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Sample records for recurrent solar jets

  1. Recurrent Solar Jets Induced by a Satellite Spot and Moving Magnetic Features

    NASA Astrophysics Data System (ADS)

    Chen, Jie; Su, Jiangtao; Yin, Zhiqiang; Priya, T. G.; Zhang, Hongqi; Liu, Jihong; Xu, Haiqing; Yu, Sijie

    2015-12-01

    Recurrent and homologous jets were observed to the west edge of active region NOAA 11513 at the boundary of a coronal hole. We find two kinds of cancellations between opposite polarity magnetic fluxes, inducing the generation of recurrent jets. First, a satellite spot continuously collides with a pre-existing opposite polarity magnetic field and causes recurrent solar jets. Second, moving magnetic features, which emerge near the sunspot penumbra, pass through the ambient plasma and eventually collide with the opposite polarity magnetic field. Among these recurrent jets, a blowout jet that occurred around 21:10 UT is investigated. The rotation of the pre-existing magnetic field and the shear motion of the satellite spot accumulate magnetic energy, which creates the possibility for the jet to experience blowout right from the standard.

  2. RECURRENT SOLAR JETS INDUCED BY A SATELLITE SPOT AND MOVING MAGNETIC FEATURES

    SciTech Connect

    Chen, Jie; Su, Jiangtao; Yin, Zhiqiang; Priya, T. G.; Zhang, Hongqi; Xu, Haiqing; Yu, Sijie; Liu, Jihong

    2015-12-10

    Recurrent and homologous jets were observed to the west edge of active region NOAA 11513 at the boundary of a coronal hole. We find two kinds of cancellations between opposite polarity magnetic fluxes, inducing the generation of recurrent jets. First, a satellite spot continuously collides with a pre-existing opposite polarity magnetic field and causes recurrent solar jets. Second, moving magnetic features, which emerge near the sunspot penumbra, pass through the ambient plasma and eventually collide with the opposite polarity magnetic field. Among these recurrent jets, a blowout jet that occurred around 21:10 UT is investigated. The rotation of the pre-existing magnetic field and the shear motion of the satellite spot accumulate magnetic energy, which creates the possibility for the jet to experience blowout right from the standard.

  3. On Recurrent/Homologous Coronal Jets Emission: Coronal Geyser Structures

    NASA Astrophysics Data System (ADS)

    Razvan Paraschiv, Alin; Donea, Alina

    2016-05-01

    Active region 11302 has shown a vast display of solar jets during its lifetime. We examine the emission mechanism responsible for multiple coronal jet events occurring at the center-east side of the active region. Identified jet events were detected in extreme-ultraviolet (EUV), hard X-ray (HXR) and radio emissions, observed by dedicated instruments such as SDO's AIA and HMI, STEREO's EUVI and WAVES, and RHESSI, respectively. We report the detection of a base-arch structure in the lower atmosphere. The site was labelled "Coronal Geyser". The structure had emitted jets quasi-periodically for the entire time the AR was visible in SDO'S field of view. The jets expand into the corona with an apparent line of sight velocity of ~200-300$ km/s. To our knowledge the long time-scale behaviour of jet recurrence and base geyser structure was not previously discussed and data analysis of this phenomena will provide new information for theoretical modelling and data interpretation of jets.

  4. Recurrent coronal jets induced by repetitively accumulated electric currents

    NASA Astrophysics Data System (ADS)

    Guo, Y.; Démoulin, P.; Schmieder, B.; Ding, M. D.; Vargas Domínguez, S.; Liu, Y.

    2013-07-01

    Context. Jets of plasma are frequently observed in the solar corona. A self-similar recurrent behavior is observed in a fraction of them. Aims: Jets are thought to be a consequence of magnetic reconnection; however, the physics involved is not fully understood. Therefore, we study some jet observations with unprecedented temporal and spatial resolutions. Methods: The extreme-ultraviolet (EUV) jets were observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory (SDO). The Helioseismic and Magnetic Imager (HMI) on board SDO measured the vector magnetic field, from which we derive the magnetic flux evolution, the photospheric velocity field, and the vertical electric current evolution. The magnetic configuration before the jets is derived by the nonlinear force-free field extrapolation. Results: Three EUV jets recurred in about one hour on 17 September 2010 in the following magnetic polarity of active region 11106. We derive that the jets are above a pair of parasitic magnetic bipoles that are continuously driven by photospheric diverging flows. The interaction drove the buildup of electric currents, which we observed as elongated patterns at the photospheric level. For the first time, the high temporal cadence of the HMI allows the evolution of such small currents to be followed. In the jet region, we found that the integrated absolute current peaks repetitively in phase with the 171 Å flux evolution. The current buildup and its decay are both fast, about ten minutes each, and the current maximum precedes the 171 Å also by about ten minutes. Then, the HMI temporal cadence is marginally fast enough to detect such changes. Conclusions: The photospheric current pattern of the jets is found to be associated with the quasi-separatrix layers deduced from the magnetic extrapolation. From previous theoretical results, the observed diverging flows are expected to continuously build such currents. We conclude that the magnetic reconnection occurs

  5. solar spicules and jets

    NASA Astrophysics Data System (ADS)

    Tavabi, E.; Koutchmy, S.; Ajabshirizadeh, A.

    2012-06-01

    In order to clear up the origin and possibly explain some solar limb and disc spicule quasi-periodic recurrences produced by overlapping effects, we present a simulation model assuming quasi- random positions of spicules. We also allow a set number of spicules with different physical properties (such as: height, lifetime and tilt angle as shown by an individual spicule) occurring randomly. Results of simulations made with three different spatial resolutions of the corresponding frames and also for different number density of spicules, are analyzed. The wavelet time/frequency method is used to obtain the exact period of spicule visibility. Results are compared with observations of the chromosphere from i/ the Transition Region and Coronal Explorer (TRACE) filtergrams taken at 1600 angstrom, ii/ the Solar Optical Telescope (SOT) of Hinode taken in the Ca II H-line and iii/ the Sac-Peak Dunn's VTT taken in H? line. Our results suggest the need to be cautious when interpreting apparent oscillations seen in spicule image sequences when overlapping is present, i.e.; when the spatial resolution is not enough to resolve individual components of spicules.

  6. Solar Jets as Sources of Outflows, Heating and Waves

    NASA Astrophysics Data System (ADS)

    Nishizuka, N.

    2013-05-01

    Recent space solar observations of the Sun, such as Hinode and SDO, have revealed that magnetic reconnection is ubiquitous in the solar atmosphere, ranging from small scale reconnection (observed as nanoflares) to large scale one (observed as long duration flares or giant arcades). Especially recent Hinode observations has found various types of tiny chromospheric jets, such as chromospheric anemone jets, penumbral microjets and light bridge jets from sunspot umbra. It was also found that the corona is full of tiny X-ray jets. Often they are seen as helical spinning jets with Alfvenic waves in the corona. Sometimes they are seen as chromospheric jets with slow-mode magnetoacoustic waves and sometimes as unresolved jet-like events at the footpoint of recurrent outflows and waves at the edge of the active region. There is increasing evidence of magnetic reconnection in these tiny jets and its association with waves. The origin of outflows and waves is one of the issues concerning coronal heating and solar wind acceleration. To answer this question, we had a challenge to reproduce solar jets with laboratory plasma experiment and directly measured outflows and waves. As a result, we could find a propagating wave excited by magnetic reconnection, whose energy flux is 10% of the released magnetic energy. That is enough for solar wind acceleration and locally enough for coronal heating, consistent with numerical MHD simulations of solar jets. Here we would discuss recent observations with Hinode, theories and experimental results related to jets and waves by magnetic reconnection, and discuss possible implication to reconnection physics, coronal heating and solar wind acceleration.

  7. Solar Coronal Jets: Observations, Theory, and Modeling

    NASA Astrophysics Data System (ADS)

    Raouafi, N. E.; Patsourakos, S.; Pariat, E.; Young, P. R.; Sterling, A. C.; Savcheva, A.; Shimojo, M.; Moreno-Insertis, F.; DeVore, C. R.; Archontis, V.; Török, T.; Mason, H.; Curdt, W.; Meyer, K.; Dalmasse, K.; Matsui, Y.

    2016-07-01

    Coronal jets represent important manifestations of ubiquitous solar transients, which may be the source of significant mass and energy input to the upper solar atmosphere and the solar wind. While the energy involved in a jet-like event is smaller than that of "nominal" solar flares and coronal mass ejections (CMEs), jets share many common properties with these phenomena, in particular, the explosive magnetically driven dynamics. Studies of jets could, therefore, provide critical insight for understanding the larger, more complex drivers of the solar activity. On the other side of the size-spectrum, the study of jets could also supply important clues on the physics of transients close or at the limit of the current spatial resolution such as spicules. Furthermore, jet phenomena may hint to basic process for heating the corona and accelerating the solar wind; consequently their study gives us the opportunity to attack a broad range of solar-heliospheric problems.

  8. DICHOTOMY OF SOLAR CORONAL JETS: STANDARD JETS AND BLOWOUT JETS

    SciTech Connect

    Moore, Ronald L.; Cirtain, Jonathan W.; Sterling, Alphonse C.; Falconer, David A.

    2010-09-01

    By examining many X-ray jets in Hinode/X-Ray Telescope coronal X-ray movies of the polar coronal holes, we found that there is a dichotomy of polar X-ray jets. About two thirds fit the standard reconnection picture for coronal jets, and about one third are another type. We present observations indicating that the non-standard jets are counterparts of erupting-loop H{alpha} macrospicules, jets in which the jet-base magnetic arch undergoes a miniature version of the blowout eruptions that produce major coronal mass ejections. From the coronal X-ray movies we present in detail two typical standard X-ray jets and two typical blowout X-ray jets that were also caught in He II 304 A snapshots from STEREO/EUVI. The distinguishing features of blowout X-ray jets are (1) X-ray brightening inside the base arch in addition to the outside bright point that standard jets have, (2) blowout eruption of the base arch's core field, often carrying a filament of cool (T {approx} 10{sup 4} - 10{sup 5} K) plasma, and (3) an extra jet-spire strand rooted close to the bright point. We present cartoons showing how reconnection during blowout eruption of the base arch could produce the observed features of blowout X-ray jets. We infer that (1) the standard-jet/blowout-jet dichotomy of coronal jets results from the dichotomy of base arches that do not have and base arches that do have enough shear and twist to erupt open, and (2) there is a large class of spicules that are standard jets and a comparably large class of spicules that are blowout jets.

  9. Dichotomy of Solar Coronal Jets: Standard Jets and Blowout Jets

    NASA Technical Reports Server (NTRS)

    Moore, R. L.; Cirtain, J. W.; Sterling, A. C.; Falconer, D. A.

    2010-01-01

    By examining many X-ray jets in Hinode/XRT coronal X-ray movies of the polar coronal holes, we found that there is a dichotomy of polar X-ray jets. About two thirds fit the standard reconnection picture for coronal jets, and about one third are another type. We present observations indicating that the non-standard jets are counterparts of erupting-loop H alpha macrospicules, jets in which the jet-base magnetic arch undergoes a miniature version of the blowout eruptions that produce major CMEs. From the coronal X-ray movies we present in detail two typical standard X-ray jets and two typical blowout X-ray jets that were also caught in He II 304 Angstrom snapshots from STEREO/EUVI. The distinguishing features of blowout X-ray jets are (1) X-ray brightening inside the base arch in addition to the outside bright point that standard jets have, (2) blowout eruption of the base arch's core field, often carrying a filament of cool (T 10(exp 4) - 10(exp 5) K) plasma, and (3) an extra jet-spire strand rooted close to the bright point. We present cartoons showing how reconnection during blowout eruption of the base arch could produce the observed features of blowout X-ray jets. We infer that (1) the standard-jet/blowout-jet dichotomy of coronal jets results from the dichotomy of base arches that do not have and base arches that do have enough shear and twist to erupt open, and (2) there is a large class of spicules that are standard jets and a comparably large class of spicules that are blowout jets.

  10. Solar-thermal jet pumping for irrigation

    NASA Astrophysics Data System (ADS)

    Clements, L. D.; Dellenback, P. A.; Bell, C. A.

    1980-01-01

    This paper describes a novel concept in solar powered irrigation pumping, gives measured performance data for the pump unit, and projected system performance. The solar-thermal jet pumping concept is centered around a conventional jet eductor pump which is commercially available at low cost. The jet eductor pump is powered by moderate temperature, moderate pressure Refrigerant-113 vapor supplied by a concentrating solar collector field. The R-113 vapor is direct condensed by the produced water and the two fluids are separated at the surface. The water goes on to use and the R-113 is repressurized and returned to the solar field. The key issue in the solar-thermal jet eductor concept is the efficiency of pump operation. Performance data from a small scale experimental unit which utilizes an electrically heated boiler in place of the solar field is presented. The solar-thermal jet eductor concept is compared with other solar irrigation concepts and optimal application situations are identified. Though having lower efficiencies than existing Rankine cycle solar-thermal irrigation systems, the mechanical and operational simplicity of this concept make it competitive with other solar powered irrigation schemes.

  11. Three-Dimensional Modeling of Quasi-Homologous Solar Jets

    NASA Technical Reports Server (NTRS)

    Pariat, E.; Antiochos, S. K.; DeVore, C. R.

    2010-01-01

    Recent solar observations (e.g., obtained with Hinode and STEREO) have revealed that coronal jets are a more frequent phenomenon than previously believed. This higher frequency results, in part, from the fact that jets exhibit a homologous behavior: successive jets recur at the same location with similar morphological features. We present the results of three-dimensional (31)) numerical simulations of our model for coronal jets. This study demonstrates the ability of the model to generate recurrent 3D untwisting quasi-homologous jets when a stress is constantly applied at the photospheric boundary. The homology results from the property of the 3D null-point system to relax to a state topologically similar to its initial configuration. In addition, we find two distinct regimes of reconnection in the simulations: an impulsive 3D mode involving a helical rotating current sheet that generates the jet, and a quasi-steady mode that occurs in a 2D-like current sheet located along the fan between the sheared spines. We argue that these different regimes can explain the observed link between jets and plumes.

  12. DARK JETS IN SOLAR CORONAL HOLES

    SciTech Connect

    Young, Peter R.

    2015-03-10

    A new solar feature termed a dark jet is identified from observations of an extended solar coronal hole that was continuously monitored for over 44 hr by the Extreme Ultraviolet Imaging Spectrometer on board the Hinode spacecraft in 2011 February 8–10 as part of Hinode Operation Plan No. 177 (HOP 177). Line of sight (LOS) velocity maps derived from the coronal Fe xii λ195.12 emission line, formed at 1.5 MK, revealed a number of large-scale, jet-like structures that showed significant blueshifts. The structures had either weak or no intensity signal in 193 Å filter images from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory, suggesting that the jets are essentially invisible to imaging instruments. The dark jets are rooted in bright points and occur both within the coronal hole and at the quiet Sun–coronal hole boundary. They exhibit a wide range of shapes, from narrow columns to fan-shaped structures, and sometimes multiple jets are seen close together. A detailed study of one dark jet showed LOS speeds increasing along the jet axis from 52 to 107 km s{sup −1} and a temperature of 1.2–1.3 MK. The low intensity of the jet was due either to a small filling factor of 2% or to a curtain-like morphology. From the HOP 177 sample, dark jets are as common as regular coronal hole jets, but their low intensity suggests a mass flux around two orders of magnitude lower.

  13. Numerical studies of solar chromospheric jets

    NASA Astrophysics Data System (ADS)

    Iijima, Haruhisa

    2016-03-01

    The solar chromospheric jet is one of the most characteristic structures near the solar surface. The quantitative understanding of chromospheric jets is of substantial importance for not only the partially ionized phenomena in the chromosphere but also the energy input and dissipation processes in the corona. In this dissertation, the formation and dynamics of chromospheric jets are investigated using the radiation magnetohydrodynamic simulations. We newly develop a numerical code for the radiation magnetohydrodynamic simulations of the comprehensive modeling of solar atmosphere. Because the solar chromosphere is highly nonlinear, magnetic pressure dominated, and turbulent, a robust and high-resolution numerical scheme is required. In Chapter 2, we propose a new algorithm for the simulation of magnetohydrodynamics. Through the test problems and accuracy analyses, the proposed scheme is proved to satisfy the requirements. In Chapter 3, the effect of the non-local radiation energy transport, Spitzer-type thermal conduction, latent heat of partial ionization and molecule formation, and gravity are implemented to the magnetohydrodynamic code. The numerical schemes for the radiation transport and thermal conduction is carefully chosen in a view of the efficiency and compatibility with the parallel computation. Based on the developed radiation magnetohydrodynamic code, the formation and dynamics of chromospheric jets are investigated. In Chapter 4, we investigate the dependence of chromospheric jets on the coronal temperature in the two-dimensional simulations. Various scale of chromospheric jets with the parabolic trajectory are found with the maximum height of 2–8 Mm, lifetime of 2–7 min, maximum upward velocity of 10– 50 km/s, and deceleration of 100–350 m/s2. We find that chromospheric jets are more elongated under the cool corona and shorter under the hot corona. We also find that the pressure gradient force caused by the periodic shock waves accelerates

  14. Numerical studies of solar chromospheric jets

    NASA Astrophysics Data System (ADS)

    Iijima, Haruhisa

    2016-03-01

    The solar chromospheric jet is one of the most characteristic structures near the solar surface. The quantitative understanding of chromospheric jets is of substantial importance for not only the partially ionized phenomena in the chromosphere but also the energy input and dissipation processes in the corona. In this dissertation, the formation and dynamics of chromospheric jets are investigated using the radiation magnetohydrodynamic simulations. We newly develop a numerical code for the radiation magnetohydrodynamic simulations of the comprehensive modeling of solar atmosphere. Because the solar chromosphere is highly nonlinear, magnetic pressure dominated, and turbulent, a robust and high-resolution numerical scheme is required. In Chapter 2, we propose a new algorithm for the simulation of magnetohydrodynamics. Through the test problems and accuracy analyses, the proposed scheme is proved to satisfy the requirements. In Chapter 3, the effect of the non-local radiation energy transport, Spitzer-type thermal conduction, latent heat of partial ionization and molecule formation, and gravity are implemented to the magnetohydrodynamic code. The numerical schemes for the radiation transport and thermal conduction is carefully chosen in a view of the efficiency and compatibility with the parallel computation. Based on the developed radiation magnetohydrodynamic code, the formation and dynamics of chromospheric jets are investigated. In Chapter 4, we investigate the dependence of chromospheric jets on the coronal temperature in the two-dimensional simulations. Various scale of chromospheric jets with the parabolic trajectory are found with the maximum height of 2-8 Mm, lifetime of 2-7 min, maximum upward velocity of 10- 50 km/s, and deceleration of 100-350 m/s2. We find that chromospheric jets are more elongated under the cool corona and shorter under the hot corona. We also find that the pressure gradient force caused by the periodic shock waves accelerates some of the

  15. SYSTEMATIC MOTION OF FINE-SCALE JETS AND SUCCESSIVE RECONNECTION IN SOLAR CHROMOSPHERIC ANEMONE JET OBSERVED WITH THE SOLAR OPTICAL TELESCOPE/HINODE

    SciTech Connect

    Singh, K. A. P.; Nishida, K.; Shibata, K.; Isobe, H.

    2012-11-20

    The Solar Optical Telescope (SOT) on board Hinode allows observations with high spatiotemporal resolution and stable image quality. A {lambda}-shaped chromospheric anemone jet was observed in high resolution with SOT/Hinode. We found that several fine-scale jets were launched from one end of the footpoint to the other. These fine-scale jets ({approx}1.5-2.5 Mm) gradually move from one end of the footpoint to the other and finally merge into a single jet. This process occurs recurrently, and as time progresses the jet activity becomes more and more violent. The time evolution of the region below the jet in Ca II H filtergram images taken with SOT shows that various parts (or knots) appear at different positions. These bright knots gradually merge into each other during the maximum phase. The systematic motion of the fine-scale jets is observed when different knots merge into each other. Such morphology would arise due to the emergence of a three-dimensional twisted flux rope in which the axial component (or the guide field) appears in the later stages of the flux rope emergence. The partial appearance of the knots could be due to the azimuthal magnetic field that appears during the early stage of the flux rope emergence. If the guide field is strong and reconnection occurs between the emerging flux rope and an ambient magnetic field, this could explain the typical feature of systematic motion in chromospheric anemone jets.

  16. Systematic Motion of Fine-scale Jets and Successive Reconnection in Solar Chromospheric Anemone Jet Observed with the Solar Optical Telescope/Hinode

    NASA Astrophysics Data System (ADS)

    Singh, K. A. P.; Isobe, H.; Nishida, K.; Shibata, K.

    2012-11-01

    The Solar Optical Telescope (SOT) on board Hinode allows observations with high spatiotemporal resolution and stable image quality. A λ-shaped chromospheric anemone jet was observed in high resolution with SOT/Hinode. We found that several fine-scale jets were launched from one end of the footpoint to the other. These fine-scale jets (~1.5-2.5 Mm) gradually move from one end of the footpoint to the other and finally merge into a single jet. This process occurs recurrently, and as time progresses the jet activity becomes more and more violent. The time evolution of the region below the jet in Ca II H filtergram images taken with SOT shows that various parts (or knots) appear at different positions. These bright knots gradually merge into each other during the maximum phase. The systematic motion of the fine-scale jets is observed when different knots merge into each other. Such morphology would arise due to the emergence of a three-dimensional twisted flux rope in which the axial component (or the guide field) appears in the later stages of the flux rope emergence. The partial appearance of the knots could be due to the azimuthal magnetic field that appears during the early stage of the flux rope emergence. If the guide field is strong and reconnection occurs between the emerging flux rope and an ambient magnetic field, this could explain the typical feature of systematic motion in chromospheric anemone jets.

  17. Oscillations in solar jets observed with the SOT of Hinode: viscous effects during reconnection

    NASA Astrophysics Data System (ADS)

    Tavabi, E.; Koutchmy, S.

    2014-07-01

    Transverse oscillatory motions and recurrence behavior in the chromospheric jets observed by Hinode/SOT are studied. A comparison is considered with the behavior that was noticed in coronal X-ray jets observed by Hinode/XRT. A jet like bundle observed at the limb in Ca II H line appears to show a magnetic topology that is similar to X-ray jets (i.e., the Eiffel tower shape). The appearance of such magnetic topology is usually assumed to be caused by magnetic reconnection near a null point. Transverse motions of the jet axis are recorded but no clear evidence of twist is appearing from the highly processed movie. The aim is to investigate the dynamical behavior of an incompressible magnetic X-point occurring during the magnetic reconnection in the jet formation region. The viscous effect is specially considered in the closed line-tied magnetic X-shape nulls. We perform the MHD numerical simulation in 2-D by solving the visco-resistive MHD equations with the tracing of velocity and magnetic field. A qualitative agreement with Hinode observations is found for the oscillatory and non-oscillatory behaviors of the observed solar jets in both the chromosphere and the corona. Our results suggest that the viscous effect contributes to the excitation of the magnetic reconnection by generating oscillations that we observed at least inside this Ca II H line cool solar jet bundle.

  18. Dichotomy of X-Ray Jets in Solar Coronal Holes

    NASA Astrophysics Data System (ADS)

    Robe, D. M.; Moore, R. L.; Falconer, D. A.

    2012-12-01

    It has been found that there are two different types of X-ray jets observed in the Sun's polar coronal holes: standard jets and blowout jets. A proposed model of this dichotomy is that a standard jet is produced by a burst of reconnection of the ambient magnetic field with the opposite-polarity leg of the base arcade. In contrast, it appears that a blowout jet is produced when the interior of the arcade has so much pent-up free magnetic energy in the form of shear and twist in the interior field that the external reconnection unleashes the interior field to erupt open. In this project, X-ray movies of the polar coronal holes taken by Hinode were searched for X-ray jets. Co-temporal movies taken by the Solar Dynamics Observatory in 304 Å emission from He II, showing solar plasma at temperatures around 80,000 K, were examined for whether the identified blowout jets carry much more He II plasma than the identified standard jets. It was found that though some jets identified as standard from the X-ray movies could be seen in the He II 304 Å movies, the blowout jets carried much more 80,000 K plasma than did most standard jets. This finding supports the proposed model for the morphology and development of the two types of jets.

  19. Magnetic Untwisting in Most Solar X-Ray Jets

    NASA Astrophysics Data System (ADS)

    Moore, Ronald L.; Sterling, A. C.; Falconer, D.; Robe, D. M.

    2013-07-01

    From 54 X-ray jets observed in the polar coronal holes by Hinode’s X-Ray Telescope (XRT) during coverage in movies from Solar Dynamic Observatory’s Atmospheric Imaging Assembly (AIA) taken in its He II 304 Å band at a cadence of 12 s, we have established a basic characteristic of solar X-ray jets: untwisting motion in the spire. In this presentation, we show the progression of few of these X-ray jets in XRT images and track their untwisting in AIA He II images. From their structure displayed in their XRT movies, 19 jets were evidently standard jets made by interchange reconnection of the magnetic-arcade base with ambient open field, 32 were evidently blowout jets made by blowout eruption of the base arcade, and 3 were of ambiguous form. As was anticipated from the >10,000 km span of the base arcade in most polar X-ray jets and from the disparity of standard jets and blowout jets in their magnetic production, few of the standard X-ray jets (3 of 19) but nearly all of the blowout X-ray jets (29 of 32) carried enough cool (T ~ 10^5 K) plasma to be seen in their He II movies. In the 32 X-ray jets that showed a cool component, the He II movies show 10-100 km/s untwisting motions about the axis of the spire in all 3 standard jets and in 26 of the 29 blowout jets. Evidently, the open magnetic field in nearly all blowout X-ray jets and probably in most standard X-ray jets carries transient twist. This twist apparently relaxes by propagating out along the open field as a torsional wave. High-resolution spectrograms and Dopplergrams have shown that most Type-II spicules have torsional motions of 10-30 km/s. Our observation of similar torsional motion in X-ray jets (1) strengthens the case for Type-II spicules being made in the same way as X-ray jets, by blowout eruption of a twisted magnetic arcade in the spicule base and/or by interchange reconnection of the twisted base arcade with the ambient open field, and hence (2) strengthens the case made by Moore et al (2011

  20. Analyses of Simulated Reconnection-Driven Solar Polar Jets

    NASA Astrophysics Data System (ADS)

    Roberts, M. A.; Uritsky, V. M.; Karpen, J. T.; DeVore, C. R.

    2014-12-01

    Solar polar jets are observed to originate in regions within the open field of solar coronal holes. These so called "anemone" regions are generally accepted to be regions of opposite polarity, and are associated with an embedded dipole topology, consisting of a fan-separatrix and a spine line emanating from a null point occurring at the top of the dome shaped fan surface. Previous analysis of these jets (Pariat et al. 2009,2010) modeled using the Adaptively Refined Magnetohydrodynamics Solver (ARMS) has supported the claim that magnetic reconnection across current sheets formed at the null point between the highly twisted closed field of the dipole and open field lines surrounding it releases the energy necessary to drive these jets. However, these initial simulations assumed a "static" environment for the jets, neglecting effects due to gravity, solar wind and the expanding spherical geometry. A new set of ARMS simulations taking into account these additional physical processes was recently performed. Initial results are qualitatively consistent with the earlier Cartesian studies, demonstrating the robustness of the underlying ideal and resistive mechanisms. We focus on density and velocity fluctuations within a narrow radial slit aligned with the direction of the spine of the jet, as well as other physical properties, in order to identify and refine their signatures in the lower heliosphere. These refined signatures can be used as parameters by which plasma processes initiated by these jets may be identified in situ by future missions such as Solar Orbiter and Solar Probe Plus.

  1. Magnetic Untwisting in Most Solar X-Ray Jets

    NASA Technical Reports Server (NTRS)

    Moore, Ronald; Sterling, Alphonse; Falconer, David; Robe, Dominic

    2013-01-01

    From 54 X-ray jets observed in the polar coronal holes by Hinode's X-Ray Telescope (XRT) during coverage in movies from Solar Dynamic Observatory's Atmospheric Imaging Assembly (AIA) taken in its He II 304 Å band at a cadence of 12 s, we have established a basic characteristic of solar X-ray jets: untwisting motion in the spire. In this presentation, we show the progression of few of these X-ray jets in XRT images and track their untwisting in AIA He II images. From their structure displayed in their XRT movies, 19 jets were evidently standard jets made by interchange reconnection of the magnetic-arcade base with ambient open field, 32 were evidently blowout jets made by blowout eruption of the base arcade, and 3 were of ambiguous form. As was anticipated from the >10,000 km span of the base arcade in most polar X-ray jets and from the disparity of standard jets and blowout jets in their magnetic production, few of the standard X-ray jets (3 of 19) but nearly all of the blowout X-ray jets (29 of 32) carried enough cool (T is approximately 105 K) plasma to be seen in their He II movies. In the 32 X-ray jets that showed a cool component, the He II movies show 10-100 km/s untwisting motions about the axis of the spire in all 3 standard jets and in 26 of the 29 blowout jets. Evidently, the open magnetic field in nearly all blowout X-ray jets and probably in most standard X-ray jets carries transient twist. This twist apparently relaxes by propagating out along the open field as a torsional wave. High-resolution spectrograms and Dopplergrams have shown that most Type-II spicules have torsional motions of 10-30 km/s. Our observation of similar torsional motion in X-ray jets strengthens the case for Type-II spicules being made in the same way as X-ray jets, by blowout eruption of a twisted magnetic arcade in the spicule base and/or by interchange reconnection of the twisted base arcade with the ambient open field. This work was funded by NASA's Heliophysics Division

  2. The Contribution of Coronal Jets to the Solar Wind

    NASA Astrophysics Data System (ADS)

    Lionello, R.; Török, T.; Titov, V. S.; Leake, J. E.; Mikić, Z.; Linker, J. A.; Linton, M. G.

    2016-11-01

    Transient collimated plasma eruptions in the solar corona, commonly known as coronal (or X-ray) jets, are among the most interesting manifestations of solar activity. It has been suggested that these events contribute to the mass and energy content of the corona and solar wind, but the extent of these contributions remains uncertain. We have recently modeled the formation and evolution of coronal jets using a three-dimensional (3D) magnetohydrodynamic (MHD) code with thermodynamics in a large spherical domain that includes the solar wind. Our model is coupled to 3D MHD flux-emergence simulations, i.e., we use boundary conditions provided by such simulations to drive a time-dependent coronal evolution. The model includes parametric coronal heating, radiative losses, and thermal conduction, which enables us to simulate the dynamics and plasma properties of coronal jets in a more realistic manner than done so far. Here, we employ these simulations to calculate the amount of mass and energy transported by coronal jets into the outer corona and inner heliosphere. Based on observed jet-occurrence rates, we then estimate the total contribution of coronal jets to the mass and energy content of the solar wind to (0.4–3.0)% and (0.3–1.0)%, respectively. Our results are largely consistent with the few previous rough estimates obtained from observations, supporting the conjecture that coronal jets provide only a small amount of mass and energy to the solar wind. We emphasize, however, that more advanced observations and simulations (including parametric studies) are needed to substantiate this conjecture.

  3. Solar coronal holes as sources of recurrent geomagnetic disturbances

    NASA Technical Reports Server (NTRS)

    Neupert, W. M.; Pizzo, V.

    1974-01-01

    Observations of the solar corona by Oso 7 have been used in a superposed epoch analysis to study the relationships between classes of coronal features and geomagnetic activity. Both bright coronal regions and regions of less than average brightness were investigated. It was found that for the period from January 1972 through January 1973, a significant enhancement in geomagnetic activity occurred 2-3 days after central meridian passage of large coronal holes that extended to within 5 deg of the solar subearth point when they were on the meridian. Large coronal holes appear to satisfy the requirements for 'M regions' which were hypothesized to be responsible for recurrent geomagnetic disturbances (Bartels, 1934). If solar wind high-speed streams originate preferentially in these regions, their velocity at the base of the corona will be substantially higher than that expected from an axisymmetric solar wind model.

  4. A SOLAR CORONAL JET EVENT TRIGGERS A CORONAL MASS EJECTION

    SciTech Connect

    Liu, Jiajia; Wang, Yuming; Shen, Chenglong; Liu, Kai; Pan, Zonghao; Wang, S.

    2015-11-10

    In this paper, we present multi-point, multi-wavelength observations and analysis of a solar coronal jet and coronal mass ejection (CME) event. Employing the GCS model, we obtained the real (three-dimensional) heliocentric distance and direction of the CME and found it to propagate at a high speed of over 1000 km s{sup −1}. The jet erupted before the CME and shared the same source region. The temporal and spacial relationship between these two events lead us to the possibility that the jet triggered the CME and became its core. This scenario hold the promise of enriching our understanding of the triggering mechanism of CMEs and their relations to coronal large-scale jets. On the other hand, the magnetic field configuration of the source region observed by the Solar Dynamics Observatory (SDO)/HMI instrument along with the off-limb inverse Y-shaped configuration observed by SDO/AIA in the 171 Å passband provide the first detailed observation of the three-dimensional reconnection process of a large-scale jet as simulated in Pariat et al. The eruption process of the jet highlights the importance of filament-like material during the eruption of not only small-scale X-ray jets, but likely also of large-scale EUV jets. Based on our observations and analysis, we propose the most probable mechanism for the whole event, with a blob structure overlaying the three-dimensional structure of the jet, to describe the interaction between the jet and the CME.

  5. Eruptions that Drive Coronal Jets in a Solar Active Region

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.; Moore, Ronald L.; Falconer, David A.; Panesar, Navdeep K.; Akiyama, Sachiko; Yashiro, Seiji; Gopalswamy, Nat

    2016-01-01

    Solar coronal jets are common in both coronal holes and in active regions (e.g., Shibata et al. 1992, Shimojo et al. 1996, Cirtain et al. 2007. Savcheva et al. 2007). Recently, Sterling et al. (2015), using data from Hinode/XRT and SDO/AIA, found that coronal jets originating in polar coronal holes result from the eruption of small-scale filaments (minifilaments). The jet bright point (JBP) seen in X-rays and hotter EUV channels off to one side of the base of the jet's spire develops at the location where the minifilament erupts, consistent with the JBPs being miniature versions of typical solar flares that occur in the wake of large-scale filament eruptions. Here we consider whether active region coronal jets also result from the same minifilament-eruption mechanism, or whether they instead result from a different mechanism (e.g. Yokoyama & Shibata 1995). We present observations of an on-disk active region (NOAA AR 11513) that produced numerous jets on 2012 June 30, using data from SDO/AIA and HMI, and from GOES/SXI. We find that several of these active region jets also originate with eruptions of miniature filaments (size scale 20'') emanating from small-scale magnetic neutral lines of the region. This demonstrates that active region coronal jets are indeed frequently driven by minifilament eruptions. Other jets from the active region were also consistent with their drivers being minifilament eruptions, but we could not confirm this because the onsets of those jets were hidden from our view. This work was supported by funding from NASA/LWS, NASA/HGI, and Hinode. A full report of this study appears in Sterling et al. (2016).

  6. Revised View of Solar X-Ray Jets

    NASA Astrophysics Data System (ADS)

    Sterling, A. C.; Moore, R. L.; Falconer, D. A.; Adams, M.

    2015-12-01

    We investigate the onset of ~20 random X-ray jets observed by Hinode/XRT. Each jetwas near the limb in a polar coronal hole, and showed a ''bright point'' in anedge of the base of the jet, as is typical for previously-observed X-ray jets. Weexamined SDO/AIA EUV images of each of the jets over multiple AIA channels,including 304 Ang, which detects chromospheric emissions, and 171, 193, and 211 Ang,which detect cooler-coronal emissions. We find the jets to result from eruptionsof miniature (size <~10 arcsec) filaments from the bases of the jets. In manycases, much of the erupting-filament material forms a chromospheric-temperaturejet. In the cool-coronal channels, often the filament appears in absorption andthe hotter EUV component of the jet appears in emission. The jet bright point formsat the location from which the miniature filament erupts, analogous to theformation of a standard solar flare arcade via flare (``internal'') reconnection in the wake of the eruption of a typical larger-scale chromospheric filament. Thespire of the jet forms on open field lines that presumably have undergoneinterchange (''external'') reconnection with the erupting field that envelops andcarries the miniature filament. This is consistent with what we found for theonset of an on-disk coronal jet we examined in Adams et al. (2014), and theobservations of other workers. It is however not consistent with the basicversion of the ''emerging-flux model'' for X-ray jets. This work was supported byfunding from NASA/LWS, Hinode, and ISSI.

  7. Solar Polar Jets Driven by Magnetic Reconnection, Gravity, and Wind

    NASA Astrophysics Data System (ADS)

    DeVore, C. Richard; Karpen, Judith T.; Antiochos, Spiro K.

    2014-06-01

    Polar jets are dynamic, narrow, radially extended structures observed in solar EUV emission near the limb. They originate within the open field of coronal holes in “anemone” regions, which are intrusions of opposite magnetic polarity. The key topological feature is a magnetic null point atop a dome-shaped fan surface of field lines. Applied stresses readily distort the null into a current patch, eventually inducing interchange reconnection between the closed and open fields inside and outside the fan surface (Antiochos 1996). Previously, we demonstrated that magnetic free energy stored on twisted closed field lines inside the fan surface is released explosively by the onset of fast reconnection across the current patch (Pariat et al. 2009, 2010). A dense jet comprised of a nonlinear, torsional Alfvén wave is ejected into the outer corona along the newly reconnected open field lines. Now we are extending those exploratory simulations by including the effects of solar gravity, solar wind, and expanding spherical geometry. We find that the model remains robust in the resulting more complex setting, with explosive energy release and dense jet formation occurring in the low corona due to the onset of a kink-like instability, as found in the earlier Cartesian, gravity-free, static-atmosphere cases. The spherical-geometry jet including gravity and wind propagates far more rapidly into the outer corona and inner heliosphere than a comparison jet simulation that excludes those effects. We report detailed analyses of our new results, compare them with previous work, and discuss the implications for understanding remote and in-situ observations of solar polar jets.This work was supported by NASA’s LWS TR&T program.

  8. Jets and Plumes: What scale coronal phenomenal can be seen by SWEAP on Solar Probe Plus?

    NASA Astrophysics Data System (ADS)

    Korreck, Kelly E.; Case, Anthony; Kasper, Justin C.; Stevens, Michael L.; Whittlesey, Phyllis

    2016-05-01

    Coronal jets are reconnection events that are found most easily in coronal holes both polar and equatorial. Previous studies of coronal jets have associated the jets with microstream peaks in Ulysses solar wind data (Neugebauer, 2012 ). Plumes have been thought to contribute to both the slow and fast solar wind. Utilizing long-term studies of jets and plumes in x-ray and extreme ultraviolet coronal observations, we examine the signatures of these coronal features as seen in simulated Solar Probe Cup data. Simulated moment data representing density, velocity and temperature are created for the first Solar Probe Plus orbit.

  9. Tailor cutting of crystalline solar cells by laser micro jet

    NASA Astrophysics Data System (ADS)

    Bruckert, F.; Pilat, E.; Piron, P.; Torres, P.; Carron, B.; Richerzhagen, B.; Pirot, M.; Monna, R.

    2012-03-01

    Coupling a laser into a hair thin water micro jet (Laser Micro Jet, LMJ) for cutting applications offers a wide range of processes that are quite unique. As the laser beam is guided by internal reflections inside of a liquid cylinder, the cuts are naturally straight and do not reflect any divergence as otherwise occurs with an unguided laser beam. Furthermore, having a liquid media at the point of contact ensures a fast removal of heat and eventual debris ensuring clean cuts, which are free of any burrs. Many applications have indeed been developed for a large variety of materials, which are as different as e.g. diamond, silicon, aluminum, ceramic and hard metals. The photovoltaic industry has enjoyed in the last decades tremendous growth rates, which are still projected into the future. We focus here on the segment of Building Integrated PV (BIPV), which requests tailored solutions to actual buildings and not-one-fits-it-all standardized modules. Having the option to tailor cut solar cells opens a new field of BIPV applications. For the first time, finished crystalline solar cells have been LMJ cut into predetermined shapes. First results show that the cut is clean and neat. Preliminary solar performance measurements are positive. This opens a new avenue of tailored made modules instead of having to rely on the one-fits-alloy approach used so far.

  10. A Series of Streamer-Puff CMEs Driven by Solar Homologous Jets

    NASA Astrophysics Data System (ADS)

    Panesar, N. K.; Sterling, A. C.; Moore, R. L.

    2015-12-01

    Solar coronal jets are magnetically channeled narrow eruptions often observed in the solar atmosphere, typically in EUV and X-ray emission, and occurring in various solar environments including active regions and coronal holes. Their driving mechanism is still under discussion, but facts that we know about jets include: (a) they are ejected from or near sites of compact magnetic explosions (compact ejective solar flares), (b) they sometimes carry chromospheric material high into the corona along with coronal-temperature plasma, (c) the cool-material jet velocities can reach 100 km s-1 or more, and (d) some active-region jets produce coronal mass ejections (CMEs). Here we investigate characteristics of EUV jets that originated from active region NOAA 12192 and produced CMEs. This active region produced many non-jet major flare eruptions (X and M class) that made no CME. A multitude of jets also occurred in the region, and in contrast to the major-flare eruptions, seven of these jets resulted in CMEs. Our jet observations are from multiple SDO/AIA EUV channels, including 304, 171, 193 and 94 Å, and our CME observations are from SOHO/LASCO C2 images. Each jet-driven CME was relatively slow-moving; had angular width (30° - 70°) comparable to that of the streamer base; and was of the "streamer-puff" variety, whereby a preexisting streamer was transiently inflated but not removed (blown out) by the passage of the CME. Much of the chromospheric-temperature plasma of the jets producing the CMEs escaped from the Sun, whereas relatively more of the chromospheric plasma in the non-CME-producing jets fell back to the solar surface. We also found that the CME-producing jets tended to be faster in speed and longer in duration than the non-CME-producing jets. This research was supported by funding from NASA's LWS program.

  11. Recurrence of solar activity - Evidence for active longitudes

    NASA Technical Reports Server (NTRS)

    Bogart, R. S.

    1982-01-01

    It is pointed out that the autocorrelation coefficients of the daily Wolf sunspot numbers over a period of 128 years reveal a number of interesting features of the variability of solar activity. Besides establishing periodicities for the solar rotation, solar activity cycle, and, perhaps, the 'Gleissberg Cycle', they suggest that active longitudes do exist, but with much greater strength and persistence in some solar cycles than in others. Evidence is adduced for a variation in the solar rotation period, as measured by sunspot number, of as much as two days between different solar cycles.

  12. Coronal holes, solar wind streams, and recurrent geomagnetic disturbances - 1973-1976

    NASA Technical Reports Server (NTRS)

    Sheeley, N. R., Jr.; Harvey, J. W.; Feldman, W. C.

    1976-01-01

    Observations of coronal holes, solar-wind streams, and geomagnetic disturbances during 1973-1976 are compared in a 27-day pictorial format which shows their long-term evolution. The results leave little doubt that coronal holes are related to the high-speed streams and their associated recurrent geomagnetic disturbances. In particular, these observations strongly support the hypothesis that coronal holes are the solar origin of the high-speed streams observed in the solar wind near the ecliptic plane.

  13. Solar Jet-Coronal Hole Collision and a Closely Related Coronal Mass Ejection

    NASA Astrophysics Data System (ADS)

    Zheng, Ruisheng; Chen, Yao; Du, Guohui; Li, Chuanyang

    2016-03-01

    Jets are defined as impulsive, well-collimated upflows, occurring in different layers of the solar atmosphere with different scales. Their relationship with coronal mass ejections (CMEs), another type of solar impulsive events, remains elusive. Using high-quality imaging data from the Atmospheric Imaging Assembly/Solar Dynamics Observatory, we show a well-observed coronal jet event, in which the part of the jet with embedding coronal loops runs into a nearby coronal hole (CH) and gets bounced in the opposite direction. This is evidenced by the flat shape of the jet front during its interaction with the CH and the V-shaped feature in the time-slice plot of the interaction region. About a half-hour later, a CME with an initially narrow and jet-like front is observed by the LASCO C2 coronagraph propagating along the direction of the post-collision jet. We also observe some 304 Å dark material flowing from the jet-CH interaction region toward the CME. We thus suggest that the jet and the CME are physically connected, with the jet-CH collision and the large-scale magnetic topology of the CH being important in defining the eventual propagating direction of this particular jet-CME eruption.

  14. Fan-shaped Jets in Three-dimensional Reconnection Simulation as a Model of Ubiquitous Solar Jets

    NASA Astrophysics Data System (ADS)

    Jiang, Rong Lin; Shibata, Kazunari; Isobe, Hiroaki; Fang, Cheng

    2011-01-01

    Magnetic reconnection is a fundamental process in space and astrophysical plasmas in which the oppositely directed magnetic field changes its connectivity and eventually converts its energy into kinetic and thermal energy of the plasma. Recently, ubiquitous jets (for example, chromospheric anemone jets, penumbral microjets, umbral light bridge jets) have been observed by the Solar Optical Telescope on board the satellite Hinode. These tiny and frequently occurring jets are considered to be a possible evidence of small-scale ubiquitous reconnection in the solar atmosphere. However, the details of three-dimensional (3D) magnetic configuration are still not very clear. Here, we propose a new model based on 3D simulations of magnetic reconnection using a typical current sheet magnetic configuration with a strong guide field. The most interesting feature is that the jets produced by the reconnection eventually move along the guide field lines. This model provides a fresh understanding of newly discovered ubiquitous jets and moreover a new observational basis for the theory of astrophysical magnetic reconnection.

  15. FAN-SHAPED JETS IN THREE-DIMENSIONAL RECONNECTION SIMULATION AS A MODEL OF UBIQUITOUS SOLAR JETS

    SciTech Connect

    Jiang Ronglin; Fang Cheng; Shibata, Kazunari; Isobe, Hiroaki

    2011-01-10

    Magnetic reconnection is a fundamental process in space and astrophysical plasmas in which the oppositely directed magnetic field changes its connectivity and eventually converts its energy into kinetic and thermal energy of the plasma. Recently, ubiquitous jets (for example, chromospheric anemone jets, penumbral microjets, umbral light bridge jets) have been observed by the Solar Optical Telescope on board the satellite Hinode. These tiny and frequently occurring jets are considered to be a possible evidence of small-scale ubiquitous reconnection in the solar atmosphere. However, the details of three-dimensional (3D) magnetic configuration are still not very clear. Here, we propose a new model based on 3D simulations of magnetic reconnection using a typical current sheet magnetic configuration with a strong guide field. The most interesting feature is that the jets produced by the reconnection eventually move along the guide field lines. This model provides a fresh understanding of newly discovered ubiquitous jets and moreover a new observational basis for the theory of astrophysical magnetic reconnection.

  16. Chromospheric anemone jets and magnetic reconnection in partially ionized solar atmosphere

    NASA Astrophysics Data System (ADS)

    Singh, K. A. P.; Shibata, K.; Nishizuka, N.; Isobe, H.

    2011-11-01

    The solar optical telescope onboard Hinode with temporal resolution of less than 5 s and spatial resolution of 150 km has observed the lower solar atmosphere with an unprecedented detail. This has led to many important findings, one of them is the discovery of chromospheric anemone jets in the solar chromosphere. The chromospheric anemone jets are ubiquitous in solar chromosphere and statistical studies show that the typical length, life time and energy of the chromospheric anemone jets are much smaller than the coronal events (e.g., jets/flares/CMEs). Among various observational parameters, the apparent length and maximum velocity shows good correlation. The velocity of chromospheric anemone jets is comparable to the local Alfvén speed in the lower solar chromosphere. Since the discovery of chromospheric anemone jets by Hinode, several evidences of magnetic reconnection in chromospheric anemone jets have been found and these observations are summarized in this paper. These observations clearly suggest that reconnection occurs quite rapidly as well as intermittently in the solar chromosphere. In the solar corona (λi > δSP), anomalous resistivity arises due to various collisionless processes. Previous MHD simulations show that reconnection becomes fast as well as strongly time-dependent due to anomalous resistivity. Such processes would not arise in the solar chromosphere which is fully collisional and partially-ionized. So, it is unclear how the rapid and strongly time-dependent reconnection would occur in the solar chromosphere. It is quite likely that the Hall and ambipolar diffusion are present in the solar chromosphere and they could play an important role in driving such rapid, strongly time-dependent reconnection in the solar chromosphere.

  17. Chromospheric anemone jets and magnetic reconnection in partially ionized solar atmosphere

    SciTech Connect

    Singh, K. A. P.; Shibata, K.; Nishizuka, N.; Isobe, H.

    2011-11-15

    The solar optical telescope onboard Hinode with temporal resolution of less than 5 s and spatial resolution of 150 km has observed the lower solar atmosphere with an unprecedented detail. This has led to many important findings, one of them is the discovery of chromospheric anemone jets in the solar chromosphere. The chromospheric anemone jets are ubiquitous in solar chromosphere and statistical studies show that the typical length, life time and energy of the chromospheric anemone jets are much smaller than the coronal events (e.g., jets/flares/CMEs). Among various observational parameters, the apparent length and maximum velocity shows good correlation. The velocity of chromospheric anemone jets is comparable to the local Alfven speed in the lower solar chromosphere. Since the discovery of chromospheric anemone jets by Hinode, several evidences of magnetic reconnection in chromospheric anemone jets have been found and these observations are summarized in this paper. These observations clearly suggest that reconnection occurs quite rapidly as well as intermittently in the solar chromosphere. In the solar corona ({lambda}{sub i} > {delta}{sub SP}), anomalous resistivity arises due to various collisionless processes. Previous MHD simulations show that reconnection becomes fast as well as strongly time-dependent due to anomalous resistivity. Such processes would not arise in the solar chromosphere which is fully collisional and partially-ionized. So, it is unclear how the rapid and strongly time-dependent reconnection would occur in the solar chromosphere. It is quite likely that the Hall and ambipolar diffusion are present in the solar chromosphere and they could play an important role in driving such rapid, strongly time-dependent reconnection in the solar chromosphere.

  18. Model for straight and helical solar jets. I. Parametric studies of the magnetic field geometry

    NASA Astrophysics Data System (ADS)

    Pariat, E.; Dalmasse, K.; DeVore, C. R.; Antiochos, S. K.; Karpen, J. T.

    2015-01-01

    Context. Jets are dynamic, impulsive, well-collimated plasma events developing at many different scales and in different layers of the solar atmosphere. Aims: Jets are believed to be induced by magnetic reconnection, a process central to many astrophysical phenomena. Studying their dynamics can help us to better understand the processes acting in larger eruptive events (e.g., flares and coronal mass ejections) as well as mass, magnetic helicity, and energy transfer at all scales in the solar atmosphere. The relative simplicity of their magnetic geometry and topology, compared with larger solar active events, makes jets ideal candidates for studying the fundamental role of reconnection in energetic events. Methods: In this study, using our recently developed numerical solver ARMS, we present several parametric studies of a 3D numerical magneto-hydrodynamic model of solar-jet-like events. We studied the impact of the magnetic field inclination and photospheric field distribution on the generation and properties of two morphologically different types of solar jets, straight and helical, which can account for the observed so-called standard and blowout jets. Results: Our parametric studies validate our model of jets for different geometric properties of the magnetic configuration. We find that a helical jet is always triggered for the range of parameters we tested. This demonstrates that the 3D magnetic null-point configuration is a very robust structure for the energy storage and impulsive release characteristic of helical jets. In certain regimes determined by magnetic geometry, a straight jet precedes the onset of a helical jet. We show that the reconnection occurring during the straight-jet phase influences the triggering of the helical jet. Conclusions: Our results allow us to better understand the energization, triggering, and driving processes of straight and helical jets. Our model predicts the impulsiveness and energetics of jets in terms of the surrounding

  19. Energy spectrum of the recurrent cosmic rays variation during the solar minimum 23/24

    NASA Astrophysics Data System (ADS)

    Gil, Agnieszka; Alania, Michael

    2016-07-01

    We study temporal changes of the power-law energy/ rigidity spectrum of the first three harmonics of the recurrent variation of the galactic cosmic rays (GCR) intensity during the unusual solar minimum 23/24 and compare with four previous minima. We show that the energy spectrum of the amplitudes of the recurrent variation is soft in the minimum 23/24. Moreover, while the energy spectrum of the amplitudes of the first harmonic of the recurrent variation of the GCR intensity practically behaves as during earlier four minima, the energy spectrum of the amplitudes of the second and the third harmonics demonstrate a valuable softening. We attribute this phenomenon to the decrease of an extension of heliosphere caused by the drop of the solar wind dynamic pressure during the solar minimum 23/24.

  20. Multiple Plasma Ejections and Intermittent Nature of Magnetic Reconnection in Solar Chromospheric Anemone Jets

    NASA Astrophysics Data System (ADS)

    Singh, K. A. P.; Isobe, H.; Nishizuka, N.; Nishida, K.; Shibata, K.

    2012-11-01

    The recent discovery of chromospheric anemone jets with the Solar Optical Telescope (SOT) on board Hinode has shown an indirect evidence of magnetic reconnection in the solar chromosphere. However, the basic nature of magnetic reconnection in chromosphere is still unclear. We studied nine chromospheric anemone jets from SOT/Hinode using Ca II H filtergrams, and we found multiple bright, plasma ejections along the jets. In most cases, the major intensity enhancements (larger than 30% relative to the background intensity) of the loop correspond to the timing of the plasma ejections. The typical lifetime and size of the plasma ejecta are about 20-60 s and 0.3-1.5 Mm, respectively. The height-time plot of jet shows many sub-structures (or individual jets) and the typical lifetime of the individual jet is about one to five minutes. Before the onset of the jet activity, a loop appears in Ca II H and gradually increases in size, and after few minutes several jets are launched from the loop. Once the jet activity starts and several individual jets are launched, the loop starts shrinking with a speed of ~4 km s-1. In some events, a downward moving blob with a speed of ~35 km s-1 was observed, associated with the upward moving plasma along one of the legs of the loop hosting the jets. The upward moving plasma gradually developed into jets. Multiple plasma ejections in chromospheric anemone jet show the strongly time-dependent as well as intermittent nature of magnetic reconnection in the solar chromosphere.

  1. MULTIPLE PLASMA EJECTIONS AND INTERMITTENT NATURE OF MAGNETIC RECONNECTION IN SOLAR CHROMOSPHERIC ANEMONE JETS

    SciTech Connect

    Singh, K. A. P.; Nishida, K.; Shibata, K.; Isobe, H.; Nishizuka, N. E-mail: nishida@kwasan.kyoto-u.ac.jp E-mail: isobe@kwasan.kyoto-u.ac.jp

    2012-11-01

    The recent discovery of chromospheric anemone jets with the Solar Optical Telescope (SOT) on board Hinode has shown an indirect evidence of magnetic reconnection in the solar chromosphere. However, the basic nature of magnetic reconnection in chromosphere is still unclear. We studied nine chromospheric anemone jets from SOT/Hinode using Ca II H filtergrams, and we found multiple bright, plasma ejections along the jets. In most cases, the major intensity enhancements (larger than 30% relative to the background intensity) of the loop correspond to the timing of the plasma ejections. The typical lifetime and size of the plasma ejecta are about 20-60 s and 0.3-1.5 Mm, respectively. The height-time plot of jet shows many sub-structures (or individual jets) and the typical lifetime of the individual jet is about one to five minutes. Before the onset of the jet activity, a loop appears in Ca II H and gradually increases in size, and after few minutes several jets are launched from the loop. Once the jet activity starts and several individual jets are launched, the loop starts shrinking with a speed of {approx}4 km s{sup -1}. In some events, a downward moving blob with a speed of {approx}35 km s{sup -1} was observed, associated with the upward moving plasma along one of the legs of the loop hosting the jets. The upward moving plasma gradually developed into jets. Multiple plasma ejections in chromospheric anemone jet show the strongly time-dependent as well as intermittent nature of magnetic reconnection in the solar chromosphere.

  2. MAGNETIC UNTWISTING IN SOLAR JETS THAT GO INTO THE OUTER CORONA IN POLAR CORONAL HOLES

    SciTech Connect

    Moore, Ronald L.; Sterling, Alphonse C.; Falconer, David A.

    2015-06-10

    We study 14 large solar jets observed in polar coronal holes. In EUV movies from the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA), each jet appears similar to most X-ray jets and EUV jets that erupt in coronal holes; but each is exceptional in that it goes higher than most, so high that it is observed in the outer corona beyond 2.2 R{sub Sun} in images from the Solar and Heliospheric Observatory/Large Angle Spectroscopic Coronagraph (LASCO)/C2 coronagraph. From AIA He ii 304 Å movies and LASCO/C2 running-difference images of these high-reaching jets, we find: (1) the front of the jet transits the corona below 2.2 R{sub Sun} at a speed typically several times the sound speed; (2) each jet displays an exceptionally large amount of spin as it erupts; (3) in the outer corona, most of the jets display measureable swaying and bending of a few degrees in amplitude; in three jets the swaying is discernibly oscillatory with a period of order 1 hr. These characteristics suggest that the driver in these jets is a magnetic-untwisting wave that is basically a large-amplitude (i.e., nonlinear) torsional Alfvén wave that is put into the reconnected open field in the jet by interchange reconnection as the jet erupts. From the measured spinning and swaying, we estimate that the magnetic-untwisting wave loses most of its energy in the inner corona below 2.2 R{sub Sun}. We point out that the torsional waves observed in Type-II spicules might dissipate in the corona in the same way as the magnetic-untwisting waves in our big jets, and thereby power much of the coronal heating in coronal holes.

  3. Simulated In Situ Measurements and Structural Analysis of Reconnection-Driven Solar Polar Jets

    NASA Astrophysics Data System (ADS)

    Roberts, Merrill A.; Uritsky, Vadim M.; Karpen, Judith T.; DeVore, C. R.

    2015-04-01

    Solar polar jets are observed to originate in regions within the open field of solar coronal holes. These so called “anemone” regions are associated with an embedded dipole topology, consisting of a fan-separatrix and a spine line emanating from a null point occurring at the top of the dome shaped fan surface (Antiochos 1998). In this study, we analyze simulations using the Adaptively Refined MHD Solver (ARMS) that take into account gravity, solar wind, and spherical geometry to generate polar jets by reconnection between a twisted embedded bipole and the surrounding open field (Karpen et al. 2015). These new simulations confirm and extend previous Cartesian studies of polar jets based on this mechanism (Pariat et al. 2009, 2010, 2015). Focusing on the plasma density, velocity, and magnetic field, we interpolate the adaptively gridded simulation data onto a regular grid, and analyze the signatures that the jet produces as it propagates outward from the solar surface. The trans-Alfvénic nature of the jet front is confirmed by temporally differencing the plasma mass density and comparing the result with the local Alfvén speed. We perform a preliminary analysis of the magnetized plasma turbulence, and examine how the turbulence affects the overall structure of the jet. We also conduct simulated spacecraft fly-throughs of the jet, illustrating the signatures that spacecraft such as Solar Probe Plus may encounter in situ as the jet propagates into the heliosphere. These fly-throughs are performed in several different velocity regimes to better model the changing velocity of Solar Probe Plus relative to the Sun and its jets over the course of the mission.This research was supported by NASA grant NNG11PL10A 670.036 to CUA/IACS (M.A.R. and V.M.U.) and the Living With a Star Targeted Research and Technology (J.T.K. and C.R.D.) program.

  4. Homologous Jet-driven Coronal Mass Ejections from Solar Active Region 12192

    NASA Astrophysics Data System (ADS)

    Panesar, Navdeep K.; Sterling, Alphonse C.; Moore, Ronald L.

    2016-05-01

    We report observations of homologous coronal jets and their coronal mass ejections (CMEs) observed by instruments onboard the Solar Dynamics Observatory (SDO) and the Solar and Heliospheric Observatory (SOHO) spacecraft. The homologous jets originated from a location with emerging and canceling magnetic field at the southeastern edge of the giant active region (AR) of 2014 October, NOAA 12192. This AR produced in its interior many non-jet major flare eruptions (X- and M- class) that made no CME. During October 20 to 27, in contrast to the major flare eruptions in the interior, six of the homologous jets from the edge resulted in CMEs. Each jet-driven CME (˜200-300 km s-1) was slower-moving than most CMEs, with angular widths (20°-50°) comparable to that of the base of a coronal streamer straddling the AR and were of the “streamer-puff” variety, whereby the preexisting streamer was transiently inflated but not destroyed by the passage of the CME. Much of the transition-region-temperature plasma in the CME-producing jets escaped from the Sun, whereas relatively more of the transition-region plasma in non-CME-producing jets fell back to the solar surface. Also, the CME-producing jets tended to be faster and longer-lasting than the non-CME-producing jets. Our observations imply that each jet and CME resulted from reconnection opening of twisted field that erupted from the jet base and that the erupting field did not become a plasmoid as previously envisioned for streamer-puff CMEs, but instead the jet-guiding streamer-base loop was blown out by the loop’s twist from the reconnection.

  5. EVIDENCE FOR POLAR X-RAY JETS AS SOURCES OF MICROSTREAM PEAKS IN THE SOLAR WIND

    SciTech Connect

    Neugebauer, Marcia

    2012-05-01

    It is proposed that the interplanetary manifestations of X-ray jets observed in solar polar coronal holes during periods of low solar activity are the peaks of the so-called microstreams observed in the fast polar solar wind. These microstreams exhibit velocity fluctuations of {+-}35 km s{sup -1}, higher kinetic temperatures, slightly higher proton fluxes, and slightly higher abundances of the low-first-ionization-potential element iron relative to oxygen ions than the average polar wind. Those properties can all be explained if the fast microstreams result from the magnetic reconnection of bright-point loops, which leads to X-ray jets which, in turn, result in solar polar plumes. Because most of the microstream peaks are bounded by discontinuities of solar origin, jets are favored over plumes for the majority of the microstream peaks.

  6. Latitude variation of recurrent fluxes in the outer solar system

    NASA Technical Reports Server (NTRS)

    Christon, S. P.; Stone, E. C.

    1985-01-01

    Recurrent low energy (greater than or = to 0.5 MeV) proton flux enhancements, reliable indicators of corotating plasma interaction regions, were observed on the Voyager 1 and 2 and Pioneer 11 spacecraft in the heliographic latitude range 2 deg S to 23 N and the heliocentric radial range 11 to 20 AU. After a period of rather high correlation between fluxes at different latitudes in early 1983, distinct differences developed in the fluxes during an overall flux decrease. The flux intensities returned to higher levels in early 1984 and differences in both the recurrence frequency and flux intensity persisted into 1985, as Voyager 1 traveled to 23 AU and 25 N latitude. Intercomparison of data from the three spacecraft indicates that the flux differences are most likely due to latitudinal rather than radial or temporal variations.

  7. The quasi-periodic behavior of recurrent jets caused by emerging magnetic flux

    NASA Astrophysics Data System (ADS)

    Li, H. D.; Jiang, Y. C.; Yang, J. Y.; Bi, Y.; Liang, H. F.

    2015-10-01

    A series of recurring jets occurred at the edge of an active region NOAA 11459 on 2012 April 20, and they were observed simultaneously at EUV and soft X-ray wavelengths. They also were sometimes associated with a hard X-ray source at the base region. The jets might have resulted from magnetic reconnection between the newly emerging flux and the preexisting magnetic field that corresponded to the footpoint region of large-scale coronal loops. We obtained two periods of 171 Å intensity variations at the jet footpoint region, which were about 5 and 13 min. At the jet base, the short and long periodic brightenings might have originated from magneto-acoustic waves and magnetic reconnection. It is plausible that the p-modes might possibly trigger magnetic reconnection, and that reconnection might release stored magnetic energy to produce the jets.

  8. SOLAR POLAR X-RAY JETS AND MULTIPLE BRIGHT POINTS: EVIDENCE FOR SYMPATHETIC ACTIVITY

    SciTech Connect

    Pucci, Stefano; Romoli, Marco; Poletto, Giannina; Sterling, Alphonse C.

    2012-02-15

    We present an analysis of X-ray bright points (BPs) and X-ray jets observed by Hinode/X-Ray Telescope on 2007 November 2-4, within the solar northern polar coronal hole. After selecting small subregions that include several BPs, we followed their brightness evolution over a time interval of a few hours, when several jets were observed. We find that most of the jets occurred in close temporal association with brightness maxima in multiple BPs: more precisely, most jets are closely correlated with the brightening of at least two BPs. We suggest that the jets result from magnetic connectivity changes that also induce the BP variability. We surmise that the jets and implied magnetic connectivity we describe are small-scale versions of the active-region-scale phenomenon, whereby flares and eruptions are triggered by interacting bipoles.

  9. Numerical Simulations of Solar Spicule Jets at a Magnetic Null-Point

    NASA Astrophysics Data System (ADS)

    Smirnova, V.; Konkol, P. M.; Solov'ev, A. A.; Murawski, K.

    2016-09-01

    Two-dimensional numerical simulations of jet-like structures in the solar atmosphere are performed. These structures result from a pressure pulse that is launched at the null point of a potential magnetic arcade. The plasma jet exhibits a double structure with two components: (a) dense, cool, and short vertical stream and (b) a less dense, hot and tall part of the jet. The upper part of the hot and tall jet may represent a direct response of the system to the pressure pulse launched at the null point, and the second, slower cool and dense part of the jet is formed later through the stretching up of the stream as a result of plasma evacuation from the top of the magnetic arcade. Numerical results show that jet-like structures mimic some properties of both type I and type II spicules, according to the classification provided by De Pontieu et al. (Publ. Astron. Soc. Japan 59, S655, 2007).

  10. Reconnection-Driven Solar Polar Jets to be Encountered by Solar Probe Plus: Simulated In Situ Measurements and Data Analysis

    NASA Astrophysics Data System (ADS)

    Uritsky, V. M.; Roberts, M. A.; Karpen, J. T.; DeVore, C. R.

