Ls = 77), and moved rapidly northward to equatorial latitudes at aerobraking conclusion. Upper atmosphere sampling ( 100-200 km) was achieved on the dayside (LT 1900-2000) before polar crossing, and on the nightside (LT = 0200-0300) thereafter. These seasonal and latitude conditions are similar to a subset of those experienced by MGS during its post hiatus aerobraking Phase 2. Derived mass densities, scale heights, and estimated temperatures are the primary data products generated from each aeropass. The most important discovery of MRO aerobraking concerns the sampling of the thermosphere up to 200 km, far higher than previous MGS and Odyssey Accelerometers have achieved. This sampling contributes to the characterization of the Mars exobase region, which is required to predict and interpret atmospheric escape rates. In addition, thermospheric densities at a constant altitude were observed to decrease toward the southern (winter) pole, as expected from previous MGS experience. No winter polar warming was typically observed near the South pole. Thereafter, densities were measured to increase on the nightside as periapsis moved toward the equator. In general, thermospheric variability was observed to increase in the vicinity of the polar vortex boundary ( 70-80ºS), and decreased again inside the vortex (high southern latitudes). Finally, longitude wave features

The VLBI time delay function for synchronous orbits

NASA Technical Reports Server (NTRS)

Rosenbaum, B.

1972-01-01

The VLBI is a satellite tracking technique that to date was applied largely to the tracking of synchronous orbits. These orbits are favorable for VLBI in that the remote satellite range allows continuous viewing from widely separated stations. The primary observable, geometric time delay is the time difference for signal propagation between satellite and baseline terminals. Extraordinary accuracy in angular position data on the satellite can be obtained by observation from baselines of continental dimensions. In satellite tracking though the common objective is to derive orbital elements. A question arises as to how the baseline vector bears on the accuracy of determining the elements. Our approach to this question is to derive an analytic expression for the time delay function in terms of Kepler elements and station coordinates. The analysis, which is for simplicity based on elliptic motion, shows that the resolution for the inclination of the orbital plane depends on the magnitude of the baseline polar component and the resolution for in-plane elements depends on the magnitude of a projected equatorial baseline component.

The effects of geography on spectrum-orbit utilization

NASA Technical Reports Server (NTRS)

Sawitz, P. H.

1979-01-01

With over forty satellites in geostationary orbit, and many more planned, it is becoming increasingly difficult to find suitable orbit positions for new systems operating at 4 and 6 GHz. Efficient spectrum-orbit utilization can be achieved with frequency-reuse techniques - orthogonal polarization, earth-station antenna discrimination, and satellite antenna discrimination - provided that service-area geography is considered. Service arc - that portion of the orbit which affords useful service to all points in a given area - is a function of the area's climate, terrain, and location as well as its size and shape. Of the three techniques, satellite antenna discrimination is the most sensitive to these factors. According to the BSS (broadcasting-satellite service) antenna reference pattern, the maximum discrimination possible is the on-axis gain, which can be as high as 49 dB for a beamwidth of 0.6 degrees, or as low as 32 dB for a 3.5-degree beamwidth. Unlike the Fixed-Satellite Service (FSS), the BSS will normally have beams that cover no more than one or two time zones.

What Is Business Japanese? Designing a Japanese Course for Business Communication.

ERIC Educational Resources Information Center

Koike, Shohei

Experiences in developing "Business Japanese" courses for the undergraduate major in Language and International Trade at Eastern Michigan University are described. In 1987, six new courses in Japanese were proposed so that Japanese could be offered as a language specialty in the program. Issues considered in defining business Japanese…

A Confirmatory Model for Substance Use Among Japanese American and Part-Japanese American Adolescents

PubMed Central

Williams, John Kino Yamaguchi; Else, 'Iwalani R. N.; Goebert, Deborah A.; Nishimura, Stephanie T.; Hishinuma, Earl S.; Andrade, Naleen N.

2013-01-01

Few studies have examined the effect of ethnicity and cultural identity on substance use among Asian and Pacific Islander adolescents. A cross-sequential study conducted in Hawai'i with 144 Japanese American and part-Japanese American adolescents assessed a model integrating Japanese ethnicity, cultural identity, substance use, major life events, and social support. Japanese American adolescents scored higher on the Japanese Culture Scale and on the Peers’ Social Support than the part-Japanese American adolescents. Significant associations for substance use and impairment included culturally intensified events and Japanese cultural identity- behavior subset. Models had good overall fits and suggested that conflict surrounding cultural identity may contribute to substance use. PMID:23480213

Monitoring volcanic ash cloud top height through simultaneous retrieval of optical data from polar orbiting and geostationary satellites

NASA Astrophysics Data System (ADS)

Zakšek, K.; Hort, M.; Zaletelj, J.; Langmann, B.

2012-09-01

Volcanic ash cloud top height (ACTH) can be monitored on the global level using satellite remote sensing. Here we propose a photogrammetric method based on the parallax between data retrieved from geostationary and polar orbiting satellites to overcome some limitations of the existing methods of ACTH retrieval. SEVIRI HRV band and MODIS band 1 are a good choice because of their high resolution. The procedure works well if the data from both satellites are retrieved nearly simultaneously. MODIS does not retrieve the data at exactly the same time as SEVIRI. To compensate for advection we use two sequential SEVIRI images (one before and one after the MODIS retrieval) and interpolate the cloud position from SEVIRI data to the time of MODIS retrieval. The proposed method was tested for the case of the Eyjafjallajökull eruption in April 2010. The parallax between MODIS and SEVIRI data can reach over 30 km which implies ACTH of more than 12 km in the beginning of the eruption. In the end of April eruption ACTH of 3-4 km is observed. The accuracy of ACTH was estimated to be 0.6 km.

Monitoring volcanic ash cloud top height through simultaneous retrieval of optical data from polar orbiting and geostationary satellites

NASA Astrophysics Data System (ADS)

Zakšek, K.; Hort, M.; Zaletelj, J.; Langmann, B.

2013-03-01

Volcanic ash cloud-top height (ACTH) can be monitored on the global level using satellite remote sensing. Here we propose a photogrammetric method based on the parallax between data retrieved from geostationary and polar orbiting satellites to overcome some limitations of the existing methods of ACTH retrieval. SEVIRI HRV band and MODIS band 1 are a good choice because of their high resolution. The procedure works well if the data from both satellites are retrieved nearly simultaneously. MODIS does not retrieve the data at exactly the same time as SEVIRI. To compensate for advection we use two sequential SEVIRI images (one before and one after the MODIS retrieval) and interpolate the cloud position from SEVIRI data to the time of MODIS retrieval. The proposed method was tested for the case of the Eyjafjallajökull eruption in April 2010. The parallax between MODIS and SEVIRI data can reach 30 km, which implies an ACTH of approximately 12 km at the beginning of the eruption. At the end of April eruption an ACTH of 3-4 km is observed. The accuracy of ACTH was estimated to be 0.6 km.

Automated calibration of the Suomi National Polar-Orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) reflective solar bands

NASA Astrophysics Data System (ADS)

Rausch, Kameron; Houchin, Scott; Cardema, Jason; Moy, Gabriel; Haas, Evan; De Luccia, Frank J.

2013-12-01

National Polar-Orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) reflective bands are currently calibrated via weekly updates to look-up tables (LUTs) utilized by operational ground processing in the Joint Polar Satellite System Interface Data Processing Segment (IDPS). The parameters in these LUTs must be predicted ahead 2 weeks and cannot adequately track the dynamically varying response characteristics of the instrument. As a result, spurious "predict-ahead" calibration errors of the order of 0.1% or greater are routinely introduced into the calibrated reflectances and radiances produced by IDPS in sensor data records (SDRs). Spurious calibration errors of this magnitude adversely impact the quality of downstream environmental data records (EDRs) derived from VIIRS SDRs such as Ocean Color/Chlorophyll and cause increased striping and band-to-band radiometric calibration uncertainty of SDR products. A novel algorithm that fully automates reflective band calibration has been developed for implementation in IDPS in late 2013. Automating the reflective solar band (RSB) calibration is extremely challenging and represents a significant advancement over the manner in which RSB calibration has traditionally been performed in heritage instruments such as the Moderate Resolution Imaging Spectroradiometer. The automated algorithm applies calibration data almost immediately after their acquisition by the instrument from views of space and on-onboard calibration sources, thereby eliminating the predict-ahead errors associated with the current offline calibration process. This new algorithm, when implemented, will significantly improve the quality of VIIRS reflective band SDRs and consequently the quality of EDRs produced from these SDRs.

Arbitrary spin-to-orbital angular momentum conversion of light

NASA Astrophysics Data System (ADS)

Devlin, Robert C.; Ambrosio, Antonio; Rubin, Noah A.; Mueller, J. P. Balthasar; Capasso, Federico

2017-11-01

Optical elements that convert the spin angular momentum (SAM) of light into vortex beams have found applications in classical and quantum optics. These elements—SAM-to-orbital angular momentum (OAM) converters—are based on the geometric phase and only permit the conversion of left- and right-circular polarizations (spin states) into states with opposite OAM. We present a method for converting arbitrary SAM states into total angular momentum states characterized by a superposition of independent OAM. We designed a metasurface that converts left- and right-circular polarizations into states with independent values of OAM and designed another device that performs this operation for elliptically polarized states. These results illustrate a general material-mediated connection between SAM and OAM of light and may find applications in producing complex structured light and in optical communication.

Electron correlation by polarization of interacting densities

NASA Astrophysics Data System (ADS)

Whitten, Jerry L.

2017-02-01

Coulomb interactions that occur in electronic structure calculations are correlated by allowing basis function components of the interacting densities to polarize dynamically, thereby reducing the magnitude of the interaction. Exchange integrals of molecular orbitals are not correlated. The modified Coulomb interactions are used in single-determinant or configuration interaction calculations. The objective is to account for dynamical correlation effects without explicitly introducing higher spherical harmonic functions into the molecular orbital basis. Molecular orbital densities are decomposed into a distribution of spherical components that conserve the charge and each of the interacting components is considered as a two-electron wavefunction embedded in the system acted on by an average field Hamiltonian plus r12-1. A method of avoiding redundancy is described. Applications to atoms, negative ions, and molecules representing different types of bonding and spin states are discussed.

Quasi-Tangency Points on the Orbits of a Small Body and a Planet at the Low-Velocity Encounter

NASA Astrophysics Data System (ADS)

Emel'yanenko, N. Yu.

2018-03-01

We propose a method for selecting a low-velocity encounter of a small body with a planet from the evolution of the orbital elements. Polar orbital coordinates of the quasi-tangency point on the orbit of a small body are determined. Rectangular heliocentric coordinates of the quasi-tangency point on the orbit of a planet are determined. An algorithm to search for low-velocity encounters in the evolution of the orbital elements of small bodies is described. The low-velocity encounter of comet 39P/Oterma with Jupiter is considered as an example.

