218
218
Jun 11, 2011
06/11
by
Refaat, Tamer F.; Abedin, M. Nurul; Sulima, Oleg V.; Singh, Upendra N.; Ismail, Sye
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Two-micron detectors are critical for atmospheric carbon dioxide profiling using the lidar technique. The characterization results of a novel infrared AlGaAsSb/ InGaAsSb phototransistor are reported. Emitter dark current variation with the collector-emitter voltage at different temperatures is acquired to examine the gain mechanism. Spectral response measurements resulted in responsivity as high as 2650 A/W at 2.05 m wavelength. Bias voltage and temperature effects on the device responsivity...
Topics: MAGNETOHYDRODYNAMICS, CORONAL HOLES, SOLAR WIND, SPHERICAL COORDINATES, MAGNETIC FIELD...
Seven solar flares that were followed by major proton events were examined to determine the diverse and common properties of major flares. The most probable site of primary proton acceleration is cospatial with the site and instant of formation of coronal loops. Because loop formation occurs through the entire duration of major solar flares over significantly large areas of active centers, it is proposed that proton injection occurs from a relatively large volume of space in the corona of...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELD RECONNECTION, PARTICLE EMISSION, SOLAR FLARES,...
283
283
May 23, 2011
05/11
by
Matthews, K.; Ghez, A. M.; Weinberger, A. J.; Neugebauer, G
texts
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The first diffraction limited, 0.05s resolution, images on the W. M. Keck Telescope have been obtained at a wavelength of 2.2 micrometers. These images were part of an experiment to test the suitability of the Keck Telescope for speckle imaging. In order to conduct this test, it was necessary to modify the pixel scale of the Keck facility Near Infrared Camera (NIRC) to optimally sample the spatial frequencies made available by the Keck telescope. The design and implementation of the external...
Topics: MAGNETIC STORMS, GEOMAGNETIC TAIL, AURORAS, PLASMA LAYERS, MAGNETIC FIELDS, MAGNETOHYDRODYNAMIC...
The physical nature of solar flares implied by the data was studied. The empirical results were obtained primarily from the OGO-5 and OSO-7 X-ray data in combination with optical data. The principal conclusions regarding the physics of flares are the following. (1) Flares are produced by magnetic field reconnection. (2) The resulting thermal X-ray plasma is cooled primarily by heat conduction rather than by radiative cooling. (3) The heating and cooling of the thermal X-ray plasma are...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELD RECONNECTION, OGO-5, OSO-7, SOLAR FLARES,...
684
684
May 26, 2011
05/11
by
Dressler, B. O.; Sharpton, V. L
texts
eye 684
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The Slate Islands impact structure is the eroded remnant of a approximately 30-32 km-diameter complex impact structure located in northern Lake Superior, Ontario, Canada. Target rocks are Archean supracrustal and igneous rocks and Proterozoic metavolcanics, metasediments, and diabase. A wide variety of breccias occurs on the islands, many of which contain fragments exhibiting shock metamorphic features. Aphanitic, narrow and inclusion-poor pseudotachylite veins, commonly with more or less...
Topics: MAGNETIC FIELD RECONNECTION, MATHEMATICAL MODELS, SPACE PLASMAS, STAGNATION POINT, MAGNETIC FIELDS,...
The THEMIS mission represents the culmination of many years of planning directed towards understanding the processes that drive and trigger geomagnetic substorms. Following Akasofu's discovery of the substorm cycle, it became increasingly clear that timing questions provide the key to discriminating between proposed 'inside-out' and 'outside-in' models for substorms, triggered respectively by current disruption and magnetic reconnection. THEMIS observations provide a wealth of information that...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC STORMS, GEOMAGNETISM, MAGNETIC FIELD RECONNECTION,...
Supra-arcade downflows (SADs) observed above flaring active regions during long-duration events are theorized to be signatures of magnetic reconnection. Observations of SADs strongly indicate an association with shrinking reconnected flux tubes characterized by a specific magnetic topology. Plasmoids comprise another proposed group of observational reconnection signatures. While some plasmoids occur under nearly the same conditions as SADs, the magnetic configuration of the two phenomena are...
Topics: NASA Technical Reports Server (NTRS), PLASMAS (PHYSICS), MAGNETIC FIELD RECONNECTION, CURRENT...
206
206
May 31, 2011
05/11
by
Woods, Judy L.; West, Jeff S.; Sulyma, Peter R
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Lockheed Martin Space Operations - Stennis Programs (LMSO) at the John C Stennis Space Center (NASA/SSC) has designed and built a Beowulf computer cluster which is owned by NASA/SSC and operated by LMSO. The design and construction of the cluster are detailed in this paper. The cluster is currently used for Computational Fluid Dynamics (CFD) simulations. The CFD codes in use and their applications are discussed. Examples of some of the work are also presented. Performance benchmark studies have...
Topics: IO, PLANETARY MAGNETIC FIELDS, TORUSES, PLANETARY MAGNETOSPHERES, JUPITER (PLANET), FIELD ALIGNED...