    2015-12-01

    Solar polar jets are observed to originate in regions within the open field of solar coronal holes. These so called "anemone" regions are associated with an embedded dipole topology, consisting of a fan-separatrix and a spine line emanating from a null point occurring at the top of the dome shaped fan surface (Antiochos 1996). In this study, we analyze simulations using the Adaptively Refined MHD Solver (ARMS) that take into account gravity, solar wind, and spherical geometry to generate polar jets by reconnection between a twisted embedded bipole and the surrounding open field (Karpen et al. 2015). These simulations confirm and extend previous Cartesian studies of polar jets based on this mechanism (Pariat et al. 2009, 2010, 2015), as well as extending the analyses from our previous work (Roberts et al. 2014,2015) out to radial distances that will be sampled by Solar Probe Plus. Focusing on the plasma density, velocity, magnetic field, and current density, we interpolate the adaptively gridded simulation data onto a regular grid, and analyze the signatures that the jet produces as it propagates outward from the solar surface into the inner heliosphere. We also conduct simulated spacecraft fly-throughs of the jet in several different velocity regimes, illustrating the signatures that Solar Probe Plus may encounter in situ as the jet propagates into the heliosphere. The trans-Alfvénic nature of the jet front is confirmed by temporally differencing the plasma mass density and comparing the result with the local Alfvén speed. Our analysis confirms the presence of a reconnection driven magnetic turbulence in the simulated plasma jet, finding spatial correlations of magnetic fluctuations inside the jet to be in agreement with the scaling model of MHD turbulence. The turbulence cascade is supported by multiscale current sheets combined with filamentary structures representing fluid vorticies. The spatial orientation of these current sheets, combined with the anisotropy

  11. A thermodynamic analysis of a solar-powered jet refrigeration system

    NASA Technical Reports Server (NTRS)

    Lansing, F. L.; Chai, V. W.

    1980-01-01

    The article describes and analyzes a method of using solar energy to drive a jet refrigeration system. A new technique is presented in the form of a performance nomogram combining the energy and momentum equations to determine the performance characteristics. A numerical example, using water as the working fluid, is given to illustrate the nomogram procedure. The resulting coefficient of performance was found comparable with other refrigeration systems such as the solar-absorption system or the solar-Rankine turbocompressor system.

  12. Small-Scale Filament Eruptions Leading to Solar X-Ray Jets

    NASA Astrophysics Data System (ADS)

    Sterling, Alphonse; Moore, Ronald; Falconer, David

    2015-04-01

    We investigate the onset of ~10 random X-ray jets observed by Hinode/XRT. Each jet was near the limb in a polar coronal hole, and showed a ``bright point'' in an edge of the base of the jet, as is typical for previously-observed X-ray jets. We examined SDO/AIA EUV images of each of the jets over multiple AIA channels, including 304 Å, which detects chromospheric emissions, and 171, 193, and 211 Å, which detect cooler-coronal emissions. We find the jets to result from eruptions of miniature (size <~10 arcsec) filaments from the bases of the jets. Much of the erupting-filament material forms a chromospheric-temperature jet. In the cool-coronal channels, often the filament appears in absorption and the hotter EUV component of the jet appears in emission. The jet bright point forms at the location from which the miniature filament erupts, analogous to the formation of a standard solar flare arcade in the wake of the eruption of a typical larger-scalechromospheric filament. The spire of the jet forms on open field lines that presumably have undergone interchange reconnection with the erupting field that envelops and carries the miniature filament. Thus these X-ray jets and their bright points are made by miniature filament eruptions via ``internal'' and ``external'' reconnection of the erupting field. This is consistent with what we found for the onset of an on-disk coronal jet we examined in Adams et al. (2014). This work was supported by funding from NASA/LWS, Hinode, and ISSI.

  13. A Series of Streamer-Puff CMEs Driven by Solar Homologous Jets from Active Region 12192

    NASA Astrophysics Data System (ADS)

    Panesar, Navdeep K.; Sterling, Alphonse C.; Moore, Ronald L.

    2016-05-01

    We investigate characteristics of solar coronal jets that originated from active region NOAA 12192 and produced coronal mass ejections (CMEs). This active region produced many non-jet major flare eruptions (X and M class) that made no CME. A multitude of jets occurred from the southeast edge of the active region, and in contrast to the major-flare eruptions in the core, six of these jets resulted in CMEs. Our jet observations are from multiple SDO/AIA EUV channels, including 304, 171 and 193Å, and CME observations are taken from SOHO/LASCO C2 coronograph. Each jet-driven CME was relatively slow-moving (~200 - 300 km s-1) compared to most CMEs; had angular width (20° - 50°) comparable to that of the streamer base; and was of the “streamer-puff” variety, whereby a preexisting streamer was transiently inflated but not removed (blown out) by the passage of the CME. Much of the chromospheric-temperature plasma of the jets producing the CMEs escaped from the Sun, whereas relatively more of the chromospheric plasma in the non-CME-producing jets fell back to the solar surface. We also found that the CME-producing jets tended to be faster in speed and longer in duration than the non-CME-producing jets. We expect that the jets result from eruptions of minifilaments (Sterling et al. 2015). We further propose that the CMEs are driven by magnetic twist injected into streamer-base coronal loops when erupting-twisted-minifilament field reconnects with the ambient field at the foot of those loops. This research was supported by funding from NASA's LWS program.

  14. Minifilament Eruptions that Drive Coronal Jets in a Solar Active Region

    NASA Astrophysics Data System (ADS)

    Sterling, Alphonse C.; Moore, Ronald L.; Falconer, David; Panesar, Navdeep; Akiyama, Sachiko; Yashiro, Seiji; Gopalswamy, Nat

    2016-05-01

    Solar coronal jets are common in both coronal holes and in active regions. Recently, Sterling et al. (2015), using data from Hinode/XRT and SDO/AIA, found that coronal jets originating in polar coronal holes result from the eruption of small-scale filaments (minifilaments). The jet bright point (JBP) seen in X-rays and hotter EUV channels off to one side of the base of the jet's spire develops at the location where the minifilament erupts, consistent with the JBPs being miniature versions of typical solar flares that occur in the wake of large-scale filament eruptions. Here we consider whether active region coronal jets also result from the same minifilament-eruption mechanism, or whether they instead result from a different mechanism, such as the hitherto popular ``emerging flux'' model for jets. We present observations of an on-disk active region that produced numerous jets on 2012 June 30, using data from SDO/AIA and HMI, and from GOES/SXI. We find that several of these active region jets also originate with eruptions of miniature filaments (size scale ~20'') emanating from small-scale magnetic neutral lines of the region. This demonstrates that active region coronal jets are indeed frequently driven by minifilament eruptions. Other jets from the active region were also consistent with their drivers being minifilament eruptions, but we could not confirm this because the onsets of those jets were hidden from our view. This work was supported by funding from NASA/LWS, NASA/HGI, and Hinode.

  15. ON A CORONAL BLOWOUT JET: THE FIRST OBSERVATION OF A SIMULTANEOUSLY PRODUCED BUBBLE-LIKE CME AND A JET-LIKE CME IN A SOLAR EVENT

    SciTech Connect

    Shen Yuandeng; Liu Yu

    2012-02-01

    The coronal blowout jet is a peculiar category among various jet phenomena, in which the sheared base arch, often carrying a small filament, experiences a miniature version of blowout eruption that produces large-scale coronal mass ejection (CME). In this paper, we report such a coronal blowout jet with high-resolution multi-wavelength and multi-angle observations taken from Solar Dynamics Observatory, Solar Terrestrial Relations Observatory, and Big Bear Solar Observatory. For the first time, we find that simultaneous bubble-like and jet-like CMEs were dynamically related to the blowout jet that showed cool and hot components next to each other. Our observational results indicate that (1) the cool component resulted from the eruption of the filament contained within the jet's base arch, and it further caused the bubble-like CME; (2) the jet-like CME was associated with the hot component, which was the outward moving heated plasma generated by the reconnection of the base arch and its ambient open field lines. On the other hand, bifurcation of the jet's cool component was also observed, which resulted from the uncoupling of the erupting filament's two legs that were highly twisted at the very beginning. Based on these results, we propose a model to interpret the coronal blowout jet, in which the external reconnection not only produces the jet-like CME, but also leads to the rising of the filament. Subsequently, internal reconnection starts underneath the rising filament and thereby causes the bubble-like CME.

  16. Stability of Rotating Magnetized Jets in the Solar Atmosphere. I. Kelvin–Helmholtz Instability

    NASA Astrophysics Data System (ADS)

    Zaqarashvili, Teimuraz V.; Zhelyazkov, Ivan; Ofman, Leon

    2015-11-01

    Observations show various jets in the solar atmosphere with significant rotational motions, which may undergo instabilities leading to heat ambient plasma. We study the Kelvin–Helmholtz instability (KHI) of twisted and rotating jets caused by the velocity jumps near the jet surface. We derive a dispersion equation with appropriate boundary conditions for total pressure (including centrifugal force of tube rotation), which governs the dynamics of incompressible jets. Then, we obtain analytical instability criteria of KHI in various cases, which were verified by numerical solutions to the dispersion equation. We find that twisted and rotating jets are unstable to KHI when the kinetic energy of rotation is more than the magnetic energy of the twist. Our analysis shows that the azimuthal magnetic field of 1–5 G can stabilize observed rotations in spicule/macrospicules and X-ray/extreme-ultraviolet (EUV) jets. On the other hand, nontwisted jets are always unstable to KHI. In this case, the instability growth time is several seconds for spicule/macrospicules and a few minutes (or less) for EUV/X-ray jets. We also find that standing kink and torsional Alfvén waves are always unstable near the antinodes, owing to the jump of azimuthal velocity at the surface, while the propagating waves are generally stable. Kelvin–Helmholtz (KH) vortices may lead to enhanced turbulence development and heating of surrounding plasma therefore, rotating jets may provide energy for chromospheric and coronal heating.

  17. STABILITY OF ROTATING MAGNETIZED JETS IN THE SOLAR ATMOSPHERE. I. KELVIN–HELMHOLTZ INSTABILITY

    SciTech Connect

    Zaqarashvili, Teimuraz V.; Zhelyazkov, Ivan; Ofman, Leon

    2015-11-10

    Observations show various jets in the solar atmosphere with significant rotational motions, which may undergo instabilities leading to heat ambient plasma. We study the Kelvin–Helmholtz instability (KHI) of twisted and rotating jets caused by the velocity jumps near the jet surface. We derive a dispersion equation with appropriate boundary conditions for total pressure (including centrifugal force of tube rotation), which governs the dynamics of incompressible jets. Then, we obtain analytical instability criteria of KHI in various cases, which were verified by numerical solutions to the dispersion equation. We find that twisted and rotating jets are unstable to KHI when the kinetic energy of rotation is more than the magnetic energy of the twist. Our analysis shows that the azimuthal magnetic field of 1–5 G can stabilize observed rotations in spicule/macrospicules and X-ray/extreme-ultraviolet (EUV) jets. On the other hand, nontwisted jets are always unstable to KHI. In this case, the instability growth time is several seconds for spicule/macrospicules and a few minutes (or less) for EUV/X-ray jets. We also find that standing kink and torsional Alfvén waves are always unstable near the antinodes, owing to the jump of azimuthal velocity at the surface, while the propagating waves are generally stable. Kelvin–Helmholtz (KH) vortices may lead to enhanced turbulence development and heating of surrounding plasma; therefore, rotating jets may provide energy for chromospheric and coronal heating.

  18. Ink jet assisted metallization for low cost flat plate solar cells

    NASA Technical Reports Server (NTRS)

    Teng, K. F.; Vest, R. W.

    1987-01-01

    Computer-controlled ink-jet-assisted metallization of the front surface of solar cells with metalorganic silver inks offers a maskless alternative method to conventional photolithography and screen printing. This method can provide low cost, fine resolution, reduced process complexity, avoidance of degradation of the p-n junction by firing at lower temperature, and uniform line film on rough surface of solar cells. The metallization process involves belt furnace firing and thermal spiking. With multilayer ink jet printing and firing, solar cells of about 5-6 percent efficiency without antireflection (AR) coating can be produced. With a titanium thin-film underlayer as an adhesion promoter, solar cells of average efficiency 8.08 percent without AR coating can be obtained. This efficiency value is approximately equal to that of thin-film solar cells of the same lot. Problems with regard to lower inorganic content of the inks and contact resistance are noted.

  19. Magnetic Untwisting in Solar Jets that Go into the Outer Corona in Polar Coronal Holes

    NASA Technical Reports Server (NTRS)

    Moore, Ronald L.; Sterling, Alphonse C.; Falconer, David A.

    2014-01-01

    We present results from 14 exceptionally high-reaching large solar jets observed in the polar coronal holes. EUV movies from SDO/AIA show that each jet is similar to many other similar-size and smaller jets that erupt in coronal holes, but each is exceptional in that it goes higher than most other jets, so high that it is observed in the outer corona beyond 2.2 R(sub Sun) in images from the SOHO/LASCO/C2 coronagraph. For these high-reaching jets, we find: (1) the front of the jet transits the corona below 2.2 R(sub Sun) at a speed typically several times the sound speed; (2) each jet displays an exceptionally large amount of spin as it erupts; (3) in the outer corona, most jets display oscillatory swaying having an amplitude of a few degrees and a period of order 1 hour. We conclude that these jets are magnetically driven, propose that the driver is a magnetic-untwisting wave that is grossly a large-amplitude (i.e., nonlinear) torsional Alfven wave that is put into the reconnected open magnetic field in the jet by interchange reconnection as the jet erupts, and estimate from the measured spinning and swaying that the magnetic-untwisting wave loses most of its energy in the inner corona below 2.2 R(sub Sun). From these results for these big jets, we reason that the torsional magnetic waves observed in Type-II spicules should dissipate in the corona in the same way and could thereby power much of the coronal heating in coronal holes.

  20. Twisting solar coronal jet launched at the boundary of an active region

    NASA Astrophysics Data System (ADS)

    Schmieder, B.; Guo, Y.; Moreno-Insertis, F.; Aulanier, G.; Yelles Chaouche, L.; Nishizuka, N.; Harra, L. K.; Thalmann, J. K.; Vargas Dominguez, S.; Liu, Y.

    2013-11-01

    Aims: A broad jet was observed in a weak magnetic field area at the edge of active region NOAA 11106 that also produced other nearby recurring and narrow jets. The peculiar shape and magnetic environment of the broad jet raised the question of whether it was created by the same physical processes of previously studied jets with reconnection occurring high in the corona. Methods: We carried out a multi-wavelength analysis using the EUV images from the Atmospheric Imaging Assembly (AIA) and magnetic fields from the Helioseismic and Magnetic Imager (HMI) both on-board the Solar Dynamics Observatory, which we coupled to a high-resolution, nonlinear force-free field extrapolation. Local correlation tracking was used to identify the photospheric motions that triggered the jet, and time-slices were extracted along and across the jet to unveil its complex nature. A topological analysis of the extrapolated field was performed and was related to the observed features. Results: The jet consisted of many different threads that expanded in around 10 minutes to about 100 Mm in length, with the bright features in later threads moving faster than in the early ones, reaching a maximum speed of about 200 km s-1. Time-slice analysis revealed a striped pattern of dark and bright strands propagating along the jet, along with apparent damped oscillations across the jet. This is suggestive of a (un)twisting motion in the jet, possibly an Alfvén wave. Bald patches in field lines, low-altitude flux ropes, diverging flow patterns, and a null point were identified at the basis of the jet. Conclusions: Unlike classical λ or Eiffel-tower-shaped jets that appear to be caused by reconnection in current sheets containing null points, reconnection in regions containing bald patches seems to be crucial in triggering the present jet. There is no observational evidence that the flux ropes detected in the topological analysis were actually being ejected themselves, as occurs in the violent phase of

  1. Corotating Solar Wind Structures and Recurrent Trains of Enhanced Diurnal Variation in Galactic Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Yeeram, T.; Ruffolo, D.; Sáiz, A.; Kamyan, N.; Nutaro, T.

    2014-04-01

    Data from the Princess Sirindhorn Neutron Monitor at Doi Inthanon, Thailand, with a vertical cutoff rigidity of 16.8 GV, were utilized to determine the diurnal anisotropy (DA) of Galactic cosmic rays (GCRs) near Earth during solar minimum conditions between 2007 November and 2010 November. We identified trains of enhanced DA over several days, which often recur after a solar rotation period (~27 days). By investigating solar coronal holes as identified from synoptic maps and solar wind parameters, we found that the intensity and anisotropy of cosmic rays are associated with the high-speed streams (HSSs) in the solar wind, which are in turn related to the structure and evolution of coronal holes. An enhanced DA was observed after the onset of some, but not all, HSSs. During time periods of recurrent trains, the DA was often enhanced or suppressed according to the sign of the interplanetary magnetic field B, which suggests a contribution from a mechanism involving a southward gradient in the GCR density, n, and a gradient anisotropy along B × ∇n. In one non-recurrent and one recurrent sequence, an HSS from an equatorial coronal hole was merged with that from a trailing mid-latitude extension of a polar coronal hole, and the slanted HSS structure in space with suppressed GCR density can account for the southward GCR gradient. We conclude that the gradient anisotropy is a source of temporary changes in the GCR DA under solar minimum conditions, and that the latitudinal GCR gradient can sometimes be explained by the coronal hole morphology.

  2. Corotating solar wind structures and recurrent trains of enhanced diurnal variation in galactic cosmic rays

    SciTech Connect

    Yeeram, T.; Ruffolo, D.; Sáiz, A.; Kamyan, N.; Nutaro, T. E-mail: david.ruf@mahidol.ac.th E-mail: p_chang24@hotmail.com

    2014-04-01

    Data from the Princess Sirindhorn Neutron Monitor at Doi Inthanon, Thailand, with a vertical cutoff rigidity of 16.8 GV, were utilized to determine the diurnal anisotropy (DA) of Galactic cosmic rays (GCRs) near Earth during solar minimum conditions between 2007 November and 2010 November. We identified trains of enhanced DA over several days, which often recur after a solar rotation period (∼27 days). By investigating solar coronal holes as identified from synoptic maps and solar wind parameters, we found that the intensity and anisotropy of cosmic rays are associated with the high-speed streams (HSSs) in the solar wind, which are in turn related to the structure and evolution of coronal holes. An enhanced DA was observed after the onset of some, but not all, HSSs. During time periods of recurrent trains, the DA was often enhanced or suppressed according to the sign of the interplanetary magnetic field B, which suggests a contribution from a mechanism involving a southward gradient in the GCR density, n, and a gradient anisotropy along B × ∇n. In one non-recurrent and one recurrent sequence, an HSS from an equatorial coronal hole was merged with that from a trailing mid-latitude extension of a polar coronal hole, and the slanted HSS structure in space with suppressed GCR density can account for the southward GCR gradient. We conclude that the gradient anisotropy is a source of temporary changes in the GCR DA under solar minimum conditions, and that the latitudinal GCR gradient can sometimes be explained by the coronal hole morphology.

  3. Jet Propulsion Laboratory's Space Explorations Part 2: Solar System Exploration

    NASA Technical Reports Server (NTRS)

    Chau, Savio

    2005-01-01

    This slide presentation reviews what is currently known about the solar system and the objects that make up the solar system. Information about the individual planets, comets, asteroids and moons is reviewed.

  4. The cool component and the dichotomy, lateral expansion, and axial rotation of solar X-ray jets

    SciTech Connect

    Moore, Ronald L.; Sterling, Alphonse C.; Falconer, David A.; Robe, Dominic

    2013-06-01

    We present results from a study of 54 polar X-ray jets that were observed in coronal X-ray movies from the X-ray Telescope on Hinode and had simultaneous coverage in movies of the cooler transition region (T ∼ 10{sup 5} K) taken in the He II 304 Å band of the Atmospheric Imaging Assembly (AIA) on Solar Dynamics Observatory. These dual observations verify the standard-jet/blowout-jet dichotomy of polar X-ray jets previously found primarily from XRT movies alone. In accord with models of blowout jets and standard jets, the AIA 304 Å movies show a cool (T ∼ 10{sup 5} K) component in nearly all blowout X-ray jets and in a small minority of standard X-ray jets, obvious lateral expansion in blowout X-ray jets but none in standard X-ray jets, and obvious axial rotation in both blowout X-ray jets and standard X-ray jets. In our sample, the number of turns of axial rotation in the cool-component standard X-ray jets is typical of that in the blowout X-ray jets, suggesting that the closed bipolar magnetic field in the jet base has substantial twist not only in all blowout X-ray jets but also in many standard X-ray jets. We point out that our results for the dichotomy, lateral expansion, and axial rotation of X-ray jets add credence to published speculation that type-II spicules are miniature analogs of X-ray jets, are generated by granule-size emerging bipoles, and thereby carry enough energy to power the corona and solar wind.

  5. A 17 June 2011 polar jet and its presence in the background solar wind

    NASA Astrophysics Data System (ADS)

    Yu, H.-S.; Jackson, B. V.; Yang, Y.-H.; Chen, N.-H.; Buffington, A.; Hick, P. P.

    2016-06-01

    High-speed jet responses in the polar solar wind are enigmatic. Here we measure a jet response that emanates from the southern polar coronal hole on 17 June 2011 at the extreme speed of over 1200 km/s. This response was recorded from the Sun-Earth line in Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) and Large Angle and Spectrometric Coronagraph/C2 and both Solar TErrestrial RElations Observatory Extreme Ultraviolet Imager and COR2 coronagraphs when the three spacecraft were situated ~90° from one another. These certify the coronal 3-D location of the response that is associated with an existing solar plume structure and show its high speed to distances of over 14 RS. This jetting is associated with magnetic flux changes in the polar region as measured by the SDO/Helioseismic and Magnetic Imager instrumentation over a period of several hours. The fastest coronal response observed can be tracked to a time near the period of greatest flux changes and to the onset of the brightest flaring in AIA. This high-speed response can be tracked directly as a small patch of outward moving brightness in coronal images as in Yu et al. (2014) where three slower events were followed from the perspective of Earth. This accumulated jet response has the largest mass and energy we have yet seen in 3-D reconstructions from Solar Mass Ejection Imager observations, and its outward motion is certified for the first time using interplanetary scintillation observations. This jet response is surrounded by similar high-speed patches, but these are smoothed out in Ulysses polar measurements, we speculate about how these dynamic activities relate to solar wind acceleration.

  6. Prevalence of small-scale jets from the networks of the solar transition region and chromosphere.

    PubMed

    Tian, H; DeLuca, E E; Cranmer, S R; De Pontieu, B; Peter, H; Martínez-Sykora, J; Golub, L; McKillop, S; Reeves, K K; Miralles, M P; McCauley, P; Saar, S; Testa, P; Weber, M; Murphy, N; Lemen, J; Title, A; Boerner, P; Hurlburt, N; Tarbell, T D; Wuelser, J P; Kleint, L; Kankelborg, C; Jaeggli, S; Carlsson, M; Hansteen, V; McIntosh, S W

    2014-10-17

    As the interface between the Sun's photosphere and corona, the chromosphere and transition region play a key role in the formation and acceleration of the solar wind. Observations from the Interface Region Imaging Spectrograph reveal the prevalence of intermittent small-scale jets with speeds of 80 to 250 kilometers per second from the narrow bright network lanes of this interface region. These jets have lifetimes of 20 to 80 seconds and widths of ≤300 kilometers. They originate from small-scale bright regions, often preceded by footpoint brightenings and accompanied by transverse waves with amplitudes of ~20 kilometers per second. Many jets reach temperatures of at least ~10(5) kelvin and constitute an important element of the transition region structures. They are likely an intermittent but persistent source of mass and energy for the solar wind. PMID:25324395

  7. Prevalence of small-scale jets from the networks of the solar transition region and chromosphere.

    PubMed

    Tian, H; DeLuca, E E; Cranmer, S R; De Pontieu, B; Peter, H; Martínez-Sykora, J; Golub, L; McKillop, S; Reeves, K K; Miralles, M P; McCauley, P; Saar, S; Testa, P; Weber, M; Murphy, N; Lemen, J; Title, A; Boerner, P; Hurlburt, N; Tarbell, T D; Wuelser, J P; Kleint, L; Kankelborg, C; Jaeggli, S; Carlsson, M; Hansteen, V; McIntosh, S W

    2014-10-17

    As the interface between the Sun's photosphere and corona, the chromosphere and transition region play a key role in the formation and acceleration of the solar wind. Observations from the Interface Region Imaging Spectrograph reveal the prevalence of intermittent small-scale jets with speeds of 80 to 250 kilometers per second from the narrow bright network lanes of this interface region. These jets have lifetimes of 20 to 80 seconds and widths of ≤300 kilometers. They originate from small-scale bright regions, often preceded by footpoint brightenings and accompanied by transverse waves with amplitudes of ~20 kilometers per second. Many jets reach temperatures of at least ~10(5) kelvin and constitute an important element of the transition region structures. They are likely an intermittent but persistent source of mass and energy for the solar wind.

  8. A coronal hole jet observed with Hinode and the Solar Dynamics Observatory

    NASA Astrophysics Data System (ADS)

    Young, Peter R.; Muglach, Karin

    2014-12-01

    A small blowout jet was observed at the boundary of the south polar coronal hole on 2011 February 8 at around 21:00 UT. Images from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) revealed an expanding loop rising from one footpoint of a compact, bipolar bright point. Magnetograms from the Helioseismic Magnetic Imager (HMI) on board SDO showed that the jet was triggered by the cancelation of a parasitic positive polarity feature near the negative pole of the bright point. The jet emission was present for 25 min and it extended 30 Mm from the bright point. Spectra from the Extreme Ultraviolet Imaging Spectrometer on board Hinode yielded a temperature and density of 1.6 MK and 0.9-1.7 × 108 cm-3 for the ejected plasma. Line-of-sight velocities reached up to 250 km s-1 and were found to increase with height, suggesting plasma acceleration within the body of the jet. Evidence was found for twisting motions within the jet based on variations of the line-of-sight velocities across the jet width. The derived angular speed was in the range (9-12) × 10-3 rad s-1, consistent with previous measurements from jets. The density of the bright point was 7.6 × 108 cm-3, and the peak of the bright point's emission measure occurred at 1.3 MK, with no plasma above 3 MK.

  9. Climate Impact and Economic Feasibility of Solar Thermochemical Jet Fuel Production.

    PubMed

    Falter, Christoph; Batteiger, Valentin; Sizmann, Andreas

    2016-01-01

    Solar thermochemistry presents a promising option for the efficient conversion of H2O and CO2 into liquid hydrocarbon fuels using concentrated solar energy. To explore the potential of this fuel production pathway, the climate impact and economic performance are analyzed. Key drivers for the economic and ecological performance are thermochemical energy conversion efficiency, the level of solar irradiation, operation and maintenance, and the initial investment in the fuel production plant. For the baseline case of a solar tower concentrator with CO2 capture from air, jet fuel production costs of 2.23 €/L and life cycle greenhouse gas (LC GHG) emissions of 0.49 kgCO2-equiv/L are estimated. Capturing CO2 from a natural gas combined cycle power plant instead of the air reduces the production costs by 15% but leads to LC GHG emissions higher than that of conventional jet fuel. Favorable assumptions for all involved process steps (30% thermochemical energy conversion efficiency, 3000 kWh/(m(2) a) solar irradiation, low CO2 and heliostat costs) result in jet fuel production costs of 1.28 €/L at LC GHG emissions close to zero. Even lower production costs may be achieved if the commercial value of oxygen as a byproduct is considered. PMID:26641878

  10. Climate Impact and Economic Feasibility of Solar Thermochemical Jet Fuel Production.

    PubMed

    Falter, Christoph; Batteiger, Valentin; Sizmann, Andreas

    2016-01-01

    Solar thermochemistry presents a promising option for the efficient conversion of H2O and CO2 into liquid hydrocarbon fuels using concentrated solar energy. To explore the potential of this fuel production pathway, the climate impact and economic performance are analyzed. Key drivers for the economic and ecological performance are thermochemical energy conversion efficiency, the level of solar irradiation, operation and maintenance, and the initial investment in the fuel production plant. For the baseline case of a solar tower concentrator with CO2 capture from air, jet fuel production costs of 2.23 €/L and life cycle greenhouse gas (LC GHG) emissions of 0.49 kgCO2-equiv/L are estimated. Capturing CO2 from a natural gas combined cycle power plant instead of the air reduces the production costs by 15% but leads to LC GHG emissions higher than that of conventional jet fuel. Favorable assumptions for all involved process steps (30% thermochemical energy conversion efficiency, 3000 kWh/(m(2) a) solar irradiation, low CO2 and heliostat costs) result in jet fuel production costs of 1.28 €/L at LC GHG emissions close to zero. Even lower production costs may be achieved if the commercial value of oxygen as a byproduct is considered.

  11. Evidence for Alfvén waves in solar x-ray jets.

    PubMed

    Cirtain, J W; Golub, L; Lundquist, L; van Ballegooijen, A; Savcheva, A; Shimojo, M; Deluca, E; Tsuneta, S; Sakao, T; Reeves, K; Weber, M; Kano, R; Narukage, N; Shibasaki, K

    2007-12-01

    Coronal magnetic fields are dynamic, and field lines may misalign, reassemble, and release energy by means of magnetic reconnection. Giant releases may generate solar flares and coronal mass ejections and, on a smaller scale, produce x-ray jets. Hinode observations of polar coronal holes reveal that x-ray jets have two distinct velocities: one near the Alfvén speed ( approximately 800 kilometers per second) and another near the sound speed (200 kilometers per second). Many more jets were seen than have been reported previously; we detected an average of 10 events per hour up to these speeds, whereas previous observations documented only a handful per day with lower average speeds of 200 kilometers per second. The x-ray jets are about 2 x 10(3) to 2 x 10(4) kilometers wide and 1 x 10(5) kilometers long and last from 100 to 2500 seconds. The large number of events, coupled with the high velocities of the apparent outflows, indicates that the jets may contribute to the high-speed solar wind. PMID:18063786

  12. EFFECT OF CORONAL TEMPERATURE ON THE SCALE OF SOLAR CHROMOSPHERIC JETS

    SciTech Connect

    Iijima; Yokoyama, T.H.

    2015-10-20

    We investigate the effect of coronal temperature on the formation process of solar chromospheric jets using two-dimensional magnetohydrodynamic simulations of the region from the upper convection zone to the lower corona. We develop a new radiative magnetohydrodynamic code for the dynamic modeling of the solar atmosphere, employing an LTE equation of state, optically thick radiative loss in the photosphere, optically thin radiative loss in the chromosphere and the corona, and thermal conduction along the magnetic field lines. Many chromospheric jets are produced in the simulations by shock waves passing through the transition region. We find that these jets are projected farther outward when the coronal temperature is lower (similar to that in coronal holes) and shorter when the coronal temperature is higher (similar to that in active regions). When the coronal temperature is high, the deceleration of the chromospheric jets is consistent with the model in which deceleration is determined by the periodic chromospheric shock waves. However, when the coronal temperature is low, the gravitational deceleration becomes more important and the chromospheric jets approach ballistic motion.

  13. Solar and heliospheric signatures of an unusual jet event on 20 November 2012

    NASA Astrophysics Data System (ADS)

    Ireland, Jack; de Nolfo, Georgia; Ryan, James Michael

    2015-04-01

    We describe the solar and heliospheric signatures of an unusual jet event seen on the Sun on 20 November 2012. The jet itself is formed very suddenly in a piece of apparently quiet Sun distant from large opposite polarity sources such as active regions. The jet event is associated with a low energy (6-12 keV) flare observed by RHESSI. Higher hard x-ray energies are not observed, indicating only low energy electrons were produced. Several hours later, a dispersive helium-3 rich event is seen in ACE/ULEIS data, which is not associated with electron-SEPs or a Type III radio burst. High resolution ACE/ULEIS ion data suggest an onset time close to the time of the jet. We discuss the heliospheric connectivity of this event using data from STEREO, ACE, WIND and estimates of the open magnetic flux arising from the solar surface around the jet. Although this event is studied in detail, we have found five other similar events in the data, and we discuss these briefly.

  14. Evidence for Alfvén waves in solar x-ray jets.

    PubMed

    Cirtain, J W; Golub, L; Lundquist, L; van Ballegooijen, A; Savcheva, A; Shimojo, M; Deluca, E; Tsuneta, S; Sakao, T; Reeves, K; Weber, M; Kano, R; Narukage, N; Shibasaki, K

    2007-12-01

    Coronal magnetic fields are dynamic, and field lines may misalign, reassemble, and release energy by means of magnetic reconnection. Giant releases may generate solar flares and coronal mass ejections and, on a smaller scale, produce x-ray jets. Hinode observations of polar coronal holes reveal that x-ray jets have two distinct velocities: one near the Alfvén speed ( approximately 800 kilometers per second) and another near the sound speed (200 kilometers per second). Many more jets were seen than have been reported previously; we detected an average of 10 events per hour up to these speeds, whereas previous observations documented only a handful per day with lower average speeds of 200 kilometers per second. The x-ray jets are about 2 x 10(3) to 2 x 10(4) kilometers wide and 1 x 10(5) kilometers long and last from 100 to 2500 seconds. The large number of events, coupled with the high velocities of the apparent outflows, indicates that the jets may contribute to the high-speed solar wind.

  15. Multi-spacecraft observations of recurrent {sup 3}He-rich solar energetic particles

    SciTech Connect

    Bučík, R.; Innes, D. E.; Mall, U.; Korth, A.; Mason, G. M.; Gómez-Herrero, R.

    2014-05-01

    We study the origin of {sup 3}He-rich solar energetic particles (<1 MeV nucleon{sup –1}) that are observed consecutively on STEREO-B, Advanced Composition Explorer (ACE), and STEREO-A spacecraft when they are separated in heliolongitude by more than 90°. The {sup 3}He-rich period on STEREO-B and STEREO-A commences on 2011 July 1 and 2011 July 16, respectively. The ACE {sup 3}He-rich period consists of two sub-events starting on 2011 July 7 and 2011 July 9. We associate the STEREO-B July 1 and ACE July 7 {sup 3}He-rich events with the same sizeable active region (AR) producing X-ray flares accompanied by prompt electron events, when it was near the west solar limb as seen from the respective spacecraft. The ACE July 9 and STEREO-A July 16 events were dispersionless with enormous {sup 3}He enrichment, lacking solar energetic electrons and occurring in corotating interaction regions. We associate these events with a small, recently emerged AR near the border of a low-latitude coronal hole that produced numerous jet-like emissions temporally correlated with type III radio bursts. For the first time we present observations of (1) solar regions with long-lasting conditions for {sup 3}He acceleration and (2) solar energetic {sup 3}He that is temporarily confined/re-accelerated in interplanetary space.

  16. Multi-spacecraft Observations of Recurrent 3He-rich Solar Energetic Particles

    NASA Astrophysics Data System (ADS)

    Bučík, R.; Innes, D. E.; Mall, U.; Korth, A.; Mason, G. M.; Gómez-Herrero, R.

    2014-05-01

    We study the origin of 3He-rich solar energetic particles (<1 MeV nucleon-1) that are observed consecutively on STEREO-B, Advanced Composition Explorer (ACE), and STEREO-A spacecraft when they are separated in heliolongitude by more than 90°. The 3He-rich period on STEREO-B and STEREO-A commences on 2011 July 1 and 2011 July 16, respectively. The ACE 3He-rich period consists of two sub-events starting on 2011 July 7 and 2011 July 9. We associate the STEREO-B July 1 and ACE July 7 3He-rich events with the same sizeable active region (AR) producing X-ray flares accompanied by prompt electron events, when it was near the west solar limb as seen from the respective spacecraft. The ACE July 9 and STEREO-A July 16 events were dispersionless with enormous 3He enrichment, lacking solar energetic electrons and occurring in corotating interaction regions. We associate these events with a small, recently emerged AR near the border of a low-latitude coronal hole that produced numerous jet-like emissions temporally correlated with type III radio bursts. For the first time we present observations of (1) solar regions with long-lasting conditions for 3He acceleration and (2) solar energetic 3He that is temporarily confined/re-accelerated in interplanetary space.

  17. Ulysses observations of a recurrent high speed solar wind stream and the heliomagnetic streamer belt

    SciTech Connect

    Bame, S.J.; Gosling, J.T.; McComas, D.J.; Phillips, J.L. ); Goldstein, B.E.; Neugebauer, M. ); Harvey, J.W.

    1993-11-05

    Near-ecliptic solar wind observations by Ulysses on its way to the polar regions of the Sun, compared with those from IMP 8 at 1 AU, showed that high-speed streams decay and broaden with heliocentric distance from IMP 8 to Ulysses, as expected. In July 1992 while travelling south at [approximately]13[degrees]S and 5.3 AU, Ulysses encountered a recurrent high-speed stream, that may also have been observed at IMP 8. The stream has been observed a total of 14 times, once in each solar rotation through June 1993 at [approximately]34[degrees]S. The source of the high-speed stream is an equatorward extension of the south polar coronal hole. From July 1992 through June 1993, averages of solar wind peak speed increased while density decreased with heliographic latitude. Both the stream and a low-speed, high-density flow, presumably associated with the heliomagnetic (coronal) streamer belt encircling the heliomagnetic equator, crossed Ulysses with the solar rotation period until April 1993 when the spacecraft was at [approximately]29[degrees]S heliographic latitude. After this time, as the spacecraft climbed to higher latitudes, the central portion of the streamer belt with lowest speed and highest density disappeared. Therefore, at its maximum inclination, the belt was tilted at [approximately]29[degrees] to the heliographic equator at this point in the solar cycle. 11 refs., 5 figs.

  18. The Contribution of Jets to Coronal and Solar Wind Energetics: MHD Simulations

    NASA Astrophysics Data System (ADS)

    Lionello, Roberto; Torok, Tibor; Titov, Viacheslav; Linker, Jon A.; Mikic, Zoran; Leake, James E.; Linton, Mark

    2016-05-01

    Transient collimated plasma eruptions in the corona, commonly known as coronal jets, are among the most interesting manifestations of solar activity.We use the 3D MHD model with thermodynamics developed at PSI to investigate the origin, dynamics, and plasma properties of coronal jets.Our model is coupled with 3D MHD flux emergence simulations, i.e, we use boundary conditions provided by such simulations to drive a time-dependent coronal evolution. It includes parametric coronal heating, radiative losses, and thermal conduction in the energy equations.This enables us to simulate the energy transfer in coronal jets in a more realistic manner than done so far and to study the amount of energy and mass transported by these phenomena into the higher corona and inner heliosphere. We discuss our results and compare them with previous estimations obtained from observations.

  19. Observations of Multiple Blobs in Homologous Solar Coronal Jets in Closed Loop

    NASA Astrophysics Data System (ADS)

    Zhang, Q. M.; Ji, H. S.; Su, Y. N.

    2016-03-01

    Coronal bright points (CBPs) and jets are ubiquitous small-scale brightenings that are often associated with each other. We here report our multiwavelength observations of two groups of homologous jets. The first group was observed by the Extreme-Ultraviolet Imager (EUVI) onboard the Solar TErrestrial RElations Observatory (STEREO) Behind spacecraft in 171 Å and 304 Å on 2014 September 10, from a location where no data from the Solar Dynamic Observatory (SDO) could be obtained. The jets (J1 - J6) recurred for six times with intervals of 5 - 15 minutes. They originated from the same primary CBP (BP1) and propagated in the northeast direction along large-scale, closed coronal loops. Two of the jets (J3 and J6) produced sympathetic CBPs (BP2 and BP3) after reaching the remote footpoints of the loops. The time delays between the peak times of BP1 and BP2 (BP3) are 240±75 s (300±75 s). The jets were not coherent. Instead, they were composed of bright and compact blobs. The sizes and apparent velocities of the blobs are 4.5 - 9 Mm and 140 - 380 km s-1. The arrival times of the multiple blobs in the jets at the far end of the loops indicate that the sympathetic CBPs are caused by jet flows and not by thermal conduction fronts. The second group was observed by the Atmospheric Imaging Assembly onboard SDO in various wavelengths on 2010 August 3. Similar to the first group, the jets originated from a short-lived BP at the boundary of Active Region 11092 and propagated along a small-scale, closed loop before flowing into the active region. Several tiny blobs with sizes of ˜1.7 Mm and an apparent velocity of ˜238 km s^{-1} were identified in the jets. We carried out differential emission measure (DEM) inversions to investigate the temperatures of the blobs, finding that the blobs were multithermal with an average temperature of 1.8 - 3.1 MK. The estimated number densities of the blobs were (1.7 - 2.8)×109 cm^{-3}.

  20. Innovative second-generation wavelets construction with recurrent neural networks for solar radiation forecasting.

    PubMed

    Capizzi, Giacomo; Napoli, Christian; Bonanno, Francesco

    2012-11-01

    Solar radiation prediction is an important challenge for the electrical engineer because it is used to estimate the power developed by commercial photovoltaic modules. This paper deals with the problem of solar radiation prediction based on observed meteorological data. A 2-day forecast is obtained by using novel wavelet recurrent neural networks (WRNNs). In fact, these WRNNS are used to exploit the correlation between solar radiation and timescale-related variations of wind speed, humidity, and temperature. The input to the selected WRNN is provided by timescale-related bands of wavelet coefficients obtained from meteorological time series. The experimental setup available at the University of Catania, Italy, provided this information. The novelty of this approach is that the proposed WRNN performs the prediction in the wavelet domain and, in addition, also performs the inverse wavelet transform, giving the predicted signal as output. The obtained simulation results show a very low root-mean-square error compared to the results of the solar radiation prediction approaches obtained by hybrid neural networks reported in the recent literature.

  1. Ink Jet Printing Approaches to Solar Cell Contacts

    SciTech Connect

    Kaydanova, T.; Miedaner, A.; Curtis, C.; Perkins, J.; Alleman, J.; Ginley, D.

    2003-05-01

    We are developing inkjet printing as a low cost, high through-put approach to the deposition of front contacts for Si solar cells. High deposition rates of 1m per printing pass were achieved with a new metalorganic ink composed of silver (trifluoroacetate) in ethylene glycol. The printing conditions were optimized to achieve a relatively high line resolution of 120 m. The optimal parameters for the piezoelectric inkjet were a pulse frequency of 50 Hz and pulse amplitude of 25 V. The best resolution and the line quality were achieved at a substrate temperature of 180 C and drop separation of 40 m.

  2. Modeling Reconnection-Driven Solar Polar Jets with Gravity and Wind

    NASA Astrophysics Data System (ADS)

    Karpen, Judith T.; DeVore, C. R.; Antiochos, S. K.

    2013-07-01

    Solar polar jets are dynamic, narrow, radially extended structures observed in EUV emission. They have been found to originate within the open magnetic field of coronal holes in “anemone” regions, which are generally accepted to be intrusions of opposite polarity. The associated embedded-dipole topology consists of a spine line emanating from a null point atop a dome-shaped fan surface. Previous work (Pariat et al. 2009, 2010) has validated the idea that magnetic free energy stored on twisted closed field lines within the fan surface can be released explosively by the onset of fast reconnection between the highly stressed closed field inside the null and the unstressed open field outside (Antiochos 1996). The simulations showed that a dense jet comprising a nonlinear, torsional Alfven wave is ejected into the outer corona on the newly reconnected open field lines. While proving the principle of the basic model, those simulations neglected the important effects of gravity, the solar wind, and an expanding spherical geometry. We introduce those additional physical processes in new simulations of reconnection-driven jets, to determine whether the model remains robust in the resulting more realistic setting, and to begin establishing the signatures of the jets in the inner heliosphere for comparison with observations. Initial results demonstrate explosive energy release and a jet in the low corona very much like that in the earlier Cartesian, gravity-free, static-atmosphere runs. We report our analysis of the results, their comparison with previous work, and their implications for observations. This work was supported by NASA’s LWS TR&T program.Abstract (2,250 Maximum Characters): Solar polar jets are dynamic, narrow, radially extended structures observed in EUV emission. They have been found to originate within the open magnetic field of coronal holes in “anemone” regions, which are generally accepted to be intrusions of opposite polarity. The associated

  3. Modeling of the Enceladus water vapor jets for interpreting UVIS star and solar occultation observations

    NASA Astrophysics Data System (ADS)

    Portyankina, Ganna; Esposito, Larry W.; Aye, Klaus-Michael; Hansen, Candice J.

    2015-11-01

    One of the most spectacular discoveries of the Cassini mission is jets emitting from the southern pole of Saturn’s moon Enceladus. The composition of the jets is water vapor and salty ice grains with traces of organic compounds. Jets, merging into a wide plume at a distance, are observed by multiple instruments on Cassini. Recent observations of the visible dust plume by the Cassini Imaging Science Subsystem (ISS) identified as many as 98 jet sources located along “tiger stripes” [Porco et al. 2014]. There is a recent controversy on the question if some of these jets are “optical illusion” caused by geometrical overlap of continuous source eruptions along the “tiger stripes” in the field of view of ISS [Spitale et al. 2015]. The Cassini’s Ultraviolet Imaging Spectrograph (UVIS) observed occultations of several stars and the Sun by the water vapor plume of Enceladus. During the solar occultation separate collimated gas jets were detected inside the background plume [Hansen et al., 2006 and 2011]. These observations directly provide data about water vapor column densities along the line of sight of the UVIS instrument and could help distinguish between the presence of only localized or also continuous sources. We use Monte Carlo simulations and Direct Simulation Monte Carlo (DSMC) to model the plume of Enceladus with multiple (or continuous) jet sources. The models account for molecular collisions, gravitational and Coriolis forces. The models result in the 3-D distribution of water vapor density and surface deposition patterns. Comparison between the simulation results and column densities derived from UVIS observations provide constraints on the physical characteristics of the plume and jets. The specific geometry of the UVIS observations helps to estimate the production rates and velocity distribution of the water molecules emitted by the individual jets.Hansen, C. J. et al., Science 311:1422-1425 (2006); Hansen, C. J. et al, GRL 38:L11202 (2011

  4. Kelvin–Helmholtz Instability in Solar Chromospheric Jets: Theory and Observation

    NASA Astrophysics Data System (ADS)

    Kuridze, D.; Zaqarashvili, T. V.; Henriques, V.; Mathioudakis, M.; Keenan, F. P.; Hanslmeier, A.

    2016-10-01

    Using data obtained by the high-resolution CRisp Imaging SpectroPolarimeter instrument on the Swedish 1 m Solar Telescope, we investigate the dynamics and stability of quiet-Sun chromospheric jets observed at the disk center. Small-scale features, such as rapid redshifted and blueshifted excursions, appearing as high-speed jets in the wings of the Hα line, are characterized by short lifetimes and rapid fading without any descending behavior. To study the theoretical aspects of their stability without considering their formation mechanism, we model chromospheric jets as twisted magnetic flux tubes moving along their axis, and use the ideal linear incompressible magnetohydrodynamic approximation to derive the governing dispersion equation. Analytical solutions of the dispersion equation indicate that this type of jet is unstable to Kelvin–Helmholtz instability (KHI), with a very short (few seconds) instability growth time at high upflow speeds. The generated vortices and unresolved turbulent flows associated with the KHI could be observed as a broadening of chromospheric spectral lines. Analysis of the Hα line profiles shows that the detected structures have enhanced line widths with respect to the background. We also investigate the stability of a larger-scale Hα jet that was ejected along the line of sight. Vortex-like features, rapidly developing around the jet’s boundary, are considered as evidence of the KHI. The analysis of the energy equation in the partially ionized plasma shows that ion–neutral collisions may lead to fast heating of the KH vortices over timescales comparable to the lifetime of chromospheric jets.

  5. Driving Solar Spicules and Jets with Magnetohydrodynamic Turbulence: Testing a Persistent Idea

    NASA Astrophysics Data System (ADS)

    Cranmer, Steven R.; Woolsey, Lauren N.

    2015-10-01

    The solar chromosphere contains thin, highly dynamic strands of plasma known as spicules. Recently, it has been suggested that the smallest and fastest (Type II) spicules are identical to intermittent jets observed by the Interface Region Imaging Spectrograph. These jets appear to expand out along open magnetic field lines rooted in unipolar network regions of coronal holes. In this paper we revisit a thirty-year-old idea that spicules may be caused by upward forces associated with Alfvén waves. These forces involve the conversion of transverse Alfvén waves into compressive acoustic-like waves that steepen into shocks. The repeated buffeting due to upward shock propagation causes nonthermal expansion of the chromosphere and a transient levitation of the transition region (TR). Some older models of wave-driven spicules assumed sinusoidal wave inputs, but the solar atmosphere is highly turbulent and stochastic. Thus, we model this process using the output of a time-dependent simulation of reduced magnetohydrodynamic turbulence. The resulting mode-converted compressive waves are strongly variable in time, with a higher TR occurring when the amplitudes are large and a lower TR when the amplitudes are small. In this picture, the TR bobs up and down by several Mm on timescales less than a minute. These motions produce narrow, intermittent extensions of the chromosphere that have similar properties as the observed jets and Type II spicules.

  6. The relation between solar jets and 3He-rich solar energetic particle events at 1 AU

    NASA Astrophysics Data System (ADS)

    Chen, Nai-Hwa; Mason, Glenn; Innes, Davina; Bucik, Radoslav

    The solar sources of (3) He-rich solar energetic particle events detected by ULEIS on ACE and SIT on STEREO-A, when two spacecraft were close to quadrature, are investigated in this study. We use the photospheric magnetic field with potential field source surface extrapolations and in-situ magnetic field to identify the candidate connected active regions (ARs). We also examine the activity in all nearby ARs by using SDO and STEREO EUV images and space-based radio observations on Wind and STEREO. The 3He-rich events seem to occur shortly after an increase in jet production from the connected ARs. To study the long-term evolution in the source ARs, we compare the 3He enrichment measured at ACE and STEREO seven days apart which is the time for a region to rotate from the ACE to the STEREO connection point.

  7. Small-scale filament eruptions as the driver of X-ray jets in solar coronal holes.

    PubMed

    Sterling, Alphonse C; Moore, Ronald L; Falconer, David A; Adams, Mitzi

    2015-07-23

    Solar X-ray jets are thought to be made by a burst of reconnection of closed magnetic field at the base of a jet with ambient open field. In the accepted version of the 'emerging-flux' model, such a reconnection occurs at a plasma current sheet between the open field and the emerging closed field, and also forms a localized X-ray brightening that is usually observed at the edge of the jet's base. Here we report high-resolution X-ray and extreme-ultraviolet observations of 20 randomly selected X-ray jets that form in coronal holes at the Sun's poles. In each jet, contrary to the emerging-flux model, a miniature version of the filament eruptions that initiate coronal mass ejections drives the jet-producing reconnection. The X-ray bright point occurs by reconnection of the 'legs' of the minifilament-carrying erupting closed field, analogous to the formation of solar flares in larger-scale eruptions. Previous observations have found that some jets are driven by base-field eruptions, but only one such study, of only one jet, provisionally questioned the emerging-flux model. Our observations support the view that solar filament eruptions are formed by a fundamental explosive magnetic process that occurs on a vast range of scales, from the biggest mass ejections and flare eruptions down to X-ray jets, and perhaps even down to smaller jets that may power coronal heating. A similar scenario has previously been suggested, but was inferred from different observations and based on a different origin of the erupting minifilament.

  8. Small-scale filament eruptions as the driver of X-ray jets in solar coronal holes.

    PubMed

    Sterling, Alphonse C; Moore, Ronald L; Falconer, David A; Adams, Mitzi

    2015-07-23

    Solar X-ray jets are thought to be made by a burst of reconnection of closed magnetic field at the base of a jet with ambient open field. In the accepted version of the 'emerging-flux' model, such a reconnection occurs at a plasma current sheet between the open field and the emerging closed field, and also forms a localized X-ray brightening that is usually observed at the edge of the jet's base. Here we report high-resolution X-ray and extreme-ultraviolet observations of 20 randomly selected X-ray jets that form in coronal holes at the Sun's poles. In each jet, contrary to the emerging-flux model, a miniature version of the filament eruptions that initiate coronal mass ejections drives the jet-producing reconnection. The X-ray bright point occurs by reconnection of the 'legs' of the minifilament-carrying erupting closed field, analogous to the formation of solar flares in larger-scale eruptions. Previous observations have found that some jets are driven by base-field eruptions, but only one such study, of only one jet, provisionally questioned the emerging-flux model. Our observations support the view that solar filament eruptions are formed by a fundamental explosive magnetic process that occurs on a vast range of scales, from the biggest mass ejections and flare eruptions down to X-ray jets, and perhaps even down to smaller jets that may power coronal heating. A similar scenario has previously been suggested, but was inferred from different observations and based on a different origin of the erupting minifilament. PMID:26147079

  9. PLASMA JETS AND ERUPTIONS IN SOLAR CORONAL HOLES: A THREE-DIMENSIONAL FLUX EMERGENCE EXPERIMENT

    SciTech Connect

    Moreno-Insertis, F.

    2013-07-01

    A three-dimensional (3D) numerical experiment of the launching of a hot and fast coronal jet followed by several violent eruptions is analyzed in detail. These events are initiated through the emergence of a magnetic flux rope from the solar interior into a coronal hole. We explore the evolution of the emerging magnetically dominated plasma dome surmounted by a current sheet and the ensuing pattern of reconnection. A hot and fast coronal jet with inverted-Y shape is produced that shows properties comparable to those frequently observed with EUV and X-ray detectors. We analyze its 3D shape, its inhomogeneous internal structure, and its rise and decay phases, lasting for some 15-20 minutes each. Particular attention is devoted to the field line connectivities and the reconnection pattern. We also study the cool and high-density volume that appears to encircle the emerged dome. The decay of the jet is followed by a violent phase with a total of five eruptions. The first of them seems to follow the general pattern of tether-cutting reconnection in a sheared arcade, although modified by the field topology created by the preceding reconnection evolution. The two following eruptions take place near and above the strong-field concentrations at the surface. They show a twisted, {Omega}-loop-like rope expanding in height, with twist being turned into writhe, thus hinting at a kink instability (perhaps combined with a torus instability) as the cause of the eruption. The succession of a main jet ejection and a number of violent eruptions that resemble mini-CMEs and their physical properties suggest that this experiment may provide a model for the blowout jets recently proposed in the literature.

  10. Energy Spectrum of the Recurrent Variation of Galactic Cosmic Rays During the Solar Minimum of Cycles 23/24

    NASA Astrophysics Data System (ADS)

    Gil, Agnieszka; Alania, Michael V.

    2016-08-01

    The Sun during the recent epoch of solar activity operated in a different way than during the last 60 years, being less active. We study temporal changes of the energy spectrum of the first three harmonics of the 27-day variation of the galactic cosmic rays (GCR) intensity during the unusual, recent solar minimum, between Solar Cycles 23 and 24 (SC 23/24) and compare with four previous minima. We show that the energy spectrum of the amplitudes of the recurrent variation of the GCR intensity is hard in the maximum epochs and is soft in the minimum epochs during Solar Cycles 20 - 24, but with peculiarities during the Solar Minimum 23/24. In particular, while the energy/rigidity spectrum of the amplitudes of the first harmonic of the recurrent variation of the GCR intensity behaves practically the same as for previous epochs, the energy/rigidity spectrum of the amplitudes of the second and the third harmonics demonstrates a pronounced softening. We attribute this phenomenon to the decrease of the extension of the heliosphere caused by the decrease of the solar-wind dynamic pressure during the unusual Solar Minimum 23/24.

  11. Origin of the High-speed Jets Fom Magnetic Flux Emergence in the Solar Transition Region as well as Their Mass and Energy Contribuctions to the Solar Wind

    NASA Astrophysics Data System (ADS)

    Liping, Y.; He, J.; Peter, H.; Tu, C. Y.; Feng, X. S.

    2015-12-01

    In the solar atmosphere, the jets are ubiquitous and found to be at various spatia-temporal scales. They are significant to understand energy and mass transport in the solar atmosphere. Recently, the high-speed transition region jets are reported from the observation. Here we conduct a numerical simulation to investigate the mechanism in their formation, as well as their mass and energy contributions to the solar wind. Driven by the supergranular convection motion, the magnetic reconnection between the magnetic loop and the background open flux occurring in the transition region is simulated with a two-dimensional MHD model. The simulation results show that not only a fast hot jet, much resemble the found transition region jets, but also a adjacent slow cool jet, mostly like classical spicules, is launched. The force analysis shows that the fast hot jet is continually driven by the Lorentz force around the reconnection region, while the slow cool jet is induced by an initial kick through the Lorentz force associated with the emerging magnetic flux. Also, the features of the driven jets change with the amount of the emerging magnetic flux, giving the varieties of both jets.With the developed one-dimensional hydrodynamic solar wind model, the time-dependent pulses are imposed at the bottom to simulate the jet behaviors. The simulation results show that without other energy source, the injected plasmas are accelerated effectively to be a transonic wind with a substantial mass flux. The rapid acceleration occurs close to the Sun, and the resulting asymptotic speeds, number density at 0.3 AU, as well as mass flux normalized to 1 AU are compatible with in site observations. As a result of the high speed, the imposed pulses lead to a train of shocks traveling upward. By tracing the motions of the injected plasma, it is found that these shocks heat and accelerate the injected plasma to make part of them propagate upward and eventually escape. The parametric study shows

  12. A Coronal Hole Jet Observed with Hinode and the Solar Dynamics Observatory

    NASA Technical Reports Server (NTRS)

    Young, Peter H.; Muglach, Karin

    2014-01-01

    A small blowout jet was observed at the boundary of the south coronal hole on 2011 February 8 at around 21:00 UT. Images from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) revealed an expanding loop rising from one footpoint of a compact, bipolar bright point. Magnetograms from the Helioseismic Magnetic Imager (HMI) on board SDO showed that the jet was triggered by the cancelation of a parasitic positive polarity feature near the negative pole of the bright point. The jet emission was present for 25 mins and it extended 30 Mm from the bright point. Spectra from the EUV Imaging Spectrometer on board Hinode yielded a temperature and density of 1.6 MK and 0.9-1.7 × 10( exp 8) cu cm for the ejected plasma. Line-of-sight velocities reached up to 250 km/s. The density of the bright point was 7.6 × 10(exp 8) cu cm, and the peak of the bright point's emission measure occurred at 1.3 MK, with no plasma above 3 MK.

  13. THE RESPONSE OF A THREE-DIMENSIONAL SOLAR ATMOSPHERE TO WAVE-DRIVEN JETS

    SciTech Connect

    Scullion, E.; Erdelyi, R.; Fedun, V.; Doyle, J. G. E-mail: robertus@sheffield.ac.uk E-mail: jgd@arm.ac.uk

    2011-12-10

    Global oscillations from the solar interior are, mainly, pressure-driven (p-modes) oscillations with a peak power of a five-minute period. These oscillations are considered to manifest in many phenomena in the lower solar atmosphere, most notably, in spicules. These small-scale jets may provide the key to understanding the powering mechanisms of the transition region (TR) and lower corona. Here, we simulate the formation of wave-driven (type-I) spicule phenomena in three dimensions and the transmission of acoustic waves from the lower chromosphere and into the corona. The outer atmosphere oscillates in response to the jet formation, and in turn, we reveal the formation of a circular seismic surface wave, which we name as a Transition Region Quake (TRQ). The TRQ forms as a consequence of an upward propelling spicular wave train that repeatedly punctures and energizes the TR. The steep density gradient enables the TRQ to develop and radially fan outward from the location where the spicular plasma column impinges the TR. We suggest the TRQ formation as a formidable mechanism in continuously sustaining part of the energy budget of the TR. We present a supporting numerical model which allow us to determine the level of energy dumping at the TR by upward-propagating p-modes. Upon applying a wavelet analysis on our simulations we identify the presence of a chromospheric cavity which resonates with the jet propagation and leaves behind an oscillatory wake with a distinctive periodicity. Through our numerical analysis we also discover type-I spicule turbulence leading to a convection-based motion in the low corona.

  14. Switch-on Shock and Nonlinear Kink Alfvén Waves in Solar Polar Jets

    NASA Astrophysics Data System (ADS)

    DeVore, C. Richard; Karpen, Judith T.; Antiochos, Spiro K.; Uritsky, Vadim

    2016-05-01

    It is widely accepted that solar polar jets are produced by fast magnetic reconnection in the low corona, whether driven directly by flux emergence from below or indirectly by instability onset above the photosphere. In either scenario, twisted flux on closed magnetic field lines reconnects with untwisted flux on nearby open field lines. Part of the twist is inherited by the newly reconnected open flux, which rapidly relaxes due to magnetic tension forces that transmit the twist impulsively into the outer corona and heliosphere. We propose that this transfer of twist launches switch-on MHD shock waves, which propagate parallel to the ambient coronal magnetic field ahead of the shock and convect a perpendicular component of magnetic field behind the shock. In the frame moving with the shock front, the post-shock flow is precisely Alfvénic in all three directions, whereas the pre-shock flow is super-Alfvénic along the ambient magnetic field, yielding a density enhancement at the shock front. Nonlinear kink Alfvén waves are exact solutions of the time-dependent MHD equations in the post-shock region when the ambient corona is uniform and the magnetic field is straight. We have performed and analyzed 3D Cartesian and spherical simulations of polar jets driven by instability onset in the corona. The results of both simulations are consistent with the generation of MHD switch-on shocks trailed predominantly by incompressible kink Alfvén waves. It is noteworthy that the kink waves are irrotational, in sharp contrast to the vorticity-bearing torsional waves reported from previous numerical studies. We will discuss the implications of the results for understanding solar polar jets and predicting their heliospheric signatures. Our research was supported by NASA’s LWS TR&T and H-SR programs.

  15. No-Needle Jet Intradermal Aminolevulinic Acid Photodynamic Therapy for Recurrent Nodular Basal Cell Carcinoma of the Nose: A Case Report

    PubMed Central

    Barolet, Daniel; Boucher, Annie

    2011-01-01

    Photodynamic therapy (PDT) with aminolevulinic acid (ALA) to treat nodular basal cell carcinoma (BCC) has been shown to be beneficial. The success rate of ALA-PDT in the treatment of nodular BCC is dependent on optimal penetration of the photosensitizing agent and subsequent PpIX production. To enhance topical delivery of drugs intradermally, a needleless jet injection (NLJI), which employs a high-speed jet to puncture the skin without the side effects of needles, was used in one patient with recurrent BCC of the nose. Photoactivation was then performed using red light emitting diode [CW @ λ 630 nm, irradiance 50 mW/cm2, total fluence 51 J/cm2] for 17 minutes. Excellent cosmesis was obtained. Aside from mild crusting present for six days, no other adverse signs were noted. Clinically, there was no recurrent lesion up two years postintervention. Additional studies in larger samples of subjects are needed to further evaluate this promising technique. PMID:21188233

  16. Evidence of cosmic recurrent and lagged millennia-scale patterns and consequent forecasts: multi-scale responses of solar activity (SA) to planetary gravitational forcing (PGF)

    NASA Astrophysics Data System (ADS)

    Sánchez-Sesma, Jorge

    2016-07-01

    Solar activity (SA) oscillations over the past millennia are analyzed and extrapolated based on reconstructed solar-related records. Here, simple recurrent models of SA signal are applied and tested. The consequent results strongly suggest the following: (a) the existence of multi-millennial ( ˜ 9500-year) scale solar patterns linked with planetary gravitational forcing (PGF), and (b) their persistence, over at least the last glacial-interglacial cycle, but possibly since the Miocene (10.5 Myr ago). This empirical modeling of solar recurrent patterns has also provided a consequent multi-millennial-scale experimental forecast, suggesting a solar decreasing trend toward grand (super) minimum conditions for the upcoming period, AD 2050-2250 (AD 3750-4450). Taking into account the importance of these estimated SA scenarios, a comparison is made with other SA forecasts. In Appendixes A and B, we provide further verification, testing and analysis of solar recurrent patterns since geological eras, and their potential gravitational forcing.

  17. DETERMINATION OF SUB-RESOLUTION STRUCTURE OF A JET BY SOLAR MAGNETOSEISMOLOGY

    SciTech Connect

    Morton, R. J.; Erdelyi, R.; Verth, G.; McLaughlin, J. A. E-mail: gary.verth@northumbria.ac.uk

    2012-01-01

    A thin dark thread is observed in a UV/EUV solar jet in the 171 A, 193 A, and 211 A, and partially in 304 A. The dark thread appears to originate in the chromosphere but its temperature does not appear to lie within the passbands of the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory. We therefore implement solar magnetoseismology to estimate the plasma parameters of the dark thread. A propagating kink (transverse) wave is observed to travel along the dark thread. The wave is tracked over a range of {approx}7000 km by placing multiple slits along the axis of the dark thread. The phase speed and amplitude of the wave are estimated and magnetoseismological theory is employed to determine the plasma parameters. We are able to estimate the plasma temperature, density gradient, magnetic field gradient, and sub-resolution expansion of the dark thread. The dark thread is found to be cool, T {approx}< 3 Multiplication-Sign 10{sup 4}, with both strong density and magnetic field gradients. The expansion of the flux tube along its length is {approx}300-400 km.

  18. Trigger of a Blowout Jet in a Solar Coronal Mass Ejection Associated with a Flare

    NASA Astrophysics Data System (ADS)

    Li, Xiaohong; Yang, Shuhong; Chen, Huadong; Li, Ting; Zhang, Jun

    2015-11-01

    Using the multi-wavelength images and the photospheric magnetograms from the Solar Dynamics Observatory, we study the flare that was associated with the only coronal mass ejection (CME) in active region (AR) 12192. The eruption of a filament caused a blowout jet, and then an M4.0 class flare occurred. This flare was located at the edge of the AR instead of in the core region. The flare was close to the apparently “open” fields, appearing as extreme-ultraviolet structures that fan out rapidly. Due to the interaction between flare materials and “open” fields, the flare became an eruptive flare, leading to the CME. Then, at the same site of the first eruption, another small filament erupted. With the high spatial and temporal resolution Hα data from the New Vacuum Solar Telescope at the Fuxian Solar Observatory, we investigate the interaction between the second filament and the nearby “open” lines. The filament reconnected with the “open” lines, forming a new system. To our knowledge, the detailed process of this kind of interaction is reported for the first time. Then the new system rotated due to the untwisting motion of the filament, implying that the twist was transferred from the closed filament system to the “open” system. In addition, the twist seemed to propagate from the lower atmosphere to the upper layers and was eventually spread by the CME to the interplanetary space.