Controlling entangled spin-orbit coupling of 5 d states with interfacial heterostructure engineering

DOE PAGES

Kim, J. -W.; Choi, Y.; Chun, S. H.; ...

2018-03-26

Here, the combination of strong electron correlations in 3d transition metal oxides and spin-orbit interactions in the 5d counterpart can give rise to exotic electronic and magnetic properties. Here, the nature of emerging phenomena at the interface between SrIrO 3 (SIO) and La 2/3Sr 1/3MnO 3 (LSMO) is presented. Nominally, SIO with strong spin-orbit interaction is metallic and nonmagnetic on the verge of a metal-insulator transition, whereas LSMO is metallic and ferromagnetic with itinerant character and high spin polarization. In the 1:1 LSMO/SIO superlattice, we observe ferromagnetic Mn moments with an insulating behavior, accompanied by antiferromagnetic ordering in SIO. Element-resolvedmore » x-ray magnetic circular dichroism proves that there is a weak net ferromagnetic Ir moment aligned antiparallel to the Mn counterpart. The branching ratio shows the formation of molecular-orbitals between the Mn and Ir layers modifying the Ir 5d electronic configuration through the mixture of t 2g and e g states, resulting in a deviation from J eff = ½. This result demonstrates a pathway to manipulate the spin-orbit entanglement in 5d states with 2-dimensional 3d spin-polarized electrons through heterostructure design.« less

Controlling entangled spin-orbit coupling of 5 d states with interfacial heterostructure engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, J. -W.; Choi, Y.; Chun, S. H.

Here, the combination of strong electron correlations in 3d transition metal oxides and spin-orbit interactions in the 5d counterpart can give rise to exotic electronic and magnetic properties. Here, the nature of emerging phenomena at the interface between SrIrO 3 (SIO) and La 2/3Sr 1/3MnO 3 (LSMO) is presented. Nominally, SIO with strong spin-orbit interaction is metallic and nonmagnetic on the verge of a metal-insulator transition, whereas LSMO is metallic and ferromagnetic with itinerant character and high spin polarization. In the 1:1 LSMO/SIO superlattice, we observe ferromagnetic Mn moments with an insulating behavior, accompanied by antiferromagnetic ordering in SIO. Element-resolvedmore » x-ray magnetic circular dichroism proves that there is a weak net ferromagnetic Ir moment aligned antiparallel to the Mn counterpart. The branching ratio shows the formation of molecular-orbitals between the Mn and Ir layers modifying the Ir 5d electronic configuration through the mixture of t 2g and e g states, resulting in a deviation from J eff = ½. This result demonstrates a pathway to manipulate the spin-orbit entanglement in 5d states with 2-dimensional 3d spin-polarized electrons through heterostructure design.« less

Controlling entangled spin-orbit coupling of 5 d states with interfacial heterostructure engineering

NASA Astrophysics Data System (ADS)

Kim, J.-W.; Choi, Y.; Chun, S. H.; Haskel, D.; Yi, D.; Ramesh, R.; Liu, J.; Ryan, P. J.

2018-03-01

The combination of strong electron correlations in 3 d transition-metal oxides and spin-orbit interactions in the 5 d counterpart can give rise to exotic electronic and magnetic properties. Here, the nature of emerging phenomena at the interface between SrIr O3 (SIO) and L a2 /3S r1 /3Mn O3 (LSMO) is presented. Nominally, SIO with strong spin-orbit interaction is metallic and nonmagnetic on the verge of a metal-insulator transition, whereas LSMO is metallic and ferromagnetic with itinerant character and high spin polarization. In the 1:1 LSMO/SIO superlattice, we observe ferromagnetic Mn moments with an insulating behavior, accompanied by antiferromagnetic ordering in SIO. Element-resolved x-ray magnetic circular dichroism proves that there is a weak net ferromagnetic Ir moment aligned antiparallel to the Mn counterpart. The branching ratio shows the formation of molecular orbitals between the Mn and Ir layers modifying the Ir 5 d electronic configuration through the mixture of t2 g and eg states, resulting in a deviation from Jeff=1 /2 . This result demonstrates a pathway to manipulate the spin-orbit entanglement in 5 d states with two-dimensional 3 d spin-polarized electrons through heterostructure design.

Mapping Vesta: First Results from Dawn's Survey Orbit

NASA Technical Reports Server (NTRS)

Jaumann, R.; Yingst, A. R.; Pieters, C. M.; Russell, C. T.; Raymond, C. A.; Neukum, G.; Mottola, S.; Keller, H. U.; Nathues, A.; Sierks, H.;

Observation of orbital angular momentum transfer between acoustic and optical vortices in optical fiber.

PubMed

Dashti, Pedram Z; Alhassen, Fares; Lee, Henry P

2006-02-03

Acousto-optic interaction in optical fiber is examined from the perspective of copropagating optical and acoustic vortex modes. Calculation of the acousto-optic coupling coefficient between different optical modes leads to independent conservation of spin and orbital angular momentum of the interacting photons and phonons. We show that the orbital angular momentum of the acoustic vortex can be transferred to a circularly polarized fundamental optical mode to form a stable optical vortex in the fiber carrying orbital angular momentum. The technique provides a useful way of generating stable optical vortices in the fiber medium.

Design and construction of the POLAR detector

NASA Astrophysics Data System (ADS)

Produit, N.; Bao, T. W.; Batsch, T.; Bernasconi, T.; Britvich, I.; Cadoux, F.; Cernuda, I.; Chai, J. Y.; Dong, Y. W.; Gauvin, N.; Hajdas, W.; Kole, M.; Kong, M. N.; Kramert, R.; Li, L.; Liu, J. T.; Liu, X.; Marcinkowski, R.; Orsi, S.; Pohl, M.; Rapin, D.; Rybka, D.; Rutczynska, A.; Shi, H. L.; Socha, P.; Sun, J. C.; Song, L. M.; Szabelski, J.; Traseira, I.; Xiao, H. L.; Wang, R. J.; Wen, X.; Wu, B. B.; Zhang, L.; Zhang, L. Y.; Zhang, S. N.; Zhang, Y. J.; Zwolinska, A.

2018-01-01

The POLAR detector is a space based Gamma Ray Burst (GRB) polarimeter with a wide field of view, which covers almost half the sky. The instrument uses Compton scattering of gamma rays on a plastic scintillator hodoscope to measure the polarization of the incoming photons. The instrument has been successfully launched on board of the Chinese space laboratory Tiangong 2 on September 15, 2016. The construction of the instrument components is described in this article. Details are provided on problems encountered during the construction phase and their solutions. Initial performance of the instrument in orbit is as expected from ground tests and Monte Carlo simulation.

Mercury radar imaging: evidence for polar ice.

PubMed

Slade, M A; Butler, B J; Muhleman, D O

1992-10-23

The first unambiguous full-disk radar mapping of Mercury at 3.5-centimeter wavelength, with the Goldstone 70-meter antenna transmitting and 26 antennas of the Very Large Array receiving, has provided evidence for the presence of polar ice. The radar experiments, conducted on 8 and 23 August 1991, were designed to image the half of Mercury not photographed by Mariner 10. The orbital geometry allowed viewing beyond the north pole of Mercury; a highly reflective region was clearly visible on the north pole during both experiments. This polar region has areas in which the circular polarization ratio (pt) was 1.0 to 1.4; values < approximately 0.1 are typical for terrestrial planets. Such high values of have hitherto been observed in radar observations only from icy regions of Mars and icy outer planet satellites.

How Thick is the North Polar Ice Cap on Mars?

NASA Technical Reports Server (NTRS)

2008-01-01

This map shows the thickness of the north polar layered deposits on Mars as measured by the Shallow Radar instrument on NASA's Mars Reconnaissance Orbiter.

The Shallow Radar instrument was provided by the Italian Space Agency. Its operations are led by the University of Rome and its data are analyzed by a joint U.S.-Italian science team. JPL, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington

High-order orbital angular momentum mode generator based on twisted photonic crystal fiber.

PubMed

Fu, Cailing; Liu, Shen; Wang, Ying; Bai, Zhiyong; He, Jun; Liao, Changrui; Zhang, Yan; Zhang, Feng; Yu, Bin; Gao, Shecheng; Li, Zhaohui; Wang, Yiping

2018-04-15

High-order orbital angular momentum (OAM) modes, namely, OAM +5 and OAM +6 , were generated and demonstrated experimentally by twisting a solid-core hexagonal photonic crystal fiber (PCF) during hydrogen-oxygen flame heating. Leaky orbital resonances in the cladding depend strongly on the twist rate and length of the helical PCF. Moreover, the generated high-order OAM mode could be a polarized mode. The secret of the successful observation of high-order modes is that leaky orbital resonances in the twisted PCF cladding have a high coupling efficiency of more than -20  dB.

South Polar Polygons

NASA Technical Reports Server (NTRS)

2003-01-01

MGS MOC Release No. MOC2-473, 4 September 2003

Looking somewhat like the roadmap of a city on Earth, this August 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows patterned ground--a mosaic of polygonal forms--highlighted by seasonal frost in the south polar region near 86.3oS, 310.2oW. Dark surfaces in this springtime view are areas from which cold, carbon dioxide frost has been subliming away. The picture covers an area 3 km (1.9 mi) across and is illuminated by sunlight from the upper left.

Asymmetric molecular-orbital tomography by manipulating electron trajectories

NASA Astrophysics Data System (ADS)

Wang, Bincheng; Zhang, Qingbin; Zhu, Xiaosong; Lan, Pengfei; Rezvani, Seyed Ali; Lu, Peixiang

2017-11-01

We present a scheme for tomographic imaging of asymmetric molecular orbital based on high-order harmonic generation with a two-color orthogonally polarized multicycle laser field. With the two-dimensional manipulation of the electron trajectories, the electrons can recollide with the target molecule from two noncollinear directions, and then the dipole moment generated from the single direction can be obtained to reconstructed the asymmetric molecular orbital. The recollision is independent from the molecular structure and the angular dependence of the ionization rate in the external field. For this reason, this scheme can avoid the negative effects arising from the modification of the angle-dependent ionization rate induced by Stark shift and be applied to various molecules.

Determination of Martian Northern Polar Insolation Levels Using a Geodetic Elevation Model

NASA Technical Reports Server (NTRS)

Arrell, J. R.; Zuber, M. T.

2000-01-01

Solar insolation levels at the Martian polar caps bear significantly on the seasonal and climatic cycling of volatiles on that planet. In the northern hemisphere, the Martian surface slopes downhill from the equator to the pole such that the north polar cap is situated in a 5-km-deep hemispheric-scale depression. This large-scale topographic setting plays an important role in the insolation of the northern polar cap. Elevations measured by the Mars Orbiter Laser Altimeter (MOLA) provide comprehensive, high-accuracy topographical information required to precisely determine polar insolation. In this study, we employ a geodetic elevation model to quantify the north polar insolation and consider implications for seasonal and climatic changes. Additional information is contained in original extended abstract.

The design and evolution of the beta two-stage-to-orbit horizontal takeoff and landing launch system

NASA Technical Reports Server (NTRS)

Burkardt, Leo A.; Norris, Rick B.

1992-01-01

The Beta launch system was originally conceived in 1986 as a horizontal takeoff and landing, fully reusable, two-stage-to-orbit, manned launch vehicle to replace the Shuttle. It was to be capable of delivering a 50,000 lb. payload to low polar orbit. The booster propulsion system consisted of JP fueled turbojets and LH fueled ramjets mounted in pods in an over/under arrangement, and a single LOX/LH fueled SSME rocket. The second stage orbiter, which staged at Mach 8, was powered by an SSME rocket. A major goal was to develop a vehicle design consistent with near term technology. The vehicle design was completed with a GLOW of approximately 2,000,000 lbs. All design goals were met. Since then, interest has shifted to the 10,000 lbs. to low polar orbit payload class. The original Beta was down-sized to meet this payload class. The GLOW of the down-sized vehicle was approximately 1,000,000 lbs. The booster was converted to exclusively air-breathing operation. Because the booster depends on conventional air-breathing propulsion only, the staging Mach number was reduced to 5.5. The orbiter remains an SSME rocket-powered stage.

Generation and dynamics of optical beams with polarization singularities.

PubMed

Cardano, Filippo; Karimi, Ebrahim; Marrucci, Lorenzo; de Lisio, Corrado; Santamato, Enrico

2013-04-08

We present a convenient method to generate vector beams of light having polarization singularities on their axis, via partial spin-to-orbital angular momentum conversion in a suitably patterned liquid crystal cell. The resulting polarization patterns exhibit a C-point on the beam axis and an L-line loop around it, and may have different geometrical structures such as "lemon", "star", and "spiral". Our generation method allows us to control the radius of L-line loop around the central C-point. Moreover, we investigate the free-air propagation of these fields across a Rayleigh range.

Martian North Polar Water-Ice Clouds During the Viking Era

NASA Technical Reports Server (NTRS)

Tamppari, L. K.; Bass, D. S.

2000-01-01

The Viking Orbiters determined that the surface of Mars' northern residual cap consists of water ice. Observed atmospheric water vapor abundances in the equatorial regions have been related to seasonal exchange between reservoirs such as the polar caps, the regolith and between different phases in the atmosphere. Kahn modeled the physical characteristics of ice hazes seen in Viking Orbiter imaging limb data, hypothesizing that ice hazes provide a method for scavenging water vapor from the atmosphere and accumulating it into ice particles. Given that Jakosky found that these particles had sizes such that fallout times were of order one Martian sol, these water-ice hazes provided a method for returning more water to the regolith than that provided by adsorption alone. These hazes could also explain the rapid hemispheric decrease in atmospheric water in late northern summer as well as the increase during the following early spring. A similar comparison of water vapor abundance versus polar cap brightness has been done for the north polar region. They have shown that water vapor decreases steadily between L(sub s) = 100-150 deg while polar cap albedo increases during the same time frame. As a result, they suggested that late summer water-ice deposition onto the ice cap may be the cause of the cap brightening. This deposition could be due to adsorption directly onto the cap surface or to snowfall. Thus, an examination of north polar waterice clouds could lend insight into the fate of the water vapor during this time period. Additional information is contained in the original extended abstract.

Jahn-Teller versus quantum effects in the spin-orbital material LuVO 3

DOE PAGES

Skoulatos, M.; Toth, S.; Roessli, B.; ...

2015-04-13

In this article, we report on combined neutron and resonant x-ray scattering results, identifying the nature of the spin-orbital ground state and magnetic excitations in LuVO 3 as driven by the orbital parameter. In particular, we distinguish between models based on orbital-Peierls dimerization, taken as a signature of quantum effects in orbitals, and Jahn-Teller distortions, in favor of the latter. In order to solve this long-standing puzzle, polarized neutron beams were employed as a prerequisite in order to solve details of the magnetic structure, which allowed quantitative intensity analysis of extended magnetic-excitation data sets. The results of this detailed studymore » enabled us to draw definite conclusions about the classical versus quantum behavior of orbitals in this system and to discard the previous claims about quantum effects dominating the orbital physics of LuVO 3 and similar systems.« less

Estimating Terra MODIS Polarization Effect Using Ocean Data

NASA Technical Reports Server (NTRS)

Wald, Andrew E.; Brinkmann, Jake; Wu, Aisheng; Xiong, Jack

2016-01-01

Terra MODIS has been known since pre-launch to have polarization sensitivity, particularly in shortest-wavelength bands 8 and 9. On-orbit reflectance trending of pseudo-invariant sites show a variation in reflectance as a function of band and scan mirror angle of incidence consistent with time-dependent polarization effects from the rotating double-sided scan mirror. The MODIS Characterization Support Team [MCST] estimates the Mueller matrix trending from this variation as observed from a single desert site, but this effect is not included in Collection 6 [C6] calibration. Here we extend the MCSTs current polarization sensitivity monitoring to two ocean sites distributed over latitude to helpestimate the uncertainties in the derived Mueller matrix. The Mueller matrix elements derived for polarization-sensitive Band 8 for a given site are found to be fairly insensitive to surface brdf modeling. The site-to-site variation is a measure of the uncertainty in the Mueller estimation.Results for band 8 show that the polarization correction reduces mirror-side striping by up to 50% and reduces the instrument polarization effect on reflectance time series of an ocean target.

Summer South Polar Cap

NASA Technical Reports Server (NTRS)

2004-01-01

13 April 2004 The martian south polar residual ice cap is composed mainly of frozen carbon dioxide. Each summer, a little bit of this carbon dioxide sublimes away. Pits grow larger, and mesas get smaller, as this process continues from year to year. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a view of a small portion of the south polar cap as it appeared in mid-summer in January 2004. The dark areas may be places where the frozen carbon dioxide contains impurities, such as dust, or places where sublimation of ice has roughened the surface so that it appears darker because of small shadows cast by irregularities in the roughened surface. The image is located near 86.9oS, 7.6oW. The image covers an area about 3 km (1.9 mi) across. Sunlight illuminates the scene from the upper left.

Design of an unmanned Martian polar exploration system

NASA Technical Reports Server (NTRS)

Baldwin, Curt; Chitwood, Denny; Demann, Brian; Ducheny, Jordan; Hampton, Richard; Kuhns, Jesse; Mercer, Amy; Newman, Shawn; Patrick, Chris; Polakowski, Tony

1994-01-01

The design of an unmanned Martian polar exploration system is presented. The system elements include subsystems for transportation of material from earth to Mars, study of the Martian north pole, power generation, and communications. Early next century, three Atlas 2AS launch vehicles will be used to insert three Earth-Mars transfer vehicles, or buses, into a low-energy transfer orbit. Capture at Mars will be accomplished by aerobraking into a circular orbit. Each bus contains four landers and a communications satellite. Six of the twelve total landers will be deployed at 60 deg intervals along 80 deg N, and the remaining six landers at 5 deg intervals along 30 deg E from 65 deg N to 90 deg N by a combination of retrorockets and parachutes. The three communications satellites will be deployed at altitudes of 500 km in circular polar orbits that are 120 deg out of phase. These placements maximize the polar coverage of the science and communications subsystems. Each lander contains scientific equipment, two microrovers, power supplies, communications equipment, and a science computer. The lander scientific equipment includes a microweather station, seismometer, thermal probe, x-ray spectrometer, camera, and sounding rockets. One rover, designed for short-range (less than 2 km) excursions from the lander, includes a mass spectrometer for mineral analysis, an auger/borescope system for depth profiling, a deployable thermal probe, and charge coupled device cameras for terrain visualization/navigation. The second rover, designed for longer-range (2-5 km) excursions from the lander, includes radar sounding/mapping equipment, a seismometer, and laser ranging devices. Power for all subsystems is supplied by a combination of solar cells, Ni-H batteries, and radioisotope thermoelectric generators. Communications are sequenced from rovers, sounding rockets, and remote sensors to the lander, then to the satellites, through the Deep Space Network to and from earth.

Homogamy and Intermarriage of Japanese and Japanese Americans with Whites Surrounding World War II

ERIC Educational Resources Information Center

Ono, Hiromi; Berg, Justin

2010-01-01

Although some sociologists have suggested that Japanese Americans quickly assimilated into mainstream America, scholars of Japanese America have highlighted the heightened exclusion that the group experienced. This study tracked historical shifts in the exclusion level of Japanese and Japanese Americans in the United States surrounding World War…

Interfacial B-site atomic configuration in polar (111) and non-polar (001) SrIrO3/SrTiO3 heterostructures

NASA Astrophysics Data System (ADS)

Anderson, T. J.; Zhou, H.; Xie, L.; Podkaminer, J. P.; Patzner, J. J.; Ryu, S.; Pan, X. Q.; Eom, C. B.

2017-09-01

The precise control of interfacial atomic arrangement in ABO3 perovskite heterostructures is paramount, particularly in cases where the subsequent electronic properties of the material exhibit geometrical preferences along polar crystallographic directions that feature inevitably complex surface reconstructions. Here, we present the B-site interfacial structure in polar (111) and non-polar (001) SrIrO3/SrTiO3 interfaces. The heterostructures were examined using scanning transmission electron microscopy and synchrotron-based coherent Bragg rod analysis. Our results reveal the preference of B-site intermixing across the (111) interface due to the polarity-compensated SrTiO3 substrate surface prior to growth. By comparison, the intermixing at the non-polar (001) interface is negligible. This finding suggests that the intermixing may be necessary to mitigate epitaxy along heavily reconstructed and non-stoichiometric (111) perovskite surfaces. Furthermore, this preferential B-site configuration could allow the geometric design of the interfacial perovskite structure and chemistry to selectively engineer the correlated electronic states of the B-site d-orbital.

The solar polar radio telescope mission: an overview

NASA Astrophysics Data System (ADS)

Sun, Weiying; Zhang, Cheng; Zheng, Jianhua; Wu, Ji; Wang, C. B.; Wang, Chi; Wang, S.