  19. TRIGGER OF A BLOWOUT JET IN A SOLAR CORONAL MASS EJECTION ASSOCIATED WITH A FLARE

    SciTech Connect

    Li, Xiaohong; Yang, Shuhong; Chen, Huadong; Li, Ting; Zhang, Jun

    2015-11-20

    Using the multi-wavelength images and the photospheric magnetograms from the Solar Dynamics Observatory, we study the flare that was associated with the only coronal mass ejection (CME) in active region (AR) 12192. The eruption of a filament caused a blowout jet, and then an M4.0 class flare occurred. This flare was located at the edge of the AR instead of in the core region. The flare was close to the apparently “open” fields, appearing as extreme-ultraviolet structures that fan out rapidly. Due to the interaction between flare materials and “open” fields, the flare became an eruptive flare, leading to the CME. Then, at the same site of the first eruption, another small filament erupted. With the high spatial and temporal resolution Hα data from the New Vacuum Solar Telescope at the Fuxian Solar Observatory, we investigate the interaction between the second filament and the nearby “open” lines. The filament reconnected with the “open” lines, forming a new system. To our knowledge, the detailed process of this kind of interaction is reported for the first time. Then the new system rotated due to the untwisting motion of the filament, implying that the twist was transferred from the closed filament system to the “open” system. In addition, the twist seemed to propagate from the lower atmosphere to the upper layers and was eventually spread by the CME to the interplanetary space.

  20. SOLAR X-RAY JETS, TYPE-II SPICULES, GRANULE-SIZE EMERGING BIPOLES, AND THE GENESIS OF THE HELIOSPHERE

    SciTech Connect

    Moore, Ronald L.; Sterling, Alphonse C.; Cirtain, Jonathan W.; Falconer, David A.

    2011-04-10

    From Hinode observations of solar X-ray jets, Type-II spicules, and granule-size emerging bipolar magnetic fields in quiet regions and coronal holes, we advocate a scenario for powering coronal heating and the solar wind. In this scenario, Type-II spicules and Alfven waves are generated by the granule-size emerging bipoles (EBs) in the manner of the generation of X-ray jets by larger magnetic bipoles. From observations and this scenario, we estimate that Type-II spicules and their co-generated Alfven waves carry into the corona an area-average flux of mechanical energy of {approx}7 x 10{sup 5} erg cm{sup -2} s{sup -1}. This is enough to power the corona and solar wind in quiet regions and coronal holes, and therefore indicates that the granule-size EBs are the main engines that generate and sustain the entire heliosphere.

  1. Sunspot waves and triggering of homologous active region jets

    NASA Astrophysics Data System (ADS)

    Chandra, R.; Gupta, G. R.; Mulay, Sargam; Tripathi, Durgesh

    2015-02-01

    We present and discuss multiwavelength observations of five homologous recurrent solar jets that occurred in active region NOAA 11133 on 2010 December 11. These jets were well observed by the Solar Dynamic observatory (SDO) with high spatial and temporal resolution. The speed of the jets ranged between 86 and 267 km s-1. A type III radio burst was observed in association with all the five jets. The investigation of the overall evolution of magnetic field in the source regions suggested that the flux was continuously emerging on longer term. However, all the jets but J5 were triggered during a local dip in the magnetic flux, suggesting the launch of the jets during localized submergence of magnetic flux. Additionally, using the PFSS modelling of the photospheric magnetic field, we found that all the jets were ejected in the direction of open field lines. We also traced sunspot oscillations from the sunspot interior to foot-point of jets and found presence of ˜3 min oscillations in all the SDO/AIA (Atmospheric Imaging Assembly) passbands. The wavelet analysis revealed an increase in amplitude of the oscillations just before the trigger of the jets, that decreased after the jets were triggered. The observations of increased amplitude of the oscillation and its subsequent decrease provides evidence of wave-induced reconnection triggering the jets.

  2. Ink jet printable silver metallization with zinc oxide for front side metallization for micro crystalline silicon solar cells

    NASA Astrophysics Data System (ADS)

    Jurk, Robert; Fritsch, Marco; Eberstein, Markus; Schilm, Jochen; Uhlig, Florian; Waltinger, Andreas; Michaelis, Alexander

    2015-12-01

    Ink jet printable water based inks are prepared by a new silver nanoparticle synthesis and the addition of nanoscaled ZnO particles. For the formation of front side contacts the inks are ink jet printed on the front side of micro crystalline silicon solar cells, and contact the cell directly during the firing step by etching through the wafers’ anti-reflection coating (ARC). In terms of Ag dissolution and precipitation the mechanism of contact formation can be compared to commercial glass containing thick film pastes. This avoids additional processing steps, like laser ablation, which are usually necessary to open the ARC prior to ink jet printing. As a consequence process costs can be reduced. In order to optimize the ARC etching and contact formation during firing, zinc oxide nanoparticles are investigated as an ink additive. By utilization of in situ contact resistivity measurements the mechanism of contacting was explored. Our results show that silver inks containing ZnO particles realize a specific contact resistance below 10 mΩṡcm2. By using a multi-pass ink jet printing and plating process a front side metallization of commercial 6  ×  6 inch2 standard micro crystalline silicone solar cells with emitter resistance of 60 Ω/◽ was achieved and showed an efficiency of 15.7%.

  3. Resolving the Fan-spine Reconnection Geometry of a Small-scale Chromospheric Jet Event with the New Solar Telescope

    NASA Astrophysics Data System (ADS)

    Zeng, Zhicheng; Chen, Bin; Ji, Haisheng; Goode, Philip R.; Cao, Wenda

    2016-03-01

    Jets are ubiquitously present in both quiet and active regions on the Sun. They are widely believed to be driven by magnetic reconnection. A fan-spine structure has been frequently reported in some coronal jets and flares, and has been regarded as a signature of ongoing magnetic reconnection in a topology consisting of a magnetic null connected by a fan-like separatrix surface and a spine. However, for small-scale chromospheric jets, clear evidence of such structures is rather rare, although it has been implied in earlier works that showed an inverted-Y-shaped feature. Here we report high-resolution (0.″16) observations of a small-scale chromospheric jet obtained by the New Solar Telescope (NST) using 10830 Å filtergrams. Bi-directional flows were observed across the separatrix regions in the 10830 Å images, suggesting that the jet was produced due to magnetic reconnection. At the base of the jet, a fan-spine structure was clearly resolved by the NST, including the spine and the fan-like surface, as well as the loops before and after the reconnection. A major part of this fan-spine structure, with the exception of its bright footpoints and part of the base arc, was invisible in the extreme ultraviolet and soft X-ray images (observed by the Atmosphere Imaging Assembly and the X-Ray Telescope, respectively), indicating that the reconnection occurred in the upper chromosphere. Our observations suggest that the evolution of this chromospheric jet is consistent with a two-step reconnection scenario proposed by Török et al.

  4. Inward Motions in the Outer Solar Corona Between 6 And 12 R : Evidence For Waves or Magnetic Reconnection Jets?

    NASA Astrophysics Data System (ADS)

    Velli, Marco; Tenerani, Anna; DeForest, Craig

    2016-05-01

    DeForest et al. (2014) used synoptic visible-light image sequences from the COR2 coronagraph on board the STEREO-A spacecraft to identify inbound wave motions in the outer corona beyond 6 solar radii and inferred, from the observation, that the Alfven surface separating the magnetically dominated corona from the ow dominated wind must be located at least 12 solar radii from the Sun over polar coronal holes and 15 solar radii in the streamer belt. Here we will discuss both this and previous observations of inflows further down and attempt identification of the observed inward signals. We will theoretically reconstruct height-speed diagrams and compare them to the observed profiles. Interpretation in terms of Alfven / magnetoacouatic modes or Alfvenic turbulence appears to be ruled out by the fact that the observed signal shows a deceleration of inward motion when approaching the Sun. Fast magnetoacoustic waves are not directly ruled out in this way, as it is possible for inward waves observed in quadrature, but not propagating exactly radially, to suffer total reflection as the Alfven speed rises close to the Sun. However, the reconstructed signal in the height speed diagram has the wrong concavity. A final possibility is decelerating reconnection jets, most probably from component reconnection, in the accelerating wind: the profile in this case appears to match the observations very well. This interpretation does not alter the conclusion that the Alfven surface must be at least 12 solar radii from the photosphere.

  5. ROTATING SOLAR JETS IN SIMULATIONS OF FLUX EMERGENCE WITH THERMAL CONDUCTION

    SciTech Connect

    Fang, Fang; Fan, Yuhong; McIntosh, Scott W.

    2014-07-01

    We study the formation of coronal jets through numerical simulation of the emergence of a twisted magnetic flux rope into a pre-existing open magnetic field. Reconnection inside the emerging flux rope in addition to that between the emerging and pre-existing fields give rise to the violent eruption studied. The simulated event closely resembles the coronal jets ubiquitously observed by the X-Ray Telescope on board Hinode and demonstrates that heated plasma is driven into the extended atmosphere above. Thermal conduction implemented in the model allows us to qualitatively compare simulated and observed emission from such events. We find that untwisting field lines after the reconnection drive spinning outflows of plasma in the jet column. The Poynting flux in the simulated jet is dominated by the untwisting motions of the magnetic fields loaded with high-density plasma. The simulated jet is comprised of ''spires'' of untwisting field that are loaded with a mixture of cold and hot plasma and exhibit rotational motion of order 20 km s{sup –1} and match contemporary observations.

  6. Inward Motions in the Outer Solar Corona between 7 and 12 R ⊙: Evidence for Waves or Magnetic Reconnection Jets?

    NASA Astrophysics Data System (ADS)

    Tenerani, Anna; Velli, Marco; DeForest, Craig

    2016-07-01

    DeForest et al. used synoptic visible-light image sequences from the COR2 coronagraph on board the STEREO-A spacecraft to identify inbound wave motions in the outer corona beyond 7 solar radii and inferred, from the observation, that the Alfvén surface separating the magnetically dominated corona from the flow dominated wind must be located beyond at least 12 solar radii from the Sun over polar coronal holes and beyond 15 solar radii in the streamer belt. Here, we attempt identification of the observed inward signal by theoretically reconstructing height-speed diagrams and comparing them to the observed profiles. Interpretation in terms of Alfvén waves or Alfvénic turbulence appears to be ruled out by the fact that the observed signal shows a deceleration of inward motion when approaching the Sun. Fast magnetoacoustic waves are not directly ruled out in this way, as it is possible for inward waves observed in quadrature, but not propagating exactly radially, to suffer total reflection as the Alfvén speed rises close to the Sun. However, the reconstructed signal in the height-speed diagram has the wrong concavity. A final possibility is decelerating reconnection jets, most probably from component reconnection, in the accelerating wind: the profile in this case appears to match the observations very well. This interpretation does not alter the conclusion that the Alfvén surface must be at least 12 solar radii from the photosphere. Further observations should help constrain this process, never identified previously in this way, in the distance range from 7 to 12 solar radii.

  7. Latitude variation of recurrent MeV-energy proton flux enhancements in the heliocentric radial range 11 to 20 AU and possible correlation with solar coronal hole dynamics

    NASA Technical Reports Server (NTRS)

    Christon, S. P.; Stone, E. C.

    1985-01-01

    Recurrent low energy (not less than 0.5 MeV) proton flux enhancements, reliable indicators of corotating plasma interaction regions in interplanetary space, have been observed on the Voyager 1 and 2 and Pioneer 11 spacecraft in the heliographic latitude range 2 deg S to 23 deg N and the heliocentric radial range 11 to 20 AU. After a period of rather high correlation between fluxes at different latitudes in early 1983, distinct differences develop. The evolution of the fluxes appears to be related to the temporal and latitudinal dynamics of solar coronal holes, suggesting that information about the latitudinal structure of solar wind stream sources propagates to these distances.

  8. Modelling of the solar/stellar wind two-jet structure induced by azimuthal stellar magnetic field

    NASA Astrophysics Data System (ADS)

    Golikov, Evgeniy; Belov, Nickolai; Alexashov, Dmitry; Izmodenov, Vladislav

    2016-07-01

    Opher et al. (2015), Drake et al. (2015) have shown that the heliospheric magnetic field results in formation of two-jet structure of the solar wind flow in the inner heliosheath, i.e. in the subsonic region between the heliospheric termination shock and the heliopause. In this scenario the heliopause has tube-like topology as compared with sheet-like topology in the most models of the global heliosphere (e.g. Izmodenov and Alexashov, 2015). In this paper we explore the two-jet scenario for the simplified astrosphere with the star is at rest with respect to the circumstellar medium and radial magnetic field is neglected as compared with azimuthal component. Our work is further elaboration of Drake et al. (2015) paper. We performed parametric numerical analyses showing how the structure of the flow changes depending on the model parameters. Also, we present three first integrals of the ideal MHD equations for the considered problem and use them to get links between analytical and numerical considerations.

  9. Magnetic Flux of EUV Arcade and Dimming Regions as a Relevant Parameter for Early Diagnostics of Solar Eruptions - Sources of Non-recurrent Geomagnetic Storms and Forbush Decreases

    NASA Astrophysics Data System (ADS)

    Chertok, I. M.; Grechnev, V. V.; Belov, A. V.; Abunin, A. A.

    2013-01-01

    This study aims at the early diagnostics of the geoeffectiveness of coronal mass ejections (CMEs) from quantitative parameters of the accompanying EUV dimming and arcade events. We study events of the 23th solar cycle, in which major non-recurrent geomagnetic storms (GMS) with Dst<-100 nT are sufficiently reliably identified with their solar sources in the central part of the disk. Using the SOHO/EIT 195 Å images and MDI magnetograms, we select significant dimming and arcade areas and calculate summarized unsigned magnetic fluxes in these regions at the photospheric level. The high relevance of this eruption parameter is displayed by its pronounced correlation with the Forbush decrease (FD) magnitude, which, unlike GMSs, does not depend on the sign of the B z component but is determined by global characteristics of ICMEs. Correlations with the same magnetic flux in the solar source region are found for the GMS intensity (at the first step, without taking into account factors determining the B z component near the Earth), as well as for the temporal intervals between the solar eruptions and the GMS onset and peak times. The larger the magnetic flux, the stronger the FD and GMS intensities are and the shorter the ICME transit time is. The revealed correlations indicate that the main quantitative characteristics of major non-recurrent space weather disturbances are largely determined by measurable parameters of solar eruptions, in particular, by the magnetic flux in dimming areas and arcades, and can be tentatively estimated in advance with a lead time from 1 to 4 days. For GMS intensity, the revealed dependencies allow one to estimate a possible value, which can be expected if the B z component is negative.

  10. Observations of high-energy jets in the corona above the quiet sun, the heating of the corona, and the acceleration of the solar wind

    NASA Technical Reports Server (NTRS)

    Brueckner, G. E.; Bartoe, J.-D. F.

    1983-01-01

    High spatial resolution observations of the ultraviolet solar spectrum which reveal high-energy events in the quiet sun are presented. The tandem Wadsworth spectrograph used to make the observations is described along with the observing techniques, and a brief description of the characteristics of high-resolution transition zone spectra is given. The sizes, velocities, line profiles, time behavior, temperature range, differential emission measures, densities, masses, energies, and birthrates of turbulent events and jets in the quiet sun are derived from the observations and discussed. Possible accelerating mechanisms for these events are discussed, and the consequences of these events for the heating of the solar corona are discussed. A cloud model of the solar wind is proposed and possible correlations between the high-energy events and other solar fine-structure features are discussed.

  11. HOMOLOGOUS HELICAL JETS: OBSERVATIONS BY IRIS, SDO, AND HINODE AND MAGNETIC MODELING WITH DATA-DRIVEN SIMULATIONS

    SciTech Connect

    Cheung, Mark C. M.; Pontieu, B. De; Tarbell, T. D.; Fu, Y.; Martínez-Sykora, J.; Boerner, P.; Wülser, J. P.; Lemen, J.; Title, A. M.; Hurlburt, N.; Tian, H.; Testa, P.; Reeves, K. K.; Golub, L.; McKillop, S.; Saar, S.; Kleint, L.; Kankelborg, C.; Jaeggli, S.; Carlsson, M.; and others

    2015-03-10

    We report on observations of recurrent jets by instruments on board the Interface Region Imaging Spectrograph, Solar Dynamics Observatory (SDO), and Hinode spacecraft. Over a 4 hr period on 2013 July 21, recurrent coronal jets were observed to emanate from NOAA Active Region 11793. Far-ultraviolet spectra probing plasma at transition region temperatures show evidence of oppositely directed flows with components reaching Doppler velocities of ±100 km s{sup −1}. Raster Doppler maps using a Si iv transition region line show all four jets to have helical motion of the same sense. Simultaneous observations of the region by SDO and Hinode show that the jets emanate from a source region comprising a pore embedded in the interior of a supergranule. The parasitic pore has opposite polarity flux compared to the surrounding network field. This leads to a spine-fan magnetic topology in the coronal field that is amenable to jet formation. Time-dependent data-driven simulations are used to investigate the underlying drivers for the jets. These numerical experiments show that the emergence of current-carrying magnetic field in the vicinity of the pore supplies the magnetic twist needed for recurrent helical jet formation.

  12. HELICAL BLOWOUT JETS IN THE SUN: UNTWISTING AND PROPAGATION OF WAVES

    SciTech Connect

    Lee, E. J.; Archontis, V.; Hood, A. W.

    2015-01-01

    We report on a numerical experiment of the recurrent onset of helical ''blowout'' jets in an emerging flux region. We find that these jets are running with velocities of ∼100-250 km s{sup –1} and they transfer a vast amount of heavy plasma into the outer solar atmosphere. During their emission, they undergo an untwisting motion as a result of reconnection between the twisted emerging and the non-twisted pre-existing magnetic field in the solar atmosphere. For the first time in the context of blowout jets, we provide direct evidence that their untwisting motion is associated with the propagation of torsional Alfvén waves in the corona.

  13. Recurrent varicocele

    PubMed Central

    Rotker, Katherine; Sigman, Mark

    2016-01-01

    Varicocele recurrence is one of the most common complications associated with varicocele repair. A systematic review was performed to evaluate varicocele recurrence rates, anatomic causes of recurrence, and methods of management of recurrent varicoceles. The PubMed database was evaluated using keywords “recurrent” and “varicocele” as well as MESH criteria “recurrent” and “varicocele.” Articles were not included that were not in English, represented single case reports, focused solely on subclinical varicocele, or focused solely on a pediatric population (age <18). Rates of recurrence vary with the technique of varicocele repair from 0% to 35%. Anatomy of recurrence can be defined by venography. Management of varicocele recurrence can be surgical or via embolization. PMID:26806078

  14. Recurrent Outbursts and Jet Ejections Expected in Swift J1644+57: Limit-Cycle Activities in a Supermassive Black Hole

    NASA Astrophysics Data System (ADS)

    Kawashima, Tomohisa; Ohsuga, Ken; Usui, Ryuichi; Kawai, Nobuyuki; Negoro, Hitoshi; Matsumoto, Ryoji

    2013-08-01

    A tidal disruption event by a supermassive black hole in Swift J1644+57 can trigger limit-cycle oscillations between a supercritically accreting X-ray bright state and a subcritically accreting X-ray dim state. The time evolution of debris gas around a black hole with mass M = 106 M⊙ is studied by performing axisymmetric, two-dimensional radiation hydrodynamic simulations. We assume the α-prescription of viscosity, in which the viscous stress is proportional to the total pressure. The mass supply rate from the outer boundary was assumed to be Msupply = 100LEddfraslc2, where LEdd is the Eddington luminosity, and c is the light speed. Since the mass accretion rate decreases inward by outflows driven by radiation pressure, the state transition from a supercritically accreting slim disk state to a subcritically accreting Shakura-Sunyaev disk starts from the inner disk, and propagates outward on a timescale of one day. The sudden drop of the X-ray flux observed in Swift J1644+57 in 2012 August can be explained by this transition. As long as Msupply exceeds the threshold for the existence of a radiation pressure dominant disk, the accumulation of accreting gas in the subcritically accreting region triggers the transition from a gas pressure dominant Shakura-Sunyaev disk to a slim disk. This transition takes place at t ˜ 50frasl(αfrasl0.1) d after the X-ray darkening. We expect that if α > 0.01, X-ray emission with luminosity gtrsim 1044 erg s-1 and jet ejection will revive in Swift J1644+57 in 2013-2014.

  15. Jet shielding of jet noise

    NASA Technical Reports Server (NTRS)

    Simonich, J. C.; Amiet, R. K.; Schlinker, R. H.

    1986-01-01

    An experimental and theoretical study was conducted to develop a validated first principle analysis for predicting the jet noise reduction achieved by shielding one jet exhaust flow with a second, closely spaced, identical jet flow. A generalized fuel jet noise analytical model was formulated in which the acoustic radiation from a source jet propagates through the velocity and temperature discontinuity of the adjacent shielding jet. Input variables to the prediction procedure include jet Mach number, spacing, temperature, diameter, and source frequency. Refraction, diffraction, and reflection effects, which control the dual jet directivity pattern, are incorporated in the theory. The analysis calculates the difference in sound pressure level between the dual jet configuration and the radiation field based on superimposing two independent jet noise directivity patterns. Jet shielding was found experimentally to reduce noise levels in the common plane of the dual jet system relative to the noise generated by two independent jets.

  16. A Summary of The 2000-2001 NASA Glenn Lear Jet AM0 Solar Cell Calibration Program

    NASA Technical Reports Server (NTRS)

    Scheiman, David; Brinker, David; Snyder, David; Baraona, Cosmo; Jenkins, Phillip; Rieke, William J.; Blankenship, Kurt S.; Tom, Ellen M.

    2002-01-01

    Calibration of solar cells for space is extremely important for satellite power system design. Accurate prediction of solar cell performance is critical to solar array sizing, often required to be within 1%. The NASA Glenn Research Center solar cell calibration airplane facility has been in operation since 1963 with 531 flights to date. The calibration includes real data to Air Mass (AM) 0.2 and uses the Langley plot method plus an ozone correction factor to extrapolate to AM0. Comparison of the AM0 calibration data indicates that there is good correlation with Balloon and Shuttle flown solar cells. This paper will present a history of the airplane calibration procedure, flying considerations, and a brief summary of the previous flying season with some measurement results. This past flying season had a record 35 flights. It will also discuss efforts to more clearly define the ozone correction factor.

  17. Recurrent novae

    NASA Technical Reports Server (NTRS)

    Hack, Margherita; Selvelli, Pierluigi

    1993-01-01

    Recurrent novae seem to be a rather inhomogeneous group: T CrB is a binary with a M III companion; U Sco probably has a late dwarf as companion. Three are fast novae; two are slow novae. Some of them appear to have normal chemical composition; others may present He and CNO excess. Some present a mass-loss that is lower by two orders of magnitude than classical novae. However, our sample is too small for saying whether there are several classes of recurrent novae, which may be related to the various classes of classical novae, or whether the low mass-loss is a general property of the class or just a peculiarity of one member of the larger class of classical novae and recurrent novae.

  18. Fuzzy jets

    NASA Astrophysics Data System (ADS)

    Mackey, Lester; Nachman, Benjamin; Schwartzman, Ariel; Stansbury, Conrad

    2016-06-01

    Collimated streams of particles produced in high energy physics experiments are organized using clustering algorithms to form jets. To construct jets, the experimental collaborations based at the Large Hadron Collider (LHC) primarily use agglomerative hierarchical clustering schemes known as sequential recombination. We propose a new class of algorithms for clustering jets that use infrared and collinear safe mixture models. These new algorithms, known as fuzzy jets, are clustered using maximum likelihood techniques and can dynamically determine various properties of jets like their size. We show that the fuzzy jet size adds additional information to conventional jet tagging variables in boosted topologies. Furthermore, we study the impact of pileup and show that with some slight modifications to the algorithm, fuzzy jets can be stable up to high pileup interaction multiplicities.

  19. Fuzzy jets

    DOE PAGES

    Mackey, Lester; Nachman, Benjamin; Schwartzman, Ariel; Stansbury, Conrad

    2016-06-01

    Here, collimated streams of particles produced in high energy physics experiments are organized using clustering algorithms to form jets . To construct jets, the experimental collaborations based at the Large Hadron Collider (LHC) primarily use agglomerative hierarchical clustering schemes known as sequential recombination. We propose a new class of algorithms for clustering jets that use infrared and collinear safe mixture models. These new algorithms, known as fuzzy jets , are clustered using maximum likelihood techniques and can dynamically determine various properties of jets like their size. We show that the fuzzy jet size adds additional information to conventional jet taggingmore » variables in boosted topologies. Furthermore, we study the impact of pileup and show that with some slight modifications to the algorithm, fuzzy jets can be stable up to high pileup interaction multiplicities.« less

  20. Water Jetting

    NASA Astrophysics Data System (ADS)

    1985-01-01

    Hi-Tech Inc., a company which manufactures water jetting equipment, needed a high pressure rotating swivel, but found that available hardware for the system was unsatisfactory. They were assisted by Marshall, which had developed water jetting technology to clean the Space Shuttles. The result was a completely automatic water jetting system which cuts rock and granite and removes concrete. Labor costs have been reduced; dust is suppressed and production has been increased.

  1. Cosmic jets

    NASA Technical Reports Server (NTRS)

    Rees, M. J.

    1986-01-01

    The evidence that active galactic nuclei produce collimated plasma jets is summarised. The strongest radio galaxies are probably energised by relativistic plasma jets generated by spinning black holes interacting with magnetic fields attached to infalling matter. Such objects can produce e(+)-e(-) plasma, and may be relevant to the acceleration of the highest-energy cosmic ray primaries. Small-scale counterparts of the jet phenomenon within our own galaxy are briefly reviewed.

  2. Nucleosynthesis in Jets from Collapsars

    SciTech Connect

    Fujimoto, Shin-ichiro; Nishimura, Nobuya; Hashimoto, Masa-aki

    2008-05-21

    We investigate nucleosynthesis inside magnetically driven jets ejected from collapsars, or rotating magnetized stars collapsing to a black hole, based on two-dimensional magnetohydrodynamic simulation of the collapsars during the core collapse. We follow the evolution of the abundances of about 4000 nuclides from the collapse phase to the ejection phase using a large nuclear reaction network. We find that the r-process successfully operates only in the energetic jets (>10{sup 51} erg), so that U and Th are synthesized abundantly, even when the collapsars have a relatively small magnetic field (10{sup 10} G) and a moderately rotating core before the collapse. The abundance patterns inside the jets are similar to that of the r-elements in the solar system. The higher energy jets have larger amounts of {sup 56}Ni. Less energetic jets, which have small amounts of {sup 56}Ni, could induce GRB without supernova, such as GRB060505 and GRB060614.

  3. Statistical Study of Network Jets Observed in the Solar Transition Region: a Comparison Between Coronal Holes and Quiet-Sun Regions

    NASA Astrophysics Data System (ADS)

    Narang, Nancy; Arbacher, Rebecca T.; Tian, Hui; Banerjee, Dipankar; Cranmer, Steven R.; DeLuca, Ed E.; McKillop, Sean

    2016-04-01

    Recent IRIS observations have revealed a prevalence of intermittent small-scale jets with apparent speeds of 80 - 250 km s^{-1}, emanating from small-scale bright regions inside network boundaries of coronal holes. We find that these network jets appear not only in coronal holes but also in quiet-sun regions. Using IRIS 1330 Å (C II) slit-jaw images, we extracted several parameters of these network jets, e.g. apparent speed, length, lifetime, and increase in foot-point brightness. Using several observations, we find that some properties of the jets are very similar, but others are obviously different between the quiet Sun and coronal holes. For example, our study shows that the coronal-hole jets appear to be faster and longer than those in the quiet Sun. This can be directly attributed to a difference in the magnetic configuration of the two regions, with open magnetic field lines rooted in coronal holes and magnetic loops often present in the quiet Sun. We also detected compact bright loops that are most likely transition region loops and are mostly located in quiet-Sun regions. These small loop-like regions are generally devoid of network jets. In spite of different magnetic structures in the coronal hole and quiet Sun in the transition region, there appears to be no substantial difference for the increase in footpoint brightness of the jets, which suggests that the generation mechanism of these network jets is very likely the same in both regions.

  4. Multiple Null Point Reconnections in a limb faint cool jet ejection event

    NASA Astrophysics Data System (ADS)

    Tavabi, E.; Koutchmy, S.

    2016-09-01

    Giant spicules and macro- spicules are an important extended rather cool structure between the solar surface and the corona, partly filling the space inside the chromosphere and surrounded by a transition thin region. Their formation and dynamical properties are still mysterious. In order to explain solar limb and disc periodic recurrences of these events, a simulation model assuming quasi- random positions of spicules above the solar limb was studied. We allow a set number of spicules with different physical properties (such as height, lifetime and tilt angle as shown by an individual spicule) randomly occurring. It is assumed that after reaching a maximum length, the spicules are less rapidly falling back to the solar surface. This kind of limb event was often reported in the literature (spike; giant spicule; Ha ejection event; spray etc) but no serious quantitative analysis could be done. Indeed from ground-based observations, it is impossible to deduce precised parameters because the earth atmospheric turbulent effects makes impossible to make small scale measurements. SOT space-borne observations we use are unique in providing well reproducible observations permitting very precise measurements. The study of X-ray jets is an important topic to understand the heating of the solar corona and the origin of the fast wind. The recently launched Hinode mission permitted to observe the cool proxies of these jets with an unprecedented high spatial resolution of 120 km on the Sun. We selected a high cadence sequence of SOT (Hinode) observations taken with both the HCaII and the Hα filter to look at the details of the dynamics revealed by a large jet event. Both wavelet and amplitude spectra analysis were used to analyze the observed kink wave and the time variations of intensities during the event. The results are discussed in the frame of different models implying reconnections with the inference of the dynamical phenomena occurring in the vicinity of several null

  5. Business Jet

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Citation Jet, developed by Cessna Aircraft Company, Wichita, KS, is the first business jet to employ Langley Research Center's natural laminar flow (NLF) technology. NLF reduces drag and therefore saves fuel by using only the shape of the wing to keep the airflow smooth, or laminar. This reduces friction between the air and wing, and therefore, reduces drag. NASA's Central Industrial Applications Center, Rural Enterprises, Inc., Durant, OK, its Kansas affiliate, and Wichita State University assisted in the technology transfer.

  6. Emerging jets

    NASA Astrophysics Data System (ADS)

    Schwaller, Pedro; Stolarski, Daniel; Weiler, Andreas

    2015-05-01

    In this work, we propose a novel search strategy for new physics at the LHC that utilizes calorimeter jets that (i) are composed dominantly of displaced tracks and (ii) have many different vertices within the jet cone. Such emerging jet signatures are smoking guns for models with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. No current LHC searches are sensitive to this type of phenomenology. We perform a detailed simulation for a benchmark signal with two regular and two emerging jets, and present and implement strategies to suppress QCD backgrounds by up to six orders of magnitude. At the 14 TeV LHC, this signature can be probed with mediator masses as large as 1.5 TeV for a range of dark pion lifetimes, and the reach is increased further at the high-luminosity LHC. The emerging jet search is also sensitive to a broad class of long-lived phenomena, and we show this for a supersymmetric model with R-parity violation. Possibilities for discovery at LHCb are also discussed.

  7. [Jet lag].

    PubMed

    Lagarde, D; Doireau, P

    1997-01-01

    Desynchronization of circadian rhythmicity resulting from rapid travel through at least four time zones leads to symptoms known in everyday English as jet-lag. The most detrimental effect of jet-lag is fatigue with poor alertness and psychomotor performance. Severity is subject to individual variation in susceptibility (morning/evening typology, age,...) and environmental factors (direction of travel, number of time zones crossed, psychosocial environment...). Many measures used to prevent or reduce jet lag are inappropriate or ineffective and some may even be dangerous, such as use of melatonin. One of the most reliable preventive techniques consists of reinforcing social synchronizers by maintaining exposure to sunlight and social activity. Only two drugs currently available on the market can be recommended, i.e. non-benzodiazepinic hypnotics which induce high quality sleep to allow quick recovery and a new time-release caffeine agent which has been shown to prolong psychomotor performance.

  8. Synthetic Jets

    NASA Technical Reports Server (NTRS)

    Milanovic, Ivana M.

    2003-01-01

    Current investigation of synthetic jets and synthetic jets in cross-flow examined the effects of orifice geometry and dimensions, momentum-flux ratio, cluster of orifices, pitch and yaw angles as well as streamwise development of the flow field. This comprehensive study provided much needed experimental information related to the various control strategies. The results of the current investigation on isolated and clustered synthetic jets with and without cross-flow will be further analyzed and documented in detail. Presentations at national conferences and publication of peer- reviewed journal articles are also expected. Projected publications will present both the mean and turbulent properties of the flow field, comparisons made with the data available in an open literature, as well as recommendations for the future work.

  9. Solar Cells

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The Heat Exchanger Method (HEM) produces high efficiency crystal ingots in an automated well-insulated furnace offering low equipment, labor and energy costs. The "grown" silicon crystals are used to make solar cells, or photovoltaic cells which convert sunlight directly into electricity. The HEM method is used by Crystal Systems, Inc. and was developed under a NASA/Jet Propulsion Laboratory contract. The square wafers which are the result of the process are sold to companies manufacturing solar panels.

  10. Inks for Ink Jet Printed Contacts for High Performance Silicon Solar Cells: Cooperative Research and Development Final Report, CRADA No. CRD-06-199

    SciTech Connect

    Ginley, D.

    2013-01-01

    The work under the proposed CRADA will be a joint effort by BP Solar and NREL to develop new types of high performance inks for high quality contacts to silicon solar cells. NREL will develop inks that have electronic properties that will allow the formation of high quality ohmic contacts to n- and p-type crystalline silicon, and BP Solar will evaluate these contacts in test contact structures.

  11. A NUMERICAL MODEL OF STANDARD TO BLOWOUT JETS

    SciTech Connect

    Archontis, V.; Hood, A. W.

    2013-06-01

    We report on three-dimensional (3D) MHD simulations of the formation of jets produced during the emergence and eruption of solar magnetic fields. The interaction between an emerging and an ambient magnetic field in the solar atmosphere leads to (external) reconnection and the formation of ''standard'' jets with an inverse Y-shaped configuration. Eventually, low-atmosphere (internal) reconnection of sheared fieldlines in the emerging flux region produces an erupting magnetic flux rope and a reconnection jet underneath it. The erupting plasma blows out the ambient field and, moreover, it unwinds as it is ejected into the outer solar atmosphere. The fast emission of the cool material that erupts together with the hot outflows due to external/internal reconnection form a wider ''blowout'' jet. We show the transition from ''standard'' to ''blowout'' jets and report on their 3D structure. The physical plasma properties of the jets are consistent with observational studies.

  12. Recurrent aphthous stomatitis

    PubMed Central

    Preeti, L; Magesh, KT; Rajkumar, K; Karthik, Raghavendhar

    2011-01-01

    Recurrent aphthous ulcers are common painful mucosal conditions affecting the oral cavity. Despite their high prevalence, etiopathogenesis remains unclear. This review article summarizes the clinical presentation, diagnostic criteria, and recent trends in the management of recurrent apthous stomatitis. PMID:22144824

  13. Turbulent Jets?

    NASA Astrophysics Data System (ADS)

    Wilde, B. H.; Rosen, P. A.; Foster, J. M.; Perry, T. S.; Steinkamp, M. J.; Robey, H. F.; Khokhlov, A. M.; Gittings, M. L.; Coker, R. F.; Keiter, P. A.; Knauer, J. P.; Drake, R. P.; Remington, B. A.; Bennett, G. R.; Sinars, D. B.; Campbell, R. B.; Mehlhorn, T. A.

    2003-10-01

    Over the last few years we have fielded numerous supersonic jet experiments on the NOVA and OMEGA lasers and Sandia's pulsed-power Z-machine in a collaboration between Los Alamos National Laboratory, the Atomic Weapons Establishment, Lawrence Livermore National Laboratory, and Sandia National Laboratory. These experiments are being conducted to help validate our radiation-hydrodynamic codes, especially the newly developing ASC codes. One of the outstanding questions is whether these types of jets should turn turbulent given their high Reynolds number. Recently we have modified our experiments to have more Kelvin-Helmholtz shear, run much later in time and therefore have a better chance of going turbulent. In order to diagnose these large (several mm) jets at very late times ( 1000 ns) we are developing point-projection imaging on both the OMEGA laser, the Sandia Z-Machine, and ultimately at NIF. Since these jets have similar Euler numbers to jets theorized to be produced in supernovae explosions, we are also collaborating with the astrophysics community to help in the validation of their new codes. This poster will present a review of the laser and pulsed-power experiments and a comparison of the data to simulations by the codes from the various laboratories. We will show results of simulations wherein these jets turn highly 3-dimensional and show characteristics of turbulence. With the new data, we hope to be able to validate the sub-grid-scale turbulent mix models (e. g. BHR) that are being incorporated into our codes.*This work is performed under the auspices of the U. S. Department of Energy by the Los Alamos National Laboratory Laboratory under Contract No. W-7405-ENG-36, Lawrence Livermore National Laboratory under Contract No. W-7405-ENG-48, the Laboratory for Laser Energetics under Contract No. DE-FC03-92SF19460, Sandia National Laboratories under Contract No. DE-AC04-94AL85000, the Office of Naval Research, and the NASA Astrophysical Theory Grant.

  14. Subperiostial recurrence of chondroblastoma.

    PubMed

    Reddy, Sumanth; Deavers, Michael; Lin, Patrick; Haygood, Tamara Miner

    2009-01-01

    We present a case of subperiosteal recurrence of chondroblastoma adjacent to the greater trochanter that was initially thought to represent septic arthritis of the hip in a 10-year-old girl. Soft-tissue recurrence of chondroblastoma is very rare, with fewer than ten cases reported in the literature. We demonstrate the recurrence on both CT and MRI. The MRI clearly demonstrates the soft-tissue recurrence and the associated inflammatory changes, with signal characteristics not unlike the primary tumor. PMID:27307836

  15. The acceleration of the jet response observed in AIA observations

    NASA Astrophysics Data System (ADS)

    Raouafi, N.; Stenborg, G.; Stekel, T.

    2013-05-01

    We present an overview on observations of SDO/AIA coronal jets and their role in the heliosphere. We particularly focus on the study of their initiation and early evolution through a detailed analysis of multi-temperature, high-cadence observations. The visibility of the jets and the determination of their kinematical parameters is greatly improved via wavelet-cleaning and -enhancing of the data, which in turn allow us to probe the detailed evolution of jet plasma as it propagates into the solar corona. Constraints on the contribution of jets to the solar wind will also be outlined.

  16. Filament Eruptions, Jets, and Space Weather

    NASA Technical Reports Server (NTRS)

    Moore, Ronald; Sterling, Alphonse; Robe, Nick; Falconer, David; Cirtain, Jonathan

    2013-01-01

    -plasma component of coronal X-ray jets. This favors the idea that Type-II spicules are miniature counterparts of coronal X-ray jets. In Moore et al (2011, ApJ, 731, L18), we pointed out that if Type-II spicules are magnetic eruptions that work like coronal X-ray jets, they carry an area-averaged mechanical energy flux of approximately 7x10)(exp 5) erg cm(exp -2) s(exp-1) into the corona in the form of MHD waves and jet outflow, enough to power the heating of the global corona and solar wind. On this basis, from our observations of mini-filament eruptions in blowout X-ray jets, we infer that magnetic explosions of the type that have erupting filaments in them are the main engines of both (1) the steady solar wind and (2) the CMEs that produce the most severe space weather by blasting out through the corona and solar wind, making solar energetic particle storms, and bashing the Earth's magnetosphere. We conclude that in focusing on prominences and filament eruptions, Einar had his eye on the main bet for understanding what powers all space weather, both the extreme and the normal.

  17. A LABORATORY EXPERIMENT OF MAGNETIC RECONNECTION: OUTFLOWS, HEATING, AND WAVES IN CHROMOSPHERIC JETS

    SciTech Connect

    Nishizuka, N.; Shimizu, T.; Hayashi, Y.; Tanabe, H.; Kuwahata, A.; Kaminou, Y.; Ono, Y.; Inomoto, M.

    2012-09-10

    Hinode observations have revealed intermittent recurrent plasma ejections/jets in the chromosphere. These are interpreted as a result of non-perfectly anti-parallel magnetic reconnection, i.e., component reconnection, between a twisted magnetic flux tube and the pre-existing coronal/chromospheric magnetic field, though the fundamental physics of component reconnection is not revealed. In this paper, we experimentally reproduced the magnetic configuration and investigated the dynamics of plasma ejections, heating, and wave generation triggered by component reconnection in the chromosphere. We set plasma parameters as in the chromosphere (density 10{sup 14} cm{sup -3}, temperature 5-10 eV, i.e., (5-10) Multiplication-Sign 10{sup 4} K, and reconnection magnetic field 200 G) using argon plasma. Our experiment shows bi-directional outflows with the speed of 5 km s{sup -1} at maximum, ion heating in the downstream area over 30 eV, and magnetic fluctuations mainly at 5-10 {mu}s period. We succeeded in qualitatively reproducing chromospheric jets, but quantitatively, we still have some differences between observations and experiments such as in jet velocity, total energy, and wave frequency. Some of them can be explained by the scale gap between solar and laboratory plasma, while the others are probably due to the difference in microscopy and macroscopy, collisionality, and the degree of ionization, which have not been achieved in our experiment.

  18. Jets and Photons

    NASA Astrophysics Data System (ADS)

    Ellis, Stephen D.; Roy, Tuhin S.; Scholtz, Jakub

    2013-03-01

    This Letter applies the concept of “jets,” as constructed from calorimeter cell four-vectors, to jets composed (primarily) of photons (or leptons). Thus jets become a superset of both traditional objects such as QCD jets, photons, and electrons, and more unconventional objects such as photon jets and electron jets, defined as collinear photons and electrons, respectively. Since standard objects such as single photons become a subset of jets in this approach, standard jet substructure techniques are incorporated into the photon finder toolbox. Using a (reasonably) realistic calorimeter model we demonstrate that, for a single photon identification efficiency of 80% or above, the use of jet substructure techniques reduces the number of QCD jets faking photons by factors of 2.5 to 4. Depending on the topology of the photon jets, the substructure variables reduce the number of photon jets faking single photons by factors of 10 to 103 at a single photon identification efficiency of 80%.

  19. A swirling flare-related EUV jet

    NASA Astrophysics Data System (ADS)

    Zhang, Q. M.; Ji, H. S.

    2014-01-01

    Aims: We report our observations of a swirling flare-related extreme-ultraviolet (EUV) jet on 2011 October 15 at the edge of NOAA active region 11314. Methods: We used the multiwavelength observations in the EUV passbands from the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory (SDO). We extracted a wide slit along the jet axis and 12 thin slits across its axis to investigate the longitudinal motion and transverse rotation. We also used data from the Extreme-Ultraviolet Imager (EUVI) aboard the Solar TErrestrial RElations Observatory (STEREO) spacecraft to investigate the three-dimensional (3D) structure of the jet. Ground-based Hα images from the El Teide Observatory, a member of the Global Oscillation Network Group (GONG), provide a good opportunity to explore the relationship between the cool surge and the hot jet. Line-of-sight magnetograms from the Helioseismic and Magnetic Imager (HMI) aboard SDO enable us to study the magnetic evolution of the flare/jet event. We carried out potential-field extrapolation to calculate the magnetic configuration associated with the jet. Results: The onset of jet eruption coincided with the start time of the C1.6 flare impulsive phase. The initial velocity and acceleration of the longitudinal motion were 254 ± 10 km s-1 and -97 ± 5 m s-2, respectively. The jet presented helical structure and transverse swirling motion at the beginning of its eruption. The counter-clockwise rotation slowed down from an average velocity of ~122 km s-1 to ~80 km s-1. The interwinding thick threads of the jet untwisted into multiple thin threads during the rotation that lasted for one cycle with a period of ~7 min and an amplitude that increases from ~3.2 Mm at the bottom to ~11 Mm at the upper part. Afterwards, the curtain-like leading edge of the jet continued rising without rotation, leaving a dimming region behind, before falling back to the solar surface. The appearance/disappearance of dimming corresponded to the

  20. Management of recurrent miscarriage.

    PubMed

    Sugiura-Ogasawara, Mayumi; Ozaki, Yasuhiko; Suzumori, Nobuhiro

    2014-05-01

    Recurrent miscarriage is classically defined as three or more consecutive pregnancy losses. Many researchers have now revised this definition to two or more pregnancy losses because of the recent increase in the prevalence of childless couples. Established causes of recurrent miscarriage are antiphospholipid antibodies, uterine anomalies and abnormal chromosomes in either partner, particularly translocations. Antiphospholipid syndrome is the most important treatable cause of recurrent miscarriage. However, it is not yet established as to what kind of testing should be conducted in patients with recurrent pregnancy loss. Standardization of tests for antiphospholipid antibodies is needed. On the other hand, embryonic aneuploidy is the most frequent cause of recurrent miscarriage. Chromosome analysis of the embryo is important, because it has good predictive value for subsequent live birth. It is not necessary to give any medications for unexplained cases of recurrent miscarriage, and provision of psychological support may be the most important to encourage the couples to continue to conceive until a live birth results.

  1. Recurrent Takotsubo Cardiomyopathy Related to Recurrent Thyrotoxicosis

    PubMed Central

    Patel, Keval; Griffing, George T.; Hauptman, Paul J.

    2016-01-01

    Takotsubo cardiomyopathy, or transient left ventricular apical ballooning syndrome, is characterized by acute left ventricular dysfunction caused by transient wall-motion abnormalities of the left ventricular apex and mid ventricle in the absence of obstructive coronary artery disease. Recurrent episodes are rare but have been reported, and several cases of takotsubo cardiomyopathy have been described in the presence of hyperthyroidism. We report the case of a 55-year-old woman who had recurrent takotsubo cardiomyopathy, documented by repeat coronary angiography and evaluations of left ventricular function, in the presence of recurrent hyperthyroidism related to Graves disease. After both episodes, the patient's left ventricular function returned to normal when her thyroid function normalized. These findings suggest a possible role of thyroid-hormone excess in the pathophysiology of some patients who have takotsubo cardiomyopathy. PMID:27127432

  2. Recurrent Takotsubo Cardiomyopathy Related to Recurrent Thyrotoxicosis.

    PubMed

    Patel, Keval; Griffing, George T; Hauptman, Paul J; Stolker, Joshua M

    2016-04-01

    Takotsubo cardiomyopathy, or transient left ventricular apical ballooning syndrome, is characterized by acute left ventricular dysfunction caused by transient wall-motion abnormalities of the left ventricular apex and mid ventricle in the absence of obstructive coronary artery disease. Recurrent episodes are rare but have been reported, and several cases of takotsubo cardiomyopathy have been described in the presence of hyperthyroidism. We report the case of a 55-year-old woman who had recurrent takotsubo cardiomyopathy, documented by repeat coronary angiography and evaluations of left ventricular function, in the presence of recurrent hyperthyroidism related to Graves disease. After both episodes, the patient's left ventricular function returned to normal when her thyroid function normalized. These findings suggest a possible role of thyroid-hormone excess in the pathophysiology of some patients who have takotsubo cardiomyopathy. PMID:27127432

  3. Inclusive Jets in PHP

    NASA Astrophysics Data System (ADS)

    Roloff, P.

    Differential inclusive-jet cross sections have been measured in photoproduction for boson virtualities Q^2 < 1 GeV^2 with the ZEUS detector at HERA using an integrated luminosity of 300 pb^-1. Jets were identified in the laboratory frame using the k_T, anti-k_T or SIScone jet algorithms. Cross sections are presented as functions of the jet pseudorapidity, eta(jet), and the jet transverse energy, E_T(jet). Next-to-leading-order QCD calculations give a good description of the measurements, except for jets with low E_T(jet) and high eta(jet). The cross sections have the potential to improve the determination of the PDFs in future QCD fits. Values of alpha_s(M_Z) have been extracted from the measurements based on different jet algorithms. In addition, the energy-scale dependence of the strong coupling was determined.

  4. More Macrospicule Jets in On-Disk Coronal Holes

    NASA Astrophysics Data System (ADS)

    Adams, Mitzi; Sterling, Alphonse; Moore, Ronald

    2015-04-01

    We examine the magnetic structure and dynamics of multiple jets found in coronal holes close to or at disk center. All data are from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) of the Solar Dynamics Observatory (SDO). We report on observations of about ten jets in an equatorial coronal hole spanning 2011 February 27 and 28. We show the evolution of these jets in AIA 193 Å, examine the magnetic field configuration and flux changes in the jet area, and discuss the probable trigger mechanism of these events. We reported on another jet in this same coronal hole on 2011 February 27, ~13:04 UT (Adams et al 2014, ApJ, 783: 11). That jet is a previously unrecognized variety of blowout jet, in which the base-edge bright point is a miniature filament-eruption flare arcade made by internal reconnection of the legs of the erupting field. In contrast, in the presently-accepted "standard" picture for blowout jets, the base-edge bright point is made by interchange reconnection of initially-closed erupting jet-base field with ambient open field. This poster presents further evidence of the production of the base-edge bright point in blowout jets by internal reconnection. Our observations suggest that most of the bigger and brighter EUV jets in coronal holes are blowout jets of the new-found variety.

  5. Microchimerism in recurrent miscarriage.

    PubMed

    Gammill, Hilary S; Stephenson, Mary D; Aydelotte, Tessa M; Nelson, J Lee

    2014-11-01

    Maternal-fetal cell exchange during pregnancy results in acquisition of microchimerism, which can durably persist in both recipients. Naturally acquired microchimerism may impact maternal-fetal interaction in pregnancy. We conducted studies to ask whether microchimerism that a woman acquired from her own mother is detectable before or during pregnancy in women with recurrent miscarriage. Fetal microchimerism was also assayed. Women with primary idiopathic recurrent miscarriage (n=23) and controls (n=31) were studied. Genotyping was conducted for probands, their mothers and the fetus, a non-shared polymorphism identified and quantitative polymerase chain reaction performed to measure microchimerismin peripheral blood mononuclear cells. Preconception comparisons were made between recurrent miscarriage subjects and controls, using logistic regression and Wilcoxon rank sum. Longitudinal microchimerism in subsequent pregnancies of recurrent miscarriage subjects was described. There was a trend toward lower preconception detection of microchimerism in recurrent miscarriage versus controls, 6% vs. 19% (1/16 vs. 6/31, P=0.2). During pregnancy, 3/11 (27%) of recurrent miscarriage subjects who went on to have a birth had detection of microchimerism from their own mother, whereas neither of two subjects who went on to miscarry had detection (0/2). This initial data suggest that microchimerism from a woman's own mother, while detectable in women with recurrent miscarriage, may differ from controls and according to subsequent pregnancy outcome. Further studies are needed to determine the cell types, quantities and any potential functional role of microchimerism in recurrent miscarriage.

  6. Recurrent mixed tumor.

    PubMed

    Batsakis, J G

    1986-01-01

    Recurrence of benign neoplasms can usually be attributed to incomplete excision. Such is the case with benign mixed tumors of salivary glands. Certain histopathologic features of mixed tumors, however, appear to facilitate recurrences. These are: a predominantly myxoid composition, and transcapsular extension by the tumor. Multicentric origin is possible, but it must be regarded as a much lower order of probability.

  7. Multi-Spacecraft Observations of Magnetosheath High Speed Jets

    NASA Astrophysics Data System (ADS)

    Plaschke, F.; Hietala, H.; Angelopoulos, V.; Nakamura, R.

    2014-12-01

    The dynamic pressure of the plasma in the dayside magnetosheath is typically much lower than in the solar wind, just upstream of the bow shock. Sometimes, however, transient enhancements in dynamic pressure (called high speed jets) can be observed. Recently, we performed a statistical study of potentially geo-effective jets in the noon sector sheath. These jets exhibit a major velocity component in anti-sunward direction, toward the magnetopause. The study was based on four years (2008-2011) of THEMIS magnetosheath and OMNI solar wind measurements, and resulted in a set of 2859 single-spacecraft-based jet identifications. During those years, by orbit design, the three inner THEMIS spacecraft (THA, THD, and THE) were flying in close configuration near their respective apogees. Hence, dayside magnetosheath jet observations by one of the spacecraft are often complemented by context-providing measurements from the other two spacecraft. The multi-point information enables us to infer the spatial structure and extend of jets. In particular, we are able to compute a distribution of scale sizes (based on a model of probability for simultaneous multi-spacecraft jet observations), due to the high number of jets in our set and the relatively large spread in corresponding distances between the spacecraft. Furthermore, we present statistical results of the plasma flow pattern within jets and in their environment, showing how the magnetosheath plasma flow is modified on jet passage.

  8. ELLERMAN BOMBS WITH JETS: CAUSE AND EFFECT

    SciTech Connect

    Reid, A.; Mathioudakis, M.; Scullion, E.; Gallagher, P.; Doyle, J. G.; Shelyag, S.

    2015-05-20

    Ellerman Bombs (EBs) are thought to arise as a result of photospheric magnetic reconnection. We use data from the Swedish 1 m Solar Telescope to study EB events on the solar disk and at the limb. Both data sets show that EBs are connected to the foot points of forming chromospheric jets. The limb observations show that a bright structure in the Hα blue wing connects to the EB initially fueling it, leading to the ejection of material upwards. The material moves along a loop structure where a newly formed jet is subsequently observed in the red wing of Hα. In the disk data set, an EB initiates a jet which propagates away from the apparent reconnection site within the EB flame. The EB then splits into two, with associated brightenings in the inter-granular lanes. Micro-jets are then observed, extending to 500 km with a lifetime of a few minutes. Observed velocities of the micro-jets are approximately 5–10 km s{sup −1}, while their chromospheric counterparts range from 50 to 80 km s{sup −1}. MURaM simulations of quiet Sun reconnection show that micro-jets with properties similar to those of the observations follow the line of reconnection in the photosphere, with associated Hα brightening at the location of increased temperature.

  9. A STANDARD-TO-BLOWOUT JET

    SciTech Connect

    Liu Chang; Deng Na; Liu Rui; Wang Shuo; Wang Haimin; Ugarte-Urra, Ignacio

    2011-07-01

    The commonly observed jets provide critical information on the small-scale energy release in the solar atmosphere. We report a near disk-center jet on 2010 July 20, observed by the Solar Dynamics Observatory. In this event, the standard interchange magnetic reconnection between an emerging flux spanning 9 x 10{sup 3} km and ambient open fields is followed by a blowout-like eruption. In the 'standard' stage, as the emerging negative element approached the nearby positive network fields, a jet with a dome-like base in EUV grew for 30 minutes before the jet spire began to migrate laterally with enhanced flux emergence. In the 'blowout' stage, the above converging fields collided and the subsequent cancellation produced a UV microflare lasting seven minutes, in which the dome of the jet seemed to be blown out as (1) the spire swung faster and exhibited an unwinding motion before vanishing, (2) a rising loop and a blob erupted leaving behind cusped structures, with the blob spiraling outward in acceleration after the flare maximum, and (3) ejecting material with a curtain-like structure at chromospheric to transition-region temperatures also underwent a transverse motion. It is thus suggested that the flare reconnection rapidly removes the outer fields of the emerging flux to allow its twisted core field to erupt, a scenario favoring the jet-scale magnetic breakout model as recently advocated by Moore et al. in 2010.

  10. Ellerman Bombs with Jets: Cause and Effect

    NASA Astrophysics Data System (ADS)

    Reid, A.; Mathioudakis, M.; Scullion, E.; Doyle, J. G.; Shelyag, S.; Gallagher, P.

    2015-05-01

    Ellerman Bombs (EBs) are thought to arise as a result of photospheric magnetic reconnection. We use data from the Swedish 1 m Solar Telescope to study EB events on the solar disk and at the limb. Both data sets show that EBs are connected to the foot points of forming chromospheric jets. The limb observations show that a bright structure in the Hα blue wing connects to the EB initially fueling it, leading to the ejection of material upwards. The material moves along a loop structure where a newly formed jet is subsequently observed in the red wing of Hα. In the disk data set, an EB initiates a jet which propagates away from the apparent reconnection site within the EB flame. The EB then splits into two, with associated brightenings in the inter-granular lanes. Micro-jets are then observed, extending to 500 km with a lifetime of a few minutes. Observed velocities of the micro-jets are approximately 5-10 km s-1, while their chromospheric counterparts range from 50 to 80 km s-1. MURaM simulations of quiet Sun reconnection show that micro-jets with properties similar to those of the observations follow the line of reconnection in the photosphere, with associated Hα brightening at the location of increased temperature.

  11. A MODEL OF THE HELIOSPHERE WITH JETS

    SciTech Connect

    Drake, J. F.; Swisdak, M.; Opher, M. E-mail: swisdak@umd.edu

    2015-08-01

    An analytic model of the heliosheath (HS) between the termination shock (TS) and the heliopause (HP) is developed in the limit in which the interstellar flow and magnetic field are neglected. The heliosphere in this limit is axisymmetric and the overall structure of the HS and HP is controlled by the solar magnetic field even in the limit in which the ratio of the plasma to magnetic field pressure, β = 8πP/B{sup 2}, in the HS is large. The tension of the solar magnetic field produces a drop in the total pressure between the TS and the HP. This same pressure drop accelerates the plasma flow downstream of the TS into the north and south directions to form two collimated jets. The radii of these jets are controlled by the flow through the TS and the acceleration of this flow by the magnetic field—a stronger solar magnetic field boosts the velocity of the jets and reduces the radii of the jets and the HP. MHD simulations of the global heliosphere embedded in a stationary interstellar medium match well with the analytic model. The results suggest that mechanisms that reduce the HS plasma pressure downstream of the TS can enhance the jet outflow velocity and reduce the HP radius to values more consistent with the Voyager 1 observations than in current global models.

  12. The Giant Jet

    NASA Astrophysics Data System (ADS)

    Neubert, T.; Chanrion, O.; Arnone, E.; Zanotti, F.; Cummer, S.; Li, J.; Füllekrug, M.; van der Velde, O.

    2012-04-01

    Thunderstorm clouds may discharge directly to the ionosphere in spectacular luminous jets - the longest electric discharges on our planet. The electric properties of jets, such as their polarity, conductivity, and currents, have been predicted by models, but are poorly characterized by measurements. Here we present an analysis of the first gigantic jet that with certainty has a positive polarity. The jet region in the mesosphere was illuminated by an unusual sprite discharge generated by a positive cloud-to-ground lightning flash shortly after the onset of the jet. The sprite appeared with elements in a ring at ~40 km distance around the jet, the elements pointing curving away from the jet. This suggests that the field close the jet partially cancels the field driving the sprite. From a simple model of the event we conclude that a substantial portion of the positive cloud potential must be carried to ~50 km altitude, which is also consistent with the observed channel expansion and the electromagnetic radiation associated with the jet. It is further shown that blue jets are likely to substantially modify the free electron content in the lower ionosphere because of increased electron attachment driven by the jet electric field. The model further makes clear the relationship between jets, gigantic jets, and sprites. This is the first time that sprites are used for sounding the properties of the mesosphere. The observations presented here will allow evaluation of theories for jet and gigantic jet generation and of their influence on the atmosphere-ionosphere system.

  13. Accelerated/abbreviated test methods for predicting life of solar cell encapsulants to Jet Propulsion Laboratory California Institute of Technology for the encapsulation task of the low-cost solar array project

    NASA Technical Reports Server (NTRS)

    Kolyer, J. M.

    1978-01-01

    An important principle is that encapsulants should be tested in a total array system allowing realistic interaction of components. Therefore, micromodule test specimens were fabricated with a variety of encapsulants, substrates, and types of circuitry. One common failure mode was corrosion of circuitry and solar cell metallization due to moisture penetration. Another was darkening and/or opacification of encapsulant. A test program plan was proposed. It includes multicondition accelerated exposure. Another method was hyperaccelerated photochemical exposure using a solar concentrator. It simulates 20 year of sunlight exposure in a short period of one to two weeks. The study was beneficial in identifying some cost effective encapsulants and array designs.

  14. Predictors of Recurrent AKI.

    PubMed

    Siew, Edward D; Parr, Sharidan K; Abdel-Kader, Khaled; Eden, Svetlana K; Peterson, Josh F; Bansal, Nisha; Hung, Adriana M; Fly, James; Speroff, Ted; Ikizler, T Alp; Matheny, Michael E

    2016-04-01

    Recurrent AKI is common among patients after hospitalized AKI and is associated with progressive CKD. In this study, we identified clinical risk factors for recurrent AKI present during index AKI hospitalizations that occurred between 2003 and 2010 using a regional Veterans Administration database in the United States. AKI was defined as a 0.3 mg/dl or 50% increase from a baseline creatinine measure. The primary outcome was hospitalization with recurrent AKI within 12 months of discharge from the index hospitalization. Time to recurrent AKI was examined using Cox regression analysis, and sensitivity analyses were performed using a competing risk approach. Among 11,683 qualifying AKI hospitalizations, 2954 patients (25%) were hospitalized with recurrent AKI within 12 months of discharge. Median time to recurrent AKI within 12 months was 64 (interquartile range 19-167) days. In addition to known demographic and comorbid risk factors for AKI, patients with longer AKI duration and those whose discharge diagnosis at index AKI hospitalization included congestive heart failure (primary diagnosis), decompensated advanced liver disease, cancer with or without chemotherapy, acute coronary syndrome, or volume depletion, were at highest risk for being hospitalized with recurrent AKI. Risk factors identified were similar when a competing risk model for death was applied. In conclusion, several inpatient conditions associated with AKI may increase the risk for recurrent AKI. These findings should facilitate risk stratification, guide appropriate patient referral after AKI, and help generate potential risk reduction strategies. Efforts to identify modifiable factors to prevent recurrent AKI in these patients are warranted.

  15. JPL tests of a LaJet concentrator facet

    SciTech Connect

    Dennison, E.W.; Argoud, M.J.

    1983-11-15

    A LaJet Energy Company (LEC) concentrator facet, 60 in. in diameter, was tested for imaging quality at the Jet Propulsion Laboratory using two methods: (1) autofocus tests with a point source of light at the facet's radius of curvature, and (2) tests with the sun close to the horizon as a distant source. These tests of the LaJet facet indicate that all of the solar image reflected by an LEC 460 solar concentrator made of like facets should fall within a 9-in. aperture if the outer facets are carefully adjusted. Such a concentrator would have acceptable performance, but complete evaluation must be made with an assembled concentrator.

  16. Recurrent pregnancy loss.

    PubMed

    Rao, Kamini A; Pillai, Jyothi R

    2006-08-01

    Recurrent abortions are hisheartening to the couple and also to the treating clinicians. Miscarriage is the loss of pregnancy weighing 500 g or less. Recurrent miscarriage or habitual abortion is defined as three or more consective abortions. Important factors involved in recurrent early pregnancy loss are genetic factors, endocrine factors, anatomic factors, immunologic factors, infectious factors and environmental factors. The factors are described in a nutshell in the text. Any severe infection that leads to bacteraemia orviraemia can cause sporadic miscarriage. Congenital uterine abnormalities have been associated most often with second-trimestar pregnancy loss. As regarding management of recurrent pregnancy loss the clinician has limited options. The use of aspiration in low dose (75 mg) and heparin is beneficial in APS positive patients. Multivitamins and folic acid assume importance in thrombophilic disorders. Tender live care with regular antenatal check-ups go a great way in achieving live term pregnancy.

  17. Control of jet noise

    NASA Astrophysics Data System (ADS)

    Schreck, Stefan

    To investigate the possibility of active control of jet noise, knowledge of the noise generation mechanisms in natural jets is essential. Once these mechanisms are determined, active control can be used to manipulate the noise production processes. We investigated the evolution of the flow fields and the acoustic fields of rectangular and circular jets. A predominant flapping mode was found in the supersonic rectangular jets. We hope to increase the spreading of supersonic jets by active control of the flapping mode found in rectangular supersonic jets.

  18. Recurrent gastric bezoars. A new approach to treatment and prevention.

    PubMed

    Klamer, T W; Max, M H

    1983-03-01

    A recurrent gastric phytobezoar was successfully dispersed using an endoscopically directed intermittent jet of dilute papain. Dissolution analysis of a retrieved bezoar fragment showed pancrelipase and Adolph's Meat Tenderizer to be effective specific solvents. The patient remained free of symptoms while on a prophylactic regimen of pancrelipase taken daily. However, when the patient discontinued his medication, the bezoar recurred. The dissolution process was successfully repeated. Selecting a reagent on the basis of demonstrated effectiveness should enhance the chance of successful dissolution of a phytobezoar, whereas prophylactic doses of the reagent may prevent its recurrence. PMID:6837873

  19. Control of jet noise

    NASA Technical Reports Server (NTRS)

    Schreck, Stefan

    1993-01-01

    This reports describes experiments conducted at the High-Speed Jet Facility at the University of Southern California on supersonic jets. The goal of the study was to develop methods for controlling the noise emitted from supersonic jets by passive and/or active means. Work by Seiner et al (1991) indicates that eddy Mach wave radiation is the dominant noise source in a heated high speed jet. Eddy Mach radiation is caused by turbulent eddies traveling at supersonic speed in the shear layer of the jet. The convection velocity of the eddies decays with increasing distance from the nozzle exit due to the mixing of the jet stream with the ambient fluid. Once the convection speed reaches subsonic velocities, eddy Mach wave radiation ceases. To control noise, a rapid decay of the convection velocity is desired. This may be accomplished by enhanced mixing in the jet. In this study, small aspect ratio rectangular jet nozzles were tested. A flapping mode was noticed in the jets. By amplifying screech components of the jets and destabilizing the jet columns with a collar device, the flapping mode was excited. The result was a rapid decay of the jet velocity. A reduction in eddy Mach radiation in rectangular supersonic jets may be achieved with this device.