: The solar polar orbit telescope (SPORT) is a mission proposed for the observation of ICMEs. The main payload is a synthetic aperture radiometer working at meter wave band taking images of the high density interplanetary plasma clouds formed by ICMEs and follows the propagation if it from the surface of the Sun all the way to as far as 0.5 AU or even further. With such a capability of observation, also the SPORT will study transient high energy phenomenon, the magnetic topology, temperature and density as well as velocity of the solar wind in the inner interplanetary heliosphere. In the practical part, the mission is also very useful for space weather forecast in advance of the geo-storm events. Other instruments are also selected to be on board of the solar polar orbit mission for in-situ measurement, such as fluxgate magnetometer, solar wind ion detector and high energy particle detectors. In this paper, we describe the scientific objective, basic principles and feasibility of the interferometric radiometer, general mission design and the status of the SPORT mission.

KENNEDY SPACE CENTER, FLA. - The Japanese Experiment Module (JEM) is moved on its workstand in the Space Station Processing Facility. The JEM will undergo pre-assembly measurements. Developed by the Japan Aerospace Exploration Agency (JAXA), the JEM will enhance the unique research capabilities of the orbiting complex by providing an additional environment for astronauts to conduct science experiments.

NASA Image and Video Library

2003-11-05

KENNEDY SPACE CENTER, FLA. - The Japanese Experiment Module (JEM) is moved on its workstand in the Space Station Processing Facility. The JEM will undergo pre-assembly measurements. Developed by the Japan Aerospace Exploration Agency (JAXA), the JEM will enhance the unique research capabilities of the orbiting complex by providing an additional environment for astronauts to conduct science experiments.

Realization of optimized quantum controlled-logic gate based on the orbital angular momentum of light.

PubMed

Zeng, Qiang; Li, Tao; Song, Xinbing; Zhang, Xiangdong

2016-04-18

We propose and experimentally demonstrate an optimized setup to implement quantum controlled-NOT operation using polarization and orbital angular momentum qubits. This device is more adaptive to inputs with various polarizations, and can work both in classical and quantum single-photon regime. The logic operations performed by such a setup not only possess high stability and polarization-free character, they can also be easily extended to deal with multi-qubit input states. As an example, the experimental implementation of generalized three-qubit Toffoli gate has been presented.

Precise interferometric tracking of the DSCS II geosynchronous orbiter

NASA Astrophysics Data System (ADS)

Border, J. S.; Donivan, F. F., Jr.; Shiomi, T.; Kawano, N.

1986-01-01

A demonstration of the precise tracking of a geosynchronous orbiter by radio metric techniques based on very-long-baseline interferometry (VLBI) has been jointly conducted by the Jet Propulsion Laboratory and Japan's Radio Research Laboratory. Simultaneous observations of a U.S. Air Force communications satellite from tracking stations in California, Australia, and Japan have determined the satellite's position with an accuracy of a few meters. Accuracy claims are based on formal statistics, which include the effects of errors in non-estimated parameters and which are supported by a chi-squared of less than one, and on the consistency of orbit solutions from disjoint data sets. A study made to assess the impact of shorter baselines and reduced data noise concludes that with a properly designed system, similar accuracy could be obtained for either a satellite viewed from stations located within the continental U.S. or for a satellite viewed from stations within Japanese territory.

Polarized single crystal neutron diffraction study of the zero-magnetization ferromagnet Sm1 -xGdxAl2 (x =0.024 )

NASA Astrophysics Data System (ADS)

Chatterji, T.; Stunault, A.; Brown, P. J.

2018-02-01

We have determined the temperature evolution of the spin and orbital moments in the zero-magnetization ferromagnet Sm1 -xGdxAl2 (x = 0.024) by combining polarized and unpolarized single crystal neutron diffraction data. The sensitivity of the polarized neutron technique has allowed the moment values to be determined with a precision of ≈0.1 μB . Our results clearly demonstrate that, when magnetized by a field of 8 T, the spin and orbital moments in Sm1 -xGdxAl2 are oppositely directed, so that the net magnetization is very small. Below 60 K the contributions from spin and orbital motions are both about 2 μB , with that due to orbital motion being slightly larger than that due to spin. Between 60 and 65 K the contributions of each to the magnetization fall rapidly and change sign at Tcomp ≈67 K , above which the aligned moments recover but with the orbital magnetization still slightly higher than the spin one. These results imply that above Tcomp the small resultant magnetization of the Sm3 + ion is oppositely directed to the magnetizing field. It is suggested that this anomaly is due to polarization of conduction electron spin associated with the doping Gd3 + ions.

Neuronal activity during a cued strategy task: Comparison of dorsolateral, orbital and polar prefrontal cortex

PubMed Central

Tsujimoto, Satoshi; Genovesio, Aldo; Wise, Steven P.

2012-01-01

We compared neuronal activity in the dorsolateral (PFdl), orbital (PFo) and polar (PFp) prefrontal cortex as monkeys performed three tasks. In two tasks, a cue instructed one of two strategies: stay with the previous response or shift to the alternative. Visual stimuli served as cues in one of these tasks; in the other, fluid rewards did so. In the third task, visuospatial cues instructed each response. A delay period followed each cue. As reported previously, PFdl encoded strategies (stay or shift) and responses (left or right) during the cue and delay periods, while PFo encoded strategies and PFp encoded neither strategies nor responses; during the feedback period, all three areas encoded responses, not strategies. Four novel findings emerged from the present analysis. (1) The strategy encoded by PFdl and PFo cells during the cue and delay periods was modality specific. (2) The response encoded by PFdl cells was task- and modality specific during the cue period, but during the delay and feedback periods it became task- and modality general. (3) Although some PFdl and PFo cells responded to or anticipated rewards, we could rule out reward effects for most strategy-and response-related activity. (4) Immediately before feedback, only PFp signaled responses that were correct according to the cued strategy; after feedback, only PFo signaled the response that had been made, whether correct or incorrect. These signals support a role in generating responses by PFdl, assigning outcomes to choices by PFo, and assigning outcomes to cognitive processes by PFp. PMID:22875935

NMR in an electric field: A bulk probe of the hidden spin and orbital polarizations

NASA Astrophysics Data System (ADS)

Ramírez-Ruiz, Jorge; Boutin, Samuel; Garate, Ion

2017-12-01

Recent theoretical work has established the presence of hidden spin and orbital textures in nonmagnetic materials with inversion symmetry. Here, we propose that these textures can be detected by nuclear magnetic resonance (NMR) measurements carried out in the presence of an electric field. In crystals with hidden polarizations, a uniform electric field produces a staggered magnetic field that points to opposite directions at atomic sites related by spatial inversion. As a result, the NMR resonance peak corresponding to inversion partner nuclei is split into two peaks. The magnitude of the splitting is proportional to the electric field and depends on the orientation of the electric field with respect to the crystallographic axes and the external magnetic field. As a case study, we present a theory of electric-field-induced splitting of NMR peaks for 77Se,125Te, and 209Bi in Bi2Se3 and Bi2Te3 . In conducting samples with current densities of ≃106A/cm 2 , the splitting for Bi can reach 100 kHz , which is comparable to or larger than the intrinsic width of the NMR lines. In order to observe the effect experimentally, the peak splitting must also exceed the linewidth produced by the Oersted field. In Bi2Se3 , this requires narrow wires of radius ≲1 μ m . We also discuss other potentially more promising candidate materials, such as SrRuO3 and BaIr2Ge2 , whose crystal symmetry enables strategies to suppress the linewidth produced by the Oersted field.

The Distribution of the Orbits in the Geminid Meteoroid Stream Based on the Dispersion of their Periods

NASA Technical Reports Server (NTRS)

Hajdukova, M., Jr.

2011-01-01

Geminid meteoroids, selected from a large set of precisely-reduced meteor orbits from the photographic and radar catalogues of the IAU Meteor Data Center (Lindblad et al. 2003), and from the Japanese TV meteor shower catalogue (SonotaCo 2010), have been analyzed with the aim of determining the orbits distribution in the stream, based on the dispersion of their periods P . The values of the reciprocal semi-major axis 1/a in the stream showed small errors in the velocity measurements. Thus, it was statistically possible to also determine the relation between the observed and the real dispersion of the Geminids.

Precise science orbits for the Swarm satellite constellation

NASA Astrophysics Data System (ADS)

van den IJssel, Jose; Encarnação, João; Doornbos, Eelco; Visser, Pieter

2015-09-01

The European Space Agency (ESA) Swarm mission was launched on 22 November 2013 to study the dynamics of the Earth's magnetic field and its interaction with the Earth system. The mission consists of three identical satellites, flying in carefully selected near polar orbits. Two satellites fly almost side-by-side at an initial altitude of about 480 km, and will descend due to drag to around 300 km during the mission lifetime. The third satellite was placed in a higher orbit of about 530 km altitude, and therefore descends much more slowly. To geolocate the Swarm observations, each satellite is equipped with an 8-channel, dual-frequency GPS receiver for Precise Orbit Determination (POD). Onboard laser retroreflectors provide the opportunity to validate the orbits computed from the GPS observations using Satellite Laser Ranging (SLR) data. Precise Science Orbits (PSOs) for the Swarm satellites are computed by the Faculty of Aerospace Engineering at Delft University of Technology in the framework of the Swarm Satellite Constellation Application and Research Facility (SCARF). The PSO product consists of both a reduced-dynamic and a kinematic orbit solution. After a short description of the Swarm GPS data characteristics, the adopted POD strategy for both orbit types is explained and first PSO results from more than one year of Swarm GPS data are presented. Independent SLR validation shows that the reduced-dynamic Swarm PSOs have an accuracy of better than 2 cm, while the kinematic orbits have a slightly reduced accuracy of about 4-5 cm. Orbit comparisons indicate that the consistency between the reduced-dynamic and kinematic Swarm PSO for most parts of the Earth is at the 4-5 cm level. Close to the geomagnetic poles and along the geomagnetic equator, however, the kinematic orbits show larger errors, which are probably due to ionospheric scintillations that affect the Swarm GPS receivers over these areas.

Polarization-dependent X-ray photoemission spectroscopy for High-Tc cuprate superconductors

NASA Astrophysics Data System (ADS)

Yamagami, Kohei; Kanai, Yuina; Naimen, Sho; Fujiwara, Hidenori; Kiss, Takayuki; Tanaka, Arata; Higashiya, Atsushi; Imada, Shin; Kadono, Toshiharu; Tamasaku, Kenji; Muro, Takayuki; Yabashi, Makina; Ishikawa, Tetsuya; Eisaki, Hiroshi; Miyasaka, Shigeki; Tajima, Setsuko; Sekiyama, Akira

2018-05-01

We have performed photon energy (hν) and linear polarization dependent X-ray photoemission for optimal doped Pb-Bi2Sr2CaCu2O8+δ (Bi2212) to investigate the ground Cu 3d orbital symmetry. We identified that the bulk Cu 3d components in valence-band spectra develop with decreasing hν from 7900 eV to 460 eV. Moreover, the photoelectron intensity ratio of the valence-band spectra measured at hν = 460 eV has shown that the Cu 3dx2-y2 orbital contributions are dominant near the Fermi level (EF). Meanwhile, we revealed that the bulk Cu 2p3/2 core-level spectra without the Bi 4s component is detected at hν = 1550 eV compared with hν and linear-polarization-dependent spectra.

Mars Global Surveyor: 7 Years in Orbit!

NASA Technical Reports Server (NTRS)

2004-01-01

12 September 2004 Today, 12 September 2004, the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) team celebrates 7 Earth years orbiting Mars. MGS first reached the red planet and performed its critical orbit insertion burn on 12 September 1997. Over the past 7 years, MOC has returned over 170,000 images; its narrow angle camera has covered about 4.5% of the surface, and its wide angle cameras have viewed 100% of the planet nearly everyday.

At this time, MOC is not acquiring data because Mars is on the other side of the Sun relative to Earth. This period, known as Solar Conjunction, occurs about once every 26 months. During Solar Conjunction, no radio communications from spacecraft that are orbiting or have landed on Mars can be received. MOC was turned off on 7 September and is expected to resume operations on 25 September 2004, when Mars re-emerges from behind the Sun.

The rotating color image of Mars shown here was compiled from MOC red and blue wide angle daily global images acquired exactly 1 Mars year ago on 26 October 2002 (Ls 86.4o). In other words, Mars today (12 September 2004) should look about the same as the view provided here. Presently, Mars is in very late northern spring, and the north polar cap has retreated almost to its summer configuration. Water ice clouds form each afternoon at this time of year over the large volcanoes in the Tharsis and Elysium regions. A discontinuous belt of clouds forms over the martian equator; it is most prominent north of the Valles Marineris trough system. In the southern hemisphere, it is late autumn and the giant Hellas Basin floor is nearly white with seasonal frost cover. The south polar cap is not visible, it is enveloped in seasonal darkness. The northern summer and southern winter seasons will begin on 20 September 2004.

Arbitrary spin-to-orbital angular momentum conversion of light.

PubMed

Devlin, Robert C; Ambrosio, Antonio; Rubin, Noah A; Mueller, J P Balthasar; Capasso, Federico

2017-11-17

Optical elements that convert the spin angular momentum (SAM) of light into vortex beams have found applications in classical and quantum optics. These elements-SAM-to-orbital angular momentum (OAM) converters-are based on the geometric phase and only permit the conversion of left- and right-circular polarizations (spin states) into states with opposite OAM. We present a method for converting arbitrary SAM states into total angular momentum states characterized by a superposition of independent OAM. We designed a metasurface that converts left- and right-circular polarizations into states with independent values of OAM and designed another device that performs this operation for elliptically polarized states. These results illustrate a general material-mediated connection between SAM and OAM of light and may find applications in producing complex structured light and in optical communication. Copyright © 2017, American Association for the Advancement of Science.

Circularly polarized zero-phonon transitions of vacancies in diamond at high magnetic fields

NASA Astrophysics Data System (ADS)

Braukmann, D.; Glaser, E. R.; Kennedy, T. A.; Bayer, M.; Debus, J.

2018-05-01

We study the circularly polarized photoluminescence of negatively charged (NV-) and neutral (NV0) nitrogen-vacancy ensembles and neutral vacancies (V0) in diamond crystals exposed to magnetic fields of up to 10 T. We determine the orbital and spin Zeeman splitting as well as the energetic ordering of their ground and first-excited states. The spin-triplet and -singlet states of the NV- are described by an orbital Zeeman splitting of about 9 μ eV /T , which corresponds to a positive orbital g -factor of gL=0.164 under application of the magnetic field along the (001) and (111) crystallographic directions, respectively. The zero-phonon line (ZPL) of the NV- singlet is defined as a transition from the 1E' states, which are split by gLμBB , to the 1A1 state. The energies of the zero-phonon triplet transitions show a quadratic dependence on intermediate magnetic field strengths, which we attribute to a mixing of excited states with nonzero orbital angular momentum. Moreover, we identify slightly different spin Zeeman splittings in the ground (gs) and excited (es) triplet states, which can be expressed by a deviation between their spin g -factors: gS ,es=gS ,gs+Δ g with values of Δ g =0.014 and 0.029 in the (001) and (111) geometries, respectively. The degree of circular polarization of the NV- ZPLs depends significantly on the temperature, which is explained by an efficient spin-orbit coupling of the excited states mediated through acoustic phonons. We further demonstrate that the sign of the circular polarization degree is switched under rotation of the diamond crystal. A weak Zeeman splitting similar to Δ g μBB measured for the NV- ZPLs is also obtained for the NV0 zero-phonon lines, from which we conclude that the ground state is composed of two optically active states with compensated orbital contributions and opposite spin-1/2 momentum projections. The zero-phonon lines of the V0 show Zeeman splittings and degrees of the circular polarization with opposite

Capsize of polarization in dilute photonic crystals.

PubMed

Gevorkian, Zhyrair; Hakhoumian, Arsen; Gasparian, Vladimir; Cuevas, Emilio

2017-11-29

We investigate, experimentally and theoretically, polarization rotation effects in dilute photonic crystals with transverse permittivity inhomogeneity perpendicular to the traveling direction of waves. A capsize, namely a drastic change of polarization to the perpendicular direction is observed in a one-dimensional photonic crystal in the frequency range 10 ÷ 140 GHz. To gain more insights into the rotational mechanism, we have developed a theoretical model of dilute photonic crystal, based on Maxwell's equations with a spatially dependent two dimensional inhomogeneous dielectric permittivity. We show that the polarization's rotation can be explained by an optical splitting parameter appearing naturally in Maxwell's equations for magnetic or electric fields components. This parameter is an optical analogous of Rashba like spin-orbit interaction parameter present in quantum waves, introduces a correction to the band structure of the two-dimensional Bloch states, creates the dynamical phase shift between the waves propagating in the orthogonal directions and finally leads to capsizing of the initial polarization. Excellent agreement between theory and experiment is found.

Nanoscale imaging of magnetization reversal driven by spin-orbit torque

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gilbert, Ian; Chen, P. J.; Gopman, Daniel B.

We use scanning electron microscopy with polarization analysis to image deterministic, spin-orbit torque-driven magnetization reversal of in-plane magnetized CoFeB rectangles in zero applied magnetic field. The spin-orbit torque is generated by running a current through heavy metal microstrips, either Pt or Ta, upon which the CoFeB rectangles are deposited. We image the CoFeB magnetization before and after a current pulse to see the effect of spin-orbit torque on the magnetic nanostructure. The observed changes in magnetic structure can be complex, deviating significantly from a simple macrospin approximation, especially in larger elements. Overall, however, the directions of the magnetization reversal inmore » the Pt and Ta devices are opposite, consistent with the opposite signs of the spin Hall angles of these materials. Lastly, our results elucidate the effects of current density, geometry, and magnetic domain structure on magnetization switching driven by spin-orbit torque.« less

Nanoscale imaging of magnetization reversal driven by spin-orbit torque

DOE PAGES

Gilbert, Ian; Chen, P. J.; Gopman, Daniel B.; ...

2016-09-23

We use scanning electron microscopy with polarization analysis to image deterministic, spin-orbit torque-driven magnetization reversal of in-plane magnetized CoFeB rectangles in zero applied magnetic field. The spin-orbit torque is generated by running a current through heavy metal microstrips, either Pt or Ta, upon which the CoFeB rectangles are deposited. We image the CoFeB magnetization before and after a current pulse to see the effect of spin-orbit torque on the magnetic nanostructure. The observed changes in magnetic structure can be complex, deviating significantly from a simple macrospin approximation, especially in larger elements. Overall, however, the directions of the magnetization reversal inmore » the Pt and Ta devices are opposite, consistent with the opposite signs of the spin Hall angles of these materials. Lastly, our results elucidate the effects of current density, geometry, and magnetic domain structure on magnetization switching driven by spin-orbit torque.« less

Workshop on the Polar Regions of Mars: Geology, Glaciology, and Climate History, part 1

NASA Technical Reports Server (NTRS)

Clifford, S. M. (Editor); Howard, A. D. (Editor); Paterson, W. S. B. (Editor)

1992-01-01

Papers and abstract of papers presented at the workshop are presented. Some representative titles are as follows: Glaciation in Elysium; Orbital, rotational, and climatic interactions; Water on Mars; Rheology of water-silicate mixtures at low temperatures; Evolution of the Martian atmosphere (the role of polar caps); Is CO2 ice permanent; Dust transport into Martian polar latitudes; Mars observer radio science (MORS) observations in polar regions; and Wind transport near the poles of Mars (timescales of changes in deposition and erosion).

The Anglo-Japanese Alliance and Japanese Expansionism 1902-1923.

DTIC Science & Technology

1992-06-05

Alienation 1919-1952. London: Cambridge University Press. 1982. • The Oriains of the Russo-Japanese War. London: Longman Group Limited. 1985. Nitobe ... Inazo . Bushido - The Soul of Japan. Tokyo: Tuttle. 1981. Okamoto, Shumpei. The Japan Oliaarchv and the Russo-Japanese War. New York: Columbia

Density of Mars' south polar layered deposits.

PubMed

Zuber, Maria T; Phillips, Roger J; Andrews-Hanna, Jeffrey C; Asmar, Sami W; Konopliv, Alexander S; Lemoine, Frank G; Plaut, Jeffrey J; Smith, David E; Smrekar, Suzanne E

2007-09-21

Both poles of Mars are hidden beneath caps of layered ice. We calculated the density of the south polar layered deposits by combining the gravity field obtained from initial results of radio tracking of the Mars Reconnaissance Orbiter with existing surface topography from the Mars Orbiter Laser Altimeter on the Mars Global Surveyor spacecraft and basal topography from the Mars Advanced Radar for Subsurface and Ionospheric Sounding on the Mars Express spacecraft. The results indicate a best-fit density of 1220 kilograms per cubic meter, which is consistent with water ice that has approximately 15% admixed dust. The results demonstrate that the deposits are probably composed of relatively clean water ice and also refine the martian surface-water inventory.