  20. Control of jet noise

    NASA Astrophysics Data System (ADS)

    Schreck, Stefan

    This reports describes experiments conducted at the High-Speed Jet Facility at the University of Southern California on supersonic jets. The goal of the study was to develop methods for controlling the noise emitted from supersonic jets by passive and/or active means. Work by Seiner et al (1991) indicates that eddy Mach wave radiation is the dominant noise source in a heated high speed jet. Eddy Mach radiation is caused by turbulent eddies traveling at supersonic speed in the shear layer of the jet. The convection velocity of the eddies decays with increasing distance from the nozzle exit due to the mixing of the jet stream with the ambient fluid. Once the convection speed reaches subsonic velocities, eddy Mach wave radiation ceases. To control noise, a rapid decay of the convection velocity is desired. This may be accomplished by enhanced mixing in the jet. In this study, small aspect ratio rectangular jet nozzles were tested. A flapping mode was noticed in the jets. By amplifying screech components of the jets and destabilizing the jet columns with a collar device, the flapping mode was excited. The result was a rapid decay of the jet velocity. A reduction in eddy Mach radiation in rectangular supersonic jets may be achieved with this device.

  1. Lateral Shock of the R Aquarii Jet

    NASA Technical Reports Server (NTRS)

    Hollis, J. M.; Pedelty, J. A.; Kafatos, M.

    1997-01-01

    The R Aqr jet was observed with the VLA B-configuration at two epochs separated by approximately 13.2 yr. Comparison of the resulting 6 cm continuum images show that the radio jet has undergone a lateral counterclockwise rotation of approximately 6 deg-12 deg on the plane of the sky. The model of jet parcels on independent trajectories is difficult to reconcile with these observations and leads us to consider a path-oriented jet (i.e., younger parcels follow the same path as older parcels). Comparison of the most recent radio image with a nearly contemporaneous HST/FOC ultraviolet image at approximately 2330 Angstroms suggests that the ultraviolet emission lies along the leading side of the rotating radio jet. In conjunction with a proper motion analysis of the jet material that yields empirical space-velocity and resulting acceleration-magnitude relationships as a function of distance from the central source, we evaluate the observational results in terms of a schematic model in which the jet emission consists of plane-parallel isothermal shocks along the leading edge of rotation. In such a radiating shock, the ultraviolet-emitting region is consistent with the adiabatic region in the form of a high-temperature, low-density sheath that surrounds the cooled postshock radio-emitting region. Within the context of the schematic model, we obtain the temperatures, densities, and pressures within the preshock, adiabatic, and postshock regions as a function of distance from the central source; the physical parameters so derived compare favorably to previously published estimates. We obtain a total jet mass of 3.1 x 10(exp -5) solar mass and an age of approximately 115 yr. We evaluate the model in the context of its density-boundary condition, its applicability to an episodic or quasi-continuous jet, and angular momentum considerations.

  2. Jets of incipient liquids

    NASA Astrophysics Data System (ADS)

    Reshetnikov, A. V.; Mazheiko, N. A.; Skripov, V. P.

    2000-05-01

    Jets of incipient water escaping into the atmosphere through a short channel are photographed. In some experiments. complete disintegration of the jet is observed. The relationship of this phenomenon with intense volume incipience is considered. The role of the Coanda effect upon complete opening of the jet is revealed. Measurement results of the recoil force R of the jets of incipient liquids are presented. Cases of negative thrust caused by the Coanda effect are noted. Generalization of experimental data is proposed.

  3. Recurrent Fever in Children

    PubMed Central

    Torreggiani, Sofia; Filocamo, Giovanni; Esposito, Susanna

    2016-01-01

    Children presenting with recurrent fever may represent a diagnostic challenge. After excluding the most common etiologies, which include the consecutive occurrence of independent uncomplicated infections, a wide range of possible causes are considered. This article summarizes infectious and noninfectious causes of recurrent fever in pediatric patients. We highlight that, when investigating recurrent fever, it is important to consider age at onset, family history, duration of febrile episodes, length of interval between episodes, associated symptoms and response to treatment. Additionally, information regarding travel history and exposure to animals is helpful, especially with regard to infections. With the exclusion of repeated independent uncomplicated infections, many infective causes of recurrent fever are relatively rare in Western countries; therefore, clinicians should be attuned to suggestive case history data. It is important to rule out the possibility of an infectious process or a malignancy, in particular, if steroid therapy is being considered. After excluding an infectious or neoplastic etiology, immune-mediated and autoinflammatory diseases should be taken into consideration. Together with case history data, a careful physical exam during and between febrile episodes may give useful clues and guide laboratory investigations. However, despite a thorough evaluation, a recurrent fever may remain unexplained. A watchful follow-up is thus mandatory because new signs and symptoms may appear over time. PMID:27023528

  4. [Treatment of recurrent furunculosis].

    PubMed

    Engelhard, Esther A N; Spanjaard, Lodewijk; Stijnis, C Kees

    2013-01-01

    The management of recurrent furunculosis is difficult, and often disappointing. We present the case of a 23-year-old female patient suffering from recurrent furunculosis. The furunculosis persisted after treatment with mupirocin nasal ointment, chlorhexidine soap and instructions for washing clothes, towels and bed sheets for a period of 7 days. Treatment with low-dose clindamycin for three months ultimately proved successful. We propose a structural approach for recurrent furunculosis in which extensive history-taking is followed by appropriate tests. Before prescribing an oral antibiotic (preferably low-dose clindamycin or a macrolide for 3 months), the patient should use an antimicrobial nasal ointment and soap and follow hygienic instructions as mentioned above. Members of the household who also have signs of the infection should be treated. Hygienic education is an essential component of treatment. We believe that this approach will lead to a treatment that is more effective and efficient.

  5. Recurrent wheezing in children

    PubMed Central

    Piazza, Michele; Piacentini, Giorgio

    2016-01-01

    Recurrent wheezing have a significant morbidity and it’s estimated that about one third of school-age children manifest the symptom during the first 5 years of life. Proper identification of children at risk of developing asthma at school age may predict long-term outcomes and improve treatment and preventive approach, but the possibility to identify these children at preschool age remains limited. For many years authors focused their studies to identify early children with recurrent wheezing at risk to develop asthma at school age. Different phenotypes have been proposed for a more precise characterization and a personalized plan of treatment. The main criticism concerns the inability to define stable phenotypes with the risk of overestimating or underestimating the characteristics of symptoms in these children. The aim of this review is to report the recent developments on the diagnosis and treatment of recurrent paediatric wheezing. PMID:26835404

  6. [Treatment of recurrent furunculosis].

    PubMed

    Engelhard, Esther A N; Spanjaard, Lodewijk; Stijnis, C Kees

    2013-01-01

    The management of recurrent furunculosis is difficult, and often disappointing. We present the case of a 23-year-old female patient suffering from recurrent furunculosis. The furunculosis persisted after treatment with mupirocin nasal ointment, chlorhexidine soap and instructions for washing clothes, towels and bed sheets for a period of 7 days. Treatment with low-dose clindamycin for three months ultimately proved successful. We propose a structural approach for recurrent furunculosis in which extensive history-taking is followed by appropriate tests. Before prescribing an oral antibiotic (preferably low-dose clindamycin or a macrolide for 3 months), the patient should use an antimicrobial nasal ointment and soap and follow hygienic instructions as mentioned above. Members of the household who also have signs of the infection should be treated. Hygienic education is an essential component of treatment. We believe that this approach will lead to a treatment that is more effective and efficient. PMID:23369819

  7. Resonant ion acceleration by plasma jets: Effects of jet breaking and the magnetic-field curvature.

    PubMed

    Artemyev, A V; Vasiliev, A A

    2015-05-01

    In this paper we consider resonant ion acceleration by a plasma jet originating from the magnetic reconnection region. Such jets propagate in the background magnetic field with significantly curved magnetic-field lines. Decoupling of ion and electron motions at the leading edge of the jet results in generation of strong electrostatic fields. Ions can be trapped by this field and get accelerated along the jet front. This mechanism of resonant acceleration resembles surfing acceleration of charged particles at a shock wave. To describe resonant acceleration of ions, we use adiabatic theory of resonant phenomena. We show that particle motion along the curved field lines significantly influences the acceleration rate. The maximum gain of energy is determined by the particle's escape from the system due to this motion. Applications of the proposed mechanism to charged-particle acceleration in the planetary magnetospheres and the solar corona are discussed. PMID:26066269

  8. Jets at CDF

    SciTech Connect

    Gallinaro, Michele; /Rockefeller U.

    2006-08-01

    Recent jet results in p{bar p} collisions at {radical}s = 1.96 TeV from the CDF experiment at the Tevatron are presented. The jet inclusive cross section is compared to next-to-leading order QCD prediction in different rapidity regions. The b-jet inclusive cross section is measured exploiting the long lifetime and large mass of B-hadrons. Jet shapes, W+jets and W/Z+photon cross sections are also measured and compared to expectations from QCD production.

  9. Protostellar Jets: Numerical Simulations

    NASA Astrophysics Data System (ADS)

    Vitorino, B. F.; Jatenco-Pereira, V.; Opher, R.

    1998-11-01

    Numerical simulations of astrophysical jets have been made in order to study their collimation and internal structure. Recently Ouyed & Pudritz (1997) did numerical simulations of axi-simetric magnetocentrifugal jets from a keplerian acretion disk employing the eulerian finite difference code Zeus-2D. During their simulation, it was raised a steady state jet confirming a lot of results of the MHD winds steady state theory. Following this scenario we did tridimensional numerial simulations of this model allowing the jet, after a perturbation, evolve into a not steady state producing the helical features observed in some protostellar jets.

  10. Recurrent pregnancy loss.

    PubMed

    Hatasaka, H H; Varner, M W

    1994-12-01

    Recurrent pregnancy loss is a frustrating clinical dilemma for both patients and physicians because, in most cases, causes are nebulous and few treatments with proven benefit can be offered. Involved, expensive tests have frequently been proposed and their use has often filtered into clinical practice before their utility has been firmly demonstrated. Proposed causes of recurrent pregnancy loss include genetic and environmental etiologies, infectious agents, maternal congenital and acquired anatomic abnormalities, and immunologic and endocrinologic dysfunction. Appropriate management relies upon a realistic understanding of the often substantial limitations of currently available therapies.

  11. Tackling a Recurrent Pinealoblastoma

    PubMed Central

    Palled, Siddanna; Kalavagunta, Sruthi; Beerappa Gowda, Jaipal; Umesh, Kavita; Aal, Mahalaxmi; Abdul Razack, Tanvir pasha Chitraduraga; Gowda, Veerabhadre; Viswanath, Lokesh

    2014-01-01

    Pineoblastomas are rare, malignant, pineal region lesions that account for <0.1% of all intracranial tumors and can metastasize along the neuroaxis. Pineoblastomas are more common in children than in adults and adults account for <10% of patients. The management of pinealoblastoma is multimodality approach, surgery followed with radiation and chemotherapy. In view of aggressive nature few centres use high dose chemotherapy with autologus stem cell transplant in newly diagnosed cases but in recurrent setting the literature is very sparse. The present case represents the management of pinealoblastoma in the recurrent setting with reirradiation and adjuvant carmustine chemotherapy wherein the management guidelines are not definitive. PMID:25210636

  12. Recurrent Aphthous Stomatitis

    PubMed Central

    Akintoye, Sunday O.; Greenberg, Martin S.

    2014-01-01

    Recurrent Aphthous Stomatitis (RAS) is the most common ulcerative disease affecting the oral mucosa. It occurs mostly in healthy individuals and has atypical clinical presentation in immunocompromised individuals. The etiology of RAS is still unknown, but several local, systemic, immunologic, genetic, allergic, nutritional, and microbial factors, as well as immunosuppressive drugs, have been proposed as causative agents. Clinical management of RAS is based on severity of symptoms, frequency, size and number of lesions using topical and systemic therapies. The goals of therapy are to decrease pain and ulcer size, promote healing and decrease frequency of recurrence. PMID:24655523

  13. Characteristics of polar coronal hole jets

    NASA Astrophysics Data System (ADS)

    Chandrashekhar, K.; Bemporad, A.; Banerjee, D.; Gupta, G. R.; Teriaca, L.

    2014-01-01

    Context. High spatial- and temporal-resolution images of coronal hole regions show a dynamical environment where mass flows and jets are frequently observed. These jets are believed to be important for the coronal heating and the acceleration of the fast solar wind. Aims: We studied the dynamics of two jets seen in a polar coronal hole with a combination of imaging from EIS and XRT onboard Hinode. We observed drift motions related to the evolution and formation of these small-scale jets, which we tried to model as well. Methods: Stack plots were used to find the drift and flow speeds of the jets. A toymodel was developed by assuming that the observed jet is generated by a sequence of single reconnection events where single unresolved blobs of plasma are ejected along open field lines, then expand and fall back along the same path, following a simple ballistic motion. Results: We found observational evidence that supports the idea that polar jets are very likely produced by multiple small-scale reconnections occurring at different times in different locations. These eject plasma blobs that flow up and down with a motion very similar to a simple ballistic motion. The associated drift speed of the first jet is estimated to be ≈27 km s-1. The average outward speed of the first jet is ≈171 km s-1, well below the escape speed, hence if simple ballistic motion is considered, the plasma will not escape the Sun. The second jet was observed in the south polar coronal hole with three XRT filters, namely, C-poly, Al-poly, and Al-mesh filters. Many small-scale (≈3″-5″) fast (≈200-300 km s-1) ejections of plasma were observed on the same day; they propagated outwards. We observed that the stronger jet drifted at all altitudes along the jet with the same drift speed of ≃7 km s-1. We also observed that the bright point associated with the first jet is a part of sigmoid structure. The time of appearance of the sigmoid and that of the ejection of plasma from the bright

  14. The Breakout Model for Coronal Jets with Filaments

    NASA Astrophysics Data System (ADS)

    Wyper, Peter; DeVore, C. Richard; Antiochos, Spiro K.

    2016-05-01

    Coronal jets are impulsive, collimated plasma outflows originating low in the solar corona. Many of these events exhibit broad, curtain-like morphologies with helical structure and motions. Recently, Sterling et al. (2015) [doi:10.1038/nature14556] reported that such jets are associated with the eruption of small filaments and, therefore, are miniature versions of corona mass ejections (CMEs). This account differs from the traditional picture of jets, in that internal flare reconnection, rather than interchange reconnection with the external ambient magnetic field, creates the bright loops observed at the jet base. We present 3D simulations, performed with the Adaptively Refined MHD Solver (ARMS), which demonstrate how the magnetic breakout mechanism generates mini-CME-type jets in a compact bipolar region energized by simple footpoint motions. Our numerical model captures the formation of the strongly sheared pre-jet filament structure, the post-jet flare-like loops and ribbons, and the curtain-like untwisting dynamics observed higher in the corona. We will discuss the significance of our new results for understanding solar EUV and X-ray jets and CMEs in general. NASA supported this research by awards to the NASA Postdoctoral Program (P.F.W.) and the LWS TR&T and H-SR programs (C.R.D. & S.K.A.).

  15. Heavy element nucleosynthesis in jets from collapsars

    SciTech Connect

    Fujimoto, Shin-ichirou; Hashimoto, Masa-aki; Kotake, Kei; Yamada, Shoichi

    2007-02-26

    We investigate nucleosynthesis in collapsars, based on long-term, magnetohydrodynamic simulations of a rapidly rotating massive star of 40M{center_dot} during the core collapse. We have calculated detailed composition of magnetically driven jets ejected from the collapsars, in which the magnetic fields before the collapse, are uniform and parallel to the rotational axis of the star and the magnitudes of the fields, B0, are 1010 G or 1012 G. We follow the evolution of chemical composition up to about 4000 nuclides inside the jets from the collapse phase to the ejection phase through the jet generation phase with use of a large nuclear reaction network. We find that the r-process successfully operates in the jets from the collapsar of B0 = 1012 G, so that U and Th are synthesized abundantly. Abundance pattern inside the jets is similar to that of r-elements in the solar system. Furthermore, we find that p-nuclei are produced without seed nuclei: not only light p-nuclei, such as 74Se, 78Kr, 84Sr, and 92Mo, but also heavy p-nuclei, 113In, 115Sn, and 138La, can be abundantly synthesized in the jets. The amounts of p-nuclei in the ejecta are much greater than those in core-collapse supernovae (SNe). In particular, 92Mo, 113In, 115Sn, and 138La deficient in the SNe, are significantly produced in the ejecta. On the other hand, in the jets from the collapsar of B0 = 1010 G, the r-process cannot operate and 56Ni, 28Si, 32S, and 4He are abundantly synthesized in the jets, as in ejecta from inner layers of Type II supernovae. An amount of 56Ni is much smaller than that from SN 1987A.

  16. Solar technology assessment project. Volume 4: Solar air conditioning: Active, hybrid and passive

    NASA Astrophysics Data System (ADS)

    Yellott, J. I.

    1981-04-01

    The status of absorption cycle solar air conditioning and the Rankine cycle solar cooling system is reviewed. Vapor jet ejector chillers, solar pond based cooling, and photovoltaic compression air conditioning are also briefly discussed. Hybrid solar cooling by direct and indirect evaporative cooling, and dehumidification by desiccation are described and discussed. Passive solar cooling by convective and radiative processes, evaporative cooling by passive processes, and cooling with roof ponds and movable insulation are reviewed. Federal and state involvement in solar cooling is discussed.

  17. Poynting Jets from Accretion Disks

    NASA Astrophysics Data System (ADS)

    Lovelace, R. V. E.; Li, H.; Koldoba, A. V.; Ustyugova, G. V.; Romanova, M. M.

    2002-06-01

    We give further consideration to the problem of the evolution of a coronal, force-free magnetic field that threads a differentially rotating, conducting Keplerian disk, extending the recent work of Li and coworkers. This situation is described by the force-free Grad-Shafranov (GS) equation for the flux function Ψ(r, z) that labels the poloidal field lines (in cylindrical coordinates). The GS equation involves a function H(Ψ) describing the distribution of the poloidal current, which is determined by the differential rotation or ``twist'' of the disk that increases linearly with time. We numerically solve the GS equation in a sequence of volumes of increasing size corresponding to the expansion of the outer perfectly conducting boundaries at (Rm, Zm). The outer boundaries model the influence of an external nonmagnetized plasma. The sequence of GS solutions provides a model for the dynamical evolution of the magnetic field in response to (1) the increasing twist of the disk and (2) the pressure of external plasma. We find solutions with magnetically collimated Poynting jets in which there is a continuous outflow of energy, angular momentum, and toroidal magnetic flux from the disk into the external space. This behavior contradicts the commonly accepted ``theorem'' of solar plasma physics that the motion of the footpoints of a magnetic loop structure leads to a stationary magnetic field configuration with zero power, angular momentum, and flux outflows. In addition, we discuss magnetohydrodynamic simulations that show quasi-stationary collimated Poynting jets similar to our GS solutions. In contrast with the GS solutions, the simulations show a steady uncollimated hydromagnetic (nonforce-free) outflow from the outer part of the disk. The Poynting jets are of interest for the understanding of the jets from active galactic nuclei, microquasars, and possibly gamma-ray burst sources.

  18. Statistical Study of Chromospheric Anemone Jets Observed with Hinode/SOT

    NASA Astrophysics Data System (ADS)

    Nishizuka, N.; Nakamura, T.; Kawate, T.; Singh, K. A. P.; Shibata, K.

    2011-04-01

    The Solar Optical Telescope on board Hinode has revealed numerous tiny jets in all regions of the chromosphere outside of sunspots. A typical chromospheric anemone jet has a cusp-shaped structure and bright footpoint, similar to the shape of an X-ray anemone jet observed previously with the Soft X-ray Telescope on board Yohkoh. The similarity in the shapes of chromospheric and X-ray anemone jets suggests that chromospheric anemone jets are produced as a result of the magnetic reconnection between a small bipole (perhaps a tiny emerging flux) and a pre-existing uniform magnetic field in the lower chromosphere. We examine various chromospheric anemone jets in the solar active region near the solar limb and study the typical features (e.g., length, width, lifetime, and velocity) of the chromospheric anemone jets. Statistical studies show that chromospheric anemone jets have: (1) a typical length ~1.0-4.0 Mm, (2) a width ~100-400 km, (3) a lifetime ~100-500 s, and (4) a velocity ~5-20 km s-1. The velocity of the chromospheric anemone jets is comparable to the local Alfvén speed in the lower solar chromosphere (~10 km s-1). The histograms of chromospheric anemone jets near the limb and near the disk center show similar averages and shapes of distributions, suggesting that the characteristic behavior of chromospheric anemone jets is independent of whether they are observed on the disk or at the limb. The observed relationship between the velocity and length of chromospheric anemone jets shows that the jets do not follow ballistic motion but are more likely accelerated by some other mechanism. This is consistent with numerical simulations of chromospheric anemone jets.

  19. STATISTICAL STUDY OF CHROMOSPHERIC ANEMONE JETS OBSERVED WITH HINODE/SOT

    SciTech Connect

    Nishizuka, N.; Nakamura, T.; Kawate, T.; Singh, K. A. P.; Shibata, K.

    2011-04-10

    The Solar Optical Telescope on board Hinode has revealed numerous tiny jets in all regions of the chromosphere outside of sunspots. A typical chromospheric anemone jet has a cusp-shaped structure and bright footpoint, similar to the shape of an X-ray anemone jet observed previously with the Soft X-ray Telescope on board Yohkoh. The similarity in the shapes of chromospheric and X-ray anemone jets suggests that chromospheric anemone jets are produced as a result of the magnetic reconnection between a small bipole (perhaps a tiny emerging flux) and a pre-existing uniform magnetic field in the lower chromosphere. We examine various chromospheric anemone jets in the solar active region near the solar limb and study the typical features (e.g., length, width, lifetime, and velocity) of the chromospheric anemone jets. Statistical studies show that chromospheric anemone jets have: (1) a typical length {approx}1.0-4.0 Mm, (2) a width {approx}100-400 km, (3) a lifetime {approx}100-500 s, and (4) a velocity {approx}5-20 km s{sup -1}. The velocity of the chromospheric anemone jets is comparable to the local Alfven speed in the lower solar chromosphere ({approx}10 km s{sup -1}). The histograms of chromospheric anemone jets near the limb and near the disk center show similar averages and shapes of distributions, suggesting that the characteristic behavior of chromospheric anemone jets is independent of whether they are observed on the disk or at the limb. The observed relationship between the velocity and length of chromospheric anemone jets shows that the jets do not follow ballistic motion but are more likely accelerated by some other mechanism. This is consistent with numerical simulations of chromospheric anemone jets.

  20. Recurrent infective endocarditis.

    PubMed Central

    Lossos, I. S.; Oren, R.

    1993-01-01

    Infective endocarditis is a serious disease associated with high mortality. Patients surviving recurrent bouts of infective endocarditis are reported infrequently. We report on a non-drug abuser patient who experienced seven episodes of infective endocarditis--the largest number reported to our knowledge in a single non-drug abuser patient. PMID:8290417

  1. Lung Cancer Indicators Recurrence

    Cancer.gov

    This study describes prognostic factors for lung cancer spread and recurrence, as well as subsequent risk of death from the disease. The investigators observed that regardless of cancer stage, grade, or type of lung cancer, patients in the study were more

  2. On Solving Linear Recurrences

    ERIC Educational Resources Information Center

    Dobbs, David E.

    2013-01-01

    A direct method is given for solving first-order linear recurrences with constant coefficients. The limiting value of that solution is studied as "n to infinity." This classroom note could serve as enrichment material for the typical introductory course on discrete mathematics that follows a calculus course.

  3. Recurrent Corneal Erosion

    MedlinePlus

    ... to apply a tight patch that restricts eye movement at night and upon waking so there is less likelihood of recurrence. If these rather simple procedures are not successful, the eye care professional may re-scrape the area to create a more irregular abrasion followed by ...

  4. On jet substructure methods for signal jets

    NASA Astrophysics Data System (ADS)

    Dasgupta, Mrinal; Powling, Alexander; Siodmok, Andrzej

    2015-08-01

    We carry out simple analytical calculations and Monte Carlo studies to better understand the impact of QCD radiation on some well-known jet substructure methods for jets arising from the decay of boosted Higgs bosons. Understanding differences between taggers for these signal jets assumes particular significance in situations where they perform similarly on QCD background jets. As an explicit example of this we compare the Y-splitter method to the more recently proposed Y-pruning technique. We demonstrate how the insight we gain can be used to significantly improve the performance of Y-splitter by combining it with trimming and show that this combination outperforms the other taggers studied here, at high p T . We also make analytical estimates for optimal parameter values, for a range of methods and compare to results from Monte Carlo studies.

  5. Observation of Reconnection Features in the Chromosphere through a Chromospheric Jet Observed by SOT/Hinode

    NASA Astrophysics Data System (ADS)

    Singh, K. A. P.; Isobe, H.; Shibata, K.

    2012-08-01

    High-resolution observations from Solar Optical Telescope (SOT) onboard Hinode has shown number of jet-like structures in the solar chromosphere. One of the key features in the observations is the clear presence of tiny, inverted Y-shaped jets called Chromospheric Anemone Jets. These jets are supposed to be formed as a result of the magnetic reconnection, however, whether and how fast magnetic reconnection is realized in partially ionized, fully collisional chromosphere is poorly understood. In this paper, we report the observation of a well resolved jet phenomenon observed from SOT. The jets were found to recur at the same location. We observed multiple blobs ejected along the jet. The jets occur after the ejection of blobs. It is noticed that the brightness enhancements at the footpoint of the jet are related with the height of the jet. These features indicate an important role of plasmoid dynamics and intermittent nature of the chromospheric reconnection. The lifetime of the plasmoid is 30 s - 50 s. We noticed the undulations in chromospheric anemone jets. The evolution of a single jet is consistent with the Sweeping-Magnetic-Twist mechanism proposed by Shibata and Uchida (1986).

  6. The eruptive events on September 30, 1998: 1. The jet

    NASA Astrophysics Data System (ADS)

    Bagalá, L. G.; Stenborg, G.; Schwenn, R.; Haerendel, G.

    2001-11-01

    The jet on September 30, 1998, is part of a complex event that involved also other eruptive phenomena. Changes in the coronal magnetic field topology were observed during the ejection of the jet, as deduced from the Fe XIV green line emission. The whole event was well observed by both the H-Alpha Solar Telescope for Argentina (HASTA) and the Mirror Coronagraph for Argentina (MICA), which are installed in the German-Argentinean Solar Observatory at El Leoncito, Argentina. The Soft X-ray Telescope (SXT) on board Yohkoh also observed the jet. In this work, observations of the first part of this complex event showing the evolution of the jet and release of blobs are presented. Certain features observed are interpreted as signatures of a magnetic reconnection process in the region. We conclude that existing theoretical and phenomenological models based on magnetic reconnection mechanisms could explain our observations, which span three temperature regimes far apart from each other.

  7. Recurrent Infections May Signal Immunodeficiencies

    MedlinePlus

    ... Search AAAAI Breadcrumb navigation Home ▸ Conditions & Treatments ▸ Library ▸ Primary Immunodeficiency Disease Library ▸ Recurrent Infections May Signal Immunodeficiencies Share | Recurrent Infections May Signal Immunodeficiencies This article has been reviewed by Thanai Pongdee, MD, FAAAAI ...

  8. Innovative approaches to recurrent training

    NASA Technical Reports Server (NTRS)

    Noon, H.; Murphy, M.

    1984-01-01

    Innovative approaches to recurrent training for regional airline aircrews are explored. Guidelines for recurrent training programs which include in corporation of cockpit resource management are discussed. B.W.

  9. THEMIS multi-spacecraft observations of magnetosheath high-speed jets: Scale sizes and other characteristics

    NASA Astrophysics Data System (ADS)

    Plaschke, Ferdinand; Hietala, Heli; Angelopoulos, Vassilis; Nakamura, Rumi

    2015-04-01

    Under quasi-radial interplanetary magnetic field conditions, the dayside magnetosheath is permeated by localized enhancements of dynamic pressure (high speed jets). When impinging on the magnetopause, these jets cause boundary distortions and excite magnetopause and magnetospheric waves. Multi-spacecraft observations of high speed jets by the THEMIS spacecraft allow us to infer jet flow-parallel and flow-perpendicular scale sizes. We find the scale size distributions to be well-modeled by exponential functions with characteristic diameters of 0.72 (parallel) and 1.34 Earth radii (perpendicular scale sizes). The median flow-parallel scale sizes increase with distance from the bow shock. We are able to link large/small size jets to specific solar wind conditions and jet characteristics. Furthermore, we present flow patterns inside and outside of jets that exhibit vortical plasma motion as a result of jet propagation through the slower-moving magnetosheath plasma.

  10. A Model of the Heliosphere with Jets

    NASA Astrophysics Data System (ADS)

    Drake, James; Swisdak, Marc; Opher, Merav

    2015-11-01

    The conventional picture of the heliosphere is that of a comet-shaped structure with an extended tail produced by the relative motion of the sun through the local interstellar medium. Recent magnetohydrodynamic (MHD) simulations of the heliosphere have revealed that the heliosphere drives magnetized jets to the north and south similar to those driven by the Crab Nebula. That the sun's magnetic field can drive such jets when β = 8 πP /B2 >> 1 in the outer heliosphere is a major surprise. An analytic model of the heliosheath (HS) is developed in the limit in which the interstellar flow and magnetic field are neglected. The heliosphere in this limit is axi-symmetric and the overall structure of the HS is controlled by the solar magnetic field even for very high β. The tension of the solar magnetic field produces a drop in the total pressure between the termination shock and the HP. This same pressure drop accelerates the plasma flow into the north and south directions to form two collimated jets. MHD simulations of the global heliosphere embedded in a stationary interstellar medium match well with the analytic model. Evidence from the distribution of energetic neutral atoms from the outer heliosphere from IBEX and CASSINI supports the picture of a heliosphere with jets.

  11. Recurrent Education: Trends and Issues.

    ERIC Educational Resources Information Center

    Organisation for Economic Cooperation and Development, Paris (France). Centre for Educational Research and Innovation.

    The document, consisting of three parts, focuses on recurrent education and the need for more effective deployment of educational resources within member countries of the Organization for Economic Cooperation and Development. The first section discusses the rationale for recurrent education. Recurrent education presents an educational opportunity…

  12. Hotspots, Jets and Environments

    NASA Astrophysics Data System (ADS)

    Hardcastle, M. J.

    2008-06-01

    I discuss the nature of `hotspots' and `jet knots' in the kpc-scale structures of powerful radio galaxies and their relationship to jet-environment interactions. I describe evidence for interaction between the jets of FRI sources and their local environments, and discuss its relationship to particle acceleration, but the main focus of the paper is the hotspots of FRIIs and on new observational evidence on the nature of the particle acceleration associated with them.

  13. Prevention of recurrent nephrolithiasis.

    PubMed

    Goldfarb, D S; Coe, F L

    1999-11-15

    The first episode of nephrolithiasis provides an opportunity to advise patients about measures for preventing future stones. Low fluid intake and excessive intake of protein, salt and oxalate are important modifiable risk factors for kidney stones. Calcium restriction is not useful and may potentiate osteoporosis. Diseases such as hyperparathyroidism, sarcoidosis and renal tubular acidosis should be considered in patients with nephrolithiasis. A 24-hour urine collection with measurement of the important analytes is usually reserved for use in patients with recurrent stone formation. In these patients, the major urinary risk factors include hypercalciuria, hyperoxaluria, hypocitraturia and hyperuricosuria. Effective preventive and treatment measures include thiazide therapy to lower the urinary calcium level, citrate supplementation to increase the urinary citrate level and, sometimes, allopurinol therapy to lower uric acid excretion. Uric acid stones are most often treated with citrate supplementation. Data now support the cost-effectiveness of evaluation and treatment of patients with recurrent stones. PMID:10593318

  14. Interpretation of extragalactic jets

    SciTech Connect

    Norman, M.L.

    1985-01-01

    The nature of extragalatic radio jets is modeled. The basic hypothesis of these models is that extragalatic jets are outflows of matter which can be described within the framework of fluid dynamics and that the outflows are essentially continuous. The discussion is limited to the interpretation of large-scale (i.e., kiloparsec-scale) jets. The central problem is to infer the physical parameters of the jets from observed distributions of total and polarized intensity and angle of polarization as a function of frequency. 60 refs., 6 figs.

  15. Chromospheric anemone jets as evidence of ubiquitous reconnection.

    PubMed

    Shibata, Kazunari; Nakamura, Tahei; Matsumoto, Takuma; Otsuji, Kenichi; Okamoto, Takenori J; Nishizuka, Naoto; Kawate, Tomoko; Watanabe, Hiroko; Nagata, Shin'ichi; Ueno, Satoru; Kitai, Reizaburo; Nozawa, Satoshi; Tsuneta, Saku; Suematsu, Yoshinori; Ichimoto, Kiyoshi; Shimizu, Toshifumi; Katsukawa, Yukio; Tarbell, Theodore D; Berger, Thomas E; Lites, Bruce W; Shine, Richard A; Title, Alan M

    2007-12-01

    The heating of the solar chromosphere and corona is a long-standing puzzle in solar physics. Hinode observations show the ubiquitous presence of chromospheric anemone jets outside sunspots in active regions. They are typically 3 to 7 arc seconds = 2000 to 5000 kilometers long and 0.2 to 0.4 arc second = 150 to 300 kilometers wide, and their velocity is 10 to 20 kilometers per second. These small jets have an inverted Y-shape, similar to the shape of x-ray anemone jets in the corona. These features imply that magnetic reconnection similar to that in the corona is occurring at a much smaller spatial scale throughout the chromosphere and suggest that the heating of the solar chromosphere and corona may be related to small-scale ubiquitous reconnection. PMID:18063790

  16. Aging jets from low-mass stars

    NASA Technical Reports Server (NTRS)

    Graham, J. A.; Chen, W. P.

    1994-01-01

    An extended faint optical jet is associated with the compact emission region plus faint star known as HH 55. HH 55 is located in the Lupus 2 cloud 2 min SW of the well studied T Tauri star RU Lupi. The HH 55 jet extends 55 sec N and 35 sec S in PA 160 deg. The HH 55 star is an emission line star of spectral type M3.5. Its image in the emission lines of H-alpha and (S II) is slightly elongated by 2 sec - 3 sec to the S but in continuum light is symmetrical and pointlike ((full width at half maximum) (FWHM) = 1.7 sec). The star and jet have several features in common with the star and jet known as Sz 102 = Th 28 in the nearby Lupus 3 cloud. We suggest that these objects are representative of the late evolutionary stage of the HH jet-outflow phenomenon and point out that such objects may be quite common although difficult to detect. With L(sub bol) approximately = 0.005 solar luminosity, and log T(sub e) approximately = 3.5, the HH 55 star is close to the main sequence and evolutionary tracks suggest an age of 3 x 10(exp 7) yr.

  17. Multiwavelength Observations of the SS 433 Jets

    NASA Astrophysics Data System (ADS)

    Marshall, Herman L.; Canizares, Claude R.; Hillwig, Todd; Mioduszewski, Amy; Rupen, Michael; Schulz, Norbert S.; Nowak, Michael; Heinz, Sebastian

    2013-09-01

    We present observations of the SS 433 jets using the Chandra High Energy Transmission Grating Spectrometer with contemporaneous optical and Very Long Baseline Array observations. The X-ray and optical emission line regions are found to be related but not coincident as the optical line emission persists for days while the X-ray emission lines fade in less than 5000 s. The line Doppler shifts from the optical and X-ray lines match well, indicating that they are less than 3 × 1014 cm apart. The jet Doppler shifts show aperiodic variations that could result from shocks in interactions with the local environment. These perturbations are consistent with a change in jet direction but not jet speed. The proper motions of the radio knots match the kinematic model only if the distance to SS 433 is 4.5 ± 0.2 kpc. Observations during eclipse show that the occulted emission is very hard, seen only above 2 keV and rising to comprise >50% of the flux at 8 keV. The soft X-ray emission lines from the jet are not blocked, constraining the jet length to >~ 2 × 1012 cm. The base jet density is in the range 1010-13 cm-3, in contrast to our previous estimate based on the Si XIII triplet, which is likely to have been affected by UV de-excitation. There is a clear overabundance of Ni by a factor of about 15 relative to the solar value, which may have resulted from an unusual supernova that formed the compact object.

  18. Capillary instability of jets

    NASA Astrophysics Data System (ADS)

    Chauhan, Anuj

    This thesis studies the capillary instability of a compound jet. A compound jet comprises an inner core of a primary fluid surrounded by an annulus of an immiscible secondary fluid. The compound jet is unstable due to capillarity. A compound jet finds applications in a variety of fields, such as, ink jet printing, particle sorting, extrusion, molding, particle production etc. In some of these applications such as molding, the disturbances that could cause the jet breakup start as periodic spatial disturbances of Fourier wave number k and grow in time. This is the temporal instability. In some other applications, such as, ink-jet printing, the disturbances initiate at the edge of the nozzle from which the jet issues out. These disturbances grow in space. This is the spatial instability. At small velocities, even if the initial disturbances are periodic in time, they grow exponentially in time. This is the absolute instability. We perform the temporal, spatial and the absolute stability analysis of an inviscid compound jet in a unified framework using the theory of transforms. Further, we solve the temporal instability problem for a viscous jet to understand the effect of viscosity on breakup dynamics. In the temporal analysis, we show that each interface of the compound jet contributes one mode to the instability. The modes contributed by the inner and outer interfaces grow for waves longer than the inner and the outer circumference of the undisturbed jet, respectively. The inner interface mode has a higher growth rate and hence dominates the breakup. The two interfaces grow exactly in phase in this mode and hence it is refereed to as the stretching mode. The other mode is the squeezing mode because the two interfaces grow exactly out of phase. The same two modes are also present in the spatial analysis. At high Weber numbers the predictions of the spatial theory reduce to those of the temporal theory because the waves simply convect with the jet velocity and there

  19. A Model of the Heliosphere with Jets

    NASA Astrophysics Data System (ADS)

    Drake, J. F.; Swisdak, M.; Opher, M.

    2015-12-01

    The conventional picture of the heliosphere is that of a comet-shaped structure with an extended tail produced by the relative motion of the sun through the local interstellar medium (LISM). On the other hand, the measurements of energetic neutral atoms (ENAs) by IBEX and CASSINI produced some surprises. The CASSINI ENA fluxes from the direction of the nose and the tail were comparable, leading the CASSINI observers to conclude that the heliosphere was ``tailless''. The IBEX observations from the tail revealed that the hardest spectrum of ENAs were localized in two lobes at high latitude while the softest spectra were at low latitudes. Recent MHD simulations of the global heliosphere have revealed that the heliosphere drives magnetized jets to the north and south similar to those driven by the Crab Nebula and other astrophysical objects [1]. That the sun's magnetic field can drive such jets when the magnetic pressure in the outer heliosphere is small compared with the local plasma pressure (β=8∏ P/B2 >> 1) is a major surprise. An analytic model of the heliosheath (HS) between the termination shock (TS) and the heliopause (HP) is developed in the limit in which the interstellar flow and magnetic field are neglected [2]. The heliosphere in this limit is axisymmetric. The overall structure of the HS and HP are controlled by the solar magnetic field even in the limit of very high β because the large pressure in the HS is to lowest order balanced by the pressure of the LISM. The tension of the solar magnetic field produces a drop in the total pressure between the TS and the HP. This same pressure drop accelerates the plasma flow downstream of the TS into the north and south directions to form two collimated jets. The radii of these jets are controlled by the flow through the TS and the acceleration of this flow by the magnetic field -- a stronger solar magnetic field boosts the velocity of the jets and reduces the radii of the jets and the HP. Magnetohydrodynamic

  20. T Pyxidis: The First Cataclysmic Variable with a Collimated Jet

    NASA Technical Reports Server (NTRS)

    Shahbaz, T.; Livio, M.; Southwell, K. A.; Charles, P. A.

    1997-01-01

    We present the first observational evidence for a collimated jet in a cataclysmic variable system; the recurrent nova T Pyxidis. Optical spectra show bipolar components of H(alpha) with velocities approx. 1400 km/s, very similar to those observed in the supersoft X-ray sources and in SS 433. We argue that a key ingredient of the formation of jets in the supersoft X-ray sources and T Pyx (in addition to an accretion disk threaded by a vertical magnetic field), is the presence of nuclear burning on the surface of the white dwarf.

  1. JPL tests of a LaJet concentrator facet

    SciTech Connect

    Dennison, E.W.; Argoud, M.J.

    1983-11-01

    A LaJet Energy Company (LEC) concentrator facet, 60 in. in diameter, was tested for imaging quality. The following two methods were used: (1) autofocus tests with a point source of light at the facet's radius of curvature and (2) tests with the Sun close to the horizon as a distant source. The tests of the LaJet facet indicate that all of the solar image reflected by an LEC 460 solar concentrator made of like facets should fall within a 9-in. aperture if the outer facets are carefully adjusted. Such a concentrator would have acceptable performance, but complete evaluation must be made with an assembled concentrator.

  2. Jet physics at CDF

    SciTech Connect

    Melese, P.

    1997-05-01

    We present high E{sub T} jet measurements from CDF at the Fermilab Tevatron Collider. The incfilusive jet cross section at {radical}s = 1800 GeV with {approximately} 5 times more data is compared to the published CDF results, preliminary D0 results, and next-to-leading order QCD predictions. The {summation}E{sub T} cross section is also compared to QCD predictions and the dijet angular distribution is used to place a limit on quark compositeness. The inclusive jet cross section at {radical}s = 630 GeV is compared with that at 1800 GeV to test the QCD predictions for the scaling of jet cross sections with {radical}s. Finally, we present momentum distributions of charged particles in jets and compare them to Modified Leading Log Approximation predictions.

  3. Instability of rectangular jets

    NASA Technical Reports Server (NTRS)

    Tam, Christopher K. W.; Thies, Andrew T.

    1992-01-01

    The instability of rectangular jets is investigated using a vortex sheet model. It is shown that such jets support four linearly independent families of instability waves. Within each family there are infinitely many modes. A way to classify these modes according to the characteristics of their mode shapes or eigenfunctions is proposed. A parametric study of the instability wave characteristics has been carried out. A sample of the numerical results is reported here. It is found that the first and third modes of each instability wave family are corner modes. The pressure fluctuations associated with these instability waves are localized near the corners of the jet. The second mode, however, is a center mode with maximum fluctuations concentrated in the central portion of the jet flow. The center mode has the largest spatial growth rate. It is anticipated that as the instability waves propagate downstream the center mode would emerge as the dominant instability of the jet.

  4. Description of Jet Breakup

    NASA Technical Reports Server (NTRS)

    Papageorgiou, Demetrios T.

    1996-01-01

    In this article we review recent results on the breakup of cylindrical jets of a Newtonian fluid. Capillary forces provide the main driving mechanism and our interest is in the description of the flow as the jet pinches to form drops. The approach is to describe such topological singularities by constructing local (in time and space) similarity solutions from the governing equations. This is described for breakup according to the Euler, Stokes or Navier-Stokes equations. It is found that slender jet theories can be applied when viscosity is present, but for inviscid jets the local shape of the jet at breakup is most likely of a non-slender geometry. Systems of one-dimensional models of the governing equations are solved numerically in order to illustrate these differences.

  5. Jet Lag in Athletes

    PubMed Central

    Lee, Aaron; Galvez, Juan Carlos

    2012-01-01

    Context: Prolonged transmeridian air travel can impart a physical and emotional burden on athletes in jet lag and travel fatigue. Jet lag may negatively affect the performance of athletes. Study Type: Descriptive review. Evidence Acquisition: A Medline search for articles relating to jet lag was performed (1990-present), as was a search relating to jet lag and athletes (1983-January, 2012). The results were reviewed for relevance. Eighty-nine sources were included in this descriptive review. Results: Behavioral strategies are recommended over pharmacological strategies when traveling with athletes; pharmacological aides may be used on an individual basis. Strategic sleeping, timed exposure to bright light, and the use of melatonin are encouraged. Conclusions: There is strong evidence that mood and cognition are adversely affected by jet lag. Some measures of individual and team performance are adversely affected as well. PMID:23016089

  6. 3-D MHD disk wind simulations of protostellar jets

    NASA Astrophysics Data System (ADS)

    Staff, Jan E.; Koning, Nico; Ouyed, Rachid; Tanaka, Kei; Tan, Jonathan C.

    2016-01-01

    We present the results of large scale, three-dimensional magnetohydrodynamics simulations of disk winds for different initial magnetic field configurations. The jets are followed from the source to distances, which are resolvable by HST and ALMA observations. Our simulations show that jets are heated along their length by many shocks. The mass of the protostar is a free parameter that can be inserted in the post processing of the data, and we apply the simulations to both low mass and high mass protostars. For the latter we also compute the expected diagnostics when the outflow is photoionized by the protostar. We compute the emission lines that are produced, and find excellent agreement with observations. For a one solar mass protostar, we find the jet width to be between 20 and 30 au while the maximum velocities perpendicular to the jet are found to be 100 km s-1. The initially less open magnetic field configuration simulations result in a wider, two-component jet; a cylindrically shaped outer jet surrounding a narrow and much faster, inner jet. For the initially most open magnetic field configuration the kink mode creates a narrow corkscrew-like jet without a clear Keplerian rotation profile and even regions where we observe rotation opposite to the disk (counter-rotating). This is not seen in the less open field configurations.

  7. Recurrent Miller Fisher syndrome.

    PubMed

    Madhavan, S; Geetha; Bhargavan, P V

    2004-07-01

    Miller Fisher syndrome (MFS) is a variant of Guillan Barre syndrome characterized by the triad of ophthalmoplegia, ataxia and areflexia. Recurrences are exceptional with Miller Fisher syndrome. We are reporting a case with two episodes of MFS within two years. Initially he presented with partial ophthalmoplegia, ataxia. Second episode was characterized by full-blown presentation characterized by ataxia, areflexia and ophthalmoplegia. CSF analysis was typical during both episodes. Nerve conduction velocity study was fairly within normal limits. MRI of brain was within normal limits. He responded to symptomatic measures initially, then to steroids in the second episode. We are reporting the case due to its rarity.

  8. Recurrent respiratory papillomatosis.

    PubMed

    Venkatesan, Naren N; Pine, Harold S; Underbrink, Michael P

    2012-06-01

    Recurrent respiratory papillomatosis (RRP) is a rare, benign disease with no known cure. RRP is caused by infection of the upper aerodigestive tract with the human papillomavirus (HPV). Passage through the birth canal is thought to be the initial transmission event, but infection may occur in utero. HPV vaccines have helped to provide protection from cervical cancer; however, their role in the prevention of RRP is undetermined. Clinical presentation of initial symptoms of RRP may be subtle. RRP course varies, and current management focuses on surgical debulking of papillomatous lesions with or without concurrent adjuvant therapy. PMID:22588043

  9. Solar Water Heater

    NASA Technical Reports Server (NTRS)

    1993-01-01

    As a Jet Propulsion Laboratory (JPL) scientist Dr. Eldon Haines studied the solar energy source and solar water heating. He concluded he could build a superior solar water heating system using the geyser pumping principle. He resigned from JPL to develop his system and later form Sage Advance Corporation to market the technology. Haines' Copper Cricket residential system has no moving parts, is immune to freeze damage, needs no roof-mounted tanks, and features low maintenance. It provides 50-90 percent of average hot water requirements. A larger system, the Copper Dragon, has been developed for commercial installations.

  10. Characteristics of EUV Coronal Jets Observed with STEREO/SECCHI

    NASA Astrophysics Data System (ADS)

    Nisticò, G.; Bothmer, V.; Patsourakos, S.; Zimbardo, G.

    2009-10-01

    In this paper we present the first comprehensive statistical study of EUV coronal jets observed with the SECCHI (Sun Earth Connection Coronal and Heliospheric Investigation) imaging suites of the two STEREO spacecraft. A catalogue of 79 polar jets is presented, identified from simultaneous EUV and white-light coronagraph observations, taken during the time period March 2007 to April 2008, when solar activity was at a minimum. The twin spacecraft angular separation increased during this time interval from 2 to 48 degrees. The appearances of the coronal jets were always correlated with underlying small-scale chromospheric bright points. A basic characterization of the morphology and identification of the presence of helical structure were established with respect to recently proposed models for their origin and temporal evolution. Though each jet appeared morphologically similar in the coronagraph field of view, in the sense of a narrow collimated outward flow of matter, at the source region in the low corona the jet showed different characteristics, which may correspond to different magnetic structures. A classification of the events with respect to previous jet studies shows that amongst the 79 events there were 37 Eiffel tower-type jet events, commonly interpreted as a small-scale (˜35 arc sec) magnetic bipole reconnecting with the ambient unipolar open coronal magnetic fields at its loop tops, and 12 lambda-type jet events commonly interpreted as reconnection with the ambient field happening at the bipole footpoints. Five events were termed micro-CME-type jet events because they resembled the classical coronal mass ejections (CMEs) but on much smaller scales. The remaining 25 cases could not be uniquely classified. Thirty-one of the total number of events exhibited a helical magnetic field structure, indicative for a torsional motion of the jet around its axis of propagation. A few jets are also found in equatorial coronal holes. In this study we present sample

  11. A Strategy for an Enterprise-Wide Data Management Capability at the Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    Fuhrman, D.

    2000-01-01

    The Jet Propulsion Laboratory (JPL) is a Federally Research and Development Center (FFRDC) operated by the California Institute of Technology that is engaged in the quest for knowledge about the solar system, the universe, and the Earth.

  12. Recurrent renal giant leiomyosarcoma.

    PubMed

    Öziş, Salih Erpulat; Gülpınar, Kamil; Şahlı, Zafer; Konak, Baha Burak; Keskin, Mete; Özdemir, Süleyman; Ataoğlu, Ömür

    2016-01-01

    Primary renal leiomyosarcomas are rare, aggressive tumors. They constitute 1-2% of adult malignant renal tumors. Although leiomyosarcomas are the most common histological type (50-60%) of renal sarcomas, information on renal leiomyosarcoma is limited. Local or systemic recurrences are common. The radiological appearance of renal leiomyosarcomas is not specific, therefore renal leiomyosarcoma cannot be distinguished from renal cell carcinoma by imaging methods in all patients. A 74-year-old female patient presented to our clinic complaining of a palpable mass on the right side of her abdomen in November 2012. The abdominal magnetic resonance imaging revealed a mass, 25 × 24 × 23 cm in size. Her past medical history revealed that she has undergone right radical nephrectomy in 2007, due to a 11 × 12 × 13 cm renal mass that was then reported as renal cell carcinoma on abdominal magnetic resonance imaging, but the pathological diagnosis was low-grade renal leiomyosarcoma. The most recent follow-up of the patient was in 2011, with no signs of local recurrence or distant metastases within this four-year period. The patient underwent laparotomy on November 2012, and a 35 cm retroperitoneal mass was excised. The pathological examination of the mass was reported as high-grade leiomyosarcoma. The formation of this giant retroperitoneal mass in 1 year can be explained by the transformation of the lesion's pathology from low-grade to a high-grade tumor. PMID:27436926

  13. Jet Noise Suppression

    NASA Technical Reports Server (NTRS)

    Gliebe, P. R.; Brausch, J. F.; Majjigi, R. K.; Lee, R.

    1991-01-01

    The objectives of this chapter are to review and summarize the jet noise suppression technology, to provide a physical and theoretical model to explain the measured jet noise suppression characteristics of different concepts, and to provide a set of guidelines for evolving jet noise suppression designs. The underlying principle for all jet noise suppression devices is to enhance rapid mixing (i.e., diffusion) of the jet plume by geometric and aerothermodynamic means. In the case of supersonic jets, the shock-cell broadband noise reduction is effectively accomplished by the elimination or mitigation of the shock-cell structure. So far, the diffusion concepts have predominantly concentrated on jet momentum and energy (kinetic and thermal) diffusion, in that order, and have yielded better noise reduction than the simple conical nozzles. A critical technology issue that needs resolution is the effect of flight on the noise suppression potential of mechanical suppressor nozzles. A more thorough investigation of this mechanism is necessary for the successful development and design of an acceptable noise suppression device for future high-speed civil transports.

  14. Recurrence theorems: A unified account

    SciTech Connect

    Wallace, David

    2015-02-15

    I discuss classical and quantum recurrence theorems in a unified manner, treating both as generalisations of the fact that a system with a finite state space only has so many places to go. Along the way, I prove versions of the recurrence theorem applicable to dynamics on linear and metric spaces and make some comments about applications of the classical recurrence theorem in the foundations of statistical mechanics.

  15. Psychosocial adjustment to recurrent cancer.

    PubMed

    Mahon, S M; Cella, D F; Donovan, M I

    1990-01-01

    This descriptive study of the perceptions and needs of people with recurrent malignancies asks three questions: How do patients describe the meaning of a recurrence of cancer? Do individuals perceive the diagnosis of recurrence and the initial diagnosis of cancer differently? What are the key psychosocial problems associated with recurrent cancer? The theoretical framework was based on Lazarus and Folkman's theory of stress, appraisal, and coping. Subjects completed the Impact of Event Scale (IES), the Psychosocial Adjustment to Illness Scale--Self-Report (PAIS), and a semistructured qualitative interview. The interview elicited perceptions of the event of recurrence and differences between the diagnosis of recurrence and the initial diagnosis. The convenience sample included 40 patients diagnosed with recurrent cancer within the last 30 days. Many subjects (78%) reported that the recurrence was more upsetting than the initial diagnosis. Scores on both the IES and the PAIS were high when compared to normative samples of patients with cancer suggesting that this sample of patients experienced a lot of psychological distress as well as problems at home, work, and in their social lives. These concerns often were unknown to caregivers. Although more research is needed, the authors propose that, with more accurate assessment, more effective intervention could be implemented and the quality of life improved for patients with recurrent cancer.

  16. AngioJet thrombectomy.

    PubMed

    Lee, Michael S; Singh, Varinder; Wilentz, James R; Makkar, Raj R

    2004-10-01

    The AngioJet rheolytic thrombectomy system is designed to remove thrombus with the Venturi-Bernoulli effect, with multiple high-velocity, high-pressure saline jets which are introduced through orifices in the distal tip of the catheter to create a localized low-pressure zone, resulting in a vacuum effect with the entrainment and dissociation of bulky thrombus. Rheolytic thrombectomy with the AngioJet catheter can reduce the thrombus burden in the setting of AMI and degenerated SVGs. The long-term follow-up appears to be favorable in patients treated with rheolytic thrombectomy in the setting of acute myocardial infarction over conventional primary angioplasty. PMID:15505358

  17. Angular Scaling In Jets

    SciTech Connect

    Jankowiak, Martin; Larkoski, Andrew J.; /SLAC

    2012-02-17

    We introduce a jet shape observable defined for an ensemble of jets in terms of two-particle angular correlations and a resolution parameter R. This quantity is infrared and collinear safe and can be interpreted as a scaling exponent for the angular distribution of mass inside the jet. For small R it is close to the value 2 as a consequence of the approximately scale invariant QCD dynamics. For large R it is sensitive to non-perturbative effects. We describe the use of this correlation function for tests of QCD, for studying underlying event and pile-up effects, and for tuning Monte Carlo event generators.

  18. Abemaciclib in Children With DIPG or Recurrent/Refractory Solid Tumors

    ClinicalTrials.gov

    2016-04-12

    Diffuse Intrinsic Pontine Glioma; Brain Tumor, Recurrent; Solid Tumor, Recurrent; Neuroblastoma, Recurrent, Refractory; Ewing Sarcoma, Recurrent, Refractory; Rhabdomyosarcoma, Recurrent, Refractory; Osteosarcoma, Recurrent, Refractory; Rhabdoid Tumor, Recurrent, Refractory

  19. A FLUX ROPE ERUPTION TRIGGERED BY JETS

    SciTech Connect

    Guo Juan; Zhang Hongqi; Deng Yuanyong; Lin Jiaben; Su Jiangtao; Liu Yu

    2010-03-10

    We present an observation of a filament eruption caused by recurrent chromospheric plasma injections (surges/jets) on 2006 July 6. The filament eruption was associated with an M2.5 two-ribbon flare and a coronal mass ejection (CME). There was a light bridge in the umbra of the main sunspot of NOAA 10898; one end of the filament was terminated at the region close to the light bridge, and recurrent surges were observed to be ejected from the light bridge. The surges occurred intermittently for about 8 hr before the filament eruption, and finally a clear jet was found at the light bridge to trigger the filament eruption. We analyzed the evolutions of the relative darkness of the filament and the loaded mass by the continuous surges quantitatively. It was found that as the occurrence of the surges, the relative darkness of the filament body continued growing for about 3-4 hr, reached its maximum, and kept stable for more than 2 hr until it erupted. If suppose 50% of the ejected mass by the surges could be trapped by the filament channel, then the total loaded mass into the filament channelwill be about 0.57x10{sup 16} g with a momentum of 0.57x10{sup 22} g cm s{sup -1} by 08:08 UT, which is a non-negligible effect on the stability of the filament. Based on the observations, we present a model showing the important role that recurrent chromospheric mass injection play in the evolution and eruption of a flux rope. Our study confirms that the surge activities can efficiently supply the necessary material for some filament formation. Furthermore, our study indicates that the continuous mass with momentum loaded by the surge activities to the filament channel could make the filament unstable and cause it to erupt.

  20. Nucleosynthesis in Magnetohydrodynamical Jets from Collapsars

    SciTech Connect

    Ono, M.; Hashimoto, M.; Fujimoto, S.; Kotake, K.

    2011-10-28

    We investigate the heavy-element nucleosynthesis of a massive star whose mass in the main sequence stage is M{sub ms} = 70 M{sub {center_dot}}. Detailed calculations of the nucleosynthesis are performed during the hydrostatic stellar evolution until the core composed of iron-group nuclei begins to collapse. As a supernova explosion model, a collapsar model is constructed whose jets are driven by magnetohydrodynamical effects of a differentially rotating core. The heavy-element nucleosynthesis inside the jet of a collapsar model is followed along the trajectories of stream lines of the jet. We combine the results of both hydrostatic and heavy-element nucleosyntheses to compare with the solar abundances. We find that neutron-rich elements of 70solar abundances. Therefore, we conclude that this scenario should be rare and elements of A < or approx. 70 are compensated for other supernova explosion models. We find also that different mass formula changes significantly the production of elements of A>140.

  1. Recurrent ovarian cancer.

    PubMed

    Pujade-Lauraine, E; Combe, P

    2016-04-01

    Recurrence still occurs in a majority of patients with advanced ovarian cancer. However, progress in the management has allowed a significant prolongation of survival for relapsing disease. These last years, the field of interest has moved from chemotherapy to targeted therapy which is dominated by anti-angiogenic and anti-PARP agents. It is assumed that platinum-free interval will not remain the main prognostic and predictive criterion in the future, and will be replaced by a multi-factorial approach. This trend for personalization of therapy has highlighted important neglected fields for clinical research such as multi-line (≥3) relapse, frail patients including elderly and symptomatic and supportive measures. PMID:27141075

  2. Recurrent vulvovaginal candidiasis.

    PubMed

    Sobel, Jack D

    2016-01-01

    Recurrent vulvovaginal candidiasis (RVVC) is a common cause of significant morbidity in women in all strata of society affecting millions of women worldwide. Previously, RVVC occurrence was limited by onset of menopause but the widespread use of hormone replacement therapy has extended the at-risk period. Candida albicans remains the dominant species responsible for RVVC, however optimal management of RVVC requires species determination and effective treatment measures are best if species-specific. Considerable progress has been made in understanding risk factors that determine susceptibility to RVVC, particularly genetic factors, as well as new insights into normal vaginal defense immune mechanisms and their aberrations in RVVC. While effective control of RVVC is achievable with the use of fluconazole maintenance suppressive therapy, cure of RVVC remains elusive especially in this era of fluconazole drug resistance. Vaccine development remains a critical challenge and need.

  3. Counterflowing Jet Subsystem Design

    NASA Technical Reports Server (NTRS)

    Farr, Rebecca; Daso, Endwell; Pritchett, Victor; Wang, Ten-See

    2010-01-01

    A counterflowing jet design (a spacecraft and trans-atmospheric subsystem) employs centrally located, supersonic cold gas jets on the face of the vehicle, ejecting into the oncoming free stream. Depending on the supersonic free-stream conditions and the ejected mass flow rate of the counterflowing jets, the bow shock of the vehicle is moved upstream, further away from the vehicle. This results in an increasing shock standoff distance of the bow shock with a progressively weaker shock. At a critical jet mass flow rate, the bow shock becomes so weak that it is transformed into a series of compression waves spread out in a much wider region, thus significantly modifying the flow that wets the outer surfaces, with an attendant reduction in wave and skin friction drag and aerothermal loads.

  4. Dilution jet mixing program

    NASA Technical Reports Server (NTRS)

    Srinivasan, R.; Coleman, E.; Johnson, K.

    1984-01-01

    Parametric tests were conducted to quantify the mixing of opposed rows of jets (two-sided injection) in a confined cross flow. Results show that jet penetrations for two sided injections are less than that for single-sided injections, but the jet spreading rates are faster for a given momentum ratio and orifice plate. Flow area convergence generally enhances mixing. Mixing characteristics with asymmetric and symmetric convergence are similar. For constant momentum ratio, the optimum S/H(0) with in-line injections is one half the optimum value for single sided injections. For staggered injections, the optimum S/H(0) is twice the optimum value for single-sided injection. The correlations developed predicted the temperature distributions within first order accuracy and provide a useful tool for predicting jet trajectory and temperature profiles in the dilution zone with two-sided injections.

  5. Jet lag prevention

    MedlinePlus

    ... your internal clock before you travel. While in flight: DO NOT sleep unless it matches the bedtime ... decrease jet lag. If you will be in flight during the bedtime of your destination, take some ...

  6. Radiation from Relativistic Jets

    NASA Technical Reports Server (NTRS)

    Nishikawa, K.-I.; Mizuno, Y.; Hardee, P.; Sol, H.; Medvedev, M.; Zhang, B.; Nordlund, A.; Frederiksen, J. T.; Fishman, G. J.; Preece, R.

    2008-01-01

    Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., gamma-ray bursts (GRBs), active galactic nuclei (AGNs), and Galactic microquasar systems usually have power-law emission spectra. Recent PIC simulations of relativistic electron-ion (electron-positron) jets injected into a stationary medium show that particle acceleration occurs within the downstream jet. In the presence of relativistic jets, instabilities such as the Buneman instability, other two-streaming instability, and the Weibel (filamentation) instability create collisionless shocks, which are responsible for particle (electron, positron, and ion) acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields. These magnetic fields contribute to the electron's transverse deflection behind the jet head. The 'jitter' radiation from deflected electrons in small-scale magnetic fields has different properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation, a case of diffusive synchrotron radiation, may be important to understand the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

  7. Extinct Radioactivities and the R-Process Jet

    NASA Technical Reports Server (NTRS)

    Cameron, A. G. W.

    2001-01-01

    All extinct radioactive species in the solar nebula were injected from a core-collapse supernova. I discuss primarily the products expected from an r-process jet in this supernova, and various supporting astrophysical observations. Additional information is contained in the original extended abstract.

  8. Nucleosynthesis in jets from rotating magnetized stars during core collapse

    SciTech Connect

    Fujimoto, Shin-ichirou; Nishimura, Nobuya; Hashimoto, Masa-aki

    2008-05-12

    We investigate nucleosynthesis inside magnetically driven jets ejected from rotating, magnetized massive stars, or collapsars, based on long-term, magnetohydrodynamic simulations of the core collapse of six collapsars with the various distributions of magnetic fields and angular momentum before the collapse. We follow the evolution of the abundances of about 4000 nuclides from the collapse phase to the ejection phase and through the jet generation phase using a large nuclear reaction network. We find that the r-process successfully operates in the jets from three collapsars, so that U and Th are synthesized abundantly, even when the collapsar have a relatively small magnetic field (10{sup 10} G) and a moderately rotating core before the collapse. The abundance patterns inside the jets are similar to that of the r-elements in the solar system.

  9. Jets and Bombs: Characterizing IRIS Spectra

    NASA Astrophysics Data System (ADS)

    Schmit, Donald; Innes, Davina

    2014-06-01

    For almost two decades, SUMER has provided an unique perspective on explosive events in the lower solar atmosphere. One of the hallmark observations during this tenure is the identification of quiet sun bi-directional jets in the lower transition region. We investigate these events through two distinct avenues of study: a MHD model for reconnection and the new datasets of the Interface Region Imaging Spectrograph (IRIS). Based on forward modeling optically thin spectral profiles, we find the spectral signatures of reconnection can vary dramatically based on viewing angle and altitude. We look to the IRIS data to provide a more complete context of the chromospheric and coronal environment during these dynamic events. During a joint IRIS-SUMER observing campaign, we observed spectra of multiple jets, a small C flare, and an Ellerman bomb event. We discuss the questions that arise from the inspection of these new data.

  10. Persistence in recurrent geomagnetic activity and its connection with Space Climate

    NASA Astrophysics Data System (ADS)

    Diego, P.; Storini, M.; Laurenza, M.

    2010-06-01

    Recurrent geomagnetic activity is mainly linked to the passage of interplanetary corotating solar wind structures in the near-Earth space. We studied geomagnetic recurrences for which an enhanced value of the autocorrelation coefficient exists between the data of two adjacent Bartels rotations in aa, Kp, Dst, AE time series, for the period 1954-2007, covering about 5 solar cycles (from cycle 19 to cycle 23). A new index (P), based on autocorrelation analysis, has been introduced to estimate also the duration up to seven Bartels rotations of each solar structure (or group of structures) producing geomagnetic recurrences with high autocorrelation (correlation coefficient ≥ 0.3). We could infer whether recurrent geomagnetic activity is due to successive short-lived (at least 2 Bartels rotations) or to long-lasting corotating structures (up to 7 or more Bartels rotations). Generally, time periods characterized by recurrent geomagnetic activity are longer during the descending phase of even-numbered cycles (20, 22). Nevertheless, we found that recurrences determined by long-lived interplanetary structures are detected mainly in the descending phase of cycles 19 and 23. Finally, we point out that the average levels of the computed indices during the descending phase of each solar cycle show a significant anticorrelation with the sunspot area integrated over the subsequent cycle, giving new insights for Space Climate forecast.