Assigning Polarity to Causal Information in Financial Articles on Business Performance of Companies

NASA Astrophysics Data System (ADS)

Sakai, Hiroyuki; Masuyama, Shigeru

We propose a method of assigning polarity to causal information extracted from Japanese financial articles concerning business performance of companies. Our method assigns polarity (positive or negative) to causal information in accordance with business performance, e.g. “zidousya no uriage ga koutyou: (Sales of cars are good)” (The polarity positive is assigned in this example). We may use causal expressions assigned polarity by our method, e.g., to analyze content of articles concerning business performance circumstantially. First, our method classifies articles concerning business performance into positive articles and negative articles. Using them, our method assigns polarity (positive or negative) to causal information extracted from the set of articles concerning business performance. Although our method needs training dataset for classifying articles concerning business performance into positive and negative ones, our method does not need a training dataset for assigning polarity to causal information. Hence, even if causal information not appearing in the training dataset for classifying articles concerning business performance into positive and negative ones exist, our method is able to assign it polarity by using statistical information of this classified sets of articles. We evaluated our method and confirmed that it attained 74.4% precision and 50.4% recall of assigning polarity positive, and 76.8% precision and 61.5% recall of assigning polarity negative, respectively.

Orbital Ordering Transition in La_4Ru_2O_10 probed by O K-edge X-ray Absorption

NASA Astrophysics Data System (ADS)

Denlinger, J. D.; Rossnagel, Kai; Allen, J. W.; Khalifah, P.; Mandrus, D.; Cava, R. J.

2004-03-01

The layered ruthenate compound La_4Ru_2O_10 undergoes a first order monoclinic-to-triclinic structural phase transition at 160 K. An accompanying loss of the Ru local moment gives evidence for a full orbital ordering transition in which the Ru d_yz orbitals become completely unoccupied in the low temperature phase.(P. Khalifah et al.), Science 297, 2237 (2002). Via hybridization of Ru t_2g and O 2p orbitals this temperature-dependent Ru orbital ordering can be indirectly probed using polarized O K-edge x-ray absorption spectroscopy (XAS). O 1s core-level energy shifts allow O site-specific separation of Ru t_2g hybridizations. Identification of O sites is accomplished using polarized XAS angular dependence as well as by O 2p valence PDOS obtained from site-selective soft x-ray emission. Distinct XAS energy and intensity changes are observed upon cooling through the phase transition and are rationalized within the framework of the complete orbital ordering scenario. Supported by the U.S. NSF at U. Mich. (DMR-03-02825) and by the DOE at the Advanced Light Source (DE-AC03-76SF00098).

A Conceptual Model of Cultural Predictors of Anxiety among Japanese American and Part-Japanese American Adolescents.

ERIC Educational Resources Information Center

Williams, John Kino Yamaguchi; Goebert, Deborah; Hishinuma, Earl; Miyamoto, Robin; Anzai, Neal; Izutsu, Satoru; Yanagida, Evelyn; Nishimura, Stephanie; Andrade, Naleen; Baker, F. M.

2002-01-01

Develops and assesses a model integrating Japanese ethnicity, cultural identity, and anxiety in Japanese American and part-Japanese American high school seniors. Japanese American adolescents scored higher on the scale and reported fewer anxiety symptoms than part-Japanese American adolescents. The model had a good overall fit, suggesting that…

Logistics support of the Japanese Experiment Module by the H-II rocket

NASA Astrophysics Data System (ADS)

Shibato, Yoji; Eto, Takao; Fukushima, Yukio; Takatsuka, Hitoshi

1988-10-01

This paper describes salient design features of the Japanese Experiment Module (JEM), which will be attached to the Space Station. Special attention is given to the logistic support of the JEM (which is planned to become operational in 1990s) by the HOPE orbiter, which will be used for the resupply and the retrieval of the JEM, and the H-II rocket, which will be used to launch the HOPE. The concepts of HOPE and the H-II rocket are discussed together with the estimated logistics requirements of this system. Configuration diagrams are included.

Theory of Covalent Adsorbate Frontier Orbital Energies on Functionalized Light-Absorbing Semiconductor Surfaces.

PubMed

Yu, Min; Doak, Peter; Tamblyn, Isaac; Neaton, Jeffrey B

2013-05-16

Functional hybrid interfaces between organic molecules and semiconductors are central to many emerging information and solar energy conversion technologies. Here we demonstrate a general, empirical parameter-free approach for computing and understanding frontier orbital energies - or redox levels - of a broad class of covalently bonded organic-semiconductor surfaces. We develop this framework in the context of specific density functional theory (DFT) and many-body perturbation theory calculations, within the GW approximation, of an exemplar interface, thiophene-functionalized silicon (111). Through detailed calculations taking into account structural and binding energetics of mixed-monolayers consisting of both covalently attached thiophene and hydrogen, chlorine, methyl, and other passivating groups, we quantify the impact of coverage, nonlocal polarization, and interface dipole effects on the alignment of the thiophene frontier orbital energies with the silicon band edges. For thiophene adsorbate frontier orbital energies, we observe significant corrections to standard DFT (∼1 eV), including large nonlocal electrostatic polarization effects (∼1.6 eV). Importantly, both results can be rationalized from knowledge of the electronic structure of the isolated thiophene molecule and silicon substrate systems. Silicon band edge energies are predicted to vary by more than 2.5 eV, while molecular orbital energies stay similar, with the different functional groups studied, suggesting the prospect of tuning energy alignment over a wide range for photoelectrochemistry and other applications.

International Polar Year Observations From the International Space Station

NASA Technical Reports Server (NTRS)

Pettit, Donald R.; Runco, Susan; Byrne, Gregory; Willis, Kim; Heydorn, James; Stefanov, William L.; Wilkinson, M. Justin; Trenchard, Michael

2006-01-01

Astronauts aboard the International Space Station (ISS) have several opportunities each day to observe and document high-latitude phenomena. Although lighting conditions, ground track and other viewing parameters change with orbital precessions and season, the 51.6 degree orbital inclination and 400 km altitude of the ISS provide the crew an excellent vantage point for collecting image-based data for IPY investigators. To date, the database of imagery acquired by the Crew Earth Observations (CEO) experiment aboard the ISS (http://eol.jsc.nasa.gov) contains more than 12,000 images of high latitude (above 50 degrees) events such as aurora, mesospheric clouds, sea-ice, high-latitude plankton blooms, volcanic eruptions, and snow cover. The ISS Program will formally participate in IPY through an activity coordinated through CEO entitled Synchronized Observations of Polar Mesospheric Clouds, Aurora and Other Large-scale Polar Phenomena from the ISS and Ground Sites. The activity will augment the existing collection of Earth images taken from the ISS by focusing astronaut observations on polar phenomena. NASA s CEO experiment will solicit requests by IPY investigators for ISS observations that are coordinated with or complement ground-based polar studies. The CEO imagery website (http://eol.jsc.nasa.gov) will provide an on-line form for IPY investigators to interact with CEO scientists and define their imagery requests. This information will be integrated into daily communications with the ISS crews about their Earth Observations targets. All data collected will be cataloged and posted on the website for downloading and assimilation into IPY projects.

Asynchronous Processing of a Constellation of Geostationary and Polar-Orbiting Satellites for Fire Detection and Smoke Estimation

NASA Astrophysics Data System (ADS)

Hyer, E. J.; Peterson, D. A.; Curtis, C. A.; Schmidt, C. C.; Hoffman, J.; Prins, E. M.

2014-12-01

The Fire Locating and Monitoring of Burning Emissions (FLAMBE) system converts satellite observations of thermally anomalous pixels into spatially and temporally continuous estimates of smoke release from open biomass burning. This system currently processes data from a constellation of 5 geostationary and 2 polar-orbiting sensors. Additional sensors, including NPP VIIRS and the imager on the Korea COMS-1 geostationary satellite, will soon be added. This constellation experiences schedule changes and outages of various durations, making the set of available scenes for fire detection highly variable on an hourly and daily basis. Adding to the complexity, the latency of the satellite data is variable between and within sensors. FLAMBE shares with many fire detection systems the goal of detecting as many fires as possible as early as possible, but the FLAMBE system must also produce a consistent estimate of smoke production with minimal artifacts from the changing constellation. To achieve this, NRL has developed a system of asynchronous processing and cross-calibration that permits satellite data to be used as it arrives, while preserving the consistency of the smoke emission estimates. This talk describes the asynchronous data ingest methodology, including latency statistics for the constellation. We also provide an overview and show results from the system we have developed to normalize multi-sensor fire detection for consistency.

Navigating highly elliptical earth orbiters with simultaneous VLBI from orthogonal baseline pairs

NASA Technical Reports Server (NTRS)

Frauenholz, Raymond B.

1986-01-01

Navigation strategies for determining highly elliptical orbits with VLBI are described. The predicted performance of wideband VLBI and Delta VLBI measurements obtained by orthogonal baseline pairs are compared for a 16-hr equatorial orbit. It is observed that the one-sigma apogee position accuracy improves two orders of magnitude to the meter level when Delta VLBI measurements are added to coherent Doppler and range, and the simpler VLBI strategy provides nearly the same orbit accuracy. The effects of differential measurement noise and acquisition geometry on orbit accuracy are investigated. The data reveal that quasar position uncertainty limits the accuracy of wideband Delta VLBI measurements, and that polar motion and baseline uncertainties and offsets between station clocks affect the wideband VLBI data. It is noted that differential one-way range (DOR) has performance nearly equal to that of the more complex Delta DOR and is recommended for use on spacecraft in high elliptical orbits.

Earth resources instrumentation for the Space Station Polar Platform

NASA Technical Reports Server (NTRS)

Donohoe, Martin J.; Vane, Deborah

1986-01-01

The spacecraft and payloads of the Space Station Polar Platform program are described in a brief overview. Present plans call for one platform in a descending morning-equator-crossing orbit at 824 km and two or three platforms in ascending afternoon-crossing orbits at 542-824 km. The components of the NASA Earth Observing System (EOS) and NOAA payloads are listed in tables and briefly characterized, and data-distribution requirements and the mission development schedule are discussed. A drawing of the platform, a graph showing the spectral coverage of the EOS instruments, and a glossary of acronyms are provided.

Statistical Machine Translation of Japanese

DTIC Science & Technology

2007-03-01

hiragana and katakana) syllabaries…………………….. 20 3.2 Sample Japanese sentence showing kanji and kana……………………... 21 3.5 Japanese formality example...syllabary. 19 Figure 3.1. Japanese kana syllabaries, hiragana for native Japanese words, word endings, and particles, and katakana for foreign...Figure 3.2. Simple Japanese sentence showing the use of kanji, hiragana , and katakana. Kanji is used for nouns and verb, adjective, and

Cassini ISS Observation of Saturn from Grand Finale Orbits

NASA Astrophysics Data System (ADS)

Blalock, J. J.; Sayanagi, K. M.; Ingersoll, A. P.; Dyudina, U.; Ewald, S. P.; McCabe, R. M.; Garland, J.; Gunnarson, J.; Gallego, A.

2017-12-01

We present images captured during Cassini's Grand Finale orbits, and their preliminary analyses. During the final 22 orbits of the mission, the spacecraft is in orbits that have 6.5 day period at an inclination of 62 degrees, apoapsis altitude of about 1,272,000 km, and periapsis altitudes of about 2,500 km. Images captured during periapsis passes show Saturn's atmosphere at unprecedented spatial resolution. We present preliminary analyses of these images, including the final images captured before the end of the mission when the spacecraft enters Saturn's atmosphere on September 15th, 2017. Prominent features captured during the final orbits include the north polar vortex and other vortices as well as very detailed views of the "popcorn clouds" that reside between the Hexagon and the north pole. In the cloud field between zonal jets, clouds either resemble linear streaks suggestive of cirrus-like clouds or round shapes suggestive of vortices or cumulus anvil. The presence of linear streaks that follow lines of constant latitudes suggests that meridional mixing is inhibited at those latitudes. The size of vortices may reflect latitudinal variation in the atmospheric deformation radius. We also compare the new images to those captured earlier in the Cassini mission to characterize the temporal evolution such as changes in the zonal jet speeds, and prevalence and colors of vortices. A particular focus of our interest is the long-term change in the color of the hexagon, the evolution of the wind speeds in the jetstream that blows eastward at the boundary of the hexagon, and the morphology of the north polar vortex. Our work has been supported by NASA PATM NNX14AK07G, NSF AAG 1212216, and NASA NESSF NNX15AQ70H.

Size Dependence of Dust Distribution around the Earth Orbit

NASA Astrophysics Data System (ADS)

Ueda, Takahiro; Kobayashi, Hiroshi; Takeuchi, Taku; Ishihara, Daisuke; Kondo, Toru; Kaneda, Hidehiro

2017-05-01

In the solar system, interplanetary dust particles (IDPs) originating mainly from asteroid collisions and cometary activities drift to Earth orbit due to Poynting-Robertson drag. We analyzed the thermal emission from IDPs that was observed by the first Japanese infrared astronomical satellite, AKARI. The observed surface brightness in the trailing direction of the Earth orbit is 3.7% greater than that in the leading direction in the 9 μm band and 3.0% in the 18 μm band. In order to reveal dust properties causing leading-trailing surface brightness asymmetry, we numerically integrated orbits of the Sun, the Earth, and a dust particle as a restricted three-body problem including radiation from the Sun. The initial orbits of particles are determined according to the orbits of main-belt asteroids or Jupiter-family comets. Orbital trapping in mean motion resonances results in a significant leading-trailing asymmetry so that intermediate sized dust (˜10-100 μm) produces a greater asymmetry than zodiacal light. The leading-trailing surface brightness difference integrated over the size distribution of the asteroidal dust is obtained to be 27.7% and 25.3% in the 9 μm and 18 μm bands, respectively. In contrast, the brightness difference for cometary dust is calculated as 3.6% and 3.1% in the 9 μm and 18 μm bands, respectively, if the maximum dust radius is set to be s max = 3000 μm. Taking into account these values and their errors, we conclude that the contribution of asteroidal dust to the zodiacal infrared emission is less than ˜10%, while cometary dust of the order of 1 mm mainly accounts for the zodiacal light in infrared.

Size Dependence of Dust Distribution around the Earth Orbit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ueda, Takahiro; Takeuchi, Taku; Kobayashi, Hiroshi

In the solar system, interplanetary dust particles (IDPs) originating mainly from asteroid collisions and cometary activities drift to Earth orbit due to Poynting–Robertson drag. We analyzed the thermal emission from IDPs that was observed by the first Japanese infrared astronomical satellite, AKARI . The observed surface brightness in the trailing direction of the Earth orbit is 3.7% greater than that in the leading direction in the 9 μ m band and 3.0% in the 18 μ m band. In order to reveal dust properties causing leading–trailing surface brightness asymmetry, we numerically integrated orbits of the Sun, the Earth, and amore » dust particle as a restricted three-body problem including radiation from the Sun. The initial orbits of particles are determined according to the orbits of main-belt asteroids or Jupiter-family comets. Orbital trapping in mean motion resonances results in a significant leading–trailing asymmetry so that intermediate sized dust (∼10–100 μ m) produces a greater asymmetry than zodiacal light. The leading–trailing surface brightness difference integrated over the size distribution of the asteroidal dust is obtained to be 27.7% and 25.3% in the 9 μ m and 18 μ m bands, respectively. In contrast, the brightness difference for cometary dust is calculated as 3.6% and 3.1% in the 9 μ m and 18 μ m bands, respectively, if the maximum dust radius is set to be s {sub max} = 3000 μ m. Taking into account these values and their errors, we conclude that the contribution of asteroidal dust to the zodiacal infrared emission is less than ∼10%, while cometary dust of the order of 1 mm mainly accounts for the zodiacal light in infrared.« less

Preliminary Results of the Ground/Orbiter Lasercomm Demonstration Experiment between Table Mountain and teh ETS-V1 Satellite

NASA Technical Reports Server (NTRS)

Wilson, K. E.; Lesh, J. R.; Araki, K.; Arimoto, Y.

1996-01-01

The Ground/Orbiter Lasercomm Demonstration (GOLD) is an optical communications demonstration between the Japanese Engineering Test Satellite (ETS-V1) and an optical ground transmitting and receiving station at the Table Mountain FAcility in Wrightwood California. Laser transmissions to the satellite are performed approximately four hours every third night when the satellite is at apogee above Table Mountain.

Detector-level spectral characterization of the Suomi National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite long-wave infrared bands M15 and M16.

PubMed

Padula, Francis; Cao, Changyong

2015-06-01

The Suomi National Polar-orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) sensor data record (SDR) product achieved validated maturity status in March 2014 after roughly two years of on-orbit characterization (S-NPP spacecraft launched on 28 October 2011). During post-launch analysis the VIIRS Sea Surface Temperature (SST) Environmental Data Record (EDR) team observed an anomalous striping pattern in the daytime SST data. Daytime SST retrievals use the two VIIRS long-wave infrared bands: M15 (10.7 μm) and M16 (11.8 μm). To assess possible root causes due to detector-level spectral response function (SRF) effects, a study was conducted to compare the radiometric response of the detector-level and operational-band averaged SRFs of VIIRS bands M15 and M16. The study used simulated hyperspectral blackbody radiance data and clear-sky ocean hyperspectral radiances under different atmospheric conditions. It was concluded that the SST product is likely impacted by small differences in detector-level SRFs and that if users require optimal radiometric performance, detector-level processing is recommended for both SDR and EDR products. Future work should investigate potential SDR product improvements through detector-level processing in support of the generation of Suomi NPP VIIRS climate quality SDRs.

Acculturation of Personality: A Three-Culture Study of Japanese, Japanese Americans, and European Americans.

PubMed

Güngör, Derya; Bornstein, Marc H; De Leersnyder, Jozefien; Cote, Linda; Ceulemans, Eva; Mesquita, Batja

2013-07-01

The present study tests the hypothesis that involvement with a new culture instigates changes in personality of immigrants that result in (a) better fit with the norms of the culture of destination and (b) reduced fit with the norms of the culture of origin. Participants were 40 Japanese first-generation immigrants to the United States, 57 Japanese monoculturals, and 60 U.S. monoculturals. All participants completed the Jackson Personality Inventory (JPI) as a measure of the Big Five; immigrants completed the Japanese American Acculturation Scale. Immigrants' fits with the cultures of destination and origin were calculated by correlating Japanese American mothers' patterns of ratings on the Big Five with the average patterns of ratings of European Americans and Japanese on the same personality dimensions. Japanese Americans became more "American" and less "Japanese" in their personality as they reported higher participation in the U.S. culture. The results support the view that personality can be subject to cultural influence.

The Mars Climate Orbiter is lifted up the Pad 17A gantry

NASA Technical Reports Server (NTRS)

1998-01-01

The Mars Climate Orbiter with its upper stage booster, wrapped in a protective covering, is mated to the second stage of a Boeing Delta II (7425) rocket at Launch Complex 17, Pad A, Cape Canaveral Air Station. Targeted for liftoff on Dec. 10, 1998, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface.

STS-47 Japanese Payload Specialist Mohri and backups during Homestead training

NASA Technical Reports Server (NTRS)

1990-01-01

STS-47 Endeavour, Orbiter Vehicle (OV) 105, Japanese Payload Specialist Mamoru Mohri (far left), backup Payload Specialist Takao Doi (center), and backup Payload Specialist Chiaki Mukai (right) participate in water survival training at Homestead Air Force Base, Florida. Dockside, Mohri and Mukai wash the salt water from their personalized helmets after a water exercise. The three-day course was attended by the STS-47 prime and alternate payload specialists shortly after they were announced for the scheduled summer of 1992 Spacelab Japan (SLJ) mission. Mohri, Doi, and Mukai all represent the National Space Development Agency of Japan (NASDA).

High Power Microwave Emission of Large and Small Orbit Gyrotron Devices in Rectangular Interaction Structures

NASA Astrophysics Data System (ADS)

Hochman, J. M.; Gilgenbach, R. M.; Jaynes, R. L.; Rintamaki, J. I.; Luginsland, J. W.; Lau, Y. Y.; Spencer, T. A.

1996-11-01

Experiments utilize large and small orbit e-beam gyrotron devices in a rectangular-cross-section (RCS) gyrotron. This device is being explored to examine polarization control. Other research issues include pulse shortening, and mode competition. MELBA generates electron beams with parameters of: -800kV, 1-10kA diode current, and 0.5-1.0 μ sec pulselengths. The small orbit gyrotron device is converted to a large orbit experiment by running MELBA's annular electron beam through a magnetic cusp. Initial experiments showed an increase in beam alpha (V_perp/V_par) of a factor of ~ 4 between small and large orbit devices. Experimental results from the RCS gyrotron will be compared for large-orbit and small-orbit electron beams. Beam transport data and frequency measurements will be presented. Computer modeling utilizing the MAGIC and E-gun codes will be shown.