  11. Recurrence plots and recurrence quantification analysis of human motion data

    NASA Astrophysics Data System (ADS)

    Josiński, Henryk; Michalczuk, Agnieszka; Świtoński, Adam; Szczesna, Agnieszka; Wojciechowski, Konrad

    2016-06-01

    The authors present exemplary application of recurrence plots, cross recurrence plots and recurrence quantification analysis for the purpose of exploration of experimental time series describing selected aspects of human motion. Time series were extracted from treadmill gait sequences which were recorded in the Human Motion Laboratory (HML) of the Polish-Japanese Academy of Information Technology in Bytom, Poland by means of the Vicon system. Analysis was focused on the time series representing movements of hip, knee, ankle and wrist joints in the sagittal plane.

  12. Electric current variations and 3D magnetic configuration of coronal jets

    NASA Astrophysics Data System (ADS)

    Schmieder, Brigitte; Harra, Louise K.; Aulanier, Guillaume; Guo, Yang; Demoulin, Pascal; Moreno-Insertis, Fernando, , Prof

    Coronal jets (EUV) were observed by SDO/AIA on September 17, 2010. HMI and THEMIS measured the vector magnetic field from which we derived the magnetic flux, the phostospheric velocity and the vertical electric current. The magnetic configuration was computed with a non linear force-free approach. The phostospheric current pattern of the recurrent jets were associated with the quasi-separatrix layers deduced from the magnetic extrapolation. The large twisted near-by Eiffel-tower-shape jet was also caused by reconnection in current layers containing a null point. This jet cannot be classified precisely within either the quiescent or the blowout jet types. We will show the importance of the existence of bald patches in the low atmosphere

  13. Miniature Filament Eruptions and their Reconnections in X-Ray Jets: Evidence for a New Paradigm

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.; Moore, Ronald L.; Falconer, David A.

    2014-01-01

    We investigate the onset of approximately10 random X-ray jets observed by Hinode/XRT. Each jet was near the limb in a polar coronal hole, and showed a ``bright point'' in an edge of the base of the jet, as is typical for previously-observed X-ray jets. We examined SDO/AIA EUV images of each of the jets over multiple AIA channels, including 304 Ang, which detects chromospheric emissions, and 171, 193, and 211 Ang, which detect cooler-coronal emissions. We find the jets to result from eruptions of miniature (size less than approximately 10 arcsec) filaments from the bases of the jets. Much of the erupting-filament material forms a chromospheric-temperature jet. In the cool-coronal channels, often the filament appears in absorption and the jet in emission. The jet bright point forms at the location from which the miniature filament is ejected, analogous to the formation of a standard solar flare in the wake of the eruption of a typical larger-scale chromospheric filament. Thus these X-ray jets and their bright points are made by miniature filament eruptions. They are evidently produced the same way as an on-disk coronal jet we observed in Adams et al. (2014); that on-disk jet had no obvious emerging magnetic field in its base. We conclude that, for many jets, the standard idea of X-ray jets forming from reconnection between emerging flux and preexisting coronal field is incorrect. ACS and RLM were supported by funding from NASA/LWS, Hinode, and ISSI.

  14. Thermal ink jet: a review

    NASA Astrophysics Data System (ADS)

    Rezanka, Ivan

    1992-05-01

    The first public demonstration of thermal ink jet printing was done by Canon in 1981 and the first thermal ink jet product, ThinkJet, was introduced by the Hewlett-Packard Company in 1984. Since then, this powerful printing technology has assumed a strong presence in the market. In this discussion, we will first briefly review the printer market, the increasing role thermal ink jet is playing in this arena, as well as the reasons for its success. The technology discussion will follow, and will focus on several highlights in thermal ink jet physics, materials, and printing. We will conclude with our comments on future thermal ink jet developments.

  15. Theory of MHD Jets and Outflows

    NASA Astrophysics Data System (ADS)

    Tsinganos, Kanaris

    A brief review is given of selected results of our analytical and numerical work on the construction of time-independent and time-dependent MHD models for non relativistic astrophysical outflows and jets. The equations for steady MHD plasma flows are first outlined. Next, 1-D spherically symmetric outflows are briefly discussed, namely the Parker thermally driven nonrotating wind, as the classical prototype of all astrophysical outflows and the Weber-Davis magnetocentrifugally driven wind together with its astrophysical implications for magnetic braking, etc. Then, we turn to the 2-D MHD problem for steady and non steady 2-D axisymmetric magnetized and rotating plasma outflows. The only available exact solutions for such outflows are those in separable coordinates, i.e. those with the symmetry of radial or meridional self-similarity. Physically accepted solutions pass from the fast magnetosonic separatrix surface in order to satisfy MHD causality. An energetic criterion is outlined for selecting radially expanding winds from cylindrically expanding jets. The basics of jet acceleration, collimation, minimum fieldline inclination and angular momentum removal are illustrated in the context of radially self similar models. Numerical simulations of magnetic self-collimation verify several results of analytical steady solutions. The outflow from solar-type inefficient magnetic rotators is very weakly collimated while that from a ten times faster rotating YSO produces a tightly collimated jet. We also propose a two-component model consisting of a wind outflow from the central object and a faster rotating outflow launched from the surrounding accretion disk which plays the role of the flow collimator. We also briefly discuss the problem of shock formation during the magnetic collimation of wind-type outflows into jets.

  16. Ram-jet Performance

    NASA Technical Reports Server (NTRS)

    Cervenko, A. J.; Friedman, R.

    1956-01-01

    The ram jet is basically one of the most dimple types of aircraft engine. It consists only of an inlet diffuser, a combustion system, and an exit nozzle. A typical ram-jet configuration is shown in figure 128. The engine operates on the Brayton cycle, and ideal cycle efficiency depends only on the ratio of engine to ambient pressure. The increased, engine pressures are obtained by ram action alone, and for this reason the ram jet has zero thrust at zero speed. Therefore, ram-jet-powered aircraft must be boosted to flight speeds close to a Mach number of 1.0 before appreciable thrust is generated by the engine. Since pressure increases are obtained by ram action alone, combustor-inlet pressures and temperatures are controlled by the flight speed, the ambient atmospheric condition, and by the efficiency of the inlet diffuser. These pressures and temperatures, as functions of flight speed and altitude, are shown in figure 129 for the NACA standard atmosphere and for practical values of diffuser efficiency. It can be seen that very wide ranges of combustor-inlet temperatures and pressures may be encountered over the ranges of flight velocity and altitude at which ram jets may be operated. Combustor-inlet temperatures from 500 degrees to 1500 degrees R and inlet pressures from 5 to 100 pounds per square inch absolute represent the approximate ranges of interest in current combustor development work. Since the ram jet has no moving parts in the combustor outlet, higher exhaust-gas temperatures than those used in current turbojets are permissible. Therefore, fuel-air ratios equivalent to maximum rates of air specific impulse or heat release can be used, and, for hydrocarbon fuels, this weight ratio is about 0.070. Lower fuel-air ratios down to about 0.015 may also be required to permit efficient cruise operation. This fuel-air-ratio range of 0.015 to 0.070 used in ram jets can be compared with the fuel-air ratios up to 0.025 encountered in current turbojets. Ram-jet

  17. A gigantic coronal jet ejected from a compact active region in a coronal hole

    NASA Technical Reports Server (NTRS)

    Shibata, K.; Nitta, N.; Strong, K. T.; Matsumoto, R.; Yokoyama, T.; Hirayama, T.; Hudson, H.; Ogawara, Y.

    1994-01-01

    A gigantic coronal jet greater than 3 x 10(exp 5) km long (nearly half the solar radius) has been found with the soft X-ray telescope (SXT) on board the solar X-ray satellite, Yohkoh. The jet was ejected on 1992 January 11 from an 'anemone-type' active region (AR) appearing in a coronal hole and is one of the largest coronal X-ray jets observed so far by SXT. This gigantic jet is the best observed example of many other smaller X-ray jets, because the spatial structures of both the jet and the AR located at its base are more easily resolved. The range of apparent translational velocities of the bulk of the jet was between 90 and 240 km s(exp -1), with the corresponding kinetic energy estimated to be of order of 10(exp 28) ergs. A detailed analysis reveals that the jet was associated with a loop brightening (a small flare) that occurred in the active region. Several features of this observation suggest and are consistent with a magnetic reconnection mechanism for the production of such a 'jet-loop-brightening' event.

  18. Magnetized Jets Driven By the Sun: The Structure of the Heliosphere Revisited

    NASA Astrophysics Data System (ADS)

    Opher, Merav

    2015-11-01

    The classic accepted view of the heliosphere is a quiescent, comet-like shape aligned in the direction of the Sun's travel through the interstellar medium (ISM) extending for thousands of astronomical units (AUs). Here, we show, based on magnetohydrodynamic (MHD) simulations, that the tension (hoop) force of the twisted magnetic field of the Sun confines the solar wind plasma beyond the termination shock and drives jets to the north and south very much like astrophysical jets. These jets are deflected into the tail region by the motion of the Sun through the ISM similar to bent galactic jets moving through the intergalactic medium. The interstellar wind blows the two jets into the tail but is not strong enough to force the lobes into a single comet-like tail, as happens to some astrophysical jets. Instead, the interstellar wind flows around the heliosphere and into the equatorial region between the two jets. As in some astrophysical jets that are kink unstable, we show here that the heliospheric jets are turbulent (due to large-scale MHD instabilities and reconnection) and strongly mix the solar wind with the ISM. The resulting turbulence has important implications for particle acceleration in the heliosphere. The two-lobe structure is consistent with the energetic neutral atom (ENA) images of the heliotail from IBEX where two lobes are visible in the north and south and the suggestion from the Cassini ENAs that the heliosphere is ``tailless.''

  19. Tracing Massive Protostellar Jets from Intermediate-Mass Protostars in the Carina Nebula

    NASA Astrophysics Data System (ADS)

    Reiter, A.

    2014-09-01

    We present new spectroscopy and imaging of four protostellar jets in the Carina nebula. Near-IR [Fe II] emission traces dense gas in the jet that is self-shielded from Lyman continuum photons from nearby O-type stars. New near-IR [Fe II] images reveal a substantial mass of dense, neutral gas that is not seen in the Halpha emission from these jets, leading to densities and mass-loss rate estimates an order of magnitude larger than those derived from the Halpha emission measure. Higher jet mass-loss rates require higher accretion rates, implying that these jets are driven by intermediate-mass (around 2 - 8 solar masses) protostars. Velocities from new proper motion and spectroscopic measurements fall among the velocities typically measured in lower-luminosity sources (100 - 200 km/s). We propose that these jets reflect essentially the same outflow phenomenon seen in low-mass protostars, but that the collimated atomic jet core is irradiated and rendered observable. Thus, the jets in Carina constitute a new view of collimated jets from intermediate-mass protostars that exist in a feedback-dominated environment, and offer strong additional evidence that stars up to 8 solar masses form by the same accretion mechanisms as low-mass stars.

  20. Magnetized Jets Driven By the Sun: the Structure of the Heliosphere Revisited

    NASA Astrophysics Data System (ADS)

    Opher, M.; Drake, J. F.; Zieger, B.; Gombosi, T. I.

    2015-02-01

    The classic accepted view of the heliosphere is a quiescent, comet-like shape aligned in the direction of the Sun’s travel through the interstellar medium (ISM) extending for thousands of astronomical units (AUs). Here, we show, based on magnetohydrodynamic (MHD) simulations, that the tension (hoop) force of the twisted magnetic field of the Sun confines the solar wind plasma beyond the termination shock and drives jets to the north and south very much like astrophysical jets. These jets are deflected into the tail region by the motion of the Sun through the ISM similar to bent galactic jets moving through the intergalactic medium. The interstellar wind blows the two jets into the tail but is not strong enough to force the lobes into a single comet-like tail, as happens to some astrophysical jets. Instead, the interstellar wind flows around the heliosphere and into the equatorial region between the two jets. As in some astrophysical jets that are kink unstable, we show here that the heliospheric jets are turbulent (due to large-scale MHD instabilities and reconnection) and strongly mix the solar wind with the ISM beyond 400 AU. The resulting turbulence has important implications for particle acceleration in the heliosphere. The two-lobe structure is consistent with the energetic neutral atom (ENA) images of the heliotail from IBEX where two lobes are visible in the north and south and the suggestion from the Cassini ENAs that the heliosphere is “tailless.”

  1. MAGNETIZED JETS DRIVEN BY THE SUN: THE STRUCTURE OF THE HELIOSPHERE REVISITED

    SciTech Connect

    Opher, M.; Drake, J. F.; Zieger, B.; Gombosi, T. I.

    2015-02-20

    The classic accepted view of the heliosphere is a quiescent, comet-like shape aligned in the direction of the Sun’s travel through the interstellar medium (ISM) extending for thousands of astronomical units (AUs). Here, we show, based on magnetohydrodynamic (MHD) simulations, that the tension (hoop) force of the twisted magnetic field of the Sun confines the solar wind plasma beyond the termination shock and drives jets to the north and south very much like astrophysical jets. These jets are deflected into the tail region by the motion of the Sun through the ISM similar to bent galactic jets moving through the intergalactic medium. The interstellar wind blows the two jets into the tail but is not strong enough to force the lobes into a single comet-like tail, as happens to some astrophysical jets. Instead, the interstellar wind flows around the heliosphere and into the equatorial region between the two jets. As in some astrophysical jets that are kink unstable, we show here that the heliospheric jets are turbulent (due to large-scale MHD instabilities and reconnection) and strongly mix the solar wind with the ISM beyond 400 AU. The resulting turbulence has important implications for particle acceleration in the heliosphere. The two-lobe structure is consistent with the energetic neutral atom (ENA) images of the heliotail from IBEX where two lobes are visible in the north and south and the suggestion from the Cassini ENAs that the heliosphere is “tailless.”.

  2. Sweeping Jet Optimization Studies

    NASA Technical Reports Server (NTRS)

    Melton, LaTunia Pack; Koklu, Mehti; Andino, Marlyn; Lin, John C.; Edelman, Louis

    2016-01-01

    Progress on experimental efforts to optimize sweeping jet actuators for active flow control (AFC) applications with large adverse pressure gradients is reported. Three sweeping jet actuator configurations, with the same orifice size but di?erent internal geometries, were installed on the flap shoulder of an unswept, NACA 0015 semi-span wing to investigate how the output produced by a sweeping jet interacts with the separated flow and the mechanisms by which the flow separation is controlled. For this experiment, the flow separation was generated by deflecting the wing's 30% chord trailing edge flap to produce an adverse pressure gradient. Steady and unsteady pressure data, Particle Image Velocimetry data, and force and moment data were acquired to assess the performance of the three actuator configurations. The actuator with the largest jet deflection angle, at the pressure ratios investigated, was the most efficient at controlling flow separation on the flap of the model. Oil flow visualization studies revealed that the flow field controlled by the sweeping jets was more three-dimensional than expected. The results presented also show that the actuator spacing was appropriate for the pressure ratios examined.

  3. Jet penetration in glass

    SciTech Connect

    Moran, B.; Glenn, L.A.; Kusubov, A.

    1991-05-01

    We describe a phenomenological model which accounts for the mechanical response of glass to intense impulsive loading. An important aspect of this response is the dilatancy accompanying fracture. We have also conducted a number of experiments with 38.1-mm diameter precision shaped charges to establish the performance against various targets and to allow evaluation of our model. At 3 charge diameters standoff, the data indicate that both virgin and damaged glass offer better (Bernoulli-scaled) resistance to penetration than either of 4340 steel, or 6061-T6 aluminum alloy. Time-resolved measurements indicate two distinct phases of jet penetration in glass: An initial hydrodynamic phase, and a second phase characterized by a slower penetration velocity. Our calculations show that at early time, a crater is formed around the jet and only the tip of the undisturbed jet interacts with the glass. At late time the glass has collapsed on the jet and degraded penetration continues via a disturbed and fragmented jet.

  4. The Twin Jet Nebula

    NASA Technical Reports Server (NTRS)

    1997-01-01

    M2-9 is a striking example of a 'butterfly' or a bipolar planetary nebula. Another more revealing name might be the 'Twin Jet Nebula.' If the nebula is sliced across the star, each side of it appears much like a pair of exhausts from jet engines. Indeed, because of the nebula's shape and the measured velocity of the gas, in excess of 200 miles per second, astronomers believe that the description as a super-super-sonic jet exhaust is quite apt. This is much the same process that takes place in a jet engine: The burning and expanding gases are deflected by the engine walls through a nozzle to form long, collimated jets of hot air at high speeds. M2-9 is 2,100 light-years away in the constellation Ophiucus. The observation was taken Aug. 2, 1997 by the Hubble telescope's Wide Field and Planetary Camera 2. In this image, neutral oxygen is shown in red, once-ionized nitrogen in green, and twice-ionized oxygen in blue.

  5. Modified shielding jet model for twin-jet shielding analysis

    NASA Technical Reports Server (NTRS)

    Gerhold, C. H.; Gilbride, J.

    1983-01-01

    An analytical model to estimate the shielding of noise emitted from a point noise source has been developed assuming the shielding jet to be a cylinder of constant radius with uniform flow across the cross section. Comparison to experiment indicated that the model overestimates diffraction of sound around the jet in the far downstream region. The shielding jet model is modified to include widening downstream of the nozzle exit. This not only represents a more realistic model of the jet, but is also expected to improve the shielding estimate downstream. The modified jet model incorporates a Mach number dependent widening rate, a corresponding decrease in flow velocity downstream and an equivalent slug flow evaluation to retain the locally parallel flow approximation of the model development. The shielding analysis with modified jet model is compared to measured data for a subsonic isothermal air jet and a simulated hot subsonic jet. Improvement of the shielding estimate is discussed.

  6. B-jets and z + b-jets at CDF

    SciTech Connect

    Jeans, Daniel; /Rome U.

    2006-06-01

    The authors present CDF cross-section measurements for the inclusive production of b jets and the production of b jets in association with a Z{sup 0} boson. Both measurements are in reasonable agreement with NLO QCD predictions.

  7. Relativistic Jets: Acceleration, Dissipation and Interactions with Ambient Gas

    NASA Astrophysics Data System (ADS)

    Giannois, Dimitrios

    Collimated, relativistic outflows, known as relativistic jets, originate from supermassive black holes in active galactic nuclei (AGN), solar-mass compact objects in x-ray binaries (XRBs), and gamma ray bursts (GRBs). Such jets are among the most well observed phenomena in astrophysics, in part because of NASA's continued commitment to funding missions that target compact objects and their outflows. Jets are thought to come from rotating objects (neutron stars, black holes, or accretion disks) that are threaded with strong magnetic fields. Despite recent progress in the field, we still lack a self-consistent model that connects the invisible processes -- jet launching, acceleration and energy dissipation -- to their observational manifestations: emission and interaction with the ambient medium. Our work over the past several years demonstrated that magnetic energy dissipation crucially affects how jets accelerate and radiate. Though still a major challenge, we believe that due to recent developments in theory and numerical simulations, we are now in a unique position, for the first time, to compute jet evolution and determine the locations at which dissipation and radiation takes place from first principles. To achieve this long-sought goal, we propose to carry out relativistic 3D magnetohydrodynamic (MHD) numerical simulations that follow jets from the central compact object out to their interactions with the ambient medium, in a variety of astrophysical contexts ranging from AGN to XRBs to GRBs. Then, using radiative transfer calculations, we will make direct connection to observations. We will complement the numerical work with analytical studies and develop a quantitative description of instabilities in the jet, and their connection to energy dissipation and emission. The MHD and radiative transfer experience of the PI Giannios and Co-I Barniol-Duran, combined with the numerical MHD expertise of the Co-I Tchekhovskoy make achieving the proposed goals realistic

  8. Renewable jet fuel.

    PubMed

    Kallio, Pauli; Pásztor, András; Akhtar, M Kalim; Jones, Patrik R

    2014-04-01

    Novel strategies for sustainable replacement of finite fossil fuels are intensely pursued in fundamental research, applied science and industry. In the case of jet fuels used in gas-turbine engine aircrafts, the production and use of synthetic bio-derived kerosenes are advancing rapidly. Microbial biotechnology could potentially also be used to complement the renewable production of jet fuel, as demonstrated by the production of bioethanol and biodiesel for piston engine vehicles. Engineered microbial biosynthesis of medium chain length alkanes, which constitute the major fraction of petroleum-based jet fuels, was recently demonstrated. Although efficiencies currently are far from that needed for commercial application, this discovery has spurred research towards future production platforms using both fermentative and direct photobiological routes. PMID:24679258

  9. Renewable jet fuel.

    PubMed

    Kallio, Pauli; Pásztor, András; Akhtar, M Kalim; Jones, Patrik R

    2014-04-01

    Novel strategies for sustainable replacement of finite fossil fuels are intensely pursued in fundamental research, applied science and industry. In the case of jet fuels used in gas-turbine engine aircrafts, the production and use of synthetic bio-derived kerosenes are advancing rapidly. Microbial biotechnology could potentially also be used to complement the renewable production of jet fuel, as demonstrated by the production of bioethanol and biodiesel for piston engine vehicles. Engineered microbial biosynthesis of medium chain length alkanes, which constitute the major fraction of petroleum-based jet fuels, was recently demonstrated. Although efficiencies currently are far from that needed for commercial application, this discovery has spurred research towards future production platforms using both fermentative and direct photobiological routes.

  10. Hypersonic jet control effectiveness

    NASA Astrophysics Data System (ADS)

    Kumar, D.; Stollery, J. L.; Smith, A. J.

    The present study aims to identify some of the parameters which determine the upstream extent and the lateral spreading of the separation front around an under-expanded transverse jet on a slender blunted cone. The tests were conducted in the Cranfield hypersonic facility at M∞ = 8.2, Re∞ /cm = 4.5 to 9.0 × 104 and at M∞ = 12.3, Re∞ /cm = 3.3 × 104. Air was used as the working gas for both the freestream and the jet. Schlieren pictures were used for the visualisation of the three-dimensional structures around the jet. Pressure, normal force and pitching moment measurements were conducted to quantitatively study the interaction region and its effects on the vehicle. An analytical algorithm has been developed to predict the shape of the separation front around the body.

  11. Recurrent Wheezing in Infants

    PubMed Central

    Belhassen, Manon; De Blic, Jacques; Laforest, Laurent; Laigle, Valérie; Chanut-Vogel, Céline; Lamezec, Liliane; Brouard, Jacques; Fauroux, Brigitte; de Pouvourville, Gérard; Ginoux, Marine; Van Ganse, Eric

    2016-01-01

    Abstract Recurrent wheezing (RW) has a significant impact on infants, caregivers, and society, but morbidity and related medical resource utilization (MRU) have not been thoroughly explored. The burden of RW needs to be documented with population-based data. The objective was to assess the characteristics, medical management, and MRU of RW infants identified from national claims data. Infants aged from 6 to 24 months, receiving ≥2 dispensations of respiratory drugs within 3 months, and presenting a marker of poor control (index date), were selected. During the 6 months after index date, MRU was described in the cohort and among 3 subgroups with more severe RW, defined as ≥4 dispensations of respiratory drugs, ≥3 dispensations of oral corticosteroids (OCS), or ≥1 hospitalization for respiratory symptoms. A total of 115,489 infants had RW, corresponding to 8.2% of subjects in this age group. During follow-up, 68.7% of infants received inhaled corticosteroids, but only 1.8 U (unit) were dispensed over 6 months, suggesting discontinuous use. Control was mostly inadequate: 61.7% of subjects received OCS, 80.2% antibiotics, and 71.2% short-acting beta-agonists, and medical/paramedical visits were numerous, particularly for physiotherapy. Severe RW concerned 39.0% of the cohort; 32.8% and 11.7% of infants had repeated use of respiratory drugs and OCS, respectively, and 5.5% were hospitalized for respiratory symptoms. In this real-life nation-wide study, RW was common and infants had poor control and high MRU. Interventions are needed to support adequate use of controller therapy, and to improve medical care. PMID:27082618

  12. Recurrence Quantification of Fractal Structures

    PubMed Central

    Webber, Charles L.

    2012-01-01

    By definition, fractal structures possess recurrent patterns. At different levels repeating patterns can be visualized at higher magnifications. The purpose of this chapter is threefold. First, general characteristics of dynamical systems are addressed from a theoretical mathematical perspective. Second, qualitative and quantitative recurrence analyses are reviewed in brief, but the reader is directed to other sources for explicit details. Third, example mathematical systems that generate strange attractors are explicitly defined, giving the reader the ability to reproduce the rich dynamics of continuous chaotic flows or discrete chaotic iterations. The challenge is then posited for the reader to study for themselves the recurrent structuring of these different dynamics. With a firm appreciation of the power of recurrence analysis, the reader will be prepared to turn their sights on real-world systems (physiological, psychological, mechanical, etc.). PMID:23060808

  13. Jet Shockwaves Produce Gamma Rays

    NASA Video Gallery

    Theorists believe that GRB jets produce gamma rays by two processes involving shock waves. Shells of material within the jet move at different speeds and collide, generating internal shock waves th...

  14. Impact of a viscoelastic jet

    NASA Astrophysics Data System (ADS)

    Lhuissier, Henri; Néel, Baptiste; Limat, Laurent

    2014-11-01

    A jet of a Newtonian liquid impacting onto a wall at right angle spreads as a thin liquid sheet which preserves the radial symmetry of the jet. We observe that for a viscoelastic jet (solution of polyethylene glycol in water) this symmetry can break: close to the wall, the jet cross-section is faceted and radial steady liquid films (membranes) form, which connect the cross-section vertices to the sheet. The number of membranes increases with increasing viscoelastic relaxation time of the solution, but also with increasing jet velocity and decreasing distance from the jet nozzle to the wall. A mechanism for this surprising destabilization of the jet, which develops perpendicularly to the direction expected for a buckling mechanism, is presented that explains these dependences. The large-scale consequences of the jet destabilization on the sheet spreading and fragmentation, which show through the faceting of hydraulic jumps and suspended (Savart) sheets, will also be discussed.

  15. Jet pump assisted artery

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A procedure for priming an arterial heat pump is reported; the procedure also has a means for maintaining the pump in a primed state. This concept utilizes a capillary driven jet pump to create the necessary suction to fill the artery. Basically, the jet pump consists of a venturi or nozzle-diffuser type constriction in the vapor passage. The throat of this venturi is connected to the artery. Thus vapor, gas, liquid, or a combination of the above is pumped continuously out of the artery. As a result, the artery is always filled with liquid and an adequate supply of working fluid is provided to the evaporator of the heat pipe.

  16. Jets from Merging Neutron Stars

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    With the recent discovery of gravitational waves from the merger of two black holes, its especially important to understand the electromagnetic signals resulting from mergers of compact objects. New simulations successfully follow a merger of two neutron stars that produces a short burst of energy via a jet consistent with short gamma-ray burst (sGRB) detections.Still from the authors simulation showing the two neutron stars, and their magnetic fields, before merger. [Adapted from Ruiz et al. 2016]Challenging SystemWe have long suspected that sGRBs are produced by the mergers of compact objects, but this model has been difficult to prove. One major hitch is that modeling the process of merger and sGRB launch is very difficult, due to the fact that these extreme systems involve magnetic fields, fluids and full general relativity.Traditionally, simulations are only able to track such mergers over short periods of time. But in a recent study, Milton Ruiz (University of Illinois at Urbana-Champaign and Industrial University of Santander, Colombia) and coauthors Ryan Lang, Vasileios Paschalidis and Stuart Shapiro have modeled a binary neutron star system all the way through the process of inspiral, merger, and the launch of a jet.A Merger TimelineHow does this happen? Lets walk through one of the teams simulations, in which dipole magnetic field lines thread through the interior of each neutron star and extend beyond its surface(like magnetic fields found in pulsars). In this example, the two neutron stars each have a mass of 1.625 solar masses.Simulation start (0 ms)Loss of energy via gravitational waves cause the neutron stars to inspiral.Merger (3.5 ms)The neutron stars are stretched by tidal effects and make contact. Their merger produces a hypermassive neutron star that is supported against collapse by its differential (nonuniform) rotation.Delayed collapse into a black hole (21.5 ms)Once the differential rotation is redistributed by magnetic fields and partially

  17. Jets from Merging Neutron Stars

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-06-01

    With the recent discovery of gravitational waves from the merger of two black holes, its especially important to understand the electromagnetic signals resulting from mergers of compact objects. New simulations successfully follow a merger of two neutron stars that produces a short burst of energy via a jet consistent with short gamma-ray burst (sGRB) detections.Still from the authors simulation showing the two neutron stars, and their magnetic fields, before merger. [Adapted from Ruiz et al. 2016]Challenging SystemWe have long suspected that sGRBs are produced by the mergers of compact objects, but this model has been difficult to prove. One major hitch is that modeling the process of merger and sGRB launch is very difficult, due to the fact that these extreme systems involve magnetic fields, fluids and full general relativity.Traditionally, simulations are only able to track such mergers over short periods of time. But in a recent study, Milton Ruiz (University of Illinois at Urbana-Champaign and Industrial University of Santander, Colombia) and coauthors Ryan Lang, Vasileios Paschalidis and Stuart Shapiro have modeled a binary neutron star system all the way through the process of inspiral, merger, and the launch of a jet.A Merger TimelineHow does this happen? Lets walk through one of the teams simulations, in which dipole magnetic field lines thread through the interior of each neutron star and extend beyond its surface(like magnetic fields found in pulsars). In this example, the two neutron stars each have a mass of 1.625 solar masses.Simulation start (0 ms)Loss of energy via gravitational waves cause the neutron stars to inspiral.Merger (3.5 ms)The neutron stars are stretched by tidal effects and make contact. Their merger produces a hypermassive neutron star that is supported against collapse by its differential (nonuniform) rotation.Delayed collapse into a black hole (21.5 ms)Once the differential rotation is redistributed by magnetic fields and partially

  18. The recurrent carpal tunnel syndrome.

    PubMed

    Kern, B C; Brock, M; Rudolph, K H; Logemann, H

    1993-01-01

    Sixteen out of 720 patients with carpal tunnel syndrome who had undergone surgery since 1979 were reoperated for a "recurrence" (2.2%). Twelve of these patients had been originally operated on in our department. Thus, our own recurrence rate is 1.7%. Three patients deteriorated following surgery, 6 had an unsatisfactory improvement, and in 7 the symptoms recurred after initial improvement. Eight of the reoperated patients had a predisposing disease (terminal renal insufficiency, insulin-dependent diabetes mellitus, acromegaly). In 10 of the 16 cases the initial operation had been carried out by surgeons in the first three years of training. Reoperation revealed incomplete splitting of the transverse carpal ligament in 10 cases, compression of the median nerve by the scar in 4, injury of the muscular branch in 1, and an anatomical variant as cause of incomplete decompression in 1 patient. "Recurrences" after carpal tunnel surgery are predominantly due to inadequacies of the first procedure. A remarkable number of patients (50%) has predisposing diseases. Interfascicular or epineural neurolysis and complete exposure and neurolysis of the median nerve and its branches is necessary only in cases of recurrence. Their omission at the first surgery does not result in an increased recurrence rate. Our observations indicate that the number of operations for recurrent carpal tunnel syndrome can probably be reduced when the first operation is performed with care and experience. Patients with carpal tunnel syndrome secondary to a systemic disease are particularly at risk.

  19. [Recurrent spontaneous abortions].

    PubMed

    Salat-Baroux, J

    1988-01-01

    The process of fertilization in humans, is remarkably inefficient. Spontaneous abortion is estimated to be between 15 and 20% of all clinical pregnancies, and the early spontaneous abortion rate is closer to 30-50% of fertilized ova. Not all authors agree on the definition of "recurrent spontaneous abortion" (RSA), so the frequency of repeated pregnancy wastage is difficult to determine; from empirically derived data, it has been estimated to range between 0.4 and 0.8%. Because of the various etiologies of RSA, their association in determining an abortive event, it is difficult to evaluate their exact incidence. Moreover, their is no prospective study on this subject, so it is advisable to distinguish between the admitted causes, the likely factors, and the etiologies to be evaluated. In the first group, the congenital or acquired müllerian anomalies (especially the septate uterus), represent about 25% of the RSA, but a lot of problems concerning the physiopathology are still debated, even if the rate of pregnancies after surgery ranges around 50% in certain series. On the other hand, the genetic factors, identified especially with the banding technique, are undeniable: however, although the rate of chromosomal aberrations in the offspring (Monosomy X, Trisony 16, Triploidy) is very high (50 to 60% of spontaneous abortions in the first trimester of pregnancy), when couples with usual abortions are subjected to karyotypic analysis, genetic anomalies (especially translocations) are been noted in only 6.2% of the women and 2.6% of the men. In the second group, the infective factors (chlamydiae, toxoplasma and mycoplasma) are difficult to analyse since the serology is not sufficient without a real proof of an endometrial colonization. Among the endocrinological causes, the classical luteal phase deficiency remains a subject of controversy (estimated between 3 and 30%) not only for the establishment of the diagnosis, but also for the efficiency of progesterone

  20. COUNTERROTATION IN MAGNETOCENTRIFUGALLY DRIVEN JETS AND OTHER WINDS

    SciTech Connect

    Sauty, C.; Cayatte, V.; Lima, J. J. G.; Matsakos, T.; Tsinganos, K.

    2012-11-01

    Rotation measurement in jets from T Tauri stars is a rather difficult task. Some jets seem to be rotating in a direction opposite to that of the underlying disk, although it is not yet clear if this affects the totality or part of the outflows. On the other hand, Ulysses data also suggest that the solar wind may rotate in two opposite ways between the northern and southern hemispheres. We show that this result is not as surprising as it may seem and that it emerges naturally from the ideal MHD equations. Specifically, counterrotating jets neither contradict the magnetocentrifugal driving of the flow nor prevent extraction of angular momentum from the disk. The demonstration of this result is shown by combining the ideal MHD equations for steady axisymmetric flows. Provided that the jet is decelerated below some given threshold beyond the Alfven surface, the flow will change its direction of rotation locally or globally. Counterrotation is also possible for only some layers of the outflow at specific altitudes along the jet axis. We conclude that the counterrotation of winds or jets with respect to the source, star or disk, is not in contradiction with the magnetocentrifugal driving paradigm. This phenomenon may affect part of the outflow, either in one hemisphere, or only in some of the outflow layers. From a time-dependent simulation, we illustrate this effect and show that it may not be permanent.

  1. Vortex diode jet

    DOEpatents

    Houck, Edward D.

    1994-01-01

    A fluid transfer system that combines a vortex diode with a jet ejector to transfer liquid from one tank to a second tank by a gas pressurization method having no moving mechanical parts in the fluid system. The vortex diode is a device that has a high resistance to flow in one direction and a low resistance to flow in the other.

  2. Stationary relativistic jets

    NASA Astrophysics Data System (ADS)

    Komissarov, Serguei S.; Porth, Oliver; Lyutikov, Maxim

    2015-11-01

    In this paper we describe a simple numerical approach which allows to study the structure of steady-state axisymmetric relativistic jets using one-dimensional time-dependent simulations. It is based on the fact that for narrow jets with vz≈ c the steady-state equations of relativistic magnetohydrodynamics can be accurately approximated by the one-dimensional time-dependent equations after the substitution z=ct. Since only the time-dependent codes are now publicly available this is a valuable and efficient alternative to the development of a high-specialised code for the time-independent equations. The approach is also much cheaper and more robust compared to the relaxation method. We tested this technique against numerical and analytical solutions found in literature as well as solutions we obtained using the relaxation method and found it sufficiently accurate. In the process, we discovered the reason for the failure of the self-similar analytical model of the jet reconfinement in relatively flat atmospheres and elucidated the nature of radial oscillations of steady-state jets.

  3. Jets and QCD

    NASA Astrophysics Data System (ADS)

    Ellis, Stephen D.; Soper, Davison E.

    2013-06-01

    An essential element of the development of the strong interaction component of the Standard Model of particle physics, QCD, has been the evolving understanding of the "jets" of particles that appear in the final states of high energy particle collisions. In this chapter we provide a historical outline of those developments...

  4. Particle Acceleration in Jets

    NASA Technical Reports Server (NTRS)

    Nishikawa, Ken-Ichi

    2005-01-01

    Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma ray burst (GRBs), and Galactic microquasar systems usually have power-law emission spectra. Fermi acceleration is the mechanism usually assumed for the acceleration of particles in astrophysical environments.

  5. The Jet Travel Challenge

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2007-01-01

    Airplane travelers are dismayed by the long lines and seemingly chaotic activities that precede boarding a full airplane. Surely, the one who can solve this problem is going to make many travelers happy. This article describes the Jet Travel Challenge, an activity that challenges students to create some alternatives to this now frustrating…

  6. Spectroscopy with Supersonic Jets.

    ERIC Educational Resources Information Center

    Skinner, Anne R.; Chandler, Dean W.

    1980-01-01

    Discusses a new technique that enables spectroscopists to study gas phase molecules at temperatures below 1 K, without traditional cryogenic apparatus. This technique uses supersonic jets as samples for gas molecular spectroscopy. Highlighted are points in the theory of supersonic flow which are important for applications in molecular…

  7. Coronal Jets in Closed Magnetic Regions on the Sun

    NASA Astrophysics Data System (ADS)

    Wyper, Peter Fraser; DeVore, C. R.

    2015-04-01

    Coronal jets are dynamic, collimated structures observed in solar EUV and X-ray emission. They appear predominantly in the open field of coronal holes, but are also observed in areas of closed field, especially active regions. A common feature of coronal jets is that they originate from the field above a parasitic polarity of opposite sign to the surrounding field. Some process - such as instability onset or flux emergence - induces explosive reconnection between the closed “anemone” field and the surrounding open field that generates the jet. The lesser number of coronal jets in closed-field regions suggests a possible stabilizing effect of the closed configuration with respect to coronal jet formation. If the scale of the jet region is small compared with the background loop length, as in for example type II spicules, the nearby magnetic field may be treated as locally open. As such, one would expect that if a stabilizing effect exists it becomes most apparent as the scale of the anemone region approaches that of the background coronal loops.To investigate if coronal jets are indeed suppressed along shorter coronal loops, we performed a number of simulations of jets driven by a rotation of the parasitic polarity (as in the previous open-jet calculations by Pariat et. al 2009, 2010, 2015) embedded in a large-scale closed bipolar field. The simulations were performed with the state of the art Adaptively Refined Magnetohydrodynamics Solver. We will report here how the magnetic configuration above the anemone region determines the nature of the jet, when it is triggered, and how much of the stored magnetic energy is released. We show that regions in which the background field and the parasitic polarity region are of comparable scale naturally suppress explosive energy release. We will also show how in the post-jet relaxation phase a combination of confined MHD waves and weak current layers are generated by the jet along the background coronal loops, both of which

  8. The recurrence rate of stones following ESWL.

    PubMed

    Köhrmann, K U; Rassweiler, J; Alken, P

    1993-01-01

    With extracorporeal shockwave lithotripsy (ESWL) stone fragmentation and the potential creation of residual stones has become an integral part of the treatment strategy. Therefore true recurrence, regrowth and pseudo-recurrence determine the rate of new stone formation. In unselected series the overall recurrence rate after ESWL varies between 6% after 1 year and 20% after 4 years. The comparison between the recurrence rate after ESWL and the natural recurrence rate reveals that the results of ESWL are better than expected. Lithotripsy has no special effect on true stone recurrence, and even pseudo-recurrence is of minor clinical significance.

  9. Review of jet reconstruction algorithms

    NASA Astrophysics Data System (ADS)

    Atkin, Ryan

    2015-10-01

    Accurate jet reconstruction is necessary for understanding the link between the unobserved partons and the jets of observed collimated colourless particles the partons hadronise into. Understanding this link sheds light on the properties of these partons. A review of various common jet algorithms is presented, namely the Kt, Anti-Kt, Cambridge/Aachen, Iterative cones and the SIScone, highlighting their strengths and weaknesses. If one is interested in studying jets, the Anti-Kt algorithm is the best choice, however if ones interest is in the jet substructures then the Cambridge/Aachen algorithm would be the best option.

  10. Interacting jets from binary protostars

    NASA Astrophysics Data System (ADS)

    Murphy, G. C.; Lery, T.; O'Sullivan, S.; Spicer, D.; Bacciotti, F.; Rosen, A.

    2008-02-01

    Aims: We investigate potential models that could explain why multiple proto-stellar systems predominantly show single jets. During their formation, stars most frequently produce energetic outflows and jets. However, binary jets have only been observed in a very small number of systems. Methods: We model numerically 3D binary jets for various outflow parameters. We also model the propagation of jets from a specific source, namely L1551 IRS 5, known to have two jets, using recent observations as constraints for simulations with a new MHD code. We examine their morphology and dynamics, and produce synthetic emission maps. Results: We find that the two jets interfere up to the stage where one of them is almost destroyed or engulfed into the second one. We are able to reproduce some of the observational features of L1551 such as the bending of the secondary jet. Conclusions: While the effects of orbital motion are negligible over the jets dynamical timeline, their interaction has significant impact on their morphology. If the jets are not strictly parallel, as in most observed cases, we show that the magnetic field can help the collimation and refocusing of both of the two jets.

  11. Jet propagation through energetic materials

    SciTech Connect

    Pincosy, P; Poulsen, P

    2004-01-08

    In applications where jets propagate through energetic materials, they have been observed to become sufficiently perturbed to reduce their ability to effectively penetrate subsequent material. Analytical calculations of the jet Bernoulli flow provides an estimate of the onset and extent of such perturbations. Although two-dimensional calculations show the back-flow interaction pressure pulses, the symmetry dictates that the flow remains axial. In three dimensions the same pressure impulses can be asymmetrical if the jet is asymmetrical. The 3D calculations thus show parts of the jet having a significant component of radial velocity. On the average the downstream effects of this radial flow can be estimated and calculated by a 2D code by applying a symmetrical radial component to the jet at the appropriate position as the jet propagates through the energetic material. We have calculated the 3D propagation of a radio graphed TOW2 jet with measured variations in straightness and diameter. The resultant three-dimensional perturbations on the jet result in radial flow, which eventually tears apart the coherent jet flow. This calculated jet is compared with jet radiographs after passage through the energetic material for various material thickness and plate thicknesses. We noted that confinement due to a bounding metal plate on the energetic material extends the pressure duration and extent of the perturbation.

  12. Flow cytometer jet monitor system

    DOEpatents

    Van den Engh, Ger

    1997-01-01

    A direct jet monitor illuminates the jet of a flow cytometer in a monitor wavelength band which is substantially separate from the substance wavelength band. When a laser is used to cause fluorescence of the substance, it may be appropriate to use an infrared source to illuminate the jet and thus optically monitor the conditions within the jet through a CCD camera or the like. This optical monitoring may be provided to some type of controller or feedback system which automatically changes either the horizontal location of the jet, the point at which droplet separation occurs, or some other condition within the jet in order to maintain optimum conditions. The direct jet monitor may be operated simultaneously with the substance property sensing and analysis system so that continuous monitoring may be achieved without interfering with the substance data gathering and may be configured so as to allow the front of the analysis or free fall area to be unobstructed during processing.

  13. Pileup subtraction for jet shapes.

    PubMed

    Soyez, Gregory; Salam, Gavin P; Kim, Ji-Hun; Dutta, Souvik; Cacciari, Matteo

    2013-04-19

    Jets in high energy hadronic collisions often contain the fingerprints of the particles that produced them. Those fingerprints, and thus the nature of the particles that produced the jets, can be read off with the help of quantities known as jet shapes. Jet shapes are, however, severely affected by pileup, the accumulation in the detector of the residues of the many simultaneous collisions taking place in the Large Hadron Collider (LHC). We introduce a method to correct for pileup effects in jet shapes. Relative to earlier, limited approaches, the key advance resides in its full generality, achieved through a numerical determination, for each jet, of a given shape's susceptibility to pileup. The method rescues the possibility of using jet shapes in the high pileup environment of current and future LHC running, as we show with examples of quark-gluon discrimination and top tagging.

  14. Blowout Jets: Evidence from Hinode/XRT for X-Ray Jets Made by Blowout Eruption of the Emerging Bipole

    NASA Technical Reports Server (NTRS)

    Moore, Ronald L.; Cirtain, Jonathan W.; Sterling, Alphonse C.

    2009-01-01

    Yamauchi et al (2004, ApJ, 605, 511) found that there are two structurally and dynamically distinct types of H macrospicules in polar coronal holes: single-column jet macrospicules and erupting-loop macrospicules. The structure and motion of the single-column jet macrospicules fit the standard Shibata reconnection picture for solar X-ray jets (Shibata et al 1992, PASJ, 44, L173). The form and motion of the erupting-loop macrospicules is reminiscent of the ejective eruption of the sheared-core-field flux rope in the filament-eruption birth of a bubble-type coronal mass ejection (CME). That roughly half of all polar H macrospicules were observed to be erupting-loop macrospicules suggests that there should be a corresponding large class of X-ray jets in which the emerging bipole at the base of the jet undergoes a blowout eruption as in a bubble-type CME, instead of staying closed as in the standard picture for X-ray jets. Along with a cartoon of the standard picture, we present a cartoon depicting the signatures to be expected of a blowout jet in high-resolution coronal X-ray movies such as from Hinode/XRT. From Hinode/XRT movies in polar coronal holes, we show: (1) examples of X-ray jets that fit the standard picture very well, and (2) other examples that do not fit the standard picture but do show signatures appropriate for blowout jets. These signatures are (1) a flare arcade inside the emerging bipole in addition to the flare arcade produced between the emerging bipole and the ambient high-reaching unipolar field by reconnection of these two fields as in the standard picture, and (2) in addition to the jet prong expected from the standard reconnection, a second jet prong or strand, one that could not be produced by the standard reconnection but could be produced by reconnection between the ambient unipolar field and one leg of an erupting core-field flux rope that has blown out the emerging bipole. We therefore infer that these "two pronged" jets are made by

  15. Geoeffective jets impacting the magnetopause are very common

    NASA Astrophysics Data System (ADS)

    Plaschke, F.; Hietala, H.; Angelopoulos, V.; Nakamura, R.

    2016-04-01

    The subsolar magnetosheath is penetrated by transient enhancements in dynamic pressure. These enhancements, also called high-speed jets, can propagate to the magnetopause, causing large-amplitude yet localized boundary indentations on impact. Possible downstream consequences of these impacts are, e.g., local magnetopause reconnection, impulsive penetration of magnetosheath plasma into the magnetosphere, inner magnetospheric and boundary surface waves, drop outs and other variations in radiation belt electron populations, ionospheric flow enhancements, and magnetic field variations observed on the ground. Consequently, jets can be geoeffective. The extend of their geoeffectiveness is influenced by the amount of mass, momentum, and energy they transport, i.e., by how large they are. Their overall importance in the framework of solar wind-magnetosphere coupling is determined by how often jets of geoeffective size hit the dayside magnetopause. In this paper, we calculate such jet impact rates for the first time. From a large data set of Time History of Events and Macroscale Interactions during Substorms (THEMIS) multispacecraft jet observations, we find distributions of scale sizes perpendicular and parallel to the direction of jet propagation. They are well modeled by an exponential function with characteristic scales of 1.34RE (perpendicular) and 0.71RE (parallel direction), respectively. Using the distribution of perpendicular scale sizes, we derive an impact rate of jets with cross-sectional diameters larger than 2RE on a reference area of about 100 RE2 of the subsolar magnetopause. That rate is about 3 per hour in general, and about 9 per hour under low interplanetary magnetic field cone angle conditions (<30°), which are favorable for jet occurrence in the subsolar magnetosheath.

  16. RECURRENT NOVAE IN M31

    SciTech Connect

    Shafter, A. W.; Henze, M.; Rector, T. A.; Schweizer, F.; Hornoch, K.; Orio, M.; Pietsch, W.; Darnley, M. J.; Williams, S. C.; Bode, M. F.; Bryan, J.

    2015-02-01

    The reported positions of 964 suspected nova eruptions in M31 recorded through the end of calendar year 2013 have been compared in order to identify recurrent nova (RN) candidates. To pass the initial screen and qualify as a RN candidate, two or more eruptions were required to be coincident within 0.′1, although this criterion was relaxed to 0.′15 for novae discovered on early photographic patrols. A total of 118 eruptions from 51 potential RN systems satisfied the screening criterion. To determine what fraction of these novae are indeed recurrent, the original plates and published images of the relevant eruptions have been carefully compared. This procedure has resulted in the elimination of 27 of the 51 progenitor candidates (61 eruptions) from further consideration as RNe, with another 8 systems (17 eruptions) deemed unlikely to be recurrent. Of the remaining 16 systems, 12 candidates (32 eruptions) were judged to be RNe, with an additional 4 systems (8 eruptions) being possibly recurrent. It is estimated that ∼4% of the nova eruptions seen in M31 over the past century are associated with RNe. A Monte Carlo analysis shows that the discovery efficiency for RNe may be as low as 10% that for novae in general, suggesting that as many as one in three nova eruptions observed in M31 arise from progenitor systems having recurrence times ≲100 yr. For plausible system parameters, it appears unlikely that RNe can provide a significant channel for the production of Type Ia supernovae.

  17. Shortest recurrence periods of novae

    SciTech Connect

    Kato, Mariko; Saio, Hideyuki; Hachisu, Izumi; Nomoto, Ken'ichi

    2014-10-01

    Stimulated by the recent discovery of the 1 yr recurrence period nova M31N 2008-12a, we examined the shortest recurrence periods of hydrogen shell flashes on mass-accreting white dwarfs (WDs). We discuss the mechanism that yields a finite minimum recurrence period for a given WD mass. Calculating the unstable flashes for various WD masses and mass accretion rates, we identified a shortest recurrence period of about two months for a non-rotating 1.38 M {sub ☉} WD with a mass accretion rate of 3.6 × 10{sup –7} M {sub ☉} yr{sup –1}. A 1 yr recurrence period is realized for very massive (≳ 1.3 M {sub ☉}) WDs with very high accretion rates (≳ 1.5 × 10{sup –7} M {sub ☉} yr{sup –1}). We revised our stability limit of hydrogen shell burning, which will be useful for binary evolution calculations toward Type Ia supernovae.

  18. Treatment of recurrent vulvovaginal candidiasis.

    PubMed

    Ringdahl, E N

    2000-06-01

    Vulvovaginal candidiasis is considered recurrent when at least four specific episodes occur in one year or at least three episodes unrelated to antibiotic therapy occur within one year. Although greater than 50 percent of women more than 25 years of age develop vulvovaginal candidiasis at some time, fewer than 5 percent of these women experience recurrences. Clinical evaluation of recurrent episodes is essential. Patients who self-diagnose may miss other causes or concurrent infections. Known etiologies of recurrent vulvovaginal candidiasis include treatment-resistant Candida species other than Candida albicans, frequent antibiotic therapy, contraceptive use, compromise of the immune system, sexual activity and hyperglycemia. If microscopic examination of vaginal secretions in a potassium hydroxide preparation is negative but clinical suspicion is high, fungal cultures should be obtained. After the acute episode has been treated, subsequent prophylaxis (maintenance therapy) is important. Because many patients experience recurrences once prophylaxis is discontinued, long-term therapy may be warranted. Patients are more likely to comply when antifungal therapy is administered orally, but oral treatment carries a greater potential for systemic toxicity and drug interactions.

  19. Coronal Mass Ejections and Non-recurrent Forbush Decreases

    NASA Astrophysics Data System (ADS)

    Belov, A.; Abunin, A.; Abunina, M.; Eroshenko, E.; Oleneva, V.; Yanke, V.; Papaioannou, A.; Mavromichalaki, H.; Gopalswamy, N.; Yashiro, S.

    2014-10-01

    Coronal mass ejections (CMEs) and their interplanetary counterparts (interplanetary coronal mass ejections, ICMEs) are responsible for large solar energetic particle events and severe geomagnetic storms. They can modulate the intensity of Galactic cosmic rays, resulting in non-recurrent Forbush decreases (FDs). We investigate the connection between CME manifestations and FDs. We used specially processed data from the worldwide neutron monitor network to pinpoint the characteristics of the recorded FDs together with CME-related data from the detailed online catalog based upon the Solar and Heliospheric Observatory (SOHO)/ Large Angle and Spectrometric Coronagraph (LASCO) data. We report on the correlations of the FD magnitude to the CME initial speed, the ICME transit speed, and the maximum solar wind speed. Comparisons between the features of CMEs (mass, width, velocity) and the characteristics of FDs are also discussed. FD features for halo, partial halo, and non-halo CMEs are presented and discussed.

  20. The Solar Flare Myth in solar-terrestrial physics

    SciTech Connect

    Gosling, J.T.

    1993-07-01

    Early observations of associations between solar flares and large non- recurrent geomagnetic storms, large {open_quote}solar{close_quote} energetic particle events, and transient shock wave disturbances in the solar wind led to a paradigm of cause and effect that gave flares a central position in the chain of events leading from solar activity to major transient disturbances in the near-earth space environment. However, research in the last two decades shows that this emphasis on flares is misplaced. In this paper the author outlines briefly the rationale for a different paradigm of cause and effect in solar- terrestrial physics that removes solar flares from their central position as the {open_quote}cause{close_quote} of major disturbances in the near-earth space environment. Instead, this central role of {open_quote}cause{close_quote} is played by events now known as coronal mass ejections, or CMEs.

  1. Plasma confinement at JET

    NASA Astrophysics Data System (ADS)

    Nunes, I.; JET Contributors

    2016-01-01

    Operation with a Be/W wall at JET (JET-ILW) has an impact on scenario development and energy confinement with respect to the carbon wall (JET-C). The main differences observed were (1) strong accumulation of W in the plasma core and (2) the need to mitigate the divertor target temperature to avoid W sputtering by Be and other low Z impurities and (3) a decrease of plasma energy confinement. A major difference is observed on the pedestal pressure, namely a reduction of the pedestal temperature which, due to profile stiffness the plasma core temperature is also reduced leading to a degradation of the global confinement. This effect is more pronounced in low β N scenarios. At high β N, the impact of the wall on the plasma energy confinement is mitigated by the weaker plasma energy degradation with power relative to the IPB98(y, 2) scaling calculated empirically for a CFC first wall. The smaller tolerable impurity concentration for tungsten (<10-5) compared to that of carbon requires the use of electron heating methods to prevent W accumulation in the plasma core region as well as gas puffing to avoid W entering the plasma core by ELM flushing and reduction of the W source by decreasing the target temperature. W source and the target temperature can also be controlled by impurity seeding. Nitrogen and Neon have been used and with both gases the reduction of the W source and the target temperature is observed. Whilst more experiments with Neon are necessary to assess its impact on energy confinement, a partial increase of plasma energy confinement is observed with Nitrogen, through the increase of edge temperature. The challenge for scenario development at JET is to extend the pulse length curtailed by its transient behavior (W accumulation or MHD), but more importantly by the divertor target temperature limits. Re-optimisation of the scenarios to mitigate the effect of the change of wall materials maintaining high global energy confinement similar to JET-C is

  2. Solar astronomy

    NASA Technical Reports Server (NTRS)

    Rosner, Robert; Noyes, Robert; Antiochos, Spiro K.; Canfield, Richard C.; Chupp, Edward L.; Deming, Drake; Doschek, George A.; Dulk, George A.; Foukal, Peter V.; Gilliland, Ronald L.

    1991-01-01

    An overview is given of modern solar physics. Topics covered include the solar interior, the solar surface, the solar atmosphere, the Large Earth-based Solar Telescope (LEST), the Orbiting Solar Laboratory, the High Energy Solar Physics mission, the Space Exploration Initiative, solar-terrestrial physics, and adaptive optics. Policy and related programmatic recommendations are given for university research and education, facilitating solar research, and integrated support for solar research.

  3. A Series of Jets that Drove Streamer-Puff CMEs from Giant Active Region of 2014

    NASA Technical Reports Server (NTRS)

    Panesar, Navdeep K.; Sterling, Alphonse C.; Moore, Ronald L.

    2016-01-01

    We investigate characteristics of solar coronal jets that originated from active region NOAA 12192 and produced coronal mass ejections (CMEs). This active region produced many non-jet major flare eruptions (X and M class) that made no CME. A multiitude of jets occurred from the southeast edge of the active region, and in contrast to the major-flare eruptions in the core, six of these jets resulted in CMEs. Our jet observations are from multiple SDO/AIA EUV channels, including 304, 171 and 193 Angstrom, and CME observations are taken from SOHO/LASCO C2 coronograph. Each jet-driven CME was relatively slow-moving (approximately 200 - 300 km s(sup-1) compared to most CMEs; had angular width (20deg - 50deg) comparable to that of the streamer base; and was of the "streamer-puff" variety, whereby a preexisting streamer was transiently inflated but not removed (blown out) by the passage of the CME. Much of the chromospheric-temperature plasma of the jets producing the CMEs escaped from the Sun, whereas relatively more of the chromospheric plasma in the non-CME-producing jets fell back to the solar surface. We also found that the CME-producing jets tended to be faster in speed and longer in duration than the non-CME-producing jets. We expect that the jets result from eruptions of mini-filaments. We further propose that the CMEs are driven by magnetic twist injected into streamer-base coronal loops when erupting twisted mini-filament field reconnects with the ambient field at the foot of those loops.

  4. A Series of Jets that Drove Streamer-Puff CMEs from Giant Active Region of 2014

    NASA Technical Reports Server (NTRS)

    Panesar, Navdeep K.; Sterling, Alphonse C.; Moore, Ronald L.

    2016-01-01

    We investigate characteristics of solar coronal jets that originated from active region NOAA 12192 and produced coronal mass ejections (CMEs). This active region produced many non­-jet major flare eruptions (X and M class) that made no CME. A multitude of jets occurred from the southeast edge of the active region, and in contrast to the major-­flare eruptions in the core, six of these jets resulted in CMEs. Our jet observations are from SDO/AIA EUV channels and from Hinode/XRT, and CME observations are from the SOHO/LASCO C2 coronograph. Each jet-­driven CME was relatively slow-­moving (approx. 200 - 300 km/s) compared to most CMEs; had angular width (20deg - 50deg) comparable to that of the streamer base; and was of the "streamer­-puff" variety, whereby a pre-existing streamer was transiently inflated but not removed (blown out) by the passage of the CME. Much of the chromospheric-­temperature plasma of the jets producing the CMEs escaped from the Sun, whereas relatively more of the chromospheric plasma in the non-CME-producing jets fell back to the solar surface. We also found that the CME-producing jets tended to be faster in speed and longer in duration than the non-CME-­producing jets. We expect that the jets result from eruptions of mini-filaments. We further propose that the CMEs are driven by magnetic twist injected into streamer-­base coronal loops when erupting twisted mini-filament field reconnects with the ambient field at the foot of those loops.

  5. [Pediatric clubfoot : Treatment of recurrence].

    PubMed

    Radler, C; Mindler, G T

    2016-10-01

    Over the last 10 years the Ponseti method has become established as the gold standard for initial treatment of clubfeet nearly worldwide. Nevertheless, there are considerable fluctuations regarding the authenticity and quality in the application of the Ponseti method. Especially the efforts to ensure and promote compliance with the foot abduction brace and subsequently the recurrence rate show great variation. As a result, we are still faced with a significant number of recurrent or residual clubfeet. In recent years it has been shown in high-volume clinics that even these can almost always be successfully treated with recasting and with minor interventions, such as anterior tibial tendon transfer and lengthening of the Achilles tendon. More invasive surgical procedures are only very rarely indicated and are reserved for severe recurrence in previously surgically treated and secondary clubfeet. PMID:27577568

  6. [The recurrent multifocal pleomorphic adenoma].

    PubMed

    Vigili, M G; Sciarretta, F; Marzetti, A; Marzetti, F

    1993-01-01

    Pleomorphic adenoma (P.A.), the most common tumor of the salivary gland, demonstrates a peculiar clinicopathological behaviour for numerous reasons: the high recurrence rate following primary surgery (up to 50%), the appearance of malignancy (2-9%), the reported number of distant metastases histologically identical to the primary P.A. From among 71 cases of benign parotid tumors treated from Nov. 89 to Nov. 92 in the ENT Department of "Regina Elena", the National Cancer Institute in Rome, six particular cases showed multiple force of P.A. recurring after primary surgery performed from 3 to 32 years previously and are object of discussion in this study. All of these six cases had multiple recurrences, usually manifest as nodular clusters in the parotid area, while in three cases appeared as well a recurrence in the soft tissue of the neck, far removed from the parotid space, with no involvement of neck nodes as was revealed through histological examination following neck dissection. A hypothetical mechanism of diffusion is discussed. The Authors agree with the opinion which holds the surgeon's inability to successfully eradicate primary tumors responsible for the high frequency of recurrences. The surgical technique of "enucleation" is, in fact, inadequate in P.A. excision owing the high risk of mishandling or rupturing the tumor capsule with a consequent seeding of the tumor onto the surgical bed. Lateral lobectomy, with identification of the facial nerve, or total conservative parotidectomy (for deep lobe adenoma) are correct techniques in treating primary P.A.. The Authors also discuss management of recurrent P.A. in relation to facial nerve involvement. Preservation of the seventh nerve with eventual post-operative radiation should be considered an alternative to nerve sacrifice in selected cases of recurrent pleomorphic adenoma.

  7. Magnetized jets driven by the Sun: The structure of the heliosphere revisited—Updates

    NASA Astrophysics Data System (ADS)

    Opher, M.; Drake, J. F.; Zieger, B.; Swisdak, M.; Toth, G.

    2016-05-01

    As the solar system moves through the interstellar medium, the solar wind is deflected forming the heliosphere. The standard picture of the heliosphere is a comet-shape like structure with the tail extending for 1000s of astronomical units. This standard picture stems from a view where magnetic forces are negligible and the solar magnetic field is convected passively down the tail. Recently, we showed that the magnetic tension of the solar magnetic field plays a crucial role on organizing the solar wind in the heliosheath into two jet-like structures. The two jets are separated by the interstellar medium that flows between them. The heliosphere then has a "croissant"-like shape where the distance to the heliopause downtail is almost the same as towards the nose. This new view of the heliosphere is in agreement with the energetic neutral atoms maps taken by the Interstellar Boundary Explorer and INCA/CASSINI. We developed as well an analytic model of the heliosheath in the axisymmetric limit that shows how the magnetic tension force is the driver for the north and south jets. We confirmed that the formation of these jets with magnetohydrodynamic (MHD) simulations. The main reason why previous global MHD simulations did not see these jets is due to spurious magnetic dissipation that was present at the heliospheric current sheet. We instead kept the same polarity for the interplanetary (solar) magnetic field in both the northern and southern hemispheres, eliminating spurious magnetic dissipation effects at the heliospheric current sheet. In this paper, we extend these previous results to include additional cases where we used: (a) weaker solar magnetic field; (b) solar magnetic field that reverses polarity at the solar equator in the axisymmetric limit; and (c) slower motion through the interstellar system. We discuss as well future challenges regarding the structure of the heliosphere.

  8. SparkJet Efficiency

    NASA Technical Reports Server (NTRS)

    Golbabaei-Asl, Mona; Knight, Doyle; Anderson, Kellie; Wilkinson, Stephen

    2013-01-01

    A novel method for determining the thermal efficiency of the SparkJet is proposed. A SparkJet is attached to the end of a pendulum. The motion of the pendulum subsequent to a single spark discharge is measured using a laser displacement sensor. The measured displacement vs time is compared with the predictions of a theoretical perfect gas model to estimate the fraction of the spark discharge energy which results in heating the gas (i.e., increasing the translational-rotational temperature). The results from multiple runs for different capacitances of c = 3, 5, 10, 20, and 40 micro-F show that the thermal efficiency decreases with higher capacitive discharges.

  9. Recurrent abdominal pain during childhood.

    PubMed Central

    Scott, R. B.

    1994-01-01

    Recurrent abdominal pain is a common presenting complaint among children. A thorough history and physical examination and limited laboratory investigation should enable a physician to make a positive diagnosis of "functional" recurrent abdominal pain in 90% to 95% of cases; an organic cause is identified in only 5% to 10%. The care and thoroughness of the history and physical examination establish the physician's credibility; explaining the clinical basis for the diagnosis and educating the child and parents on what is known about the condition reassures the parents. PMID:8199511

  10. Phenomenology of photon-jets

    NASA Astrophysics Data System (ADS)

    Ellis, Stephen D.; Roy, Tuhin S.; Scholtz, Jakub

    2013-01-01

    One of the challenges of collider physics is to unambiguously associate detector-based objects with the corresponding elementary physics objects. A particular example is the association of calorimeter-based objects such as “jets,” identified with a standard (IR-safe) jet algorithm, with the underlying physics objects, which may be QCD-jets (arising from a scattered parton), electrons, photons or, as discussed here, photon-jets (a group of collinear photons). This separation is especially interesting in the context of Higgs search, where the signal includes events with two photons (in the Standard Model) as well as events with two photon-jets (in a variety of Beyond the Standard Model scenarios), while QCD provides ever-present background. Here we describe the implementation of techniques from the rapidly evolving area of jet substructure studies, not only to enhance the more familiar photon-QCD separation, but also to separately distinguish photon-jets, i.e., to separate usual jets into three categories: single photons, photon-jets and QCD-jets. The efficacy of these techniques for separation is illustrated through studies of simulated data.

  11. Jet-Environment Interactions as Diagnostics of Jet Physics

    NASA Astrophysics Data System (ADS)

    Heinz, Sebastian

    2014-09-01

    In this chapter, we will explore the interaction of jets with their environments. Jets can transport a sizable fraction of accretion energy away from black holes and neutron stars. Because they are collimated, they can travel to distances far beyond the gravitational sphere of influence of the black hole. Yet, their interaction with the interstellar and intergalactic medium must eventually halt their advance and dissipate the energy they carry. The termination of the jet, and the inflation of large scale cavities of relativistic plasma offers one of the most powerful ways to constrain the physics of jets. In this chapter, we will review the inflation of radio lobes, the propagation of hot spots, the creation of shells and cavities, and the bending of jet by proper motion through their environment, both in the context of AGN jets and microquasars.

  12. Ram jet engine

    SciTech Connect

    Crispin, B.; Pohl, W.D.; Thomaier, D.; Voss, N.

    1983-11-29

    In a ram jet engine, a tubular combustion chamber is divided into a flame chamber followed by a mixing chamber. The ram air is supplied through intake diffusers located on the exterior of the combustion chamber. The intake diffusers supply combustion air directly into the flame chamber and secondary air is conveyed along the exterior of the combustion chambers and then supplied directly into the mixing chamber.

  13. Alternative jet aircraft fuels

    NASA Technical Reports Server (NTRS)

    Grobman, J.

    1979-01-01

    Potential changes in jet aircraft fuel specifications due to shifts in supply and quality of refinery feedstocks are discussed with emphasis on the effects these changes would have on the performance and durability of aircraft engines and fuel systems. Combustion characteristics, fuel thermal stability, and fuel pumpability at low temperature are among the factors considered. Combustor and fuel system technology needs for broad specification fuels are reviewed including prevention of fuel system fouling and fuel system technology for fuels with higher freezing points.

  14. Micromachined chemical jet dispenser

    SciTech Connect

    Swierkowski, S.; Ciarlo, D.

    1996-05-13

    Goal is to develop a multi-channel micromachined chemical fluid jet dispenser that is applicable to prototype tests with biological samples that demonstrate its utility for molecular biology experiments. Objective is to demonstrate a new device capable of ultrasonically ejecting droplets from 10-200 {mu}m diameter capillaries that are arranged in an array that is linear or focused. The device is based on several common fabrication procedures used in MEMS (micro electro mechanical systems) technology: piezoelectric actuators, silicon, etc.

  15. Lapatinib in Treating Young Patients With Recurrent or Refractory Central Nervous System Tumors

    ClinicalTrials.gov

    2014-05-07

    Recurrent Childhood Anaplastic Astrocytoma; Recurrent Childhood Brain Stem Glioma; Recurrent Childhood Ependymoma; Recurrent Childhood Giant Cell Glioblastoma; Recurrent Childhood Glioblastoma; Recurrent Childhood Gliosarcoma; Recurrent Childhood Medulloblastoma; Recurrent Childhood Oligodendroglioma

  16. Determining the Composition of the Vela Pulsar's Jet

    NASA Technical Reports Server (NTRS)

    Ogelman, Hakki

    1997-01-01

    The pulsar jet is significant in explaining how the Vela pulsar's rotational energy is transported outward to the rest of the SNR, since direct radiation from the pulsar only accounts for a small percentage of the total power. Our previous ROSAT observations presented the first evidence that the pulsar is driving a narrow, collimated, and remarkably symmetrical jet into the SNR (Markwardt, C. and Oegelman, H., 1995, Nature, 375, p. 40) which we interpret to be from a 'cocoon' of hot gas surrounding the jet itself. We obtained an ASCA exposure of the jet in order to determine whether the spectrum is thermal or power-law continuum. The jet cocoon is detected with ASCA at approximately 2-3 x 10(exp -3) ct/s. The X-ray spectrum of the jet is remarkably similar to the surrounding supernova remnant spectrum and extends to X-ray energies of at least 7 keV, with a total flux of approximately 2 x 10(exp -13) erg/s sq cm sq arcmin. The only strong emission line is from He-like Neon at approx. 0.9 keV; otherwise the spectrum is quite smooth. The spectrum cannot be fit by any one standard plasma emission model, so we used models with two-components. The lower energy component is thermal and has a temperature of 0.29 +/- 0.03 keV; the higher energy portion can either be fit by a thermal component of temperature approx. 4 keV or a power law with photon index approx. 2.0. If the observed spectrum is of a 'traditional' jet cocoon, then we estimate the speed of the jet to be at least 800 km/s, depending on the angle of inclination of the jet axis to our line of sight. The mechanical power driving the jet is greater than or equal to 10(exp 36) erg/s which is comparable to the pulsar's spin-down luminosity of 7 x 10(exp 36) erg/s. and the mass flow rate at the head is greater than or equal to 10(exp -6) solar radius/yr. We conclude that the jet must be entraining material all along its length in order to generate such a large mass flow rate.

  17. Behavior of Electrospinning Jet

    NASA Astrophysics Data System (ADS)

    Xu, Han; Reneker, Darrell

    2002-03-01

    During the electrospinning of jets of polymer solutions such as polyethylene oxide in water, interference colors similar to those seen in the walls of soap bubbles are seen if the proper illumination is provided. The colors can be seen both in the straight part of the jet and in the loops formed by the electrically driven bending instability. The colors were correlated with measurements of the diameter of segments of a particular color. The path of a slowly moving jet of polyisobutylene in a mixture of acetone and paraffin oil was recorded. A well-developed expanding spiral that moved downward was observed. The downward velocity of a typical segment was .13 m/s, and the radial velocity of the same segment was .23m/s. The development of the second bending instability occurred 180 ms after the first, and a third bending instability occurred 280 ms after the first. The growth of the bending instability clearly demonstrated its self-similar, fractal nature. A network of electrospun polyisobutylene fibers was collected in an isopropyl alcohol precipitation bath.

  18. Magnetotail Reconnection Jets at Lunar Distances

    NASA Astrophysics Data System (ADS)

    Hietala, H.; Eastwood, J. P.; Drake, J. F.; Phan, T.; Mistry, R.; McFadden, J. P.

    2015-12-01

    Magnetic reconnection redistributes energy by releasing magnetic energy into particle energies—high speed bulk flows, heating, and particle acceleration. With near-Earth in situ observations, we have access to different parameter regimes: The magnetotail has typically a very large magnetic shear and symmetric boundary conditions. Reconnection at the magnetopause, in contrast, usually takes place under asymmetric boundary conditions and a variety of shear angles. Finally, reconnecting current sheets in the solar wind are typically large scale and not affected by nearby obstacles, and observations are typically made extremely far downstream from the X-line. As such, magnetotail reconnection, especially at lunar distances where the effect of the Earth's dipole is small, should be closest to simple models. Ion heating has recently been studied systematically in solar wind and magnetopause reconnection, but not in the magnetotail. The energetics of magnetotail reconnection jets are particularly interesting as the available magnetic energy per particle (Bin2/μ0nin = miVA,in2) is typically orders of magnitude higher and the inflow plasma beta much lower than in the solar wind and at the magnetopause. We survey ARTEMIS data from 2011-2014 for fast reconnection flows and analyse their statistical properties. In particular, we address (i) the ion temperature increase (ii) ion temperature anisotropy and firehose instability, and (iii) the underlying ion dynamics. We examine the spatial structure of the ion temperature across the exhaust, and compare with particle-in-cell simulations. We find that the temperature parallel to the magnetic field dominates near the edges of the jet, while the very center of the exhaust has Tperp > Tpara, indicating Speiser-like ion motion.

  19. The three-dimensional analysis of hinode polar jets using images from LASCO C2, the STEREO COR2 coronagraphs, and SMEI

    SciTech Connect

    Yu, H.-S.; Jackson, B. V.; Buffington, A.; Hick, P. P.; Shimojo, M.; Sako, N.

    2014-04-01

    Images recorded by the X-ray Telescope on board the Hinode spacecraft are used to provide high-cadence observations of solar jetting activity. A selection of the brightest of these polar jets shows a positive correlation with high-speed responses traced into the interplanetary medium. LASCO C2 and STEREO COR2 coronagraph images measure the coronal response to some of the largest jets, and also the nearby background solar wind velocity, thereby giving a determination of their speeds that we compare with Hinode observations. When using the full Solar Mass Ejection Imager (SMEI) data set, we track these same high-speed solar jet responses into the inner heliosphere and from these analyses determine their mass, flow energies, and the extent to which they retain their identity at large solar distances.

  20. Wall jets created by single and twin high pressure jet impingement

    NASA Astrophysics Data System (ADS)

    Miller, P.; Wilson, M.

    1993-03-01

    An extensive experimental investigation into the nature of the wall jets produced by single and twin normal jet impingement has been undertaken. Wall jet velocity profiles have been recorded up to 70 jet diameters from the impingement point, at pressures representative of current VStol technology. The tests used fixed convergent nozzles, with nozzle height and spacing and jet pressure being varied. Single jet impingement displays a consistent effect of nozzle height on wall jet development. For twin jet cases a powerful reinforcement exists along the wall jet interaction plane. Remote from the interaction plane the wall jets are weaker than those produced by a single jet impingement.

  1. [Radiodiagnosis of recurrences of lymphogranulomatosis].

    PubMed

    Mendeleev, I M; Miasnikov, A A; Balashov, A T; Polezhaev, Iu N

    1988-01-01

    The authors discuss the role and place of chest x-ray tomography, scintigraphy with 67Ga-citrate, ultrasonic investigation, angiography, angioscintigraphy, computed tomography, scintigraphy of the liver and bones in the diagnosis of recurrences of Hodgkin's disease and in control of a progress of disease. Indications for a successive use of one or the other method have been defined.

  2. Onychomycosis: Strategies to Minimize Recurrence.

    PubMed

    Gupta, Aditya K; Elewski, Boni E; Rosen, Ted; Caldwell, Bryan; Pariser, David M; Kircik, Leon H; Bhatia, Neal; Tosti, Antonella

    2016-03-01

    Recurrence (relapse or re-infection) in onychomycosis is common, occurring in 10% to 53% of patients. However, data on prevalence is limited as few clinical studies follow patients beyond 12 months. It has been suggested that recurrence after continuous terbinafine treatment may be less common than with intermittent or continuous itraconazole therapy, probably due to the fungicidal activity of terbinafine, although these differences tended not to be significant. Relapse rates also increase with time, peaking at month 36. Although a number of factors have been suggested to play a role in recurrence, only the co-existence of diabetes has been shown to have a significant impact. Data with topical therapy is sparse; a small study showed amorolfine prophylaxis may delay recurrence. High concentrations of efinaconazole have been reported in the nail two weeks' post-treatment suggesting twice monthly prophylaxis with topical treatments may be a realistic option, and may be an important consideration in diabetic patients with onychomycosis. Data suggest that prophylaxis may need to be continued for up to three years for optimal effect. Treating tinea pedis and any immediate family members is also critical. Other preventative strategies include avoiding communal areas where infection can spread (such as swimming pools), and decontaminating footwear. PMID:26954312

  3. Recurrent Processing during Object Recognition

    PubMed Central

    O’Reilly, Randall C.; Wyatte, Dean; Herd, Seth; Mingus, Brian; Jilk, David J.

    2013-01-01

    How does the brain learn to recognize objects visually, and perform this difficult feat robustly in the face of many sources of ambiguity and variability? We present a computational model based on the biology of the relevant visual pathways that learns to reliably recognize 100 different object categories in the face of naturally occurring variability in location, rotation, size, and lighting. The model exhibits robustness to highly ambiguous, partially occluded inputs. Both the unified, biologically plausible learning mechanism and the robustness to occlusion derive from the role that recurrent connectivity and recurrent processing mechanisms play in the model. Furthermore, this interaction of recurrent connectivity and learning predicts that high-level visual representations should be shaped by error signals from nearby, associated brain areas over the course of visual learning. Consistent with this prediction, we show how semantic knowledge about object categories changes the nature of their learned visual representations, as well as how this representational shift supports the mapping between perceptual and conceptual knowledge. Altogether, these findings support the potential importance of ongoing recurrent processing throughout the brain’s visual system and suggest ways in which object recognition can be understood in terms of interactions within and between processes over time. PMID:23554596

  4. Recurrent Education. A Resource Guide.

    ERIC Educational Resources Information Center

    Rochte, Newton C.

    To assist both practitioner and reader to find answers to questions on the theory and practice of recurrent education, this resource guide compiles 715 abstracts of relevant articles, books, and monographs, from many countries. Descriptors and identifiers, used in computer searches to identify the materials, are arranged alphabetically in the…

  5. [Recurrent erysipelas and cellulitis: management].

    PubMed

    Zürcher, Sven; Trellu, Laurence Toutous

    2015-04-01

    Erysipelas and infectious cellulitis are skin infections that develop following the entry of bacteria through gaps in the skin. The most common complication is recurrence. Control of predisposing factors remains essential to prevent it. Prophylactic antibiotics are sometimes prescribed, but this approach is based on small studies and expert opinion. This article reflects the current state of knowledge and the standard of care.

  6. Recurrent malignant salivary gland neoplasms.

    PubMed

    Rodriguez-Bigas, M A; Sako, K; Razack, M S; Shedd, D P; Bakamjian, V Y; Castillo, N B; Rao, U

    1989-10-01

    Recurrent salivary gland malignancies present difficult therapeutic decisions and poor prognosis in many instances, and treatment becomes of a palliative nature only. As many of the salivary gland malignancies we see are of the recurrent type, the following study was done to determine the efficacy of a vigorous attempt at retreatment. During the period January 1, 1960, through December 31, 1984, 352 patients with major and minor salivary gland tumors were evaluated at our institution. There were 149 benign lesions and 203 patients with malignant tumors. Of these, 99 patients had recurrent and metastatic tumors that had been treated initially elsewhere. Thirty-three of these patients were able to be treated with curative intent: surgery, 21; surgery plus radiation, 9; radiation therapy alone, 2; and radiation plus chemotherapy, 1. The 5 year survival with no evidence of disease was achieved in three patients with surgery alone and two patients with surgery plus radiation therapy. The group of five patients was comprised of two patients with adenoid cystic carcinomas of the parotid, one with intermediate grade mucoepidermoid carcinoma of the parotid, one, sebaceous cell carcinoma of the parotid, and one, adenoid cystic carcinoma of an accessory salivary gland. The results of this study serve to re-emphasize the relative poor yield of attempts at retreatment of loco-regional recurrence of salivary gland tumors.

  7. W + jet production at CDF

    SciTech Connect

    Messina, Andrea; /INFN, Rome

    2006-10-01

    A measurement of W {yields} e{nu} + n-jet cross sections in p{bar p} collisions at {radical}s = 1.96 TeV using the Collider Detector at Fermilab in Run II (CDF II) is presented. The measurement is based on an integrated luminosity of 320 pb{sup -1}, and includes events with up to 4 or more jets. In each jet multiplicity sample the differential and cumulative cross sections with respect to the transverse energy of the i{sup th} jet are measured. For W+ {ge} 2 jets the differential cross section with respect to the 2-leading jets invariant mass m{sub j{sub 1}j{sub 2}} and angural separation {Delta} R{sub j{sub 1}j{sub 2}} is also reported. The data are compared to predictions from Monte Carlo simulations.

  8. 30 CFR 56.7801 - Jet drills.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Jet drills. 56.7801 Section 56.7801 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Rotary Jet Piercing § 56.7801 Jet drills. Jet piercing drills shall be provided with— (a) A system...

  9. 30 CFR 56.7801 - Jet drills.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Jet drills. 56.7801 Section 56.7801 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Rotary Jet Piercing § 56.7801 Jet drills. Jet piercing drills shall be provided with— (a) A system...

  10. 30 CFR 57.7801 - Jet drills.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Jet drills. 57.7801 Section 57.7801 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Rotary Jet Piercing-Surface Only § 57.7801 Jet drills. Jet piercing drills shall be provided with: (a)...

  11. 30 CFR 56.7801 - Jet drills.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Jet drills. 56.7801 Section 56.7801 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Rotary Jet Piercing § 56.7801 Jet drills. Jet piercing drills shall be provided with— (a) A system...

  12. 30 CFR 56.7801 - Jet drills.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Jet drills. 56.7801 Section 56.7801 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Rotary Jet Piercing § 56.7801 Jet drills. Jet piercing drills shall be provided with— (a) A system...

  13. 30 CFR 57.7801 - Jet drills.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Jet drills. 57.7801 Section 57.7801 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Rotary Jet Piercing-Surface Only § 57.7801 Jet drills. Jet piercing drills shall be provided with: (a)...

  14. 30 CFR 56.7801 - Jet drills.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Jet drills. 56.7801 Section 56.7801 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Rotary Jet Piercing § 56.7801 Jet drills. Jet piercing drills shall be provided with— (a) A system...

  15. 30 CFR 57.7801 - Jet drills.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Jet drills. 57.7801 Section 57.7801 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Rotary Jet Piercing-Surface Only § 57.7801 Jet drills. Jet piercing drills shall be provided with: (a)...

  16. 30 CFR 57.7801 - Jet drills.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Jet drills. 57.7801 Section 57.7801 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Rotary Jet Piercing-Surface Only § 57.7801 Jet drills. Jet piercing drills shall be provided with: (a)...

  17. 30 CFR 57.7801 - Jet drills.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Jet drills. 57.7801 Section 57.7801 Mineral... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Rotary Jet Piercing-Surface Only § 57.7801 Jet drills. Jet piercing drills shall be provided with: (a)...

  18. Synthesis of Silane and Silicon in a Non-equilibrium Plasma Jet

    NASA Technical Reports Server (NTRS)

    Calcote, H. F.

    1978-01-01

    The original objective of this program was to determine the feasibility of high volume, low-cost production of high purity silane or solar cell grade silicon using a non equilibrium plasma jet. The emphasis was changed near the end of the program to determine the feasibility of preparing photovoltaic amorphous silicon films directly using this method. The non equilibrium plasma jet should be further evaluated as a technique for producing high efficiency photovoltaic amorphous silicon films.

  19. Radiation-Driven Astrophysical Jets

    NASA Astrophysics Data System (ADS)

    Fukue, Jun

    2000-10-01

    Radiative winds and jets from luminous accretion disks/tori are reviewed. Among various models of astrophysical jets, plasma outflows emanating from accretion disks/tori and accelerated by the radiation pressure is the most promising one. Here explained are the roles of radiation pressure force and radiation drag force. Rise and fall of a torus model are also discussed, following its revenge. Finally, the millennium jet model, where the multistage acceleration takes place, is proposed.

  20. Starlight Nulling Technology at the Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    Martin, Stefan

    2007-01-01

    The current interests in extra-solar planet detection and space-based and ground-based interferometry for astronomical observations has led to the development of a number of nulling instrument designs at the Jet Propulsion Laboratory (JPL) and elsewhere. This paper summarizes briefly JPL's efforts in nulling interferometry to date and consists of illustrations of some key nulling activities. Basic layouts of nulling testbeds are described and key applications discussed.

  1. Case Study: Formal Inspections at the Jet Propulsion Laboratory

    NASA Technical Reports Server (NTRS)

    Kelly, J. C.; Welz, L. W.

    1993-01-01

    The Jet Propulsion Laboratory (JPL) of the California Institute of Technology is a federally funded research and development center operating under contract to the National Aeronautics and Space Administration (NASA). JPL's charter emphasizes the exploration of the solar system including observations of Earth as well as other stellar systems and extra-solar-system bodies. Within JPL, the Software Product Assurance (SPA) Section helps to ensure the operational integrity of the software within the system. SPA evaluates the operational requirements, the acceptability and readiness of all software, hardware/software interfaces, and the integrity of the completed software before its final release into the operational environment.

  2. Determination of a Definition of Solar Grade Silicon

    NASA Technical Reports Server (NTRS)

    Hill, D. E.; Gutsche, H. W.

    1975-01-01

    A definition of solar grade silicon was determined by investigating the singular and the combined effect of the impurities usually found in metallurgical grade silicon on solar cell device performance. The impurity matrix was defined by Jet Propulsion Laboratory Technical Direction Memorandum. The initial work was focussed on standardizing the solar cell process and test procedure, growing baseline crystals, growing crystals contaminated with carbon, iron, nickel, zirconium, aluminum and vanadium, solar blank preparation, and material characterization.

  3. Electromagnetic Models of Extragalactic Jets

    SciTech Connect

    Lisanti, M.; Blandford, R.; /KIPAC, Menlo Park

    2007-10-22

    Relativistic jets may be confined by large-scale, anisotropic electromagnetic stresses that balance isotropic particle pressure and disordered magnetic field. A class of axisymmetric equilibrium jet models will be described and their radiative properties outlined under simple assumptions. The partition of the jet power between electromagnetic and mechanical forms and the comoving energy density between particles and magnetic field will be discussed. Current carrying jets may be recognized by their polarization patterns. Progress and prospects for measuring this using VLBI and GLAST observations will be summarized.

  4. Photon + jets at D0

    SciTech Connect

    Sonnenschein, Lars; /RWTH Aachen U.

    2009-06-01

    Photon plus jet production has been studied by the D0 experiment in Run II of the Fermilab Tevatron Collider at a centre of mass energy of {radical}s = 1.96 TeV. Measurements of the inclusive photon, inclusive photon plus jet, photon plus heavy flavour jet cross sections and double parton interactions in photon plus three jet events are presented. They are based on integrated luminosities between 0.4 fb{sup -1} and 1.0 fb{sup -1}. The results are compared to perturbative QCD calculations in various approximations.

  5. Microplasma jet at atmospheric pressure

    SciTech Connect

    Hong, Yong Cheol; Uhm, Han Sup

    2006-11-27

    A nitrogen microplasma jet operated at atmospheric pressure was developed for treating thermally sensitive materials. For example, the plasma sources in treatment of vulnerable biological materials must operate near the room temperature at the atmospheric pressure, without any risk of arcing or electrical shock. The microplasma jet device operated by an electrical power less than 10 W exhibited a long plasma jet of about 6.5 cm with temperature near 300 K, not causing any harm to human skin. Optical emission measured at the wide range of 280-800 nm indicated various reactive species produced by the plasma jet.

  6. The formation of interstellar jets

    NASA Technical Reports Server (NTRS)

    Tenorio-Tagle, G.; Canto, J.; Rozyczka, M.

    1988-01-01

    The formation of interstellar jets by convergence of supersonic conical flows and the further dynamical evolution of these jets are investigated theoretically by means of numerical simulations. The results are presented in extensive graphs and characterized in detail. Strong radiative cooling is shown to result in jets with Mach numbers 2.5-29 propagating to lengths 50-100 times their original widths, with condensation of swept-up interstellar matter at Mach 5 or greater. The characteristics of so-called molecular outflows are well reproduced by the simulations of low-Mach-number and quasi-adiabatic jets.

  7. Fan-shaped jets above the light bridge of a sunspot driven by reconnection

    NASA Astrophysics Data System (ADS)

    Robustini, Carolina; Leenaarts, Jorrit; de la Cruz Rodriguez, Jaime; Rouppe van der Voort, Luc

    2016-05-01

    We report on a fan-shaped set of high-speed jets above a strongly magnetized light bridge (LB) of a sunspot observed in the Hα line. We study the origin, dynamics, and thermal properties of the jets using high-resolution imaging spectroscopy in Hα from the Swedish 1m Solar Telescope and data from the Solar Dynamics Observatory and Hinode. The Hα jets have lengths of 7-38 Mm, are impulsively accelerated to a speed of ~100 km s-1 close to photospheric footpoints in the LB, and exhibit a constant deceleration consistent with solar effective gravity. They are predominantly launched from one edge of the light bridge, and their footpoints appear bright in the Hα wings. Atmospheric Imaging Assembly data indicates elongated brightenings that are nearly co-spatial with the Hα jets. We interpret them as jets of transition region temperatures. The magnetic field in the light bridge has a strength of 0.8-2 kG and it is nearly horizontal. All jet properties are consistent with magnetic reconnection as the driver. Movies associated to Figs. 1 and 2 are available in electronic form at http://www.aanda.org

  8. Field of Flow About a Jet and Effect of Jets on Stability of Jet-Propelled Airplanes

    NASA Technical Reports Server (NTRS)

    Ribner, Herbert S.

    1946-01-01

    A theoretical investigation was conducted on jet-induced flow deviation. Analysis is given of flow inclination induced outside cold and hot jets and jet deflection caused by angle of attack. Applications to computation of effects of jet on longitudinal stability and trim are explained. Effect of jet temperature on flow inclination was found small when thrust coefficient is used as criterion for similitude. The average jet-induced downwash over tail plane was obtained geometrically.

  9. FAST EXTREME-ULTRAVIOLET DIMMING ASSOCIATED WITH A CORONAL JET SEEN IN MULTI-WAVELENGTH AND STEREOSCOPIC OBSERVATIONS

    SciTech Connect

    Lee, K.-S.; Moon, Y.-J.; Lee, Jin-Yi; Innes, D. E.; Shibata, K.; Park, Y.-D.

    2013-03-20

    We have investigated a coronal jet observed near the limb on 2010 June 27 by the Hinode/X-Ray Telescope (XRT), EUV Imaging Spectrograph (EIS), and Solar Optical Telescope (SOT), and by the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA), and on the disk by STEREO-A/EUVI. From EUV (AIA and EIS) and soft X-ray (XRT) images we have identified both cool and hot jets. There was a small loop eruption seen in Ca II images of the SOT before the jet eruption. We found that the hot jet preceded its associated cool jet by about 2 minutes. The cool jet showed helical-like structures during the rising period which was supported by the spectroscopic analysis of the jet's emission. The STEREO observation, which enabled us to observe the jet projected against the disk, showed dimming at 195 A along a large loop connected to the jet. We measured a propagation speed of {approx}800 km s{sup -1} for the dimming front. This is comparable to the Alfven speed in the loop computed from a magnetic field extrapolation of the photospheric field measured five days earlier by the SDO/Helioseismic and Magnetic Imager, and the loop densities obtained from EIS Fe XIV {lambda}264.79/274.20 line ratios. We interpret the dimming as indicating the presence of Alfvenic waves initiated by reconnection in the upper chromosphere.

  10. Genetics Home Reference: recurrent hydatidiform mole

    MedlinePlus

    ... Rashid Y, Sheridan E, Bonthron DT. Genetic and epigenetic analysis of recurrent hydatidiform mole. Hum Mutat. 2009 ... on PubMed Nguyen NM, Slim R. Genetics and Epigenetics of Recurrent Hydatidiform Moles: Basic Science and Genetic ...

  11. 21 CFR 880.5475 - Jet lavage.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Jet lavage. (a) Identification. A jet lavage is a device used to clean a wound by a pulsatile jet of..., and a means of propelling the fluid through the tubing, such as an electric roller pump....

  12. 21 CFR 880.5475 - Jet lavage.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Jet lavage. (a) Identification. A jet lavage is a device used to clean a wound by a pulsatile jet of..., and a means of propelling the fluid through the tubing, such as an electric roller pump....

  13. Lifted turbulent jet flames

    NASA Astrophysics Data System (ADS)

    Hammer, Jay A.

    Experiments were conducted on lifted, turbulent jet diffusion flames. An automated technique using a linear photodiode array was implemented to measure the temporal history of the liftoff height h. The measurements enabled accurate determination of the mean liftoff height [...] under a wide range of flow conditions, including several fuels, nozzle diameters, and exit velocities [...]. The results showed an approximately linear relationship between [...] and [...], with a slight dependence on Reynolds number. A strain-rate model for liftoff, based on far-field scaling of turbulent jets, provides an explanation for the linear dependence of [...] on [...]. Measurements were also made in which the nozzle fluid contained varying amounts of air, where it was found that the slope of the [...] vs. [...] line increases faster than predicted by far-field scaling of turbulent jets. The discrepancy is attributed to near-field effects.The amplitudes of the fluctuations in h were found to be of the order of the local large scale of the jet. There is a slight increase in normalized fluctuation level [...] with [...], and there is some variation of [...] with fuel type. The time scales of the fluctuations of h were found to be considerably longer than the local large-scale time of the turbulence [...]. By using fuels of different chemical times to vary [...], the measured correlation time [...] normalized by [...] was found to collapse with Richardson number [...]. Experiments in which the nozzles were oriented horizontally showed no change in [...], however. Additional experiments were conducted to investigate alternative explanations for the variation of [...] with [...]. These experiments included measuring the flame length L simultaneously with h, and measuring the visible radiation I simultaneously with h. L(t) was found to be nearly uncorrelated with h(t), dismissing the possibility that a feedback mechanism from L to h controls the fluctuations of h. Although I(t) is highly

  14. Recurrent geomagnetic storms and relativistic electron enhancements in the outer magnetosphere: ISTP coordinated measurements

    SciTech Connect

    Baker, D.N.; Li, X.; Turner, N.; Allen, J.H.; Blake, J.B.; Sheldon, R.B.; Spence, H.E.; Belian, R.D.; Reeves, G.D.; Kanekal, S.G.; Lepping, R.P.; Ogilvie, K.; Mewaldt, R.A.; Onsager, T.; Singer, H.J.

    1997-07-01

    New, coordinated measurements from the International Solar-Terrestrial Physics (ISTP) constellation of spacecraft are presented to show the causes and effects of recurrent geomagnetic activity during recent solar minimum conditions. It is found using WIND and POLAR data that even for modest geomagnetic storms, relativistic electron fluxes are strongly and rapidly enhanced within the outer radiation zone of the Earth{close_quote}s magnetosphere. Solar wind data are utilized to identify the drivers of magnetospheric acceleration processes. Yohkoh solar soft X-ray data are also used to identify the solar coronal holes that produce the high-speed solar wind streams which, in turn, cause the recurrent geomagnetic activity. It is concluded that even during extremely quiet solar conditions (sunspot minimum) there are discernible coronal holes and resultant solar wind streams which can produce intense magnetospheric particle acceleration. As a practical consequence of this Sun-Earth connection, it is noted that a long-lasting E{gt}1MeV electron event in late March 1996 appears to have contributed significantly to a major spacecraft (Anik E1) operational failure.{copyright} 1997 American Geophysical Union

  15. 14 CFR 91.1107 - Recurrent training.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Recurrent training. 91.1107 Section 91.1107... Management § 91.1107 Recurrent training. (a) Each program manager must ensure that each crewmember receives recurrent training and is adequately trained and currently proficient for the type aircraft and...

  16. 14 CFR 121.427 - Recurrent training.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Recurrent training. 121.427 Section 121.427..., FLAG, AND SUPPLEMENTAL OPERATIONS Training Program § 121.427 Recurrent training. (a) Recurrent training must ensure that each crew member or dispatcher is adequately trained and currently proficient...

  17. 14 CFR 135.351 - Recurrent training.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Recurrent training. 135.351 Section 135.351... AND ON DEMAND OPERATIONS AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT Training § 135.351 Recurrent training. (a) Each certificate holder must ensure that each crewmember receives recurrent...

  18. Endocrinology of recurrent pregnancy loss.

    PubMed

    Arredondo, Francisco; Noble, Luis S

    2006-02-01

    Following implantation, the maintenance of the pregnancy is dependent on a multitude of endocrinological events that will eventually aid in the successful growth and development of the fetus. Although the great majority of pregnant women have no pre-existing endocrine abnormalities, a small number of women can have certain endocrine alterations that could potentially lead to recurrent pregnancy losses. It is estimated that approximately 8 to 12% of all pregnancy losses are the result of endocrine factors. During the preimplantation period, the uterus undergoes important developmental changes stimulated by estrogen, and more importantly, progesterone. Progesterone is essential for the successful implantation and maintenance of pregnancy. Therefore, disorders related to inadequate progesterone secretion by the corpus luteum are likely to affect the outcome of the pregnancy. Luteal phase deficiency, hyperprolactinemia, and polycystic ovarian syndrome are some examples. Several other endocrinological abnormalities such as thyroid disease, hypoparathyroidism, uncontrolled diabetes, and decreased ovarian reserve have been implicated as etiologic factors for recurrent pregnancy loss.

  19. Training recurrent networks by Evolino.

    PubMed

    Schmidhuber, Jürgen; Wierstra, Daan; Gagliolo, Matteo; Gomez, Faustino

    2007-03-01

    In recent years, gradient-based LSTM recurrent neural networks (RNNs) solved many previously RNN-unlearnable tasks. Sometimes, however, gradient information is of little use for training RNNs, due to numerous local minima. For such cases, we present a novel method: EVOlution of systems with LINear Outputs (Evolino). Evolino evolves weights to the nonlinear, hidden nodes of RNNs while computing optimal linear mappings from hidden state to output, using methods such as pseudo-inverse-based linear regression. If we instead use quadratic programming to maximize the margin, we obtain the first evolutionary recurrent support vector machines. We show that Evolino-based LSTM can solve tasks that Echo State nets (Jaeger, 2004a) cannot and achieves higher accuracy in certain continuous function generation tasks than conventional gradient descent RNNs, including gradient-based LSTM.

  20. Clopidogrel-Induced Recurrent Polyarthritis

    PubMed Central

    Harburger, Joseph; Stallings, Gary; Agrawal, Nikhil; Garg, Jalaj

    2013-01-01

    Clopidogrel is an oral thienopyridine and together with aspirin is a component of dual antiplatelet therapy for the prevention of stent thrombosis after intracoronary stent placement. The common adverse effects from its use are an increased risk of bleeding, neutropenia, and rash. Arthralgia and backache are also known to occur with its use. There have been case reports linking arthritis with the use of clopidogrel. We describe the case of a 64-year-old man who reported symptoms of fever and joint pains following initiation of therapy with clopidogrel. Acute-phase reactants were elevated. Laboratory and radiologic testing were unremarkable. Incidentally, he reported experiencing a similar arthritis after he received a loading dose of clopidogrel prior to a diagnostic coronary angiography in the past. The symptoms improved dramatically on discontinuation of clopidogrel. There was no recurrence of symptoms with prasugrel. This describes possibly the second incidence of recurrent arthritis with clopidogrel therapy. PMID:26425581

  1. Recurrent Dislocation of the Patella

    PubMed Central

    Benítez, Gustavo

    2015-01-01

    Purpose: To evaluate results of medial patellofemoral ligament (MPFL) reconstruction associated with lateral release and advancement of vastus medialis in recurrent dislocation of the patella. Methods: We retrospectively evaluated 11 patients with a mean follow-up of 19 months. Mean age was 23, mainly women. We did MPFL reconstruction with semitendinosus or gracilis tendon depending on BMI, associated with advancement of vastus medialis and lateral release. Results: Mean Kujala score improved from 46,54 pts. preoperative to 88,36 postoperative. Our main complication was 1 patient with rigid knee, who required movilization under anesthesia and arthroscopic arthrolisis to improve her outcome. Conclusion: The combination of this techniques are a good alternative to treat patients with recurrent patella disclocation, with good short and mid-term results. Biomechanic intra and postop complications of MPFL reconstruction are related to patellar fixation, anatomic positioning of femoral tunnel and knee position of the graft fixation.

  2. Training recurrent networks by Evolino.

    PubMed

    Schmidhuber, Jürgen; Wierstra, Daan; Gagliolo, Matteo; Gomez, Faustino

    2007-03-01

    In recent years, gradient-based LSTM recurrent neural networks (RNNs) solved many previously RNN-unlearnable tasks. Sometimes, however, gradient information is of little use for training RNNs, due to numerous local minima. For such cases, we present a novel method: EVOlution of systems with LINear Outputs (Evolino). Evolino evolves weights to the nonlinear, hidden nodes of RNNs while computing optimal linear mappings from hidden state to output, using methods such as pseudo-inverse-based linear regression. If we instead use quadratic programming to maximize the margin, we obtain the first evolutionary recurrent support vector machines. We show that Evolino-based LSTM can solve tasks that Echo State nets (Jaeger, 2004a) cannot and achieves higher accuracy in certain continuous function generation tasks than conventional gradient descent RNNs, including gradient-based LSTM. PMID:17298232

  3. Ink Jet Printing for Silicon Photovoltaics: Cooperative Research and Development Final Report, CRADA Number CRD-04-00139

    SciTech Connect

    Ginley, D. S.

    2010-08-01

    The purpose of this CRADA was to combine the strengths of NREL and Evergreen Solar in the area of ink jet printing to develop a new manufacturing technology necessary to produce Si solar cells based on ribbon technology comparable to or exceeding current technologies.

  4. Jet charge at the LHC.

    PubMed

    Krohn, David; Schwartz, Matthew D; Lin, Tongyan; Waalewijn, Wouter J

    2013-05-24

    Knowing the charge of the parton initiating a light-quark jet could be extremely useful both for testing aspects of the standard model and for characterizing potential beyond-the-standard-model signals. We show that despite the complications of hadronization and out-of-jet radiation such as pileup, a weighted sum of the charges of a jet's constituents can be used at the LHC to distinguish among jets with different charges. Potential applications include measuring electroweak quantum numbers of hadronically decaying resonances or supersymmetric particles, as well as standard model tests, such as jet charge in dijet events or in hadronically decaying W bosons in tt[over ¯] events. We develop a systematically improvable method to calculate moments of these charge distributions by combining multihadron fragmentation functions with perturbative jet functions and pertubative evolution equations. We show that the dependence on energy and jet size for the average and width of the jet charge can be calculated despite the large experimental uncertainty on fragmentation functions. These calculations can provide a validation tool for data independent of Monte Carlo fragmentation models.

  5. Magnetic Field Topology in Jets

    NASA Technical Reports Server (NTRS)

    Gardiner, T. A.; Frank, A.

    2000-01-01

    We present results on the magnetic field topology in a pulsed radiative. jet. For initially helical magnetic fields and periodic velocity variations, we find that the magnetic field alternates along the, length of the jet from toroidally dominated in the knots to possibly poloidally dominated in the intervening regions.

  6. Nonlinear Dynamics in Viscoelastic Jets

    NASA Astrophysics Data System (ADS)

    Majmudar, Trushant; Varagnat, Matthieu; McKinley, Gareth

    2008-11-01

    Instabilities in free surface continuous jets of non-Newtonian fluids, although relevant for many industrial processes, remain poorly understood in terms of fundamental fluid dynamics. Inviscid, and viscous Newtonian jets have been studied in considerable detail, both theoretically and experimentally. Instability in viscous jets leads to regular periodic coiling of the jet, which exhibits a non-trivial frequency dependence with the height of the fall. Here we present a systematic study of the effect of viscoelasticity on the dynamics of continuous jets of worm-like micellar surfactant solutions of varying viscosities and elasticities. We observe complex nonlinear spatio-temporal dynamics of the jet, and uncover a transition from periodic to quasi-periodic to a multi-frequency, broad-spectrum dynamics. Beyond this regime, the jet dynamics smoothly crosses over to exhibit the ``leaping shampoo'' or the Kaye effect. We examine different dynamical regimes in terms of scaling variables, which depend on the geometry (dimensionless height), kinematics (dimensionless flow rate), and the fluid properties (elasto-gravity number) and present a regime map of the dynamics of the jet in terms of these dimensionless variables.

  7. Nonlinear Dynamics in Viscoelastic Jets

    NASA Astrophysics Data System (ADS)

    Majmudar, Trushant; Varagnat, Matthieu; McKinley, Gareth

    2009-03-01

    Instabilities in free surface continuous jets of non-Newtonian fluids, although relevant for many industrial processes, remain poorly understood in terms of fundamental fluid dynamics. Inviscid, and viscous Newtonian jets have been studied in considerable detail, both theoretically and experimentally. Instability in viscous jets leads to regular periodic coiling of the jet, which exhibits a non-trivial frequency dependence with the height of the fall. Here we present a systematic study of the effect of viscoelasticity on the dynamics of continuous jets of worm-like micellar surfactant solutions of varying viscosities and elasticities. We observe complex nonlinear spatio-temporal dynamics of the jet, and uncover a transition from periodic to quasi-periodic to a multi-frequency, broad-spectrum dynamics. Beyond this regime, the jet dynamics smoothly crosses over to exhibit the ``leaping shampoo'' or the Kaye effect. We examine different dynamical regimes in terms of scaling variables, which depend on the geometry (dimensionless height), kinematics (dimensionless flow rate), and the fluid properties (elasto-gravity number) and present a regime map of the dynamics of the jet in terms of these dimensionless variables.

  8. OPENING ANGLES OF COLLAPSAR JETS

    SciTech Connect

    Mizuta, Akira; Ioka, Kunihito

    2013-11-10

    We investigate the jet propagation and breakout from the stellar progenitor for gamma-ray burst (GRB) collapsars by performing two-dimensional relativistic hydrodynamic simulations and analytical modeling. We find that the jet opening angle is given by θ{sub j} ∼ 1/5Γ{sub 0} and infer the initial Lorentz factor of the jet at the central engine, Γ{sub 0}, is a few for existing observations of θ{sub j}. The jet keeps the Lorentz factor low inside the star by converging cylindrically via collimation shocks under the cocoon pressure and accelerates at jet breakout before the free expansion to a hollow-cone structure. In this new picture, the GRB duration is determined by the sound crossing time of the cocoon, after which the opening angle widens, reducing the apparent luminosity. Some bursts violating the maximum opening angle θ{sub j,{sub max}} ∼ 1/5 ∼ 12° imply the existence of a baryon-rich sheath or a long-acting jet. We can explain the slopes in both Amati and Yonetoku spectral relations using an off-centered photosphere model, if we make only one assumption that the total jet luminosity is proportional to the initial Lorentz factor of the jet. We also numerically calibrate the pre-breakout model (Bromberg et al.) for later use.

  9. Gluon jets from heavy paraquarkonium

    SciTech Connect

    Kamal, A.N.; Kodaira, J.; Muta, T.

    1982-02-01

    The GGG and qq-barG jets in the decay of very heavy paraquarkonia are analyzed in perturbative quantum chromodynamics. The thrust distributions are calculated and the result is compared with the thrust distributions in the orthoquarkonium decay and in e/sup +/e/sup -/..-->..qq-barG jets.

  10. Dense Hypervelocity Plasma Jets

    NASA Astrophysics Data System (ADS)

    Case, Andrew; Witherspoon, F. Douglas; Messer, Sarah; Bomgardner, Richard; Phillips, Michael; van Doren, David; Elton, Raymond; Uzun-Kaymak, Ilker

    2007-11-01

    We are developing high velocity dense plasma jets for fusion and HEDP applications. Traditional coaxial plasma accelerators suffer from the blow-by instability which limits the mass accelerated to high velocity. In the current design blow-by is delayed by a combination of electrode shaping and use of a tailored plasma armature created by injection of a high density plasma at a few eV generated by arrays of capillary discharges or sparkgaps. Experimental data will be presented for a complete 32 injector gun system built for driving rotation in the Maryland MCX experiment, including data on penetration of the plasma jet through a magnetic field. We present spectroscopic measurements of plasma velocity, temperature, and density, as well as total momentum measured using a ballistic pendulum. Measurements are in agreement with each other and with time of flight data from photodiodes and a multichannel PMT. Plasma density is above 10^15 cm-3, velocities range up to about 100 km/s. Preliminary results from a quadrature heterodyne HeNe interferometer are consistent with these results.

  11. [Belated recurrence of anaphylactic reaction].

    PubMed

    Schelske, Christa

    2012-01-30

    Anaphylaxis is a serious allergic reaction, and the incidence is increasing. A biphasic anaphylactic reaction with recurrent symptoms after a long period without any symptoms is described. Guidelines recommend adrenalin as first line treatment, but some patients are only treated with glucocorticoids and antihistamines. The importance of correct treatment with adrenalin, instructions in correct self administration with adrenalin after admission, and examination for allergies is underlined.

  12. Recurrent Benign Salivary Gland Neoplasms.

    PubMed

    Witt, Robert Lee; Nicolai, Piero

    2016-01-01

    The most important causes of recurrence of benign pleomorphic adenoma are enucleation with intraoperative spillage and incomplete tumor excision in association with characteristic histologic findings for the lesion (incomplete pseudocapsule and the presence of pseudopodia). Most recurrent pleomorphic adenomas (RPAs) are multinodular. MRI is the imaging method of choice for their assessment. Nerve integrity monitoring may reduce morbidity of RPA surgery. Although treatment of RPA must be individualized, total parotidectomy is generally recommended given the multicentricity of the lesions. However, surgery alone may be inadequate for controlling RPA over the long term. There is growing evidence from retrospective series that postoperative radiotherapy results in significantly better local control. A high percentage of RPAs are incurable. All patients should therefore be informed about the possibility of needing multiple treatment procedures, with possible impairment of facial nerve function, and radiation therapy for RPA. Reappearance of Warthin tumor is a metachronous occurrence of a new focus or residual incomplete excision of all primary multicentric foci of Warthin tumor. Selected cases can be observed. Conservative surgical management can include partial superficial parotidectomy or extracapsular dissection. Not uncommonly, other major and minor salivary gland neoplasms, including myoepithelioma, basal cell adenoma, oncocytoma, canalicular adenoma, cystadenoma, and ductal papilloma, follow an indolent course after surgical resection, with rare cases of recurrence.

  13. Sub-0.1'' optical imaging of the Z CMa jets with SPHERE/ZIMPOL

    NASA Astrophysics Data System (ADS)

    Antoniucci, S.; Podio, L.; Nisini, B.; Bacciotti, F.; Lagadec, E.; Sissa, E.; La Camera, A.; Giannini, T.; Schmid, H. M.; Gratton, R.; Turatto, M.; Desidera, S.; Bonnefoy, M.; Chauvin, G.; Dougados, C.; Bazzon, A.; Thalmann, C.; Langlois, M.

    2016-09-01

    Context. Crucial information on the mass accretion-ejection connection in young stars can be obtained from high spatial resolution images of jets in sources with known recurrent accretion outbursts. Aims: Using the VLT/SPHERE ZIMPOL instrument, we observed the young binary Z CMa that is composed of a Herbig Be star and a FUor object, both driving a jet. We aim to analyse the structure of the two jets, their relation with the properties of the driving sources, and their connection with previous accretion events observed in this target. Methods: We obtained optical images in the Hα and [O i] 6300 Å lines at the unprecedented angular resolution of ~0.03 arcsec, on which we have performed both continuum subtraction and deconvolution, thereby deriving results that are consistent with each other. Results: Our images reveal extended emission from both sources: a fairly compact and poorly collimated emission SW of the Herbig component and an extended collimated and precessing jet from the FUor component. The compact emission from the Herbig star is compatible with a wide-angle wind and is possibly connected to the recent outburst events shown by this component. The FUor jet is traced down to 70 mas (80 AU) from the source and is highly collimated with a width of 26-48 AU at distances 100-200 AU, which is similar to the width of jets from T Tauri stars. This strongly suggests that the same magneto-centrifugal jet-launching mechanism also operates in FUors. The observed jet wiggle can be modelled as originating from an orbital motion with a period of 4.2 yr around an unseen companion with mass between 0.48 and 1 M⊙. The jet mass loss rate Ṁjet was derived from the [O i] luminosity and comprises of between 1 × 10-8 and 1 × 10-6M⊙ yr-1. This is the first direct Ṁjet measurement from a jet in a FUor. If we assume previous mass accretion rate estimates obtained through modelling of the accretion disk, the derived range of Ṁjet would imply a very low mass

  14. Multiwavelength study of 20 jets that emanate from the periphery of active regions

    NASA Astrophysics Data System (ADS)

    Mulay, Sargam M.; Tripathi, Durgesh; Del Zanna, Giulio; Mason, Helen

    2016-05-01

    Aims: We present a multiwavelength analysis of 20 EUV jets which occurred at the periphery of active regions close to sunspots. We discuss the physical parameters of the jets and their relation with other phenomena such as Hα surges, nonthermal type-III radio bursts and hard X-ray (HXR) emission. Methods: These jets were observed between August 2010 and June 2013 by the Atmospheric Imaging Assembly (AIA) instrument that is onboard the Solar Dynamic Observatory (SDO). We selected events that were observed on the solar disk within +/-60° latitude. Using AIA wavelength channels that are sensitive to coronal temperatures, we studied the temperature distribution in the jets using the line of sight (LOS) differential emission measure (DEM) technique. We also investigated the role of the photospheric magnetic field using the LOS magnetogram data from the Helioseismic and Magnetic Imager (HMI) onboard SDO. Results: It has been observed that most of the jets originated from the western periphery of active regions. Their lifetimes range from 5 to 39 min with an average of 18 min and their velocities range from 87 to 532 km s-1 with an average of 271 km s-1. All the jets are co-temporally associated with Hα surges. Most of the jets are co-temporal with nonthermal type-III radio bursts observed by the Wind/WAVES spacecraft in the frequency range from 20 kHz to 13 MHz. We confirm the source region of these bursts using the potential field source surface (PFSS) technique. Using Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) observations, we found that half of the jets produced HXR emission and they often shared the same source region as the HXR emission (6-12 keV). Ten out of 20 events showed that the jets originated in a region of flux cancellation and six jets in a region of flux emergence. Four events showed flux emergence and then cancellation during the jet evolution. DEM analyses showed that for most of the spires of the jets, the DEM peaked at around log

  15. Magnetically driven jets and winds

    NASA Technical Reports Server (NTRS)

    Lovelace, R. V. E.; Berk, H. L.; Contopoulos, J.

    1991-01-01

    Four equations for the origin and propagation of nonrelativistic jets and winds are derived from the basic conservation laws of ideal MHD. The axial current density is negative in the vicinity of the axis and positive at larger radii; there is no net current because this is energetically favored. The magnetic field is essential for the jet solutions in that the zz-component of the magnetic stress acts, in opposition to gravity, to drive matter through the slow magnetosonic critical point. For a representative self-consistent disk/jet solution relevant to a protostellar system, the reaction of the accreted mass expelled in the jets is 0.1, the ratio of the power carried by the jets to the disk luminosity is 0.66, and the ratio of the boundary layer to disk luminosities is less than about 0.13. The star's rotation rate decreases with time even for rotation rates much less than the breakup rate.

  16. How often do jets of geoeffective size hit the dayside magnetopause?

    NASA Astrophysics Data System (ADS)

    Plaschke, Ferdinand; Hietala, Heli

    2016-04-01

    Magnetosheath high-speed jets are characterized by a larger dynamic pressure with respect to the surrounding plasma. In the subsolar sheath, they occur much more frequently under quasi-radial, i. e., low interplanetary magnetic field (IMF) cone angle conditions. Jets transport mass, momentum, and energy from the bow shock to the magnetopause in a concentrated manner. It has been shown that these jets can cause large amplitude boundary indentations, if they impinge on the dayside magnetopause, and trigger magnetopause surface waves and inner-magnetospheric ULF waves. These waves may then be able, e. g., to modify the drift paths of radiation belt electrons and/or to remove electrons from the radiation belts by magnetopause shadowing. Clearly, the severity of the downstream consequences of impacting jets scales with their size. An important question is: How often do jets of geoeffective size hit the dayside magnetopause? We are able to address this question, for the first time, by inferring scale size distributions of magnetosheath high-speed jets from THEMIS multi-spacecraft observations. We find that a reference area of 100 RE2 (Earth radii squared) of the subsolar magnetopause should be hit almost 3 times per hour, in general, by jets with cross-sectional diameters of 2 RE or larger. Under low IMF cone angle conditions (less than 30°) that rate increases to 9 times per hour, which emphasizes the significance of the magnetosheath jet phenomenon within the framework of solar wind-magnetosphere-ionosphere coupling.

  17. Impact jetting as the origin of chondrules.

    PubMed

    Johnson, Brandon C; Minton, David A; Melosh, H J; Zuber, Maria T

    2015-01-15

    Chondrules are the millimetre-scale, previously molten, spherules found in most meteorites. Before chondrules formed, large differentiating planetesimals had already accreted. Volatile-rich olivine reveals that chondrules formed in extremely solid-rich environments, more like impact plumes than the solar nebula. The unique chondrules in CB chondrites probably formed in a vapour-melt plume produced by a hypervelocity impact with an impact velocity greater than 10 kilometres per second. An acceptable formation model for the overwhelming majority of chondrules, however, has not been established. Here we report that impacts can produce enough chondrules during the first five million years of planetary accretion to explain their observed abundance. Building on a previous study of impact jetting, we simulate protoplanetary impacts, finding that material is melted and ejected at high speed when the impact velocity exceeds 2.5 kilometres per second. Using a Monte Carlo accretion code, we estimate the location, timing, sizes, and velocities of chondrule-forming impacts. Ejecta size estimates indicate that jetted melt will form millimetre-scale droplets. Our radiative transfer models show that these droplets experience the expected cooling rates of ten to a thousand kelvin per hour. An impact origin for chondrules implies that meteorites are a byproduct of planet formation rather than leftover building material.

  18. Impact jetting as the origin of chondrules.

    PubMed

    Johnson, Brandon C; Minton, David A; Melosh, H J; Zuber, Maria T

    2015-01-15

    Chondrules are the millimetre-scale, previously molten, spherules found in most meteorites. Before chondrules formed, large differentiating planetesimals had already accreted. Volatile-rich olivine reveals that chondrules formed in extremely solid-rich environments, more like impact plumes than the solar nebula. The unique chondrules in CB chondrites probably formed in a vapour-melt plume produced by a hypervelocity impact with an impact velocity greater than 10 kilometres per second. An acceptable formation model for the overwhelming majority of chondrules, however, has not been established. Here we report that impacts can produce enough chondrules during the first five million years of planetary accretion to explain their observed abundance. Building on a previous study of impact jetting, we simulate protoplanetary impacts, finding that material is melted and ejected at high speed when the impact velocity exceeds 2.5 kilometres per second. Using a Monte Carlo accretion code, we estimate the location, timing, sizes, and velocities of chondrule-forming impacts. Ejecta size estimates indicate that jetted melt will form millimetre-scale droplets. Our radiative transfer models show that these droplets experience the expected cooling rates of ten to a thousand kelvin per hour. An impact origin for chondrules implies that meteorites are a byproduct of planet formation rather than leftover building material. PMID:25592538

  19. Erlotinib and Temozolomide in Treating Young Patients With Recurrent or Refractory Solid Tumors

    ClinicalTrials.gov

    2013-06-04

    Previously Treated Childhood Rhabdomyosarcoma; Recurrent Childhood Brain Tumor; Recurrent Childhood Cerebellar Astrocytoma; Recurrent Childhood Cerebral Astrocytoma; Recurrent Childhood Ependymoma; Recurrent Childhood Malignant Germ Cell Tumor; Recurrent Childhood Medulloblastoma; Recurrent Childhood Rhabdomyosarcoma; Recurrent Childhood Soft Tissue Sarcoma; Recurrent Childhood Supratentorial Primitive Neuroectodermal Tumor; Recurrent Neuroblastoma; Recurrent Osteosarcoma

  20. Stress Reduction in Improving Quality of Life in Patients With Recurrent Gynecologic or Breast Cancer

    ClinicalTrials.gov

    2015-10-08

    Anxiety Disorder; Depression; Fatigue; Leydig Cell Tumor; Ovarian Sarcoma; Ovarian Stromal Cancer; Pain; Peritoneal Carcinomatosis; Pseudomyxoma Peritonei; Recurrent Breast Cancer; Recurrent Cervical Cancer; Recurrent Endometrial Carcinoma; Recurrent Fallopian Tube Cancer; Recurrent Gestational Trophoblastic Tumor; Recurrent Ovarian Epithelial Cancer; Recurrent Ovarian Germ Cell Tumor; Recurrent Primary Peritoneal Cavity Cancer; Recurrent Uterine Sarcoma; Recurrent Vaginal Cancer; Recurrent Vulvar Cancer

  1. Collective Dynamics of Oscillator Networks: Why do we suffer from heavy jet lag?

    NASA Astrophysics Data System (ADS)

    Kori, Hiroshi

    The circadian rhythm of the entire body in mammals is orchestrated by a small tissue in the brain called the suprachiamatic nucleus (SCN). The SCN consists of a population of neurons, each of which exhibit circadian (i.e., approximately 24 h) gene expression. Neurons form a complex network and interact with each other using various types of neurotransmitters. The rhythmic gene expressions of individual cells in the SCN synchronize through such interaction. Jet-lag symptoms arise from temporal mismatch between the internal circadian clock orchestrated by the SCN and external solar time. It may take about one week or even longer to recover from jet lag after a long-distance trip. We recently found that recovery from jet lag is considerably accelerated in the knocked-out (KO) mice lacking the receptors of a certain neurotransmitter in the SCN. Importantly, all other properties of mice including sleep-awake rhythms and breeding seem to be intact. Only the response to the jet lag changes. It was also found that after a few days of jet lag, cells in the SCN desynchronize in the wild type (WT) mice, whereas they do not in KO mice. This desynchrony might be a main reason for heavy jet lag symptoms. To understand the mechanism underlying jet lag, we propose a simple model of the SCN, which is a network of phase oscillators. Despite its simplicity, this model can reproduce important dynamical properties of the SCN. For example, this model reproduces the desynchrony of oscillators after jet lag. Moreover, when intercellular interaction is weaker, this desynchrony is suppressed and the recover from jet lag is considerably accelerated. Our mathematical study provides a deeper understanding of jet lag and an idea how to circumvent heavy jet lag symptoms

  2. Obatoclax and Bortezomib in Treating Patients With Aggressive Relapsed or Recurrent Non-Hodgkin Lymphoma

    ClinicalTrials.gov

    2015-12-03

    Adult Non-Hodgkin Lymphoma; Recurrent Adult Diffuse Large Cell Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Small Lymphocytic Lymphoma

  3. CIRCULAR RIBBON FLARES AND HOMOLOGOUS JETS

    SciTech Connect

    Wang Haimin; Liu Chang

    2012-12-01

    Solar flare emissions in the chromosphere often appear as elongated ribbons on both sides of the magnetic polarity inversion line (PIL), which has been regarded as evidence of a typical configuration of magnetic reconnection. However, flares having a circular ribbon have rarely been reported, although it is expected in the fan-spine magnetic topology involving reconnection at a three-dimensional (3D) coronal null point. We present five circular ribbon flares with associated surges, using high-resolution and high-cadence H{alpha} blue wing observations obtained from the recently digitized films of Big Bear Solar Observatory. In all the events, a central parasitic magnetic field is encompassed by the opposite polarity, forming a circular PIL traced by filament material. Consequently, a flare kernel at the center is surrounded by a circular flare ribbon. The four homologous jet-related flares on 1991 March 17 and 18 are of particular interest, as (1) the circular ribbons brighten sequentially, with cospatial surges, rather than simultaneously, (2) the central flare kernels show an intriguing 'round-trip' motion and become elongated, and (3) remote brightenings occur at a region with the same magnetic polarity as the central parasitic field and are co-temporal with a separate phase of flare emissions. In another flare on 1991 February 25, the circular flare emission and surge activity occur successively, and the event could be associated with magnetic flux cancellation across the circular PIL. We discuss the implications of these observations combining circular flare ribbons, homologous jets, and remote brightenings for understanding the dynamics of 3D magnetic restructuring.

  4. Collimation and Stability of Three Dimensional Jets

    NASA Astrophysics Data System (ADS)

    Hardee, P. E.; Clarke, D. A.; Howell, D. A.

    1993-12-01

    Three-dimensional numerical simulations of cylindrical jets established in equilibrium with a surrounding uniform medium have been performed. Large scale structures such as helical twisting of the jet, elliptical distortion and bifurcation of the jet, and triangular distortion and trifurcation of the jet have been seen in the simulations. The grid resolution has been sufficient to allow the development of structures on smaller scales and has revealed higher order distortions of the jet surface and complex structure internal to the jet. However, smaller scale surface distortion and internal jet structure do not significantly modify the large scale dynamics. It is the large scale surface distortions and accompanying filamentation that dominate the jet dynamics. Decollimation occurs as the jet bifurcates or trifurcates. Jets with density less than the immediately surrounding medium rapidly decollimate and expand as the jet filaments into multiple streams leading to shock heating and mass entrainment. The resulting morphology resembles a turbulent plume and might be relevant to some FRI type radio sources. Jet densities higher than the immediately surrounding medium are required to produce FRII type radio source jet morphology and protostellar jet morphology. Thus, while jets may be denser or lighter than the external medium through which they propagate, it is the conditions in the cocoon or lobe around the jet that governs the dynamics far behind the jet front. This work was supported by NSF grant AST-8919180, EPSCoR grant EHR-9108761 and NSF-REU grant AST-9300413.

  5. Inclusive jet cross sections and jet shapes at CDF

    SciTech Connect

    Wainer, N.

    1991-09-01

    The inclusive jet cross section and jet shapes at {radical}s = 1.8 TeV have been measured by CDF at the Fermilab Tevatron Collider. results are compared to recent next-to-leading order QCD calculations, which predict variation of the cross section with cone size, as well as variation of the jet shape with energy. A lower limit on the parameter {Lambda}{sub c}, which characterize a contact interaction associated with quark sub-structure is determined to be 1400 GeV at the 95% confidence level. 3 refs., 4 figs.

  6. Rotary-Jet Thrust Augmentor with Jet-Flapped Blades.

    NASA Astrophysics Data System (ADS)

    Cordier, Stephane Jean

    The concepts and the mechanisms of thrust augmentation are analyzed. The theoretical performance of different types of thrust augmentors is discussed with an emphasis on the Rotary-Jet ejector. The application of thrust augmentors to STOVL aircrafts and the merits of the ejector in this application are discussed where the theoretical performance of the Rotary-Jet is shown to be particularly attractive. A review of previous steady-flow and Rotary-Jet ejector experimental data shows equivalent performance levels. Recent experimental work on the Rotary-Jet is analyzed and several factors adversely affecting performance are identified and discussed. To address these problems a new configuration is proposed where the rotor is fitted with blades, allowing better control of the primary/secondary interaction. The jet sheet exiting at the trailing edge of the foil forms a jet flap. A two-dimensional analysis of the aerodynamics around a jet-flapped airfoil is performed for the first time using a fluid finite element code. Whereas in previous models the presence of the pressure gradient across the jet sheet is an assumption, its presence is predicted by the present method. Results of a test run show good agreement with experimental results by others. This method is applied to the geometry of blade model #10. An original three-dimensional model of the self -driven, jet-flapped bladed rotor is presented which, given set geometrical parameters and operating conditions, solves at each section for the jet and blade angle and calculates the rotor thrust augmentation. The results of parametric runs identify favorable design trends which are applied to the design of prototype test models. An experimental test program has been performed. Flow visualization and local flow velocity and pressure measurements were used to identify favorable jet sheet characteristics. The presence of losses in the spinning rotor are evidenced. Seven blade models were tested in a parametric study. Rotor

  7. Multiple jet study data correlations. [data correlation for jet mixing flow of air jets

    NASA Technical Reports Server (NTRS)

    Walker, R. E.; Eberhardt, R. G.

    1975-01-01

    Correlations are presented which allow determination of penetration and mixing of multiple cold air jets injected normal to a ducted subsonic heated primary air stream. Correlations were obtained over jet-to-primary stream momentum flux ratios of 6 to 60 for locations from 1 to 30 jet diameters downstream of the injection plane. The range of geometric and operating variables makes the correlations relevant to gas turbine combustors. Correlations were obtained for the mixing efficiency between jets and primary stream using an energy exchange parameter. Also jet centerplane velocity and temperature trajectories were correlated and centerplane dimensionless temperature distributions defined. An assumption of a Gaussian vertical temperature distribution at all stations is shown to result in a reasonable temperature field model. Data are presented which allow comparison of predicted and measured values over the range of conditions specified above.

  8. Classification and Physical parameters EUV coronal jets with STEREO/SECCHI.

    NASA Astrophysics Data System (ADS)

    Nistico, Giuseppe; Bothmer, Volker; Patsourakos, Spiro; Zimbardo, Gaetano

    In this work we present observations of EUV coronal jets, detected with the SECCHI (Sun Earth Connection Coronal and Heliospheric Investigation) imaging suites of the two STEREO spacecraft. Starting from catalogues of polar and equatorial coronal hole jets (Nistico' et al., Solar Phys., 259, 87, 2009; Ann. Geophys. in press), identified from simultaneous EUV and white-light coronagraph observations, taken during the time period March 2007 to April 2008 when solar activity was at minimum, we perfom a detailed study of some events. A basic char-acterisation of the magnetic morphology and identification of the presence of helical structure were established with respect to recently proposed models for their origin and temporal evo-lution. A classification of the events with respect to previous jet studies shows that amongst the 79 events, identified into polar coronal holes, there were 37 Eiffel tower -type jet events commonly interpreted as a small-scale ( 35 arcsec) magnetic bipole reconnecting with the ambi-ent unipolar open coronal magnetic fields at its looptops, 12 lambda-type jet events commonly interpreted as reconnection with the ambient field happening at the bipoles footpoints. Five events were termed micro-CME type jet events because they resembled classical three-part structured coronal mass ejections (CMEs) but on much smaller scales. The remainig 25 cases could not be uniquely classified. Thirty-one of the total number of events exhibited a helical magnetic field structure, indicative for a torsional motion of the jet around its axis of propaga-tion. The jet events are found to be also present in equatorial coronal holes. We also present the 3-D reconstruction, temperature, velocity, and density measurements of a number of jets during their evolution.

  9. Micromachined chemical jet dispenser

    DOEpatents

    Swierkowski, S.P.

    1999-03-02

    A dispenser is disclosed for chemical fluid samples that need to be precisely ejected in size, location, and time. The dispenser is a micro-electro-mechanical systems (MEMS) device fabricated in a bonded silicon wafer and a substrate, such as glass or silicon, using integrated circuit-like fabrication technology which is amenable to mass production. The dispensing is actuated by ultrasonic transducers that efficiently produce a pressure wave in capillaries that contain the chemicals. The 10-200 {micro}m diameter capillaries can be arranged to focus in one spot or may be arranged in a larger dense linear array (ca. 200 capillaries). The dispenser is analogous to some ink jet print heads for computer printers but the fluid is not heated, thus not damaging certain samples. Major applications are in biological sample handling and in analytical chemical procedures such as environmental sample analysis, medical lab analysis, or molecular biology chemistry experiments. 4 figs.

  10. Micromachined chemical jet dispenser

    DOEpatents

    Swierkowski, Steve P.

    1999-03-02

    A dispenser for chemical fluid samples that need to be precisely ejected in size, location, and time. The dispenser is a micro-electro-mechanical systems (MEMS) device fabricated in a bonded silicon wafer and a substrate, such as glass or silicon, using integrated circuit-like fabrication technology which is amenable to mass production. The dispensing is actuated by ultrasonic transducers that efficiently produce a pressure wave in capillaries that contain the chemicals. The 10-200 .mu.m diameter capillaries can be arranged to focus in one spot or may be arranged in a larger dense linear array (.about.200 capillaries). The dispenser is analogous to some ink jet print heads for computer printers but the fluid is not heated, thus not damaging certain samples. Major applications are in biological sample handling and in analytical chemical procedures such as environmental sample analysis, medical lab analysis, or molecular biology chemistry experiments.