Curvature-enhanced Spin-orbit Coupling and Spinterface Effect in Fullerene-based Spin Valves

NASA Astrophysics Data System (ADS)

Liang, Shiheng; Geng, Rugang; Yang, Baishun; Zhao, Wenbo; Chandra Subedi, Ram; Li, Xiaoguang; Han, Xiufeng; Nguyen, Tho Duc

2016-01-01

We investigated curvature-enhanced spin-orbit coupling (SOC) and spinterface effect in carbon-based organic spin valves (OSVs) using buckyball C60 and C70 molecules. Since the naturally abundant 12C has spinless nuclear, the materials have negligible hyperfine interaction (HFI) and the same intrinsic SOC, but different curvature SOC due to their distinct curvatures. We fitted the thickness dependence of magnetoresistance (MR) in OSVs at various temperatures using the modified Jullière equation. We found that the spin diffusion length in the C70 film is above 120 nm, clearly longer than that in C60 film at all temperatures. The effective SOC ratio of the C70 film to the C60 film was estimated to be about 0.8. This was confirmed by the magneto-electroluminescence (MEL) measurement in fullerene-based light emitting diodes (LED). Next, the effective spin polarization in C70-based OSVs is smaller than that in C60-based OSVs implying that they have different spinterface effect. First principle calculation study shows that the spin polarization of the dz2 orbital electrons of Co atoms contacted with C60 is larger causing better effective spin polarization at the interface.

Monitoring the Arctic during Polar Darkness

NASA Image and Video Library

2017-12-08

. “Things start changing rapidly in the late fall: sea ice formation and snow cover extent at the highest latitudes. This lets us see rapid-growth areas in detail.” The day-night band is also useful for following weather systems, including severe storms, which can develop and strike populous areas at night as well as day. Geostationary Operational Environmental Satellites orbit the Earth’s equator. The satellites offer uninterrupted observations of North America, but high-latitude areas such as Alaska may benefit more from polar-orbiting satellites. Miller explains, “In the high latitudes, the orbits begin to overlap considerably, which gives you a lot more passes in Alaska. If you start to look at multiple passes and stitch them together, you can get a version of a poor man’s geostationary time loop of the weather.” Day-night band imagery at high latitudes has already proven useful for tracking rapid ice movement and diagnosing Gulf of Alaska circulations. The day-night band is even useful at tracking ship movement at high latitudes. NASA Earth Observatory image by Jesse Allen and Robert Simmon, using VIIRS Day-Night Band data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Michon Scott. Instrument: Suomi NPP - VIIRS Credit: NASA Earth Observatory Click here to view all of the Earth at Night 2012 images Click here to read more about this image NASA image use policy. NASA Goddard Space Flight Center enables NASA

Remote Monitoring of the Polarized Target's Control for E1039

NASA Astrophysics Data System (ADS)

Fox, David; SeaQuest Collaboration

2017-09-01

The 1039 experiment at FNAL will further our understanding of spin structure by measuring the contribution that sea quarks orbital angular momentum provide to overall nucleon spin. It is accepted that the valence-quarks of nucleons only provide 30% of the total nucleon spin. To study the nucleon's sea quark contribution, E1039 will use the Drell-Yan process by colliding 120 GeV un-polarized beam protons with polarized ammonia targets of hydrogen and deuterium. The asymmetric spin distributions of resulting dimuons will be measured. These asymmetries are sensitive, among other effects, to the orbital angular momentum contribution of the sea quarks. The polarized target requires a multi-stage vacuum pump located near the target. Since access to its present controls will not be possible during running, remote control and monitoring upgrades were required. A secondary control panel was purchased and tested. Information from the programmable logic controller (PLC) must be fed into our data stream to enable remote monitoring and to signal possible alarm conditions. This solution and the program created using explicit TCP/IP messaging to extract data tags from the PLC and log it within our databases will be presented. Supported by U.S. D.O.E. Medium Energy Nuclear Physics under Grant DE-FG02-03ER41243.

Suomi-NPP Mission On-Orbit Experience with Toroid Ball Bearing Retainers Under Unidirectional and Reversing Motion

NASA Technical Reports Server (NTRS)

Bruegman, Otto; Thakore, Kamal; Loewenthal, Stu; Cymerman, John

2016-01-01

The Advanced Technology Microwave Sounder (ATMS) instrument scan system on the Suomi National Polar-orbiting Partnership (SNPP) spacecraft has experienced several randomly occurring increased torque 'events' since its on-orbit activation in November 2011. Based on a review of on-orbit telemetry data and data gathered from scan mechanism bearing life testing on the ground, the conclusion was drawn that some degradation of Teflon toroid ball retainers was occurring in the instrument Scan Drive Mechanism. A life extension program was developed and executed on-orbit with very good results to date. The life extension program consisted of reversing the mechanism for a limited number of consecutive scans every day.

Radio emission from RS CVn binaries. II - Polarization and spectral properties

NASA Technical Reports Server (NTRS)

Mutel, R. L.; Morris, D. H.; Doiron, D. J.; Lestrade, J. F.

1987-01-01

Multiepoch radio observations of circular polarization and spectral characteristics of several close, late-type stellar binaries are reported. The median luminosity of four well-studied systems ranged from 16.2 to 17.1 ergs/s/Hz. For individual systems, the fractional circular polarization decreases with increasing luminosity, particularly at frequencies above 5 GHz. Eclipsing binaries have significantly lower average circular polarization compared with noneclipsing systems. Helicity reversal is almost always observed between 1.4 and 4.9 GHz for systems with high orbital inclination. Comparison with ten years of previously published polarization observations for two RS CVn stellar systems show that the same helicity occurs at a given frequency for a given source, indicating a very stable, large-scale magnetic field geometry. These spectral and polarization characteristics strongly support a model of inhomogeneous gyrosynchrotron emission arising from electrons with power law energy spectra interacting with inhomogeneous magnetic fields.

Planet-B: A Japanese Mars aeronomy observer

NASA Technical Reports Server (NTRS)

Tsuruda, K.

1992-01-01

An introduction is given to a Japanese Mars mission (Planet-B) which is being planned at the Institute of Space and Aeronautical Science (ISAS), Japan. Planet-B aims to study the upper atmosphere of Mars and its interaction with the solar wind. The launch of Planet-B is planned for 1996 on a new launcher, M-L, which is being developed at ISAS. In addition to the interaction with the solar wind, the structure of the Martian upper atmosphere is thought to be controlled by the meteorological condition in the lower atmosphere. The orbit of Planet-B was chosen so that it will pass two important regions, the region where the solar wind interacts with the Martian upper atmosphere and the tail region where ion acceleration is taking place. Considering the drag due to the Martian atmosphere, the periapsis altitude of 150 km and apoapsis of 10 Martian radii are planned. The orbit plane will be nearly parallel to the ecliptic plane. The altitude of the spacecraft will be spin stabilized and its spin axis will be controlled to the point of the earth. The dry weight of the spacecraft will be about 250 kg, including the scientific payload which consists of a magnetometer, plasma instruments, HF sounder, UV imaging spectrometer, and lower atmosphere monitor.

Americans and Japanese Nonverbal Communication. Linguistic Communications 15 (Papers in Japanese Linguistics 3).

ERIC Educational Resources Information Center

Taylor, Harvey M.

Each culture has its own nonverbal as well as its verbal language. Movements, gestures and sounds have distinct and often conflicting interpretations in different countries. For Americans communicating with Japanese, misunderstandings are of two types: Japanese behavior which is completely new to the American, and Japanese behavior which is…

Illumination Conditions of the Lunar Polar Regions Using LOLA Topography

NASA Technical Reports Server (NTRS)

Mazarico, E.; Neumann, G. A.; Smith, D. E.; Zuber, M. T.; Torrence, M. H.

2011-01-01

We use high-resolution altimetry data obtained by the Lunar Orbiter Laser Altimeter instrument onboard the Lunar Reconnaissance Orbiter to characterize present illumination conditions in the polar regions of the Moon. Compared to previous studies, both the spatial and temporal extent of the simulations are increased significantly, as well as the coverage (fill ratio) of the topographic maps used, thanks to the 28 Hz firing rate of the five-beam instrument. We determine the horizon elevation in a number of directions based on 240 m-resolution polar digital elevation models reaching down to 75 latitude. The illumination of both polar regions extending to 80 can be calculated for any geometry from those horizon longitudinal profiles. We validated our modeling with recent Lunar Reconnaissance Orbiter Wide-Angle Camera images. We assessed the extent of permanently shadowed regions (PSRs, defined as areas that never receive direct solar illumination), and obtained total areas generally larger than previous studies (12,866 and 16,055 km2, in the north and south respectively). We extended our direct illumination model to account for singly-scattered light, and found that every PSR does receive some amount of scattered light during the year. We conducted simulations over long periods (several 18.6-years lunar precession cycles) with a high temporal resolution (6 h), and identified the most illuminated locations in the vicinity of both poles. Because of the importance of those sites for exploration and engineering considerations, we characterized their illumination more precisely over the near future. Every year, a location near the Shackleton crater rim in the south polar region is sunlit continuously for 240 days, and its longest continuous period in total darkness is about 1.5 days. For some locations small height gains ( 10 m) can dramatically improve their average illumination and reduce the night duration, rendering some of those particularly attractive energy-wise as

Detraditionalisation: Japanese Students in the USA.

ERIC Educational Resources Information Center

Ueno, Junko

2001-01-01

Focuses on the identity formation of Japanese students temporarily living in the United States. The students were enrolled in Japanese Saturday school and in American public schools. Student interviews reveal a mixture of Japanese and American characteristics. Suggests Japanese students do not reject either culture--Japanese or American--but that…

Japanese-English language equivalence of the Cognitive Abilities Screening Instrument among Japanese-Americans.

PubMed

Gibbons, Laura E; McCurry, Susan; Rhoads, Kristoffer; Masaki, Kamal; White, Lon; Borenstein, Amy R; Larson, Eric B; Crane, Paul K

2009-02-01

The Cognitive Abilities Screening Instrument (CASI) was designed for use in cross-cultural studies of Japanese and Japanese-American elderly in Japan and the U.S.A. The measurement equivalence in Japanese and English had not been confirmed in prior studies. We analyzed the 40 CASI items for differential item functioning (DIF) related to test language, as well as self-reported proficiency with written Japanese, age, and educational attainment in two large epidemiologic studies of Japanese-American elderly: the Kame Project (n=1708) and the Honolulu-Asia Aging Study (HAAS; n = 3148). DIF was present if the demographic groups differed in the probability of success on an item, after controlling for their underlying cognitive functioning ability. While seven CASI items had DIF related to language of testing in Kame (registration of one item; recall of one item; similes; judgment; repeating a phrase; reading and performing a command; and following a three-step instruction), the impact of DIF on participants' scores was minimal. Mean scores for Japanese and English speakers in Kame changed by <0.1 SD after accounting for DIF related to test language. In HAAS, insufficient numbers of participants were tested in Japanese to assess DIF related to test language. In both studies, DIF related to written Japanese proficiency, age, and educational attainment had minimal impact. To the extent that DIF could be assessed, the CASI appeared to meet the goal of measuring cognitive function equivalently in Japanese and English. Stratified data collection would be needed to confirm this conclusion. DIF assessment should be used in other studies with multiple language groups to confirm that measures function equivalently or, if not, form scores that account for DIF.