  11. Commercial jet transport crashworthiness

    NASA Technical Reports Server (NTRS)

    Widmayer, E.; Brende, O. B.

    1982-01-01

    The results of a study to identify areas of research and approaches that may result in improved occupant survivability and crashworthiness of transport aircraft are given. The study defines areas of structural crashworthiness for transport aircraft which might form the basis for a research program. A 10-year research and development program to improve the structural impact resistance of general aviation and commercial jet transport aircraft is planned. As part of this program parallel studies were conducted to review the accident experience of commercial transport aircraft, assess the accident performance of structural components and the status of impact resistance technology, and recommend areas of research and development for that 10-year plan. The results of that study are also given.

  12. Water cooled steam jet

    DOEpatents

    Wagner, Jr., Edward P.

    1999-01-01

    A water cooled steam jet for transferring fluid and preventing vapor lock, or vaporization of the fluid being transferred, has a venturi nozzle and a cooling jacket. The venturi nozzle produces a high velocity flow which creates a vacuum to draw fluid from a source of fluid. The venturi nozzle has a converging section connected to a source of steam, a diffuser section attached to an outlet and a throat portion disposed therebetween. The cooling jacket surrounds the venturi nozzle and a suction tube through which the fluid is being drawn into the venturi nozzle. Coolant flows through the cooling jacket. The cooling jacket dissipates heat generated by the venturi nozzle to prevent vapor lock.

  13. Upgrading jet turbine technology

    SciTech Connect

    Valenti, M.

    1995-12-01

    This article describes a joint government/industry program that is developing a new breed of turbine components, including bearings, blades, and seals, to double the propulsion capacity of both military and commercial jet engines. Although the tensions of the Cold War have receded with the demise of the Soviet Union, the US continually seeks to improve the operational readiness of its weapon systems. The challenge facing the Pentagon today is maintaining US technological superiority in the face of post-Cold War budget cuts. A model program for doing so is the joint government/industry Integrated High Performance Turbine Engine Technology program, or IHPTET (pronounced ip-tet). The goal of the IHPTET program is to develop technologies that will double the propulsion capability of military turbine engines by the turn of the century.

  14. Water cooled steam jet

    DOEpatents

    Wagner, E.P. Jr.

    1999-01-12

    A water cooled steam jet for transferring fluid and preventing vapor lock, or vaporization of the fluid being transferred, has a venturi nozzle and a cooling jacket. The venturi nozzle produces a high velocity flow which creates a vacuum to draw fluid from a source of fluid. The venturi nozzle has a converging section connected to a source of steam, a diffuser section attached to an outlet and a throat portion disposed there between. The cooling jacket surrounds the venturi nozzle and a suction tube through which the fluid is being drawn into the venturi nozzle. Coolant flows through the cooling jacket. The cooling jacket dissipates heat generated by the venturi nozzle to prevent vapor lock. 2 figs.

  15. SOLAR SOURCES OF {sup 3}He-RICH SOLAR ENERGETIC PARTICLE EVENTS IN SOLAR CYCLE 24

    SciTech Connect

    Nitta, Nariaki V.; Wang, Linghua; Cohen, Christina M. S.; Wiedenbeck, Mark E. E-mail: glenn.mason@jhuapl.edu E-mail: cohen@srl.caltech.edu

    2015-06-20

    Using high-cadence EUV images obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory, we investigate the solar sources of 26 {sup 3}He-rich solar energetic particle events at ≲1 MeV nucleon{sup −1} that were well-observed by the Advanced Composition Explorer during solar cycle 24. Identification of the solar sources is based on the association of {sup 3}He-rich events with type III radio bursts and electron events as observed by Wind. The source locations are further verified in EUV images from the Solar and Terrestrial Relations Observatory, which provides information on solar activities in the regions not visible from the Earth. Based on AIA observations, {sup 3}He-rich events are not only associated with coronal jets as emphasized in solar cycle 23 studies, but also with more spatially extended eruptions. The properties of the {sup 3}He-rich events do not appear to be strongly correlated with those of the source regions. As in the previous studies, the magnetic connection between the source region and the observer is not always reproduced adequately by the simple potential field source surface model combined with the Parker spiral. Instead, we find a broad longitudinal distribution of the source regions extending well beyond the west limb, with the longitude deviating significantly from that expected from the observed solar wind speed.

  16. Solar Sources of 3He-rich Solar Energetic Particle Events in Solar Cycle 24

    NASA Astrophysics Data System (ADS)

    Nitta, Nariaki V.; Mason, Glenn M.; Wang, Linghua; Cohen, Christina M. S.; Wiedenbeck, Mark E.

    2015-06-01

    Using high-cadence EUV images obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory, we investigate the solar sources of 26 3He-rich solar energetic particle events at ≲1 MeV nucleon-1 that were well-observed by the Advanced Composition Explorer during solar cycle 24. Identification of the solar sources is based on the association of 3He-rich events with type III radio bursts and electron events as observed by Wind. The source locations are further verified in EUV images from the Solar and Terrestrial Relations Observatory, which provides information on solar activities in the regions not visible from the Earth. Based on AIA observations, 3He-rich events are not only associated with coronal jets as emphasized in solar cycle 23 studies, but also with more spatially extended eruptions. The properties of the 3He-rich events do not appear to be strongly correlated with those of the source regions. As in the previous studies, the magnetic connection between the source region and the observer is not always reproduced adequately by the simple potential field source surface model combined with the Parker spiral. Instead, we find a broad longitudinal distribution of the source regions extending well beyond the west limb, with the longitude deviating significantly from that expected from the observed solar wind speed.

  17. Jet control carburetor

    SciTech Connect

    Fujikake, K.; Idota, Y.; Ohsawa, K.; Sugiyama, K.

    1982-06-29

    A jet control type carburetor according to the present invention includes an intake pipe having an intake passage formed in an inner wall thereof, the intake passage allowing an intake air to flow therethrough; a venturi provided in the intake pipe, for controlling flow velocity and pressure of the intake air in the intake passage; a fuel nozzle opened into the intake passage and connected to a fuel supply source through a fuel passage for sucking the fuel within the intake passage from the fuel nozzle in order to introduce the mixture of air and fuel within the intake passage; a throttle valve provided downstream of the venturi, for controlling the flow rate of the mixture of intake air and fuel; a control air nozzle opened into the intake passage and connected to an air supply source through a control air passage for jetting the flow of the control air to the fuel spurted from the fuel nozzle to afford the kinetic energy of the control air to the fuel; and a throttle means provided upstream of the control air nozzle in the control air passage, for controlling the flow rate of the control air. The control air nozzle has a predetermined inner diameter (da) and is provided at a portion apart from the fuel nozzle with a predetermined spacing (w), and a dimensional relationship of the spacing W between the fuel nozzle and the control air nozzle to the inner diameter (da) of the control air nozzle is set as follows: w/da < or = 20.

  18. Performance of jets at CMS

    NASA Astrophysics Data System (ADS)

    Schröder, Matthias; CMS Collaboration

    2015-02-01

    The calibration and reconstruction of jets critically relies on the performance of the calorimeters. Extending out to large pseudorapidities, the measurements depend on the interplay between forward calorimeters, central calorimeters, and the tracking system. The high number of additional pile-up interactions poses further complications. In CMS, these difficulties are overcome using the 'particle-flow' approach, which aims at reconstructing individually each particle in the event prior to the jet clustering. Measurements of the jet energy scale and the procedure for jet energy calibration in CMS are reviewed, which are performed with dijet, photon + jet, and Z+jet data collected in proton-proton collisions at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.6 fb-1. The effect of pile-up interactions and the state of the art mitigation techniques used in CMS as well as the main sources of uncertainty of the jet energy calibration are also presented.

  19. About the magnetic origin of Chromospheric Spicules and Coronal Jets

    NASA Astrophysics Data System (ADS)

    Koutchmy, S.; Filippov, B.; Tavabi, E.

    2012-06-01

    Observations of jet- like phenomena near the solar limb are reported for a long time, first in Hα (Secchi observations of spicules in the 1870 ies), and after, from eclipse high resolution coronal images taken in white-light (1920-1973) as spiky structures. EUV jets were reported in the 70 ies from rocket and space-borne CIV filtergrams and finally X-EUV jets were reported from SXT observations of Yohkoh and from EIT and CDS SoHO observations. There is now little doubt that they are of magnetic origin although no magnetic field measurements exist for these regions and thermo-dynamical models are still work out. New observations of both spicules and jets with the SOT/SXT of Hinode were subjected to an analysis showing the influence of the null point(s) of the magnetic field. The collective behavior of the H CaII SOT(Hinode) time sequences of processed with the Madmax operator images of limb spicules show the torsional effects which were partly suggested before from the interpretation of high resolution limb spectra taken on Russian coronagraphs and the VTT at SacPeak. 100 s and shorter period waves are recorded. We propose a reconnection process occurring at the top of an emerging twisted flux tube for explaining some peculiarities of the spicular eruptions and possibly, as a viable mechanism for explaining the SXR jet eruptions. The result of a numerical 3D modeling illustrates this erupting mechanism although the behavior of the magneto-plasma structure near a null point, as shown by coronal filtergrams, does not necessary imply reconnections, especially the case of jets making a long coronal ray we observed in white-light with Lasco C2.

  20. Triggering of Solar Magnetic Eruptions on Various Size Scales

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.

    2010-01-01

    Solar eruptions occur on many different scales. (Schrijver 2010: bipole eruptions more frequent as size decreases.) Trigger might be any of several different candidates, working independently or in tandem. How about larger scales than (solar) CMEs? (Stellar eruptions.) How about smaller scales than X-ray jets? (Spicules? Moore 1989)

  1. The aeroacoustics of supersonic jets

    NASA Technical Reports Server (NTRS)

    Morris, Philip J.; McLaughlin, Dennis K.

    1995-01-01

    This research project was a joint experimental/computational study of noise in supersonic jets. The experiments were performed in a low to moderate Reynolds number anechoic supersonic jet facility. Computations have focused on the modeling of the effect of an external shroud on the generation and radiation of jet noise. This report summarizes the results of the research program in the form of the Masters and Doctoral theses of those students who obtained their degrees with the assistance of this research grant. In addition, the presentations and publications made by the principal investigators and the research students is appended.

  2. Jet vectoring through nozzle asymmetry

    NASA Astrophysics Data System (ADS)

    Roh, Chris; Rosakis, Alexandros; Gharib, Morteza

    2015-11-01

    Previously, we explored the functionality of a tri-leaflet anal valve of a dragonfly larva. We saw that the dragonfly larva is capable of controlling the three leaflets independently to asymmetrically open the nozzle. Such control resulted in vectoring of the jet in various directions. To further understand the effect of asymmetric nozzle orifice, we tested jet flow through circular asymmetric nozzles. We report the relationship between nozzle asymmetry and redirecting of the jet at various Reynolds numbers. This material is based upon work supported by the National Science Foundation under Grant No. CBET-1511414; additional support by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144469.

  3. Jet stream related observations by MST radars

    NASA Technical Reports Server (NTRS)

    Gage, K. S.

    1983-01-01

    An overview of the jet stream and its observation by MST radar is presented. The climatology and synoptic and mesoscale structure of jet streams is briefly reviewed. MST radar observations of jet stream winds, and associated waves and turbulence are then considered. The possibility of using a network of ST radars to track jet stream winds in near real time is explored.

  4. Jet mixer noise suppressor using acoustic feedback

    NASA Technical Reports Server (NTRS)

    Rice, Edward J. (Inventor)

    1995-01-01

    The present invention generally relates to providing an improved jet mixer noise suppressor for high speed jets that rapidly mixes high speed air flow with a lower speed air flow, and more particularly, relates to an improved jet mixer noise suppressor that uses feedback of acoustic waves produced by the interaction of shear flow instability waves with an obstacle downstream of the jet nozzle.

  5. Jet mixer noise suppressor using acoustic feedback

    NASA Technical Reports Server (NTRS)

    Rice, Edward J. (Inventor)

    1994-01-01

    The present invention generally relates to providing an improved jet mixer noise suppressor for high speed jets that rapidly mixes high speed air flow with a lower speed air flow, and more particularly, relates to an improved jet mixer noise suppressor that uses feedback of acoustic waves produced by the interaction of sheer flow instability waves with an obstacle downstream of the jet nozzle.

  6. Detection of Recurrent Fluorescence Photons

    NASA Astrophysics Data System (ADS)

    Ebara, Yuta; Furukawa, Takeshi; Matsumoto, Jun; Tanuma, Hajime; Azuma, Toshiyuki; Shiromaru, Haruo; Hansen, Klavs

    2016-09-01

    We have detected visible photons emitted from the thermally populated electronic excited state, namely recurrent fluorescence (RF), of C6- stored in an electrostatic ion storage ring. Clear evidence is provided to distinguish RF from normal fluorescence, based on the temporal profile of detected photons synchronized with the revolution of C6- in the ring, for which the time scale is far longer than the lifetime of the intact photoexcited state. The relaxation (cooling) process via RF is likely to be commonplace for isolated molecular systems and crucial to the stabilization of molecules in interstellar environments.

  7. Jet Measurements for Development of Jet Noise Prediction Tools

    NASA Technical Reports Server (NTRS)

    Bridges, James E.

    2006-01-01

    The primary focus of my presentation is the development of the jet noise prediction code JeNo with most examples coming from the experimental work that drove the theoretical development and validation. JeNo is a statistical jet noise prediction code, based upon the Lilley acoustic analogy. Our approach uses time-average 2-D or 3-D mean and turbulent statistics of the flow as input. The output is source distributions and spectral directivity.

  8. The solar cell laser scanner

    NASA Technical Reports Server (NTRS)

    Miller, E. L.; Chern, S.-S.; Shumka, A.

    1981-01-01

    As part of the Low Cost Solar Array Program at Jet Propulsion Laboratory, failure analyses have been performed on over 300 photovoltaic modules from thirty different manufacturers and five countries. Because of the volume of work and the variety of module types encountered, it has been necessary to develop non-destructive techniques to rapidly locate the failure sites. This paper will present design details and results obtained with one instrument developed specifically for this purpose, the Solar Cell Laser Scanner (SCLS). The effects of applying a bias current to the modules will also be discussed, based upon experimental observations and computer generated predictions.

  9. Needle-free jet injections: dependence of jet penetration and dispersion in the skin on jet power.

    PubMed

    Schramm-Baxter, Joy; Mitragotri, Samir

    2004-07-01

    Jet injection is a needle-free drug delivery method in which a high-speed stream of fluid impacts the skin and delivers drugs. Although a number of jet injectors are commercially available, especially for insulin delivery, a quantitative understanding of the energetics of jet injection is still lacking. Here, we describe the dependence of jet injections into human skin on the power of the jet. Dermal delivery of liquid jets was quantified using two measurements, penetration of a radiolabeled solute, mannitol, into skin and the shape of jet dispersion in the skin which was visualized using sulforhodamine B (SRB). The power of the jet at the nozzle was varied from 1 to 600 W by independently altering the nozzle diameter (30-560 microm) and jet velocity (100-200 m/s). The dependence of the amount of liquid delivered in the skin and the geometric measurements of jet dispersion on nozzle diameter and jet velocity was captured by a single parameter, jet power. Additional experiments were performed using a model material, polyacrylamide gel, to further understand the dependence of jet penetration on jet power. These experiments demonstrated that jet power also effectively describes gel erosion due to liquid impingement.

  10. Acoustics of Excited Jets: A Historical Perspective

    NASA Technical Reports Server (NTRS)

    Brown, Cliffard A.

    2005-01-01

    The idea that a jet may be excited by external forcing is not new. The first published demonstration of a jet responding to external pressure waves occurred in the mid-1800's. It was not, however, until the 1950's, with the advent of commercial jet aircraft, that interest in the subject greatly increased. Researchers first used excited jets to study the structure of the jet and attempt to determine the nature of the noise sources. The jet actuators of the time limited the range (Reynolds and Mach numbers) of jets that could be excited. As the actuators improved, more realistic jets could be studied. This has led to a better understanding of how jet excitation may be used not only as a research tool to understand the flow properties and noise generation process, but also as a method to control jet noise.

  11. Commission 10: Solar Activity

    NASA Astrophysics Data System (ADS)

    Klimchuk, James A.; van Driel-Gesztelyi, Lidia; Schrijver, Carolus J.; Melrose, Donald B.; Fletcher, Lyndsay; Gopalswamy, Natchimuthuk; Harrison, Richard A.; Mandrini, Cristina H.; Peter, Hardi; Tsuneta, Saku; Vršnak, Bojan; Wang, Jing-Xiu

    Commission 10 deals with solar activity in all of its forms, ranging from the smallest nanoflares to the largest coronal mass ejections. This report reviews scientific progress over the roughly two-year period ending in the middle of 2008. This has been an exciting time in solar physics, highlighted by the launches of the Hinode and STEREO missions late in 2006. The report is reasonably comprehensive, though it is far from exhaustive. Limited space prevents the inclusion of many significant results. The report is divided into the following sections: Photosphere and chromosphere; Transition region; Corona and coronal heating; Coronal jets; flares; Coronal mass ejection initiation; Global coronal waves and shocks; Coronal dimming; The link between low coronal CME signatures and magnetic clouds; Coronal mass ejections in the heliosphere; and Coronal mass ejections and space weather. Primary authorship is indicated at the beginning of each section.

  12. Slitless Solar Spectroscopy

    NASA Technical Reports Server (NTRS)

    Davila, Joseph M.; Jones, Sahela

    2011-01-01

    Spectrographs have traditionally suffered from the inability to obtain line intensities, widths, and Doppler shifts over large spatial regions of the Sun quickly because of the narrow instantaneous field of view. This has limited the spectroscopic analysis of rapidly varying solar features like, flares, CME eruptions, coronal jets, and reconnection regions. Imagers have provided high time resolution images of the full Sun with limited spectral resolution. In this paper we present recent advances in deconvolving spectrally dispersed images obtained through broad slits. We use this new theoretical formulation to examine the effectiveness of various potential observing scenarios, spatial and spectral resolutions, signal to noise ratio, and other instrument characteristics. This information will lay the foundation for a new generation of spectral imagers optimized for slitless spectral operation, while retaining the ability to obtain spectral information in transient solar events.

  13. Arrhenius reconsidered: astrophysical jets and the spread of spores

    NASA Astrophysics Data System (ADS)

    Sheldon, Malkah I.; Sheldon, Robert B.

    2015-09-01

    In 1871, Lord Kelvin suggested that the fossil record could be an account of bacterial arrivals on comets. In 1903, Svante Arrhenius suggested that spores could be transported on stellar winds without comets. In 1984, Sir Fred Hoyle claimed to see the infrared signature of vast clouds of dried bacteria and diatoms. In 2012, the Polonnaruwa carbonaceous chondrite revealed fossilized diatoms apparently living on a comet. However, Arrhenius' spores were thought to perish in the long transit between stars. Those calculations, however, assume that maximum velocities are limited by solar winds to ~5 km/s. Herbig-Haro objects and T-Tauri stars, however, are young stars with jets of several 100 km/s that might provide the necessary propulsion. The central engine of bipolar astrophysical jets is not presently understood, but we argue it is a kinetic plasma instability of a charged central magnetic body. We show how to make a bipolar jet in a belljar. The instability is non-linear, and thus very robust to scaling laws that map from microquasars to active galactic nuclei. We scale up to stellar sizes and recalculate the viability/transit-time for spores carried by supersonic jets, to show the viability of the Arrhenius mechanism.

  14. Recurrent corneal erosion: clinical features.

    PubMed

    Hope-Ross, M W; Chell, P B; Kervick, G N; McDonnell, P J

    1994-01-01

    The clinical features of a group of 30 patients with recalcitrant recurrent corneal erosions (i.e. those who failed to respond to conventional therapy) were evaluated. Associated ocular and facial abnormalities were documented. Meibomian gland dysfunction was present in all patients as manifest by dropout and inspissation of the meibomian glands, reduced tear film break-up time and debris in the tear film. Dropout of meibomian glands was present in 25 (83%) patients and was maximum in the medial half of the lid in 21 (84%) of these 25 patients. Tear film break-up time was reduced in all patients, being instant in 7 (23%), between 1 and 5 seconds in 22 (74%) and between 10 and 15 seconds in 1 (3%) patient. Superficial corneal abnormalities were present in 28 (93%) patients as manifest by maps, dots and fingerprints. Facial abnormalities such as telangiectasia, rhinophyma and acne rosacea were present in 22 (73%) patients. The findings of our study suggest an association between recalcitrant recurrent corneal erosions and meibomian gland dysfunction.

  15. Medical treatment of recurrent meningiomas.

    PubMed

    Chamberlain, Marc C; Barnholtz-Sloan, Jill S

    2011-10-01

    Meningiomas are the second most common primary brain tumor and are primarily treated with surgery (with or without embolization) and radiotherapy. Increasingly today, meningiomas undergo multiple resections and two radiotherapy treatments (either stereotactic or conventional external beam) before consideration for hormonal, chemotherapy or targeted therapy. The failure of hormonal and cytotoxic chemotherapy in the treatment of recurrent meningioma and increasing understanding of potential molecular targets in meningioma has resulted in multiple studies utilizing single-agent targeted therapy directed at biologically relevant signaling pathways, such as somatostatin (Sandostatin(®) LAR, SOM230c), PDGF (imatinib), EGF (erlotinib) and VEGF (sunitinib and vatalanib). Early results using a targeted approach have been modest at best and are often associated with significant toxicity. Consequently and at present, the brain tumor guidelines recognize only three medical therapies for inoperable and radiation-refractory meningiomas: hydroxyurea, IFN-α and Sandostatin LAR, a somatostatin analogue. Clearly, there remains an unmet need in neuro-oncology with respect to the medical treatment of recurrent meningiomas. PMID:21955199

  16. How to calibrate the jet energy scale?

    SciTech Connect

    Hatakeyama, K.; /Rockefeller U.

    2006-01-01

    Top quarks dominantly decay into b-quark jets and W bosons, and the W bosons often decay into jets, thus the precise determination of the jet energy scale is crucial in measurements of many top quark properties. I present the strategies used by the CDF and D0 collaborations to determine the jet energy scale. The various cross checks performed to verify the determined jet energy scale and evaluate its systematic uncertainty are also discussed.

  17. Latest jet results from the Tevatron

    SciTech Connect

    Price, Darren D.

    2010-05-01

    A brief overview of the latest status of jet physics studies at the Tevatron in proton-antiproton collisions at {radical}s = 1.96 TeV is presented. In particular, measurements of the inclusive jet production cross-section, dijet production and searches for new physics, the ratio of the 3-jet to 2-jet production cross-sections, and the three-jet mass are discussed.

  18. Transient gas jets into liquids

    NASA Astrophysics Data System (ADS)

    Lin, Jane Ming-Chin

    An experimental investigation of the development of high velocity, impulsively initiated gas jets into liquid was conducted in an effort to understand some of the physical processes that occur for a jet of very light fluid into a dense ambient atmosphere. Four gases, refrigerants 12 and 22, nitrogen, and helium were injected into water at nozzle exit Mach numbers from 1.0 to 2.2.The study showed that a gas jet into water develops in at least three stages: startup, transition, and global steady state. The startup is characterized by bubble growth; the growth rate is well predicted by classical bubble-growth theory. Jet transition is marked by axially directed flow, which penetrates through the startup bubble and which forms a cylindrical protrusion along the axis of symmetry. A combination of strong recirculating flow and liquid entrainment causes the startup bubble to deflate and to lift off and move downstream. In the steady state, instantaneous photographs show small-scale fluctuations of the jet boundary, but time-averaged photographs show the expected conical spreading of the steady jet; the measured spreading angles range from 18-25 degrees.However, the most significant finding of this study is that under some conditions, the gas jet into liquid never reaches the global steady state. Instead, the jet boundary exhibits chugging: large nonlinear oscillations which lead to irregular collapses of the gas column followed by explosive outward bursts of gas. The unsteadiness observed is much more violent than the familiar fluctuations typical of constant-density jets. The length scale of the motion is generally on the order of several jet diameters; the time scale is on the order of the period for bubble collapse.It was found that the amplitude and frequency of chugging are strongly dependent on the ratio of the liquid density to the gas density, the jet Mach number, and the operating pressure ratio. The conditions under which unsteadiness occurs were determined

  19. Radial flow pulse jet mixer

    SciTech Connect

    VanOsdol, John G.

    2013-06-25

    The disclosure provides a pulse jet mixing vessel for mixing a plurality of solid particles. The pulse jet mixing vessel is comprised of a sludge basin, a flow surface surrounding the sludge basin, and a downcoming flow annulus between the flow surface and an inner shroud. The pulse jet mixing vessel is additionally comprised of an upper vessel pressurization volume in fluid communication with the downcoming flow annulus, and an inner shroud surge volume separated from the downcoming flow annulus by the inner shroud. When the solid particles are resting on the sludge basin and a fluid such as water is atop the particles and extending into the downcoming flow annulus and the inner shroud surge volume, mixing occurs by pressurization of the upper vessel pressurization volume, generating an inward radial flow over the flow surface and an upwash jet at the center of the sludge basin.

  20. Jet-Induced Star Formation

    SciTech Connect

    van Breugel, W; Fragile, C; Anninos, P; Murray, S

    2003-12-16

    Jets from radio galaxies can have dramatic effects on the medium through which they propagate. We review observational evidence for jet-induced star formation in low ('FR-I') and high ('FR-II') luminosity radio galaxies, at low and high redshifts respectively. We then discuss numerical simulations which are aimed to explain a jet-induced starburst ('Minkowski's Object') in the nearby FR-I type radio galaxy NGC 541. We conclude that jets can induce star formation in moderately dense (10 cm{sup -3}), warm (10{sup 4} K) gas; that this may be more common in the dense environments of forming, active galaxies; and that this may provide a mechanism for 'positive' feedback from AGN in the galaxy formation process.

  1. Instabilities in coaxial rotating jets

    NASA Astrophysics Data System (ADS)

    Ivanic, Tanja; Foucault, Eric; Pecheux, Jean; Gilard, Virginie

    2000-12-01

    The aim of this study is the characterization of the cylindrical mixing layer resulting from the interaction of two coaxial swirling jets. The experimental part of this study was performed in a cylindrical water tunnel, permitting an independent rotation of two coaxial jets. The rotations are generated by means of 2×36 blades localized in two swirling chambers. As expected, the evolution of the main instability modes presents certain differences compared to the plane-mixing-layer case. Experimental results obtained by tomography showed the existence of vortex rings and streamwise vortex pairs in the near field region. This method also permitted the observation of the evolution and interaction of different modes. PIV velocity measurements realized in the meridian plans and the plans perpendicular to the jet axis show that rotation distorts the typical top-hat axial velocity profile. The transition of the axial velocity profile from jet-like into wake-like is also observed.

  2. Synthetic Jets in Quiescent Air

    NASA Technical Reports Server (NTRS)

    Yao, C. S.; Chen, F. J.; Neuhart, D.; Harris, J.

    2007-01-01

    An oscillatory jet with zero net mass flow is generated by a cavity-pumping actuator. Among the three test cases selected for the Langley CFD validation workshop to assess the current CFD capabilities to predict unsteady flow fields, this basic oscillating jet flow field is the least complex and is selected as the first test case. Increasing in complexity, two more cases studied include jet in cross flow boundary layer and unsteady flow induced by suction and oscillatory blowing with separation control geometries. In this experiment, velocity measurements from three different techniques, hot-wire anemometry, Laser Doppler Velocimetry (LDV) and Particle Image Velocimetry (PIV), documented the synthetic jet flow field. To provide boundary conditions for computations, the experiment also monitored the actuator operating parameters including diaphragm displacement, internal cavity pressure, and internal cavity temperature.

  3. Jet Perturbation by HE target

    SciTech Connect

    Poulsen, P; Kuklo, R M

    2001-03-01

    We have previously reported the degree of attenuation and perturbation by a Cu jet passing through Comp B explosive. Similar tests have now been performed with high explosive (HE) targets having CJ pressures higher than and lower than the CJ pressure of Comp B. The explosives were LX-14 and TNT, respectively. We found that the measured exit velocity of the jet where it transitions from perturbed to solid did not vary significantly as a function of HE type for each HE thickness. The radial momentum imparted to the perturbed jet segment did vary as a function of HE type, however, and we report the radial spreading of the jet and the penetration of a downstream target as a function of HE type and thickness.

  4. Spacecraft Images Comet Target's Jets

    NASA Video Gallery

    The Deep Impact spacecraft's High- and Medium-Resolution Imagers (HRI and MRI) have captured multiple jets turning on and off while the spacecraft is 8 million kilometers (5 million miles) away fro...

  5. Widespread Recurrent Evolution of Genomic Features

    PubMed Central

    Maeso, Ignacio; Roy, Scott William; Irimia, Manuel

    2012-01-01

    The recent explosion of genome sequences from all major phylogenetic groups has unveiled an unexpected wealth of cases of recurrent evolution of strikingly similar genomic features in different lineages. Here, we review the diverse known types of recurrent evolution in eukaryotic genomes, with a special focus on metazoans, ranging from reductive genome evolution to origins of splice-leader trans-splicing, from tandem exon duplications to gene family expansions. We first propose a general classification scheme for evolutionary recurrence at the genomic level, based on the type of driving force—mutation or selection—and the environmental and genomic circumstances underlying these forces. We then discuss various cases of recurrent genomic evolution under this scheme. Finally, we provide a broader context for repeated genomic evolution, including the unique relationship of genomic recurrence with the genotype–phenotype map, and the ways in which the study of recurrent genomic evolution can be used to understand fundamental evolutionary processes. PMID:22417916

  6. [Recurrent urological cancer--diagnose and treatment].

    PubMed

    Takeshima, H; Akaza, H

    1998-02-01

    Clinical efforts to spare bladder function even in the case of muscle invasive recurrent bladder cancer is taking. Early detection of recurrence is essential for bladder sparing, and both urinary NMP22 and BTA are thought to have potency to detect recurrence of bladder cancer earlier than urinary cytology. Intravesical administration of BCG for superficial bladder cancer and intraarterial injection of chemoagents (Methotrexate and Cisplatin) with radiation for muscle invasive bladder cancer are thought to play important roles in sparing the bladder. Early detection of recurrent prostate cancer is becoming easier by ultrasensitive PSA assay. Though the value of early detection of recurrence is not proven since the benefits of early hormonal treatment have not yet been established, that should be a good indicator to evaluate new and coming treatments and play a important role to develop an effective treatment for recurrent prostate cancer.

  7. Top Jets at the LHC

    SciTech Connect

    Almeida, L.G.; Lee, S.J.; Perez, G.; Sung, I.; Virzi, J.

    2008-10-06

    We investigatethe reconstruction of high pT hadronically-decaying top quarksat the Large Hadron Collider. One of the main challenges in identifying energetictop quarks is that the decay products become increasingly collimated. This reducesthe efficacy of conventional reconstruction methods that exploit the topology of thetop quark decay chain. We focus on the cases where the decay products of the topquark are reconstructed as a single jet, a"top-jet." The most basic"top-tag" methodbased on jet mass measurement is considered in detail. To analyze the feasibility ofthe top-tagging method, both theoretical and experimental aspects of the large QCDjet background contribution are examined. Based on a factorization approach, wederive a simple analytic approximation for the shape of the QCD jet mass spectrum.We observe very good agreement with the Monte Carlo simulation. We consider high pT tt bar production in the Standard Model as an example, and show that our theoretical QCD jet mass distributions can efficiently characterize the background via sideband analyses. We show that with 25 fb-1 of data, our approach allows us to resolve top-jets with pT _> 1 TeV, from the QCD background, and about 1.5 TeV top-jets with 100 fb-1, without relying on b-tagging. To further improve the significancewe consider jet shapes (recently analyzed in 0807.0234 [hep-ph]), which resolve thesubstructure of energy flow inside cone jets. A method of measuring the top quarkpolarization by using the transverse momentum of the bottom quark is also presented.The main advantages of our approach are: (i) the mass distributions are driven byfirst principle calculations, instead of relying solely on Monte Carlo simulation; (ii) for high pT jets (pT _> 1 TeV), IR-safe jet shape variables are robust against detectorresolution effects. Our analysis can be applied to other boosted massive particlessuch as the electroweak gauge bosons and the Higgs.

  8. Rectangular subsonic jet flowfield study

    NASA Technical Reports Server (NTRS)

    Morrison, Gerald L.; Tatterson, Gary B.; Swan, David H.

    1987-01-01

    The flowfield of a rectangular jet with 2:1 aspect ratio was studied at an axial Reynolds number of 127,000, using a three-dimensional laser anemometer. The flowfield surveys resulted in mean velocity vector field plots and contour plots of the Reynolds stress tensor components for the major and minor axes. These data contribute substantially to currently available data of jet flowfields.

  9. Perspectives on dilution jet mixing

    NASA Technical Reports Server (NTRS)

    Holdeman, J. D.

    1986-01-01

    A microcomputer code which displays 3-D oblique and 2-D plots of the temperature distribution downstream of jets mixing with a confined crossflow has been used to investigate the effects of varying the several independent flow and geometric parameters on the mixing. Temperature profiles calculated with this empirical model are presented to show the effects of orifice size and spacing, momentum flux ratio, density ratio, variable temperature mainstream, flow area convergence, orifice aspect ratio, and opposed and axially staged rows of jets.

  10. Recurrence quantification analysis of chimera states

    NASA Astrophysics Data System (ADS)

    Santos, M. S.; Szezech, J. D.; Batista, A. M.; Caldas, I. L.; Viana, R. L.; Lopes, S. R.

    2015-10-01

    Chimera states, characterised by coexistence of coherence and incoherence in coupled dynamical systems, have been found in various physical systems, such as mechanical oscillator networks and Josephson-junction arrays. We used recurrence plots to provide graphical representations of recurrent patterns and identify chimera states. Moreover, we show that recurrence plots can be used as a diagnostic of chimera states and also to identify the chimera collapse.

  11. Recurrence of spinal schwannoma: Is it preventable?

    PubMed Central

    Senapati, Satya B.; Mishra, Sudhansu S.; Dhir, Manmath K.; Patnaik, Ashis; Panigrahi, Souvagya

    2016-01-01

    Spinal schwannomas account for about 25% of primary intradural spinal cord tumors in adult. The prognosis for spinal schwannomas is excellent in most cases. Complete resection is curative. However following subtotal removal, recurrence develops after several years. We describe a case of recurrent spinal schwannoma who had been operated twice before for same disease. The possible cause of recurrence and difficulties in reoperation are discussed.

  12. Quantum recurrences: probe to study quantum chaos

    PubMed

    Saif

    2000-11-01

    We study the phase space of periodically modulated gravitational cavity by means of quantum recurrence phenomena. We report that the quantum recurrences serve as a tool to connect phase space of the driven system with a spectrum in the quantum domain. With the help of quantum recurrences we investigate the quasienergy spectrum of the system for a certain fixed modulation strength. In addition, we study transition of spectrum from discrete to continuum as a function of modulation strength. PMID:11101963

  13. Recurrence of spinal schwannoma: Is it preventable?

    PubMed Central

    Senapati, Satya B.; Mishra, Sudhansu S.; Dhir, Manmath K.; Patnaik, Ashis; Panigrahi, Souvagya

    2016-01-01

    Spinal schwannomas account for about 25% of primary intradural spinal cord tumors in adult. The prognosis for spinal schwannomas is excellent in most cases. Complete resection is curative. However following subtotal removal, recurrence develops after several years. We describe a case of recurrent spinal schwannoma who had been operated twice before for same disease. The possible cause of recurrence and difficulties in reoperation are discussed. PMID:27695564

  14. Comparison of Magnetospheric Multiscale ion jet signatures with predicted reconnection site locations at the magnetopause

    NASA Astrophysics Data System (ADS)

    Petrinec, S. M.; Burch, J. L.; Fuselier, S. A.; Gomez, R. G.; Lewis, W.; Trattner, K. J.; Ergun, R.; Mauk, B.; Pollock, C. J.; Schiff, C.; Strangeway, R. J.; Russell, C. T.; Phan, T.-D.; Young, D.

    2016-06-01

    Magnetic reconnection at the Earth's magnetopause is the primary process by which solar wind plasma and energy gains access to the magnetosphere. One indication that magnetic reconnection is occurring is the observation of accelerated plasma as a jet tangential to the magnetopause. The direction of ion jets along the magnetopause surface as observed by the Fast Plasma Instrument (FPI) and the Hot Plasma Composition Analyzer (HPCA) instrument on board the recently launched Magnetospheric Multiscale (MMS) set of spacecraft is examined. For those cases where ion jets are clearly discerned, the direction of origin compares well statistically with the predicted location of magnetic reconnection using convected solar wind observations in conjunction with the Maximum Magnetic Shear model.

  15. Instability of viscoelastic compound jets

    NASA Astrophysics Data System (ADS)

    Ye, Han-Yu; Yang, Li-Jun; Fu, Qing-Fei

    2016-04-01

    This paper investigates the axisymmetric instability of a viscoelastic compound jet, for which the constitutive relation is described by the Oldroyd B model. It is found that a viscoelastic compound jet is more unstable than a Newtonian compound jet, regardless of whether the viscoelastic compound jet is inner-Newtonian-outer-viscoelastic, inner-viscoelastic-outer-Newtonian, or fully viscoelastic. It is also found that an increase in the stress relaxation time of the inner or outer fluid renders the jet more unstable, while an increase in the time constant ratio makes the jet less unstable. An analysis of the energy budget of the destabilization process is performed, in which a formulation using the relative rate of change of energy is adopted. The formulation is observed to provide a quantitative analysis of the contribution of each physical factor (e.g., release of surface energy and viscous dissipation) to the temporal growth rate. The energy analysis reveals the mechanisms of various trends in the temporal growth rate, including not only how the growth rate changes with the parameters, but also how the growth rate changes with the wavenumber. The phenomenon of the dispersion relation presenting two local maxima, which occurred in previous research, is explained by the present energy analysis.

  16. Palbociclib Isethionate in Treating Younger Patients With Recurrent, Progressive, or Refractory Central Nervous System Tumors

    ClinicalTrials.gov

    2016-10-19

    Childhood Choroid Plexus Tumor; Childhood Ependymoblastoma; Childhood Grade III Meningioma; Childhood High-grade Cerebellar Astrocytoma; Childhood High-grade Cerebral Astrocytoma; Childhood Medulloepithelioma; Recurrent Childhood Anaplastic Astrocytoma; Recurrent Childhood Anaplastic Oligoastrocytoma; Recurrent Childhood Anaplastic Oligodendroglioma; Recurrent Childhood Brain Stem Glioma; Recurrent Childhood Cerebellar Astrocytoma; Recurrent Childhood Cerebral Astrocytoma; Recurrent Childhood Giant Cell Glioblastoma; Recurrent Childhood Glioblastoma; Recurrent Childhood Gliomatosis Cerebri; Recurrent Childhood Gliosarcoma; Recurrent Childhood Medulloblastoma; Recurrent Childhood Pineoblastoma; Recurrent Childhood Supratentorial Primitive Neuroectodermal Tumor

  17. Relationships between solar activity and climate change

    NASA Technical Reports Server (NTRS)

    Roberts, W. O.

    1975-01-01

    The relationship between recurrent droughts in the High Plains of the United States and the double sunspot cycle is discussed in detail. It is suggested that high solar activity is generally related to an increase in meridional circulation and blocking patterns at high and intermediate latitudes, especially in winter, and the effect is related to the sudden formation of cirrus clouds during strong geomagnetic activity that originates in the solar corpuscular emission.

  18. Plasma jet ignition device

    DOEpatents

    McIlwain, Michael E.; Grant, Jonathan F.; Golenko, Zsolt; Wittstein, Alan D.

    1985-01-15

    An ignition device of the plasma jet type is disclosed. The device has a cylindrical cavity formed in insulating material with an electrode at one end. The other end of the cylindrical cavity is closed by a metal plate with a small orifice in the center which plate serves as a second electrode. An arc jumping between the first electrode and the orifice plate causes the formation of a highly-ionized plasma in the cavity which is ejected through the orifice into the engine cylinder area to ignite the main fuel mixture. Two improvements are disclosed to enhance the operation of the device and the length of the plasma plume. One improvement is a metal hydride ring which is inserted in the cavity next to the first electrode. During operation, the high temperature in the cavity and the highly excited nature of the plasma breaks down the metal hydride, liberating hydrogen which acts as an additional fuel to help plasma formation. A second improvement consists of a cavity insert containing a plurality of spaced, metal rings. The rings act as secondary spark gap electrodes reducing the voltage needed to maintain the initial arc in the cavity.

  19. Chromospheric Anemone Jets Observed with Hinode/SOT and Hida Ca II Spectroheliograph

    NASA Astrophysics Data System (ADS)

    Morita, S.; Shibata, K.; Ueno, S.; Ichimoto, K.; Kitai, R.; Otsuji, K.

    2012-08-01

    We present the first simultaneous observations of chromospheric “anemone” jets in active regions with the Ca II H broadband filetergram on the Hinode/SOT and with the Ca II K spetroheliogram on the Domeless Solar Telescope (DST) at the Hida Observatory. During coordinated observation period, 9 chromospheric anemone jets were simultaneously observed with the two instruments. These observations revealed: (1) the jets are generated in the low chromosphere because these cannot be seen in Ca II K3, (2) these jets are associated with mixed polarity regions which are either small emerging flux regions or moving magnetic features, (3) the Ca II K line often show red or blue asymmetry in K2/K1 component; the footpoint of the jets associated with emerging flux regions often show red asymmetry (2-16 km s-1), while the one with moving magnetic features show blue asymmetry (˜5 km s-1). The magnetic cancellations were observed at the footpoint of the jets. The canceling rates are of order of 1016 Mx s-1, and the resulting magnetic energy release rate (1.1-10)×1024 erg s-1, with the total energy release (1-13)×1026 erg for the duration of the magnetic cancellations, ˜130 s. These are comparable to the estimated total energy, ˜1026 erg, in a single chromospheric anemone jet.

  20. Sunset jets observed on comet 67P/Churyumov-Gerasimenko sustained by subsurface thermal lag

    NASA Astrophysics Data System (ADS)

    Shi, X.; Hu, X.; Sierks, H.; Güttler, C.; A'Hearn, M.; Blum, J.; El-Maarry, M. R.; Kührt, E.; Mottola, S.; Pajola, M.; Oklay, N.; Fornasier, S.; Tubiana, C.; Keller, H. U.; Vincent, J.-B.; Bodewits, D.; Höfner, S.; Lin, Z.-Y.; Gicquel, A.; Hofmann, M.; Barbieri, C.; Lamy, P. L.; Rodrigo, R.; Koschny, D.; Rickman, H.; Barucci, M. A.; Bertaux, J.-L.; Bertini, I.; Cremonese, G.; Da Deppo, V.; Davidsson, B.; Debei, S.; De Cecco, M.; Fulle, M.; Groussin, O.; Gutiérrez, P. J.; Hviid, S. F.; Ip, W.-H.; Jorda, L.; Knollenberg, J.; Kovacs, G.; Kramm, J.-R.; Küppers, M.; Lara, L. M.; Lazzarin, M.; Lopez-Moreno, J. J.; Marzari, F.; Naletto, G.; Thomas, N.

    2016-01-01

    We present observations of sunset jets on comet 67P/Churyumov-Gerasimenko by Rosetta/OSIRIS camera. In late April 2015, when the comet was at a heliocentric distance of ~1.8 AU, clusters of dust jets that originated in the Ma'at region on the comet's small lobe were identified from multipleimages and were apparently sustained for about an hour beyond local sunset. Emanating from the shadowed nucleus, these jets became visible by solar illumination at their apparent sources up to only a few tens of meters above the nucleus surface. We investigate the plausibility of these jets as having been triggered by water ice sublimation and sustained by thermal lag in the subsurface beyond sunset. A general thermo-physical model was parameterized such that the thermal lag in the subsurface is consistent with the elapsed time of observation after sunset. It is found that the sublimation of water ice from a depth of 6 mm and with a low thermal inertia of 50 W m-2 K-1 s1/2 could explain the spatial pattern and evolution of the apparent sources, particularly their disappearance due to the eventual cooling of the subsurface. Our analysis suggests that these sunset jets were essentially day-side dust activities that continued after sunset. Specific observational conditions for the sunset jets constrain their possible sources to mostly within the less abrupt, dusty terrains. The uneven distribution of these jets is possibly related to subsurface inhomogeneities in the dusty area.

  1. 3D Numerical Simulation of a New Model for Coronal Jets

    NASA Astrophysics Data System (ADS)

    Pariat, E.; Antiochos, S.; DeVore, C. R.; Patsourakos, S.

    2008-09-01

    Recent solar observations with STEREO and HINODE have revealed evidence of twisting motions during the evolution of coronal jets. Furthermore, the observations indicate that some jets achieve near-Alfvenic velocities. Most models of jet are not capable of explaining these new observational features. In addition, the impulsiveness of jets, manifested as a brief, violent energy release phase in contrast to a slow, quasi-static energy storage phase storage, is an issue not easily addressed. We will present the results of 3D numerical simulations of our model for coronal jets. The simulations were performed with our state-of-art adaptive mesh MHD solver ARMS. The basic idea of the model is that a jet is due to the release of magnetic twist when a closed field region undergoes interchange reconnection with surrounding open field. The fast reconnection between open and closed field results in the generation of nonlinear Alfven waves that propagate along the open field, accelerating plasma upward. We will show how the new stereoscopically-observed features of jets can be explained by the results of our numerical simulations

  2. A ROTATING MOLECULAR JET FROM A PERSEUS PROTOSTAR

    SciTech Connect

    Pech, Gerardo; Zapata, Luis A.; Rodriguez, Luis F.; Loinard, Laurent

    2012-05-20

    We present the {sup 12}CO(2-1) line and 1.4 mm continuum archival observations, made with the Submillimeter Array, of the outflow HH 797 located in the IC 348 cluster in Perseus. The continuum emission is associated with a circumstellar disk surrounding the class 0 object IC 348-MMS/SMM2, a very young solar analog. The line emission, on the other hand, delineates a collimated outflow and reveals velocity asymmetries about the flow axis over the entire length of the flow. The amplitude of velocity differences is of the order of 2 km s{sup -1} over distances of about 1000 AU, and we interpret them as evidence for jet rotation-although we also discuss alternative possibilities. A comparison with theoretical models suggests that the magnetic field lines threading the protostellar jet might be anchored to the disk of a radius of about 20 AU.

  3. Rotating plasma jets in the photospheric intergranular lanes

    NASA Astrophysics Data System (ADS)

    Lemmerer, Birgit; Hanslmeier, Arnold; Muthsam, Herbert; Piantschitsch, Isabell; Zaqarashvili, Teimuraz

    2016-07-01

    High resolution simulations and observations of the solar photosphere reveal the population of small granular cells with diameters less than 600 km. However, the underlying mechanisms of their generation are still unclear. Simulations show that the majority of small granules may not result from fragmentation of larger granular cells but instead evolve and dissolve in the intergranular lanes. We study the dynamics of these granular cells in high resolution simulations. We found that the small granules show a jet-like behavior with strong horizontal and vertical vortex motions. A newly developed algorithm that tracks the evolution of the 3D plasma cells in the convection zone and lower photosphere shows strong vertical vorticity within the small granular cells. The rotating plasma jets, which are visible as small granules, may generate magnetized vortex flows and torsional Alfvén waves observed at upper layers and hence can play a distinct role in the energy supply to the chromosphere and corona.

  4. Numerical simulations of protostellar jets

    NASA Astrophysics Data System (ADS)

    Suttner, Gerhard; Smith, Michael D.; Yorke, Harold W.; Zinnecker, Hans

    Molecular jets announce the successful birth of a protostar. We develop here a model for the jets and their environments, adapting a multi-dimensional hydrocode to follow the molecular-atomic transitions of hydrogen. We examine powerful outflows into dense gas. The cocoon which forms around a jet is a very low density cavity of atomic gas. These atoms originate from strong shocks which dissociate the molecules. The rest of the molecules are either within the jet or swept up into very thin layers. Pulsed jets produce wider cavities and molecular layers which can grow onto resolvable jet knots. Three-dimensional simulations produce shocked molecular knots, distorted and multiple bow shocks and arclike structures. Spectroscopic and excitation properties of the hydrogen molecules are calculated. In the infrared, strong emission is seen from shocks within the jet (when pulsed) as well as from discrete regions along the cavity walls. Excitation, as measured by line ratios, is not generally constant. Broad double-peaked, shifted emission lines are predicted. The jet model for protostellar outflows is confronted with the constraints imposed by CO spectroscopic observations. From the three dimensional simulations we calculate line profiles and construct position-velocity diagrams for the (low-J) CO transitions. We find (1) the profiles imply power law variation of integrated brightness with velocity over a wide range of velocities, (2) the velocity field resembles a `Hubble Law' and (3) a hollow-shell structure at low velocities becomes an elongated lobe at high velocities. Deviations from the simple power law dependence of integrated brightness versus velocity occur at high velocities in our simulations. The curve first dips to a shallow minimum and then rises rapidly and peaks sharply. Reanalysis of the NGC 2264G and Cepheus E data confirm these predictions. We identify these two features with a jet-ambient shear layer and the jet itself. A deeper analysis reveals that

  5. Poincare Recurrences and Topological Diversity

    NASA Astrophysics Data System (ADS)

    Kleban, M.; Porrati, M.; Rabadan, R.

    2004-10-01

    Finite entropy thermal systems undergo Poincaré recurrences. In the context of field theory, this implies that at finite temperature, timelike two-point functions will be quasi-periodic. In this note we attempt to reproduce this behavior using the AdS/CFT correspondence by studying the correlator of a massive scalar field in the bulk. We evaluate the correlator by summing over all the SL(2,Bbb Z) images of the BTZ spacetime. We show that all the terms in this sum receive large corrections after at certain critical time, and that the result, even if convergent, is not quasi-periodic. We present several arguments indicating that the periodicity will be very difficult to recover without an exact re-summation, and discuss several toy models which illustrate this. Finally, we consider the consequences for the information paradox.

  6. Recurrent Glioblastoma: Where we stand

    PubMed Central

    Roy, Sanjoy; Lahiri, Debarshi; Maji, Tapas; Biswas, Jaydip

    2015-01-01

    Current first-line treatment regimens combine surgical resection and chemoradiation for Glioblastoma that provides a slight increase in overall survival. Age on its own should not be used as an exclusion criterion of glioblastoma multiforme (GBM) treatment, but performance should be factored heavily into the decision-making process for treatment planning. Despite aggressive initial treatment, most patients develop recurrent diseases which can be treated with re-resection, systemic treatment with targeted agents or cytotoxic chemotherapy, reirradiation, or radiosurgery. Research into novel therapies is investigating alternative temozolomide regimens, convection-enhanced delivery, immunotherapy, gene therapy, antiangiogenic agents, poly ADP ribose polymerase inhibitors, or cancer stem cell signaling pathways. Given the aggressive and resilient nature of GBM, continued efforts to better understand GBM pathophysiology are required to discover novel targets for future therapy. PMID:26981507

  7. Recurrent pregnancy loss and obesity.

    PubMed

    Sugiura-Ogasawara, Mayumi

    2015-05-01

    Recurrent pregnancy loss (RPL) was defined as two or more miscarriages. Antiphospholipid syndrome, uterine anomalies, and parental chromosomal abnormalities, particularly translocation and abnormal embryonic karyotype, are identifiable causes of RPL. Obesity may increase the risk of sporadic miscarriage in pregnancies conceived spontaneously. Obesity with body mass index (BMI)>30 kg/m2 is an independent risk factor for further miscarriage with odds ratio 1.7-3.5 in patients with early RPL. Obesity is associated with euploid miscarriage. Unexplained RPL with euploid embryo might be a common disease caused by both polymorphisms of multiple susceptibility genes and lifestyle factors such as women's age, obesity, and smoking. Patients with a history of RPL were found to have a higher risk of cardiovascular disease, celiac disease, gastric ulcer, gastritis, and atopic dermatitis. No study has examined the effect of weight loss on the prevention of further miscarriage in patients with RPL.

  8. Thrombophilia and Recurrent Pregnancy Loss

    PubMed Central

    Abu-Heija, Adel

    2014-01-01

    The association between thrombophilia and recurrent pregnancy loss (RPL) has become an undisputed fact. Thorombophilia creates a hypercoaguable state which leads to arterial and/or venous thrombosis at the site of implantation or in the placental blood vessels. Anticoagulants are an effective treatment against RPL in women with acquired thrombophilia due to antiphospholipid syndrome. The results of the use of anticoagulants for treating RPL in women with inherited thrombophilia (IT) are encouraging, but recently four major multicentre studies have shown that fetal outcomes (determined by live birth rates) may not be as favourable as previously suggested. Although the reported side-effects for anticoagulants are rare and usually reversible, the current recommendation is not to use anticoagulants in women with RPL and IT, or for those with unexplained losses. This review examines the strength of the association between thrombophilia and RPL and whether the use of anticoagulants can improve fetal outcomes. PMID:24516750

  9. Recurrence of neuroleptic malignant syndrome.

    PubMed

    González-Blanco, Leticia; García-Prada, Hilario; Santamarina, Susana; Jiménez-Treviño, Luis; Bobes, Julio

    2013-01-01

    Neuroleptic malignant syndrome (NMS) is a rare idiosyncratic reaction associated with the use of neuroleptics that has an incidence of 0.02 to 3% among patients taking these drugs. This is a very serious complication with a mortality rate that reaches 10-20%. It is therefore very important to have high clinical suspicion and use appropriate criteria to objectify this clinical picture early, stopping the medication causing the picture and to avoid the subsequent complications as much as possible that would be responsible for both its mortality and sequels. We present that case of an 81-year old woman who was admitted to the Psychiatric Hospitalization Unit (PHU) for a depressive episode with psychotic symptoms who developed a neuroleptic malignant syndrome (NMS) when Haloperidol was introduced. After its suspension and subsequent clinical recovery, antipsychotic treatment with Risperidone was reintroduced and she suffered a recurrence of NMS. Finally, significant improvement was achieved with several sessions of electroshock therapy (EST).

  10. Recurrent Excitation in Neocortical Circuits

    NASA Astrophysics Data System (ADS)

    Douglas, Rodney J.; Koch, Christof; Mahowald, Misha; Martin, Kevan A. C.; Suarez, Humbert H.

    1995-08-01

    The majority of synapses in the mammalian cortex originate from cortical neurons. Indeed, the largest input to cortical cells comes from neighboring excitatory cells. However, most models of cortical development and processing do not reflect the anatomy and physiology of feedback excitation and are restricted to serial feedforward excitation. This report describes how populations of neurons in cat visual cortex can use excitatory feedback, characterized as an effective "network conductance," to amplify their feedforward input signals and demonstrates how neuronal discharge can be kept proportional to stimulus strength despite strong, recurrent connections that threaten to cause runaway excitation. These principles are incorporated into models of cortical direction and orientation selectivity that emphasize the basic design principles of cortical architectures.

  11. Velocity field near the jet orifice of a round jet in a crossflow

    NASA Technical Reports Server (NTRS)

    Fearn, R. L.; Benson, J. P.

    1979-01-01

    Experimentally determined velocities at selected locations near the jet orifice are presented and analyzed for a round jet in crossflow. Jet-to-crossflow velocity ratios of four and eight were studied experimentally for a round subsonic jet of air exhausting perpendicularly through a flat plate into a subsonic crosswind of the same temperature. Velocity measurements were made in cross sections to the jet plume located from one to four jet diameters from the orifice. Jet centerline and vortex properties are presented and utilized to extend the results of a previous study into the region close to the jet orifice.

  12. Chemoradiotherapy response in recurrent rectal cancer

    PubMed Central

    Yu, Stanley K T; Bhangu, Aneel; Tait, Diana M; Tekkis, Paris; Wotherspoon, Andrew; Brown, Gina

    2014-01-01

    The efficacy of response to preoperative chemoradiotherapy (CRT) in recurrent versus primary rectal cancer has not been investigated. We compared radiological downsizing between primary and recurrent rectal cancers following CRT and determined the optimal size reduction threshold for response validated by survival outcomes. The proportional change in tumor length for primary and recurrent rectal cancers following CRT was compared using the independent sample t-test. Overall survival (OS) was calculated using the Kaplan–Meier product limit method and differences between survival for tumor size reduction thresholds of 30% (response evaluation criteria in solid tumors [RECIST]), 40%, and 50% after CRT in primary and recurrent rectal cancer groups. A total of 385 patients undergoing CRT were analyzed, 99 with recurrent rectal cancer and 286 with primary rectal cancer. The mean proportional reduction in maximum craniocaudal length was significantly higher for primary rectal tumors (33%) compared with recurrent rectal cancer (11%) (P < 0.01). There was no difference in OS for either primary or recurrent rectal cancer when ≤30% or ≤40% definitions were used. However, for both primary and recurrent tumors, significant differences in median 3-year OS were observed when a RECIST cut-off of 50% was used. OS was 99% versus 77% in primary and 100% versus 42% in recurrent rectal cancer (P = 0.002 and P = 0.03, respectively). Only patients that demonstrated >50% size reduction showed a survival benefit. Recurrent rectal cancer appears radioresistant compared with primary tumors for tumor size after CRT. Further investigation into improving/intensifying chemotherapy and radiotherapy for locally recurrent rectal cancer is justified. PMID:24403010

  13. The solar thermal report. Volume 3, Number 5

    SciTech Connect

    1982-09-01

    This report is published by the Jet Propulsion Laboratory for the DOE Solar Thermal Technology Division to provide an account of work sponsored by the Division and to aid the community of people interested in solar thermal technology in gaining access to technical information. Contents include articles entitled the following: Solar system supplies thermal energy for producing chemicals at USS plant; Solar thermal power module designed for small community market; Roof-mounted trough system supplies process heat for Caterpillar plant; Solar thermal update -- 10 MW(e) pilot plant and 3-MW(t) total energy system; Solar steam processes crude oil; New York investigates solar ponds as a source of thermal energy; On-farm solar -- Finding new uses for the sun; and Topical index of solar thermal report articles.

  14. Mechanisms controlling the number and latitudinal spacing of jets-streams on multiple jet planets: from terrestrial planets to gas giants

    NASA Astrophysics Data System (ADS)

    Kaspi, Yohai; Chemke, Rei

    2015-11-01

    Zonal jets dominate the atmospheric dynamics of a wide range of planetary systems as observed in all Solar System planetary atmospheres and even observed on exoplanets. Specifically, when the ratio between the eddy length scale and the planetary scale becomes small these planetary atmospheres develop multiple jets. In this study we use an idealized general circulation model to demonstrate how such multiple-jets are formed and what controls their latitudinal width and spacing. We find that for each latitude, over a wide range of parameters, the jet spacing scales with the Rhines scale. The simulations show the presence of a critical latitude, where poleward (equatorward) of this latitude the Rhines scale is larger (smaller) than the Rossby deformation radius. Poleward of this latitude, a classic geostrophic turbulence picture appears with a -5/3 spectral slope of inverse energy cascade from the deformation radius up to the Rhines scale. A shallower slope than the classic -3 slope of forward cascade is found from the deformation radius down to the viscosity scale, due to the broad input of baroclinic eddy kinetic energy. At these latitudes, eddy-eddy interactions transfer barotropic eddy kinetic energy from the input scales of baroclinic eddy kinetic energy up to the jet scale and down to smaller scales. We provide scaling laws for the number of eddy driven jets, their latitudinal width and speed as a function of a broad range of planetary parameters.

  15. Airframe-Jet Engine Integration Noise

    NASA Technical Reports Server (NTRS)

    Tam, Christopher; Antcliff, Richard R. (Technical Monitor)

    2003-01-01

    It has been found experimentally that the noise radiated by a jet mounted under the wing of an aircraft exceeds that of the same jet in a stand-alone environment. The increase in noise is referred to as jet engine airframe integration noise. The objectives of the present investigation are, (1) To obtain a better understanding of the physical mechanisms responsible for jet engine airframe integration noise or installation noise. (2) To develop a prediction model for jet engine airframe integration noise. It is known that jet mixing noise consists of two principal components. They are the noise from the large turbulence structures of the jet flow and the noise from the fine scale turbulence. In this investigation, only the effect of jet engine airframe interaction on the fine scale turbulence noise of a jet is studied. The fine scale turbulence noise is the dominant noise component in the sideline direction. Thus we limit out consideration primarily to the sideline.

  16. Investigation of two plane parallel jets

    NASA Astrophysics Data System (ADS)

    Elbanna, H.; Gahin, S.; Rashed, M. I. I.

    1983-07-01

    Flow measurements made downstream from two air jets are reported. The exit Re was 20,000 and turbulence was kept to 1 pct. X-wire constant temperature anemometers were employed to measure the mean velocities and the three component turbulent intensities. Data were gathered on the flowfield of both a single jet and from two jets. A velocity profile from two jets was found to be similar to that of a single jet, with the combined jets width spreading linearly downstream as a single jet, but with a slightly lower spread angle. The turbulent velocity fluctuations were, however, dissimilar up to 120 nozzle diameters downstream. Finally, the maximum shear stress was nearly the same with two jets as with one jet.

  17. Analytical study of twin-jet shielding

    NASA Technical Reports Server (NTRS)

    Gerhold, C. H.

    1980-01-01

    The development of an analytical model, an aircraft noise prediction computer program, to estimate the shielding of one jet by an adjacent jet in a twin jet configuration, is discussed. Noise estimations included consideration not only of noise sources on the aircraft, but also of the propagation path between source and receiver. A three-dimensional case is considered in which noise source is a discrete frequency point source at rest with respect to the jet axis. The shielding jet is assumed to be a cylinder of heated flow in which the temperature and flow velocity profiles are constant across the jet. The effect on shielding of the orientation of the emitting jet with respect to the shielding jet was investigated. Forward and backward scattering phenomena as well as the influence of jet flow speed were also investigated.

  18. Exotic interactions among C-jets and Pb-jets

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The C-jets and Pb-jets were surveyed on the part of Chacaltaya emulsion chamber No.19 amounting to an exposure of 28.8 sq m yr. It is shown that the adopted events make up an unbiased sample of C-jets for sigma sub E gamma TeV. Mini-Centauro interaction gives the most natural explanation for the eight pinaught-less C-jets with three or more constituent shower core. Out of the eight double-cored pinaught-less events, three are found to have visible invariant masses 1.8 GeV/c. Three Pb-jets-lower are composed of double cores whose respective visible transverse momenta are greater than 0.5 GeV/c, suggesting that they are of Geminion origin or chiron origin. The energies of the parent particles are estimated to be 100 to 200 TeV for all three kinds of events. The implications of this energy estimate and the frequency of observed exotic events are discussed.

  19. Jet Performance and Jet Energy Scale Determination at CMS

    SciTech Connect

    Bhatti, Anwar A.

    2006-10-27

    We describe the jet response of the CMS calorimeter which will be used to study pp collisions at Large Hadron Collider at CERN, Geneva, Switzerland at {radical}(s) = 14 TeV. The electromagnetic section of calorimeter consists of lead tungstate crystals which gives an excellent resolution for electrons. The hadron section is brass-scintillator sampling calorimeter read by wavelength shifting fibers in the central region (vertical bar {eta} vertical bar < 3.0) and steel/quartz-fibers in the forward (3.0 < vertical bar {eta} vertical bar < 5.0) region. Extensive test beam calibration data has been collected. A GEANT-based calorimeter simulation has been tuned to reproduce the test beam measurements. The calorimeter response to jets has been determined using this tuned simulation. We describe the calorimeter response to jets, the jet energy resolution, and the procedure we plan to use to establish the jet energy scale from a combination of test beam and pp data when we start taking data in September 2007.

  20. ISS Solar Array Management

    NASA Technical Reports Server (NTRS)

    Williams, James P.; Martin, Keith D.; Thomas, Justin R.; Caro, Samuel

    2010-01-01

    The International Space Station (ISS) Solar Array Management (SAM) software toolset provides the capabilities necessary to operate a spacecraft with complex solar array constraints. It monitors spacecraft telemetry and provides interpretations of solar array constraint data in an intuitive manner. The toolset provides extensive situational awareness to ensure mission success by analyzing power generation needs, array motion constraints, and structural loading situations. The software suite consists of several components including samCS (constraint set selector), samShadyTimers (array shadowing timers), samWin (visualization GUI), samLock (array motion constraint computation), and samJet (attitude control system configuration selector). It provides high availability and uptime for extended and continuous mission support. It is able to support two-degrees-of-freedom (DOF) array positioning and supports up to ten simultaneous constraints with intuitive 1D and 2D decision support visualizations of constraint data. Display synchronization is enabled across a networked control center and multiple methods for constraint data interpolation are supported. Use of this software toolset increases flight safety, reduces mission support effort, optimizes solar array operation for achieving mission goals, and has run for weeks at a time without issues. The SAM toolset is currently used in ISS real-time mission operations.

  1. The Aeroacoustics of Supersonic Coaxial Jets

    NASA Technical Reports Server (NTRS)

    Dahl, Milo D.

    1994-01-01

    Instability waves have been established as the dominant source of mixing noise radiating into the downstream arc of a supersonic jet when the waves have phase velocities that are supersonic relative to ambient conditions. Recent theories for supersonic jet noise have used the concepts of growing and decaying linear instability waves for predicting radiated noise. This analysis is extended to the prediction of noise radiation from supersonic coaxial jets. Since the analysis requires a known mean flow and the coaxial jet mean flow is not described easily in terms of analytic functions, a numerical prediction is made for its development. The Reynolds averaged, compressible, boundary layer equations are solved using a mixing length turbulence model. Empirical correlations are developed for the effects of velocity and temperature ratios and Mach number. Both normal and inverted velocity profile coaxial jets are considered. Comparisons with measurements for both single and coaxial jets show good agreement. The results from mean flow and stability calculations are used to predict the noise radiation from coaxial jets with different operating conditions. Comparisons are made between different coaxial jets and a single equivalent jet with the same total thrust, mass flow, and exit area. Results indicate that normal velocity profile jets can have noise reductions compared to the single equivalent jet. No noise reductions are found for inverted velocity profile jets operated at the minimum noise condition compared to the single equivalent jet. However, it is inferred that changes in area ratio may provide noise reduction benefits for inverted velocity profile jets.

  2. Jetting during vertical impacts of spherical projectiles

    NASA Astrophysics Data System (ADS)

    Johnson, B. C.; Bowling, T. J.; Melosh, H. J.

    2014-08-01

    The extreme pressures reached during jetting, a process by which material is squirted out from the contact point of two colliding objects, causes melting and vaporization at low impact velocities. Jetting is a major source of melting in shocked porous material, a potential source of tektites, a possible origin of chondrules, and even a conceivable origin of the Moon. Here, in an attempt to quantify the importance of jetting, we present numerical simulation of jetting during the vertical impacts of spherical projectiles on both flat and curved targets. We find that impacts on curved targets result in more jetted material but that higher impact velocities result in less jetted material. For an aluminum impactor striking a flat Al target at 2 km/s we find that 3.4% of a projectile mass is jetted while 8.3% is jetted for an impact between two equal sized Al spheres. Our results indicate that the theory of jetting during the collision of thin plates can be used to predict the conditions when jetting will occur. However, we find current analytic models do not make accurate predictions of the amount of jetted mass. Our work indicates that the amount of jetted mass is independent of model resolution as long as some jetted material is resolved. This is the result of lower velocity material dominating the mass of the jet.

  3. Sweeping Jet Actuator in a Quiescent Environment

    NASA Technical Reports Server (NTRS)

    Koklu, Mehti; Melton, Latunia P.

    2013-01-01

    This study presents a detailed analysis of a sweeping jet (fluidic oscillator) actuator. The sweeping jet actuator promises to be a viable flow control actuator candidate due to its simple, no moving part structure and its high momentum, spatially oscillating flow output. Hot-wire anemometer and particle image velocimetry measurements were carried out with an emphasis on understanding the actuator flow field in a quiescent environment. The time averaged, fluctuating, and instantaneous velocity measurements are provided. A modified actuator concept that incorporates high-speed solenoid valves to control the frequency of oscillation enabled phase averaged measurements of the oscillating jet. These measurements reveal that in a given oscillation cycle, the oscillating jet spends more time on each of the Coanda surfaces. In addition, the modified actuator generates four different types of flow fields, namely: a non oscillating downward jet, a non oscillating upward jet, a non oscillating straight jet, and an oscillating jet. The switching from an upward jet to a downward jet is accomplished by providing a single pulse from the solenoid valve. Once the flow is switched, the flow stays there until another pulse is received. The oscillating jet is compared with a non oscillating straight jet, which is a typical planar turbulent jet. The results indicate that the oscillating jet has a higher (5 times) spreading rate, more flow entrainment, and higher velocity fluctuations (equal to the mean velocity).

  4. MICRO-SIGMOIDS AS PROGENITORS OF CORONAL JETS: IS ERUPTIVE ACTIVITY SELF-SIMILARLY MULTI-SCALED?

    SciTech Connect

    Raouafi, N.-E.; Rust, D. M.; Bernasconi, P. N.; Georgoulis, M. K.

    2010-08-01

    Observations from the X-ray telescope (XRT) on Hinode are used to study the nature of X-ray-bright points, sources of coronal jets. Several jet events in the coronal holes are found to erupt from small-scale, S-shaped bright regions. This finding suggests that coronal micro-sigmoids may well be progenitors of coronal jets. Moreover, the presence of these structures may explain numerous observed characteristics of jets such as helical structures, apparent transverse motions, and shapes. Analogous to large-scale sigmoids giving rise to coronal mass ejections (CMEs), a promising future task would perhaps be to investigate whether solar eruptive activity, from coronal jets to CMEs, is self-similar in terms of properties and instability mechanisms.

  5. On the Relationship Between Solar Wind Speed, Geomagnetic Activity, and the Solar Cycle Using Annual Values

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.; Hathaway, David H.

    2008-01-01

    The aa index can be decomposed into two separate components: the leading sporadic component due to solar activity as measured by sunspot number and the residual or recurrent component due to interplanetary disturbances, such as coronal holes. For the interval 1964-2006, a highly statistically important correlation (r = 0.749) is found between annual averages of the aa index and the solar wind speed (especially between the residual component of aa and the solar wind speed, r = 0.865). Because cyclic averages of aa (and the residual component) have trended upward during cycles 11-23, cyclic averages of solar wind speed are inferred to have also trended upward.

  6. Oxaliplatin in Treating Young Patients With Recurrent Solid Tumors That Have Not Responded to Previous Treatment

    ClinicalTrials.gov

    2013-06-04

    Childhood Central Nervous System Germ Cell Tumor; Childhood Extragonadal Germ Cell Tumor; Childhood Hepatoblastoma; Childhood Hepatocellular Carcinoma; Childhood High-grade Cerebral Astrocytoma; Childhood Low-grade Cerebral Astrocytoma; Childhood Malignant Ovarian Germ Cell Tumor; Childhood Malignant Testicular Germ Cell Tumor; Childhood Teratoma; Recurrent Adrenocortical Carcinoma; Recurrent Childhood Brain Stem Glioma; Recurrent Childhood Cerebellar Astrocytoma; Recurrent Childhood Cerebral Astrocytoma; Recurrent Childhood Ependymoma; Recurrent Childhood Liver Cancer; Recurrent Childhood Malignant Germ Cell Tumor; Recurrent Childhood Rhabdomyosarcoma; Recurrent Childhood Soft Tissue Sarcoma; Recurrent Childhood Visual Pathway and Hypothalamic Glioma; Recurrent Colon Cancer; Recurrent Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor; Recurrent Nasopharyngeal Cancer; Recurrent Neuroblastoma; Recurrent Osteosarcoma; Recurrent Rectal Cancer; Recurrent Renal Cell Cancer

  7. Turbulent swirling jets with excitation

    NASA Technical Reports Server (NTRS)

    Taghavi, Rahmat; Farokhi, Saeed

    1988-01-01

    An existing cold-jet facility at NASA Lewis Research Center was modified to produce swirling flows with controllable initial tangential velocity distribution. Two extreme swirl profiles, i.e., one with solid-body rotation and the other predominated by a free-vortex distribution, were produced at identical swirl number of 0.48. Mean centerline velocity decay characteristics of the solid-body rotation jet flow exhibited classical decay features of a swirling jet with S - 0.48 reported in the literature. However, the predominantly free-vortex distribution case was on the verge of vortex breakdown, a phenomenon associated with the rotating flows of significantly higher swirl numbers, i.e., S sub crit greater than or equal to 0.06. This remarkable result leads to the conclusion that the integrated swirl effect, reflected in the swirl number, is inadequate in describing the mean swirling jet behavior in the near field. The relative size (i.e., diameter) of the vortex core emerging from the nozzle and the corresponding tangential velocity distribution are also controlling factors. Excitability of swirling jets is also investigated by exciting a flow with a swirl number of 0.35 by plane acoustic waves at a constant sound pressure level and at various frequencies. It is observed that the cold swirling jet is excitable by plane waves, and that the instability waves grow about 50 percent less in peak r.m.s. amplitude and saturate further upstream compared to corresponding waves in a jet without swirl having the same axial mass flux. The preferred Strouhal number based on the mass-averaged axial velocity and nozzle exit diameter for both swirling and nonswirling flows is 0.4.

  8. DECELERATING RELATIVISTIC TWO-COMPONENT JETS

    SciTech Connect

    Meliani, Z.; Keppens, R. E-mail: Rony.Keppens@wis.kuleuven.b

    2009-11-10

    Transverse stratification is a common intrinsic feature of astrophysical jets. There is growing evidence that jets in radio galaxies consist of a fast low-density outflow at the jet axis, surrounded by a slower, denser, extended jet. The inner and outer jet components then have a different origin and launching mechanism, making their effective inertia, magnetization, associated energy flux, and angular momentum content different as well. Their interface will develop differential rotation, where disruptions may occur. Here we investigate the stability of rotating, two-component relativistic outflows typical for jets in radio galaxies. For this purpose, we parametrically explore the long-term evolution of a transverse cross section of radially stratified jets numerically, extending our previous study where a single, purely hydrodynamic evolution was considered. We include cases with poloidally magnetized jet components, covering hydro and magnetohydrodynamic (MHD) models. With grid-adaptive relativistic MHD simulations, augmented with approximate linear stability analysis, we revisit the interaction between the two jet components. We study the influence of dynamically important poloidal magnetic fields, with varying contributions of the inner component jet to the total kinetic energy flux of the jet, on their non-linear azimuthal stability. We demonstrate that two-component jets with high kinetic energy flux and inner jet effective inertia which is higher than the outer jet effective inertia are subject to the development of a relativistically enhanced, rotation-induced Rayleigh-Taylor-type instability. This instability plays a major role in decelerating the inner jet and the overall jet decollimation. This novel deceleration scenario can partly explain the radio source dichotomy, relating it directly to the efficiency of the central engine in launching the inner jet component. The FRII/FRI transition could then occur when the relative kinetic energy flux of the

  9. Holographic Jet Quenching

    NASA Astrophysics Data System (ADS)

    Ficnar, Andrej

    In this dissertation we study the phenomenon of jet quenching in quark-gluon plasma using the AdS/CFT correspondence. We start with a weakly coupled, perturbative QCD approach to energy loss, and present a Monte Carlo code for computation of the DGLV radiative energy loss of quarks and gluons at an arbitrary order in opacity. We use the code to compute the radiated gluon distribution up to n=9 order in opacity, and compare it to the thin plasma (n=1) and the multiple soft scattering (n=infinity) approximations. We furthermore show that the gluon distribution at finite opacity depends in detail on the screening mass mu and the mean free path lambda. In the next part, we turn to the studies of how heavy quarks, represented as "trailing strings" in AdS/CFT, lose energy in a strongly coupled plasma. We study how the heavy quark energy loss gets modified in a "bottom-up" non-conformal holographic model, constructed to reproduce some properties of QCD at finite temperature and constrained by fitting the lattice gauge theory results. The energy loss of heavy quarks is found to be strongly sensitive to the medium properties. We use this model to compute the nuclear modification factor RAA of charm and bottom quarks in an expanding plasma with Glauber initial conditions, and comment on the range of validity of the model. The central part of this thesis is the energy loss of light quarks in a strongly coupled plasma. Using the standard model of "falling strings", we present an analytic derivation of the stopping distance of light quarks, previously available only through numerical simulations, and also apply it to the case of Gauss-Bonnet higher derivative gravity. We then present a general formula for computing the instantaneous energy loss in non-stationary string configurations. Application of this formula to the case of falling strings reveals interesting phenomenology, including a modified Bragg-like peak at late times and an approximately linear path dependence. Based

  10. Jets from jets: re-clustering as a tool for large radius jet reconstruction and grooming at the LHC

    NASA Astrophysics Data System (ADS)

    Nachman, Benjamin; Nef, Pascal; Schwartzman, Ariel; Swiatlowski, Maximilian; Wanotayaroj, Chaowaroj

    2015-02-01

    Jets with a large radius R ≳ 1 and grooming algorithms are widely used to fully capture the decay products of boosted heavy particles at the Large Hadron Collider (LHC). Unlike most discriminating variables used in such studies, the jet radius is usually not optimized for specific physics scenarios. This is because every jet configuration must be calibrated, insitu, to account for detector response and other experimental effects. One solution to enhance the availability of large- R jet configurations used by the LHC experiments is jet re-clustering. Jet re-clustering introduces an intermediate scale r < R at which jets are calibrated and used as the inputs to reconstruct large radius jets. In this paper we systematically study and propose new jet re-clustering configurations and show that re-clustered large radius jets have essentially the same jet mass performance as large radius groomed jets. Jet re-clustering has the benefit that no additional large-R calibration is necessary, allowing the re-clustered large radius parameter to be optimized in the context of specific precision measurements or searches for new physics.

  11. Late breast recurrence after lumpectomy and irradiation

    SciTech Connect

    Kurtz, J.M.; Spitalier, J.M.; Amalric, R.

    1983-08-01

    For 276 patients with early breast cancer followed from 10 to 21 years after lumpectomy and radiotherapy, the recurrence rate in the treated breast was 15.6%, and 7.2% developed contralateral breast cancer. Only 63% of breast recurrences occurred within 5 years, and the remainder were late failures, with 5 of the 43 recurrences observed after 10 years. The proportion of failures occurring late was greater for T/sub 1/ than for T/sub 2/ tumors (53% vs 25%). Twenty-six percent of early recurrences were inoperable, and an adverse impact of early recurrence on 10-year survival was clearly demonstrable. Late recurrences were all operable and did not appear to be associated with decreased survival. Only 16 of the 36 patients (44%) with operable breast recurrence ever developed metastatic disease, and 5 year survival following salvage therapy was 62%. Although the treated breast remains at continuous cancer risk even beyond 5 years, the prognosis of late recurrence appears quite similar to that of contralateral breast cancer.

  12. 28 CFR 51.14 - Recurrent practices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Recurrent practices. 51.14 Section 51.14 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) PROCEDURES FOR THE ADMINISTRATION OF SECTION 5 OF THE VOTING RIGHTS ACT OF 1965, AS AMENDED General Provisions § 51.14 Recurrent practices. Where a jurisdiction implements a practice...

  13. Lesson Learned from (some) Recurrent Novae

    NASA Astrophysics Data System (ADS)

    Mason, E.; Walter, F. M.

    2014-12-01

    In this talk we present early decline and nebular spectra of the recurrent novae YY Dor and nova LMC 2009. These and a few other recurrent novae of the same type, share similar spectral characteristics and evolution. We will discuss those common features critically suggesting same white dwarf progenitor and post outburst phases for all of them.

  14. Recurrence Effects in the Parametric Spring Pendulum.

    ERIC Educational Resources Information Center

    Falk, Lars

    1978-01-01

    Gives a perturbation analysis to recurrence effects of the spring pendulum. The recurrence depends on two conservation laws which determine the motion in an intermediate region; oscillations outside this region are unstable and must return. Gives the relation to Fermi-Pasta-Ulam problem together with the explicit solution. (Author/GA)

  15. 14 CFR 121.427 - Recurrent training.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... required by §§ 121.421(b) and 121.422(b), respectively. (4) Approved recurrent CRM training. For flight... operational flight training (LOFT) session. The recurrent CRM training requirement does not apply until a person has completed the applicable initial CRM training required by §§ 121.419, 121.421, or 121.422....

  16. Local Recurrence After Uveal Melanoma Proton Beam Therapy: Recurrence Types and Prognostic Consequences

    SciTech Connect

    Caujolle, Jean-Pierre; Paoli, Vincent; Chamorey, Emmanuel; Maschi, Celia; Baillif, Stéphanie; Herault, Joël; Gastaud, Pierre; Hannoun-Levi, Jean Michel

    2013-04-01

    Purpose: To study the prognosis of the different types of uveal melanoma recurrences treated by proton beam therapy (PBT). Methods and Materials: This retrospective study analyzed 61 cases of uveal melanoma local recurrences on a total of 1102 patients treated by PBT between June 1991 and December 2010. Survival rates have been determined by using Kaplan-Meier curves. Prognostic factors have been evaluated by using log-rank test or Cox model. Results: Our local recurrence rate was 6.1% at 5 years. These recurrences were divided into 25 patients with marginal recurrences, 18 global recurrences, 12 distant recurrences, and 6 extrascleral extensions. Five factors have been identified as statistically significant risk factors of local recurrence in the univariate analysis: large tumoral diameter, small tumoral volume, low ratio of tumoral volume over eyeball volume, iris root involvement, and safety margin inferior to 1 mm. In the local recurrence-free population, the overall survival rate was 68.7% at 10 years and the specific survival rate was 83.6% at 10 years. In the local recurrence population, the overall survival rate was 43.1% at 10 years and the specific survival rate was 55% at 10 years. The multivariate analysis of death risk factors has shown a better prognosis for marginal recurrences. Conclusion: Survival rate of marginal recurrences is superior to that of the other recurrences. The type of recurrence is a clinical prognostic value to take into account. The influence of local recurrence retreatment by proton beam therapy should be evaluated by novel studies.

  17. Supersonic Jet Noise Reductions Predicted with Increased Jet Spreading Rate

    NASA Technical Reports Server (NTRS)

    Dahl, Milo D.; Morris, Philip J.

    1995-01-01

    In this paper, predictions are made of noise radiation from single, supersonic, axisymmetric jets. We examine the effects of changes in operating conditions and the effects of simulated enhanced mixing that would increase the spreading rate of the jet shear layer on radiated noise levels. The radiated noise in the downstream direction is dominated by mixing noise and it is well described by the instability wave noise radiation analysis. A numerical prediction scheme is used for the mean flow providing an efficient method to obtain the mean flow development for various operating conditions and to simulate the enhanced mixing. Using far field radiated noise measurements as a reference, the calculations predict that enhanced jet spreading results in a reduction of radiated noise.

  18. Inclusive jet spectrum for small-radius jets

    NASA Astrophysics Data System (ADS)

    Dasgupta, Mrinal; Dreyer, Frédéric A.; Salam, Gavin P.; Soyez, Gregory

    2016-06-01

    Following on our earlier work on leading-logarithmic (LL R ) resummations for the properties of jets with a small radius, R, we here examine the phenomenological considerations for the inclusive jet spectrum. We discuss how to match the NLO predictions with small- R resummation. As part of the study we propose a new, physically-inspired prescription for fixed-order predictions and their uncertainties. We investigate the R-dependent part of the next-to-next-to-leading order (NNLO) corrections, which is found to be substantial, and comment on the implications for scale choices in inclusive jet calculations. We also examine hadronisation corrections, identifying potential limitations of earlier analytical work with regards to their p t -dependence. Finally we assemble these different elements in order to compare matched (N)NLO+LLR predictions to data from ALICE and ATLAS, finding improved consistency for the R-dependence of the results relative to NLO predictions.

  19. High activity iodine 125 endocurietherapy for recurrent skull base tumors

    SciTech Connect

    Kumar, P.P.; Good, R.R.; Leibrock, L.G.; Mawk, J.R.; Yonkers, A.J.; Ogren, F.P.

    1988-04-15

    Experience with endocurietherapy of skull base tumors is reviewed. We present our cases of recurrent pituitary hemangiopericytoma, radiation-induced recurrent meningioma, recurrent clival chordoma, recurrent nasopharyngeal cancer involving the cavernous sinus, and recurrent parotid carcinoma of the skull base which were all successfully retreated with high-activity 125-iodine (I-125) permanent implantation.76 references.

  20. JETS FROM TIDAL DISRUPTIONS OF STARS BY BLACK HOLES

    SciTech Connect

    Krolik, Julian H.; Piran, Tsvi E-mail: tsvi@phys.huji.ac.il

    2012-04-10

    Tidal disruption of main-sequence stars by black holes has generally been thought to lead to a signal dominated by UV emission. If, however, the black hole spins rapidly and the poloidal magnetic field intensity on the black hole horizon is comparable to the inner accretion disk pressure, a powerful jet may form whose luminosity can easily exceed the thermal UV luminosity. When the jet beam points at Earth, its non-thermal luminosity can dominate the emitted spectrum. The thermal and non-thermal components decay differently with time. In particular, the thermal emission should remain roughly constant for a significant time after the period of maximum accretion, beginning to diminish only after a delay, whereas after the peak accretion rate, the non-thermal jet emission decays, but then reaches a plateau. Both transitions are tied to a characteristic timescale t{sub Edd} at which the accretion rate falls below Eddington. Making use of this timescale in a new parameter-inference formalism for tidal disruption events with significant emission from a jet, we analyze the recent flare source Swift J2058. It is consistent with an event in which a main-sequence solar-type star is disrupted by a black hole of mass {approx}4 Multiplication-Sign 10{sup 7} M{sub Sun }. The beginning of the flat phase in the non-thermal emission from this source can possibly be seen in the late-time light curve. Optical photometry over the first {approx_equal} 40 days of this flare is also consistent with this picture, but is only weakly constraining because the bolometric correction is very uncertain. We suggest that future searches for main-sequence tidal disruptions use methods sensitive to jet radiation as well as to thermal UV radiation.

  1. Interstitial Photodynamic Therapy in Treating Patients With Recurrent Head and Neck Cancer

    ClinicalTrials.gov

    2016-10-20

    Recurrent Laryngeal Squamous Cell Carcinoma; Recurrent Laryngeal Verrucous Carcinoma; Recurrent Lip and Oral Cavity Squamous Cell Carcinoma; Recurrent Metastatic Squamous Cell Carcinoma in the Neck With Occult Primary; Recurrent Oral Cavity Verrucous Carcinoma; Recurrent Oropharyngeal Squamous Cell Carcinoma; Tongue Carcinoma

  2. Des Vents et des Jets Astrophysiques

    NASA Astrophysics Data System (ADS)

    Sauty, C.

    Plasma outflows from a central gravitating object are a widespread phenomenon in astrophysics. They include the solar and stellar winds, jets from Young Stellar Objects, jets from compact stellar objects and extra-galactic jets associated with Active Galactic Nuclei and quasars. Beyond this huge zoology, a common theoretical ground exists. The aim of this review is to present qualitatively the various theories of winds (Part 1) and how different astrophysical domains interplay. A more or less complete catalog of the ideas proposed for explaining the acceleration and the morphologies of winds and jets is intended. All this part avoids getting into any mathematical formalism. Some macroscopic properties of such outflows may be described by solving the time-independent and axisymmetric magnetohydrodynamic equations. This formalism, underlying most of the theories, is presented in Part 2. It helps to introduce quantitatively the free integrals that such systems possess. Those integrals play an important role in the basic physics of acceleration and collimation, in particular the mass loss rate, the angular momentum loss rate and the energy of the magnetic rotator. Most of the difficulty in modelling flows lies in the necessity to cross critical points, characteristic of non linear equations. The physical nature and the location of such critical points is debated because they are the clue towards the resolution. We thus introduce the notions of topology and critical points (Parts 3 and 4) from the simplest hydrodynamic and spherically symmetric case to the most sophisticated, MHD and axisymmetric cases. Particular attention is given to self-similar models which allows to give some general and simple ideas on the problem due to their semi-analytical treatment. With the use of these notions, a more quantitative comparison of the various models is given (Parts 3 and 4), especially on the shape of the flows. It is thus shown that magnetic collimation of winds into jets is a

  3. Jets, Coronal “Puffs,” and a Slow Coronal Mass Ejection Caused by an Opposite-polarity Region within an Active Region Footpoint

    NASA Astrophysics Data System (ADS)

    Alzate, N.; Morgan, H.

    2016-06-01

    During a period of three days beginning 2013 January 17, twelve recurrent reconnection events occur within a small region of opposing flux embedded within one footpoint of an active region, accompanied by flares and jets observed in EUV and fast and faint structureless “puffs” observed by coronagraphs. During the same period a slow structured CME gradually erupts, with one end anchored close to, or within, the jetting region. Four of the jet events occur in pairs—a narrow, primary jet followed within a few tens of minutes by a wider, more massive, jet. All the jets are slow, with an apparent speed of ˜100 km s-1. The speed of the wide puffs in the coronagraph data is ˜300 km s-1, and the timing of their appearance rules out a direct association with the EUV jetting material. The jet material propagates along large-scale closed-field loops and does not escape to the extended corona. The rapid reconfiguration of the closed loops following reconnection causes an outwardly propagating disturbance, or wave front, which manifests as puffs in coronagraph data. Furthermore, the newly expanded closed flux tube forms a pressure imbalance, which can result in a secondary jet. The reconnection events, through recurrent field reconfiguration, also leads to the gradual eruption of the structured flux tube appearing as the slow CME. Faint propagating coronal disturbances resulting from flares/jets may be common, but are usually obscured by associated ejections. Occasionally, the associated material ejections are absent, and coronal puffs may be clearly observed.

  4. Evidence-based management of recurrent miscarriages

    PubMed Central

    Jeve, Yadava B.; Davies, William

    2014-01-01

    Recurrent miscarriages are postimplantation failures in natural conception; they are also termed as habitual abortions or recurrent pregnancy losses. Recurrent pregnancy loss is disheartening to the couple and to the treating clinician. There has been a wide range of research from aetiology to management of recurrent pregnancy loss. It is one of the most debated topic among clinicians and academics. The ideal management is unanswered. This review is aimed to produce an evidence-based guidance on clinical management of recurrent miscarriage. The review is structured to be clinically relevant. We have searched electronic databases (PubMed and Embase) using different key words. We have combined the searches and arranged them with the hierarchy of evidences. We have critically appraised the evidence to produce a concise answer for clinical practice. We have graded the evidence from level I to V on which these recommendations are based. PMID:25395740

  5. Nanofluid impingement jet heat transfer.

    PubMed

    Zeitoun, Obida; Ali, Mohamed

    2012-02-17

    Experimental investigation to study the heat transfer between a vertical round alumina-water nanofluid jet and a horizontal circular round surface is carried out. Different jet flow rates, jet nozzle diameters, various circular disk diameters and three nanoparticles concentrations (0, 6.6 and 10%, respectively) are used. The experimental results indicate that using nanofluid as a heat transfer carrier can enhance the heat transfer process. For the same Reynolds number, the experimental data show an increase in the Nusselt numbers as the nanoparticle concentration increases. Size of heating disk diameters shows reverse effect on heat transfer. It is also found that presenting the data in terms of Reynolds number at impingement jet diameter can take into account on both effects of jet heights and nozzle diameter. Presenting the data in terms of Peclet numbers, at fixed impingement nozzle diameter, makes the data less sensitive to the percentage change of the nanoparticle concentrations. Finally, general heat transfer correlation is obtained verses Peclet numbers using nanoparticle concentrations and the nozzle diameter ratio as parameters.

  6. Nanofluid impingement jet heat transfer

    PubMed Central

    2012-01-01

    Experimental investigation to study the heat transfer between a vertical round alumina-water nanofluid jet and a horizontal circular round surface is carried out. Different jet flow rates, jet nozzle diameters, various circular disk diameters and three nanoparticles concentrations (0, 6.6 and 10%, respectively) are used. The experimental results indicate that using nanofluid as a heat transfer carrier can enhance the heat transfer process. For the same Reynolds number, the experimental data show an increase in the Nusselt numbers as the nanoparticle concentration increases. Size of heating disk diameters shows reverse effect on heat transfer. It is also found that presenting the data in terms of Reynolds number at impingement jet diameter can take into account on both effects of jet heights and nozzle diameter. Presenting the data in terms of Peclet numbers, at fixed impingement nozzle diameter, makes the data less sensitive to the percentage change of the nanoparticle concentrations. Finally, general heat transfer correlation is obtained verses Peclet numbers using nanoparticle concentrations and the nozzle diameter ratio as parameters. PMID:22340669

  7. Experiments in dilution jet mixing

    NASA Technical Reports Server (NTRS)

    Holdeman, J. D.; Srinivasan, R.; Berenfeld, A.

    1983-01-01

    Experimental results are given on the mixing of a single row of jets with an isothermal mainstream in a straight duct, to include flow and geometric variations typical of combustion chambers in gas turbine engines. The principal conclusions reached from these experiments were: at constant momentum ratio, variations in density ratio have only a second-order effect on the profiles; a first-order approximation to the mixing of jets with a variable temperature mainstream can be obtained by superimposing the jets-in-an isothermal-crossflow and mainstream profiles; flow area convergence, especially injection-wall convergence, significantly improves the mixing; for opposed rows of jets, with the orifice centerlines in-line, the optimum ratio of orifice spacing to duct height is one half of the optimum value for single side injection at the same momentum ratio; and for opposed rows of jets, with the orifice centerlines staggered, the optimum ratio of orifice spacing to duct height is twice the optimum value for single side injection at the same momentum ratio.

  8. Plasma Jet Modeling for PLX

    NASA Astrophysics Data System (ADS)

    Mason, Caroline F.; Mason, Rodney J.; Faehl, R. J.; Kirkpatrick, R. C.

    2011-10-01

    The implicit simulation code ePLAS has been applied to plasma jets generated with mini-rail guns for plasma production and compression aimed at use with PLX. The rails are typically planar, 2.5 cm apart and arranged to transport an initial 1 cm or wider vertical plasma fill some 10 cm into a void. The driving magnetic field is 3.2 T. The plasma singly ionized argon at 1017 cm-3. We use ePLAS in both its traditional implicit/hybrid form where it is restricted by an electron Courant time step, and in a new super-hybrid form that extracts the main electron moments from the E&B-field solutions. This provides numerical stability at ion Courant limits, for at least a 10 times larger time step, thus probing microsecond jet dynamics with computational economy. We examine possible field penetration at the cathode and anode gun electrodes. Cathode erosion and EMHD B - Field penetration are possible at lower jet densities. We examine jet transport beyond the gun, modeling possible ionization with either analytic or tabular EOSs. We study the merger of jets with ions represented as either fluids or particles. Work supported by the USDOE under SBIR GRANT DE-SC0004207.

  9. Sources of magnetic fields in recurrent interplanetary streams

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Behannon, K. W.; Hansen, S. F.; Pneuman, G. W.; Feldman, W. C.

    1977-01-01

    The sources of magnetic fields in recurrent streams were examined. Most fields and plasmas at 1 AU were related to coronal holes, and the magnetic field lines were open in those holes. Some of the magnetic fields and plasmas were related to open field line regions on the sun which were not associated with known coronal holes, indicating that open field lines are more basic than coronal holes as sources of the solar wind. Magnetic field intensities in five equatorial coronal holes ranged from 2G to 18G. Average measured photospheric magnetic fields along the footprints of the corresponding unipolar fields on circular equatorial arcs at 2.5 solar radii had a similar range and average, but in two cases the intensities were approximately three times higher than the projected intensities. The coronal footprints of the sector boundaries on the source surface at 2.5 solar radii, meandered between -45 deg and +45 deg latitude, and their inclination ranged from near zero to near ninety degrees.

  10. Solar Energy.

    ERIC Educational Resources Information Center

    Eaton, William W.

    Presented is the utilization of solar radiation as an energy resource principally for the production of electricity. Included are discussions of solar thermal conversion, photovoltic conversion, wind energy, and energy from ocean temperature differences. Future solar energy plans, the role of solar energy in plant and fossil fuel production, and…

  11. Isolated magnetic field structures in Mercury's magnetosheath as possible analogues for terrestrial magnetosheath plasmoids and jets

    NASA Astrophysics Data System (ADS)

    Karlsson, Tomas; Liljeblad, Elisabet; Kullen, Anita; Raines, Jim M.; Slavin, James A.; Sundberg, Torbjörn

    2016-09-01

    We have investigated MESSENGER magnetic field data from the Mercury magnetosheath and near solar wind, to identify isolated magnetic field structures (defined as clear, isolated changes in the field magnitude). Their properties are studied in order to determine if they may be considered as analogues to plasmoids and jets known to exist in Earth's magnetosheath. Both isolated decreases of the magnetic field absolute value ('negative magnetic field structures') and increases ('positive structures') are found in the magnetosheath, whereas only negative structures are found in the solar wind. The similar properties of the solar wind and magnetosheath negative magnetic field structures suggests that they are analogous to diamagnetic plasmoids found in Earth's magnetosheath and near solar wind. The latter have earlier been identified with solar wind magnetic holes. Positive magnetic field structures are only found in the magnetosheath, concentrated to a region relatively close to the magnetopause. Their proximity to the magnetopause, their scale sizes, and the association of a majority of the structures with bipolar magnetic field signatures identify them as flux transfer events (which generally are associated with a decrease of plasma density in the magnetosheath). The positive magnetic field structures are therefore not likely to be analogous to terrestrial paramagnetic plasmoids but possibly to a sub-population of magnetosheath jets. At Earth, a majority of magnetosheath jets are associated with the quasi-parallel bow shock. We discuss some consequences of the findings of the present investigation pertaining to the different nature of the quasi-parallel bow shock at Mercury and Earth.

  12. Predicting Solar Cycle 24 Using a Geomagnetic Precursor Pair

    NASA Technical Reports Server (NTRS)

    Pesnell, W. Dean

    2014-01-01

    We describe using Ap and F(10.7) as a geomagnetic-precursor pair to predict the amplitude of Solar Cycle 24. The precursor is created by using F(10.7) to remove the direct solar-activity component of Ap. Four peaks are seen in the precursor function during the decline of Solar Cycle 23. A recurrence index that is generated by a local correlation of Ap is then used to determine which peak is the correct precursor. The earliest peak is the most prominent but coincides with high levels of non-recurrent solar activity associated with the intense solar activity of October and November 2003. The second and third peaks coincide with some recurrent activity on the Sun and show that a weak cycle precursor closely following a period of strong solar activity may be difficult to resolve. A fourth peak, which appears in early 2008 and has recurrent activity similar to precursors of earlier solar cycles, appears to be the "true" precursor peak for Solar Cycle 24 and predicts the smallest amplitude for Solar Cycle 24. To determine the timing of peak activity it is noted that the average time between the precursor peak and the following maximum is approximately equal to 6.4 years. Hence, Solar Cycle 24 would peak during 2014. Several effects contribute to the smaller prediction when compared with other geomagnetic-precursor predictions. During Solar Cycle 23 the correlation between sunspot number and F(10.7) shows that F(10.7) is higher than the equivalent sunspot number over most of the cycle, implying that the sunspot number underestimates the solar-activity component described by F(10.7). During 2003 the correlation between aa and Ap shows that aa is 10 % higher than the value predicted from Ap, leading to an overestimate of the aa precursor for that year. However, the most important difference is the lack of recurrent activity in the first three peaks and the presence of significant recurrent activity in the fourth. While the prediction is for an amplitude of Solar Cycle 24 of

  13. Observations of Chromospheric Anemone Jets with Hinode CaII Broadband Filtergraph and Hida CaII Spectroheliograph

    NASA Astrophysics Data System (ADS)

    Morita, Satoshi; Shibata, Kazunari; Ueno, Satoru; Ichimoto, Kiyoshi; Kitai, Reizaburo; Otsuji, Ken-Ichi

    2010-08-01

    We report on the first simultaneous observations of chromospheric ``anemone'' jets in solar active regions with the Hinode Solar Optical Telescope (SOT) CaII H broadband filtergraph and the CaII K spetroheliograph on the Domeless Solar Telescope (DST) at Hida Observatory. During the period of coordinated observations, nine chromospheric anemone jets were simultaneously observed with the two instruments. These observations revealed three important features: (1) the jets are generated in the lower chromosphere; i.e., these cannot be seen in CaII K3; (2) the length and lifetime of the jets are 0.4-5 Mm and 40-320 s, respectively; (3) the apparent velocity of the jets observed with the SOT is 3-24 km s-1, while the CaII K3 component at the jets shows a blueshift (in 5 events) in the range of 2-6 km s-1. The chromospheric anemone jets are associated with mixed polarity regions, which are either small emerging flux regions or moving magnetic features. It is found that the CaII K line often shows red or blue asymmetry in the K2/K1 component; the footpoint of the jets associated with emerging flux regions often shows a redshift (2-16 km s-1), while the one with moving magnetic features shows a blueshift (˜5 km s-1). A detailed analysis of the magnetic evolution of the jet-forming regions revealed that the reconnection rate (or canceling rate) of the total magnetic flux at the footpoint of the jets is on the order of 1016 Mx s-1, and the resulting magnetic energy release rate is (1.1-10) × 1024 erg s-1, with a total energy release of (1-13) × 1026 erg for the duration of the magnetic cancellation, ˜130 s. These are comparable to the estimated total energy, ˜1026 erg, in a single chromospheric anemone jet. In addition to the DST CaII K spectroheliogram and the SOT CaII H broadband filtergram, we also used for analysis an SOT magnetogram as well as a Hida Hα filtergram. We present a physical model of the jet based on the observation, and discuss the relation between

  14. Solar energy

    NASA Technical Reports Server (NTRS)

    Rapp, D.

    1981-01-01

    The book opens with a review of the patterns of energy use and resources in the United States, and an exploration of the potential of solar energy to supply some of this energy in the future. This is followed by background material on solar geometry, solar intensities, flat plate collectors, and economics. Detailed attention is then given to a variety of solar units and systems, including domestic hot water systems, space heating systems, solar-assisted heat pumps, intermediate temperature collectors, space heating/cooling systems, concentrating collectors for high temperatures, storage systems, and solar total energy systems. Finally, rights to solar access are discussed.

  15. Solar energy

    NASA Astrophysics Data System (ADS)

    Rapp, D.

    The book opens with a review of the patterns of energy use and resources in the United States, and an exploration of the potential of solar energy to supply some of this energy in the future. This is followed by background material on solar geometry, solar intensities, flat plate collectors, and economics. Detailed attention is then given to a variety of solar units and systems, including domestic hot water systems, space heating systems, solar-assisted heat pumps, intermediate temperature collectors, space heating/cooling systems, concentrating collectors for high temperatures, storage systems, and solar total energy systems. Finally, rights to solar access are discussed.

  16. Strategic Forcing of Jets in Crossflow

    NASA Astrophysics Data System (ADS)

    Davitian, Juliett; Rodriguez, Edson; M'closkey, Robert; Karagozian, Ann

    2007-11-01

    This presentation will describe recent experiments that explore the response of a gaseous jet in crossflow to alternative methods of acoustic forcing. Building on an extensive prior exploration of transverse jet upstream shear layer instabilitiesootnotetextMegerian, Davitian, Alves, and Karagozian, JFM, to appear., the present studies employ alternative temporal waveforms for jet forcing, depending on the jet-to- crossflow velocity ratio R, through which transverse jet behavior may be strategically controlled. Smoke visualization is used to observe jet response to forcing. Jets that are injected both flush and elevated with respect to the wind tunnel surface are considered. For values of R > 3.5, prior studies show that the jet's shear layer instabilities appear convective in nature, and hence low to moderate sinusoidal jet forcing can impact jet shear layer response and spread. In contrast, for relatively low values of R (below 3.5 for the flush jet and below 1.2 for the elevated jet), strong natural shear layer instabilities are generated, hence even high amplitude sinusoidal forcing has little effect. At these low R conditions, much higher amplitude square wave forcing is required to produce a jet response, necessitating the introduction of a characteristic time scale associated with vorticity generation.

  17. Radio Jet Interactions with Massive Clouds

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Wiita, P. J.; Joyce, J.; Hooda, J. S.

    1998-12-01

    Rather high resolution three-dimensional simulations of hydrodynamical jets are computed using the Zeus-3D code. The parameters we employ are suitable for moderate to high power radio jets emerging through a galactic atmosphere or halo, and eventually crossing a tilted pressure matched interface with a hotter intracluster medium. Before they cross this interface, these simulations aim the jets so that they hit massive clouds within the galactic halo, with densities 10 or more times higher than the ambient atmospheric density, and 100's of times the jet density. Such clouds are set up with radii several times that of the jet, and could correspond to giant molecular cloud complexes or small cannibalized galaxies. We find that powerful jets eventually disperse the clouds, but that, for off-center collisions, non-axisymmetric instabilities are induced in those jets. Those instabilities grow faster for lower Mach number jets, and can produce disruptions substantially sooner than occurred in our earlier work on jets crossing tilted interfaces in the absence of collisions with massive clouds. Such interactions, particularly with weaker jets, could be related to some Compact Steep Spectrum source morphologies. Very weak jets can be effectively halted by reasonably massive clouds, and this may have relevance for the paucity of radio jets in spiral galaxies. The possibility of jets being bent, yet remaining stable, after such collisions is also investigated. This work was supported by NPACI allocation GSU200 on the Cray T90 and by RPE funds at Georgia State University.

  18. Solar Systems

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The solar collectors shown are elements of domestic solar hot water systems produced by Solar One Ltd., Virginia Beach, Virginia. Design of these systems benefited from technical expertise provided Solar One by NASA's Langley Research Center. The company obtained a NASA technical support package describing the d e sign and operation of solar heating equipment in NASA's Tech House, a demonstration project in which aerospace and commercial building technology are combined in an energy- efficient home. Solar One received further assistance through personal contact with Langley solar experts. The company reports that the technical information provided by NASA influenced Solar One's panel design, its selection of a long-life panel coating which increases solar collection efficiency, and the method adopted for protecting solar collectors from freezing conditions.

  19. Numerical Simulations of Chromospheric Anemone Jets Associated with Moving Magnetic Features

    NASA Astrophysics Data System (ADS)

    Yang, Liping; He, Jiansen; Peter, Hardi; Tu, Chuanyi; Zhang, Lei; Feng, Xueshang; Zhang, Shaohua

    2013-11-01

    Observations with the space-based solar observatory Hinode show that small-scale magnetic structures in the photosphere are found to be associated with a particular class of jets of plasma in the chromosphere called anemone jets. The goal of our study is to conduct a numerical experiment of such chromospheric anemone jets related to the moving magnetic features (MMFs). We construct a 2.5 dimensional numerical MHD model to describe the process of magnetic reconnection between the MMFs and the pre-existing ambient magnetic field, which is driven by the horizontal motion of the magnetic structure in the photosphere. We include thermal conduction parallel to the magnetic field and optically thin radiative losses in the corona to account for a self-consistent description of the evaporation process during the heating of the plasma due to the reconnection process. The motion of the MMFs leads to the expected jet and our numerical results can reproduce many observed characteristics of chromospheric anemone jets, topologically and quantitatively. As a result of the tearing instability, plasmoids are generated in the reconnection process that are consistent with the observed bright moving blobs in the anemone jets. An increase in the thermal pressure at the base of the jet is also driven by the reconnection, which induces a train of slow-mode shocks propagating upward. These shocks are a secondary effect, and only modulate the outflow of the anemone jet. The jet itself is driven by the energy input due to the reconnection of the MMFs and the ambient magnetic field.

  20. NUMERICAL SIMULATIONS OF CHROMOSPHERIC ANEMONE JETS ASSOCIATED WITH MOVING MAGNETIC FEATURES

    SciTech Connect

    Yang, Liping; He, Jiansen; Tu, Chuanyi; Zhang, Lei; Peter, Hardi; Feng, Xueshang; Zhang, Shaohua

    2013-11-01

    Observations with the space-based solar observatory Hinode show that small-scale magnetic structures in the photosphere are found to be associated with a particular class of jets of plasma in the chromosphere called anemone jets. The goal of our study is to conduct a numerical experiment of such chromospheric anemone jets related to the moving magnetic features (MMFs). We construct a 2.5 dimensional numerical MHD model to describe the process of magnetic reconnection between the MMFs and the pre-existing ambient magnetic field, which is driven by the horizontal motion of the magnetic structure in the photosphere. We include thermal conduction parallel to the magnetic field and optically thin radiative losses in the corona to account for a self-consistent description of the evaporation process during the heating of the plasma due to the reconnection process. The motion of the MMFs leads to the expected jet and our numerical results can reproduce many observed characteristics of chromospheric anemone jets, topologically and quantitatively. As a result of the tearing instability, plasmoids are generated in the reconnection process that are consistent with the observed bright moving blobs in the anemone jets. An increase in the thermal pressure at the base of the jet is also driven by the reconnection, which induces a train of slow-mode shocks propagating upward. These shocks are a secondary effect, and only modulate the outflow of the anemone jet. The jet itself is driven by the energy input due to the reconnection of the MMFs and the ambient magnetic field.

  1. THE PARABOLIC JET STRUCTURE IN M87 AS A MAGNETOHYDRODYNAMIC NOZZLE

    SciTech Connect

    Nakamura, Masanori; Asada, Keiichi E-mail: asada@asiaa.sinica.edu.tw

    2013-10-01

    The structure and dynamics of the M87 jet from sub-milliarcsec to arcsecond scales are continuously examined. We analyzed the Very Long Baseline Array archival data taken at 43 and 86 GHz to measure the size of very long baseline interferometry (VLBI) cores. Millimeter/sub-millimeter VLBI cores are considered as innermost jet emissions, which has been originally suggested by Blandford and Königl. Those components fairly follow an extrapolated parabolic streamline in our previous study so that the jet has a single power-law structure with nearly 5 orders of magnitude in the distance starting from the vicinity of the supermassive black hole (SMBH), less than 10 Schwarzschild radius (r{sub s}). We further inspect the jet parabolic structure as a counterpart of the magnetohydrodynamic (MHD) nozzle in order to identify the property of a bulk acceleration. We interpret that the parabolic jet consists of Poynting-flux dominated flows, powered by large-amplitude, nonlinear torsional Alfvén waves. We examine the non-relativistic MHD nozzle equation in a parabolic shape. The nature of trans-fast magnetosonic flow is similar to the one of transonic solution of Parker's hydrodynamic solar wind; the jet becomes super-escape as well as super-fast magnetosonic at around ∼10{sup 3} r{sub s}, while the upstream trans-Alfvénic flow speed increases linearly as a function of the distance at ∼10{sup 2}-10{sup 3} r{sub s}. We here point out that this is the first evidence to identify these features in astrophysical jets. We propose that the M87 jet is magnetically accelerated, but thermally confined by the stratified interstellar medium inside the sphere of gravitational influence of the SMBH potential, which may be a norm in active galactic nucleus jets.

  2. The Source Of Dust Jets Seen In Comet 103p/hartley 2.

    NASA Astrophysics Data System (ADS)

    Belton, Michael J. S.

    2012-10-01

    Comet 103P/Hartley 2 displays at least three different types of jet phenomena: highly structured CO2 driven jets seen in EPOXI encounter images (A’Hearn et al 2011), large scale jet phenomena that show in CN emission (e.g. Knight and Schleicher, 2012), and fainter dust jet or “cloud” structures seen in ground-based images (Lara et al., (2011), Mueller et al., (2012), Tozzi et al., 2012, Knight and Schleicher, 2012). The dust jets are observed to change their projected orientations slowly from night-to-night, and even during a night. From this behavior Knight and Schleicher (2012) have suggested that the source of the jets might be located near the comet’s total angular momentum vector and that they might be driven by CO, or more likely, CO2. In this paper we investigate the source of the dust jets using the shape modelof the comet’s nucleus (Thomas et al 2012) and a model of the comet’s complex spin state (Belton et al 2012) based on EPOXI observations. We show that the reason why the dust jet changes its projected direction is most likely the changing orientation of the surface at the sub-solar region during the spin cycle. In this scenario the jet source is not tied to the surface and is most likely driven by H2O sublimation. A’Hearn et al. 2011. Science 332, 1396-1400. Lara et al. 2011, A&A 532, A87 Mueller et al. 2012, AAS meeting 220, Abstract #120.03 Tozzi et al. 2012, preprint, submitted to Icarus Knight & Schleicher, 2012, Icarus, accepted for publication Thomas et al. 2012, Icarus, accepted for publication Belton et al. 2012, Icarus, accepted for publication

  3. Sonoporation from Jetting Cavitation Bubbles

    PubMed Central

    Ohl, Claus-Dieter; Arora, Manish; Ikink, Roy; de Jong, Nico; Versluis, Michel; Delius, Michael; Lohse, Detlef

    2006-01-01

    The fluid dynamic interaction of cavitation bubbles with adherent cells on a substrate is experimentally investigated. We find that the nonspherical collapse of bubbles near to the boundary is responsible for cell detachment. High-speed photography reveals that a wall bounded flow leads to the detachment of cells. Cells at the edge of the circular area of detachment are found to be permanently porated, whereas cells at some distance from the detachment area undergo viable cell membrane poration (sonoporation). The wall flow field leading to cell detachment is modeled with a self-similar solution for a wall jet, together with a kinetic ansatz of adhesive bond rupture. The self-similar solution for the δ-type wall jet compares very well with the full solution of the Navier-Stokes equation for a jet of finite thickness. Apart from annular sites of sonoporation we also find more homogenous patterns of molecule delivery with no cell detachment. PMID:16950843

  4. Whipping of electrified liquid jets.

    PubMed

    Guerrero, Josefa; Rivero, Javier; Gundabala, Venkata R; Perez-Saborid, Miguel; Fernandez-Nieves, Alberto

    2014-09-23

    We apply an electric field to a moderately conducting liquid surrounded by another coflowing liquid, all inside a glass-based microfluidic device, to study nonaxisymmetric instabilities. We find that the bending of the electrified jet results in a steady-state, helicoidal structure with a constant opening angle. Remarkably, the characteristic phase speed of the helicoidal wave only depends on the charge carried by the jet in the helicoidal region and its stability critically depends on the properties of the coflowing liquid. In fact, the steady-state helical structure becomes chaotic when the longest characteristic time is that of the inner liquid rather than that of the outer coflowing liquid. We also perform a numerical analysis to show that the natural preference of the jet is to adopt the conical helix structure observed experimentally. PMID:25201984

  5. Launching jets from accretion belts

    NASA Astrophysics Data System (ADS)

    Schreier, Ron; Soker, Noam

    2016-05-01

    We propose that sub-Keplerian accretion belts around stars might launch jets. The sub-Keplerian inflow does not form a rotationally supported accretion disk, but it rather reaches the accreting object from a wide solid angle. The basic ingredients of the flow are a turbulent region where the accretion belt interacts with the accreting object via a shear layer, and two avoidance regions on the poles where the accretion rate is very low. A dynamo that is developed in the shear layer amplifies magnetic fields to high values. It is likely that the amplified magnetic fields form polar outflows from the avoidance regions. Our speculative belt-launched jets model has implications on a rich variety of astrophysical objects, from the removal of common envelopes to the explosion of core collapse supernovae by jittering jets.

  6. Crossflow Mixing of Noncircular Jets

    NASA Technical Reports Server (NTRS)

    Liscinsky, D. S.; True, B.; Holdeman, J. D.

    1995-01-01

    An experimental investigation has been conducted of the isothermal mixing of a turbulent jet injected perpendicular to a uniform crossflow through several different types of sharp-edged orifices. Jet penetration and mixing was studied using planar Mie scattering to measure time-averaged mixture fraction distributions of circular, square, elliptical, and rectangular orifices of equal geometric area injected into a constant velocity crossflow. Hot-wire anemometry was also used to measure streamwise turbulence intensity distributions at several downstream planes. Mixing effectiveness was determined using (1) a spatial unmixedness parameter based on the variance of the mean jet concentration distributions and (2) by direct comparison of the planar distributions of concentration and of turbulence intensity. No significant difference in mixing performance was observed for the six configurations based on comparison of the mean properties.

  7. Electron jet of asymmetric reconnection

    NASA Astrophysics Data System (ADS)

    Khotyaintsev, Yu. V.; Graham, D. B.; Norgren, C.; Eriksson, E.; Li, W.; Johlander, A.; Vaivads, A.; André, M.; Pritchett, P. L.; Retinò, A.; Phan, T. D.; Ergun, R. E.; Goodrich, K.; Lindqvist, P.-A.; Marklund, G. T.; Le Contel, O.; Plaschke, F.; Magnes, W.; Strangeway, R. J.; Russell, C. T.; Vaith, H.; Argall, M. R.; Kletzing, C. A.; Nakamura, R.; Torbert, R. B.; Paterson, W. R.; Gershman, D. J.; Dorelli, J. C.; Avanov, L. A.; Lavraud, B.; Saito, Y.; Giles, B. L.; Pollock, C. J.; Turner, D. L.; Blake, J. D.; Fennell, J. F.; Jaynes, A.; Mauk, B. H.; Burch, J. L.

    2016-06-01

    We present Magnetospheric Multiscale observations of an electron-scale current sheet and electron outflow jet for asymmetric reconnection with guide field at the subsolar magnetopause. The electron jet observed within the reconnection region has an electron Mach number of 0.35 and is associated with electron agyrotropy. The jet is unstable to an electrostatic instability which generates intense waves with E∥ amplitudes reaching up to 300 mV m-1 and potentials up to 20% of the electron thermal energy. We see evidence of interaction between the waves and the electron beam, leading to quick thermalization of the beam and stabilization of the instability. The wave phase speed is comparable to the ion thermal speed, suggesting that the instability is of Buneman type, and therefore introduces electron-ion drag and leads to braking of the electron flow. Our observations demonstrate that electrostatic turbulence plays an important role in the electron-scale physics of asymmetric reconnection.

  8. Two Jet Production at CDF

    SciTech Connect

    Dell'Agnello, Simone; /INFN, Pisa

    1989-01-01

    CDF (Collider Detector at Fermilab) is a full-coverage magnetic detector studying p{bar p} collisions at the {radical}s = 1.8 TeV Tevatron Collider. The experiment has collected a handful of demonstration events towards the end 1985, and had its first significant run in spring 1987. Most of this run was operated with a 'buffet trigger', one stream of which was an inclusive large-E{sub t} trigger. Large E{sub t} (E{sub t} >50 GeV) events at the Tevatron show an increasingly dominant component with two or more hard jets. This thesis consists in an analysis of these jet events. The invariant cross-secton as a function of jet pair mass (M{sub jj}) is derived.

  9. Flow induction by rotary jets

    NASA Astrophysics Data System (ADS)

    Garris, Charles A.; Foa, Joseph V.

    Theoretical analyses of generalized flow induction were carried out which showed that the least dissipative mode of flow induction is the cryptosteady mode. Studies were carried out on the energetics of vortex formation showing that in pulsatile thrust augmentors, considerable energy is carried away as kinetic energy of rotation. Parametric studies were conducted on rotary-jet thrust augmentation yielding a best thrust augmentation of 1.97. Theoretical and experimental studies on the utilization of propagating stall were conducted. The promise of eliminating moving parts for the rotary-jet thrust augmentor was explored and parametric testing was conducted to establish conditions for obtaining stall. Experiments showed, however, that stall is relatively difficult to obtain in configurations compatible with the rotary jet thrust augmentor.

  10. Whipping of electrified liquid jets

    PubMed Central

    Guerrero, Josefa; Rivero, Javier; Gundabala, Venkata R.; Perez-Saborid, Miguel; Fernandez-Nieves, Alberto

    2014-01-01

    We apply an electric field to a moderately conducting liquid surrounded by another coflowing liquid, all inside a glass-based microfluidic device, to study nonaxisymmetric instabilities. We find that the bending of the electrified jet results in a steady-state, helicoidal structure with a constant opening angle. Remarkably, the characteristic phase speed of the helicoidal wave only depends on the charge carried by the jet in the helicoidal region and its stability critically depends on the properties of the coflowing liquid. In fact, the steady-state helical structure becomes chaotic when the longest characteristic time is that of the inner liquid rather than that of the outer coflowing liquid. We also perform a numerical analysis to show that the natural preference of the jet is to adopt the conical helix structure observed experimentally. PMID:25201984

  11. Whipping of electrified liquid jets.

    PubMed

    Guerrero, Josefa; Rivero, Javier; Gundabala, Venkata R; Perez-Saborid, Miguel; Fernandez-Nieves, Alberto

    2014-09-23

    We apply an electric field to a moderately conducting liquid surrounded by another coflowing liquid, all inside a glass-based microfluidic device, to study nonaxisymmetric instabilities. We find that the bending of the electrified jet results in a steady-state, helicoidal structure with a constant opening angle. Remarkably, the characteristic phase speed of the helicoidal wave only depends on the charge carried by the jet in the helicoidal region and its stability critically depends on the properties of the coflowing liquid. In fact, the steady-state helical structure becomes chaotic when the longest characteristic time is that of the inner liquid rather than that of the outer coflowing liquid. We also perform a numerical analysis to show that the natural preference of the jet is to adopt the conical helix structure observed experimentally.

  12. Z (+jets) At The Tevatron

    SciTech Connect

    Hesketh, Gavin G.

    2008-10-01

    We report on recent Z (+jets) measurements from the Fermilab Tevatron proton anti-proton collider. A new D0 measurement of the transverse momentum of Z bosons yields the best measurement to date of the non-perturbative form factor, g2. The production of Z+jets is an major background to many rare signals, and is a vital testing ground for theoretical predictions. Measurements from CDF and D0 of differential cross sections in Z+jet production test NLO pQCD, and in the case of D0, the latest tree-level matrix element with matched parton shower calculations. Improving modeling of this signal will impact results from the Fermilab Tevatron and CERN LHC.

  13. Comparing different Ultraviolet Imaging Spectrograph (UVIS) occultation observations using modeling of water vapor jets

    NASA Astrophysics Data System (ADS)

    Portyankina, Ganna; Esposito, Larry W.; Hansen, Candice; Aye, Klaus-Michael

    2016-10-01

    Motivation: On March 11, 2016 the Cassini UVIS observed its 6th star occultation by Enceladus' plume. This observation was aimed to determine variability in the total gas flux from the Enceladus' southern polar region. The analysis of the received data suggests that the total gas flux is moderately increased comparing to the average gas flux observed by UVIS from 2005 to 2011 [1]. However, UVIS detected variability in individual jets. In particular, Baghdad 1 is more collimated in 2016 than in 2005, meaning its gas escapes at higher velocity.Model and fits: We use 3D DSMC model for water vapor jets to compare different UVIS occultation observations from 2005 to 2016. The model traces test articles from jets' sources [2] into space and results in coordinates and velocities for a set of test particles. We convert particle positions into the particle number density and integrate along UVIS line of sight (LoS) for each time step of the UVIS observation using precise observational geometry derived from SPICE [3]. We integrate all jets that are crossed by the LoS and perform constrained least-squares fit of resulting modeled opacities to the observed data to solved for relative strengths of jets. The geometry of each occultation is specific, for example, during solar occultation in 2010 UVIS LoS was almost parallel to tiger stripes, which made it possible to distinguish jets venting from different tiger stripes. In 2011 Eps Orionis occultation LoS was perpendicular to tiger stripes and thus many of the jets were geometrically overlapping. Solar occultation provided us with the largest inventory of active jets – our model fit detects at least 43 non-zero jet contributions. Stellar occultations generally have lower temporal resolution and observe only a sub-set of these jets: 2011 Eps Orionis needs minimum 25 non-zero jets to fit UVIS data. We will discuss different occultations and models fits, including the most recent Epsilon Orionis occultation of 2016.[1] Hansen et

  14. HUBBLE IMAGES REVEAL A YOUNG STAR'S DYNAMIC DISK AND JETS

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These images of HH 30 show changes over only a five-year period in the disk and jets of this newborn star, which is about half a million years old. The pictures were taken between 1995 and 2000 with the Wide Field and Planetary Camera 2 aboard NASA's Hubble Space Telescope. Astronomers are interested in the disk because it is probably similar to the one from which the Sun and the planets in our solar system formed. Hubble reveals an edge-on disk (located at the bottom of the images), which appears as a flattened cloud of dust split into two halves by a dark lane. The disk blocks light from the central star. All that is visible is the reflection of the star's light by dust above and below the plane of the disk. The disk's diameter is 450 astronomical units (one astronomical unit equals the Earth-Sun distance). Shadows billions of miles in size can be seen moving across the disk. In 1995 and 2000, the left and right sides of the disk were about the same brightness, but in 1998 the right side was brighter. These patterns may be caused by bright spots on the star or variations in the disk near the star. The dust cloud near the top of these frames is illuminated by the star and reflects changes in its brightness. The star's magnetic field plays a major role in forming the jets (located above and below the disk), which look like streams of water from a fire hose. The powerful magnetic field creates the jets by channeling gas from the disk along the magnetic poles above and below the star. The gaps between the compact knots of gas seen in the jet above the disk indicate that this is a sporadic process. By tracking the motion of these knots over time, astronomers have measured the jet's speed at between 200,000 to 600,000 miles per hour (160,000 and 960,000 kilometers per hour). Oddly, the jet below the disk is moving twice as fast as the one above it. Credits: NASA, Alan Watson (Universidad Nacional Autonoma de Mexico), Karl Stapelfeldt (Jet Propulsion Laboratory), John

  15. Advanced thermally stable jet fuels

    SciTech Connect

    Schobert, H.H.

    1999-01-31

    The Pennsylvania State University program in advanced thermally stable coal-based jet fuels has five broad objectives: (1) Development of mechanisms of degradation and solids formation; (2) Quantitative measurement of growth of sub-micrometer and micrometer-sized particles suspended in fuels during thermal stressing; (3) Characterization of carbonaceous deposits by various instrumental and microscopic methods; (4) Elucidation of the role of additives in retarding the formation of carbonaceous solids; (5) Assessment of the potential of production of high yields of cycloalkanes by direct liquefaction of coal. Future high-Mach aircraft will place severe thermal demands on jet fuels, requiring the development of novel, hybrid fuel mixtures capable of withstanding temperatures in the range of 400--500 C. In the new aircraft, jet fuel will serve as both an energy source and a heat sink for cooling the airframe, engine, and system components. The ultimate development of such advanced fuels requires a thorough understanding of the thermal decomposition behavior of jet fuels under supercritical conditions. Considering that jet fuels consist of hundreds of compounds, this task must begin with a study of the thermal degradation behavior of select model compounds under supercritical conditions. The research performed by The Pennsylvania State University was focused on five major tasks that reflect the objectives stated above: Task 1: Investigation of the Quantitative Degradation of Fuels; Task 2: Investigation of Incipient Deposition; Task 3: Characterization of Solid Gums, Sediments, and Carbonaceous Deposits; Task 4: Coal-Based Fuel Stabilization Studies; and Task 5: Exploratory Studies on the Direct Conversion of Coal to High Quality Jet Fuels. The major findings of each of these tasks are presented in this executive summary. A description of the sub-tasks performed under each of these tasks and the findings of those studies are provided in the remainder of this volume

  16. A symmetrically pulsed jet of gas from an invisible protostar in Orion.

    PubMed

    Zinnecker, H; McCaughrean, M J; Rayner, J T

    1998-08-27

    Young stars are thought to accumulate most of their mass through an accretion disk, which channels the gas and dust of a collapsing cloud onto the central protostellar object. The rotational and magnetic forces in the star-disk system often produce high-velocity jets of outflowing gas. These jets can in principle be used to study the accretion and ejection history of the system, which is hidden from direct view by the dust and dense gas of the parent cloud. But the structures of these jets are often too complex to determine which features arise at the source and which are the result of subsequent interactions with the surrounding gas. Here we present infrared observations of a very young jet driven by an invisible protostar in the vicinity of the Horsehead nebula in Orion. These observations reveal a sequence of geyser-like eruptions occurring at quasi-regular intervals and with near-perfect mirror symmetry either side of the source. This symmetry is strong evidence that such features must be associated with the formation of the jet, probably related to recurrent or even chaotic instabilities in the accretion disk.

  17. A symmetrically pulsed jet of gas from an invisible protostar in Orion.

    PubMed

    Zinnecker, H; McCaughrean, M J; Rayner, J T

    1998-08-27

    Young stars are thought to accumulate most of their mass through an accretion disk, which channels the gas and dust of a collapsing cloud onto the central protostellar object. The rotational and magnetic forces in the star-disk system often produce high-velocity jets of outflowing gas. These jets can in principle be used to study the accretion and ejection history of the system, which is hidden from direct view by the dust and dense gas of the parent cloud. But the structures of these jets are often too complex to determine which features arise at the source and which are the result of subsequent interactions with the surrounding gas. Here we present infrared observations of a very young jet driven by an invisible protostar in the vicinity of the Horsehead nebula in Orion. These observations reveal a sequence of geyser-like eruptions occurring at quasi-regular intervals and with near-perfect mirror symmetry either side of the source. This symmetry is strong evidence that such features must be associated with the formation of the jet, probably related to recurrent or even chaotic instabilities in the accretion disk. PMID:9732868

  18. Alisertib in Treating Young Patients With Recurrent or Refractory Solid Tumors or Leukemia

    ClinicalTrials.gov

    2016-07-20

    Hepatoblastoma; Previously Treated Childhood Rhabdomyosarcoma; Recurrent Childhood Acute Lymphoblastic Leukemia; Recurrent Childhood Acute Myeloid Leukemia; Recurrent Childhood Kidney Neoplasm; Recurrent Childhood Malignant Germ Cell Tumor; Recurrent Childhood Rhabdomyosarcoma; Recurrent Childhood Soft Tissue Sarcoma; Recurrent Ewing Sarcoma/Peripheral Primitive Neuroectodermal Tumor; Recurrent Neuroblastoma; Recurrent Osteosarcoma

  19. Dasatinib in Treating Patients With Recurrent or Persistent Ovarian, Fallopian Tube, Endometrial or Peritoneal Cancer

    ClinicalTrials.gov

    2016-11-02

    Endometrial Clear Cell Adenocarcinoma; Estrogen Receptor Negative; Ovarian Clear Cell Cystadenocarcinoma; Recurrent Fallopian Tube Carcinoma; Recurrent Ovarian Carcinoma; Recurrent Primary Peritoneal Carcinoma; Recurrent Uterine Corpus Carcinoma

  20. Particle Acceleration in Collapsing Magnetic Traps with a Braking Plasma Jet

    NASA Astrophysics Data System (ADS)

    Borissov, Alexei; Neukirch, Thomas; Threlfall, James

    2016-05-01

    Collapsing magnetic traps (CMTs) are one proposed mechanism for generating non-thermal particle populations in solar flares. CMTs occur if an initially stretched magnetic field structure relaxes rapidly into a lower-energy configuration, which is believed to happen as a by-product of magnetic reconnection. A similar mechanism for energising particles has also been found to operate in the Earth's magnetotail. One particular feature proposed to be of importance for particle acceleration in the magnetotail is that of a braking plasma jet, i.e. a localised region of strong flow encountering stronger magnetic field which causes the jet to slow down and stop. Such a feature has not been included in previously proposed analytical models of CMTs for solar flares. In this work we incorporate a braking plasma jet into a well studied CMT model for the first time. We present results of test particle calculations in this new CMT model. We observe and characterise new types of particle behaviour caused by the magnetic structure of the jet braking region, which allows electrons to be trapped both in the braking jet region and the loop legs. We compare and contrast the behaviour of particle orbits for various parameter regimes of the underlying trap by examining particle trajectories, energy gains and the frequency with which different types of particle orbit are found for each parameter regime.