301
301
Jun 2, 2011
06/11
by
Spruce, Joseph P.; Giardino, Marc
texts
eye 301
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Cultural resource surveys are important for compliance with Federal and State law. Stennis Space Center (SSC) in Mississippi is researching, developing, and validating remote sensing and Geographical Information System (GIS) methods for aiding cultural resource assessments on the center's own land. The suitability of IKONOS satellite imagery for georeferencing scanned historic maps is examined in this viewgraph presentation. IKONOS data can be used to map historic buildings and farmland in...
Topics: MAGNETOHYDRODYNAMICS, MAGNETOHYDRODYNAMIC FLOW, SOLAR WIND, MAGNETOSPHERES, PLASMA INTERACTIONS,...
434
434
May 23, 2011
05/11
by
Lee, Inhwan; Iyer, Ravishankar K
texts
eye 434
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Based on extensive field failure data for Tandem's GUARDIAN operating system this paper discusses evaluation of the dependability of operational software. Software faults considered are major defects that result in processor failures and invoke backup processes to take over. The paper categorizes the underlying causes of software failures and evaluates the effectiveness of the process pair technique in tolerating software faults. A model to describe the impact of software faults on the...
Topics: ACCRETION DISKS, ASTROPHYSICS, MAGNETIC FIELD RECONNECTION, INTERNAL WAVES, MAGNETOHYDRODYNAMIC...
220
220
May 6, 2010
05/10
by
Mittlefehldt, David W.; Yingst, R. A; Gellert, R.; Herkenhoff, K. E.; Clark, B. C.; Cohen, B. A.; Fleischer, I.; Jolliff, B. L.; Klingelhoefer, G.; Ming, D. W.
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While rolling over the Meridiani Planum sedimentary terrane, the rover Opportunity has occasionally discovered large, 10 cm erratics. Most of these have proven to be meteorites [1], but one - Bounce Rock - is a martian basaltic rock similar in composition to the meteorite EETA79001 lithology B [2]. Presently, Opportunity is intensively investigating an --30 cm tall rock named Marquette Island that may be a distinct type of martian mafic lithology. We report the results of its continuing...
Topics: CORONAL MASS EJECTION, MAGNETIC FIELD RECONNECTION, MAGNETIC FIELDS, SOLAR X-RAYS, CORONAL HOLES,...
The question of whether the microscale controls the macroscale or vice-versa remains one of the most challenging problems in plasmas. A particular topic of interest within this context is collisionless magnetic reconnection, where both points of views are espoused by different groups of researchers. This presentation will focus on this topic. We will begin by analyzing the properties of electron diffusion region dynamics both for guide field and anti-parallel reconnection, and how they can be...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELD RECONNECTION, MATHEMATICAL MODELS, ELECTRON...
291
291
May 24, 2011
05/11
by
NON
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Summary of research/publications include:(1) Comment on broadening of water microwave lines by collisions with helium atoms; (2) Calculations of ion-molecule deuterium fractionation reactions involving HD; (3) Ab initio predictions on the rotational spectra of carbon-chain carbene molecules; (4) Theoretical IR spectra of ionized naphthalene; (5) Improved collisional excitation rates for interstellar water; (6) Calculations on the competition between association and reaction for C3H H2; (7)...
Topics: MAGNETIC FIELD RECONNECTION, CONVECTION, MAGNETIC SIGNATURES, SOLAR FLARES, PHOTOSPHERE, SOLAR...
The role of turbulence in producing fast reconnection rates is an important unresolved question. Scant in situ analyses exist. We apply multiple spacecraft techniques to a case of nonlinear turbulent reconnection in the magnetosheath to test various theoretical results for turbulent reconnection rates. To date, in situ estimates of the contribution of turbulence to reconnection rates have been calculated from an effective electric field derived through linear wave theory. However, estimates of...
Topics: NASA Technical Reports Server (NTRS), MAGNETOSHEATH, TURBULENCE EFFECTS, HALL EFFECT, CLUSTER...
The question of whether the micro scale controls the macro scale or vice-versa remains one of the most challenging problems in plasmas. A particular topic of interest within this context is collisionless magnetic reconnection, where both points of views are espoused by different groups of researchers. This presentation will focus on this topic. We will begin by analyzing the global properties of magnetic reconnection. Following that, we discuss properties of electron diffusion region dynamics...
Topics: NASA Technical Reports Server (NTRS), ELECTRON DIFFUSION, TEMPORAL DISTRIBUTION, SECULAR...
The question of whether the microscale controls the macroscale or vice-versa remains one of the most challenging problems in plasmas. A particular topic of interest within this context is collisionless magnetic reconnection, where both points of views are espoused by different groups of researchers. This presentation will focus on this topic. We will begin by analyzing the properties of electron diffusion region dynamics both for guide field and anti-parallel reconnection, and how they can be...
Topics: NASA Technical Reports Server (NTRS), ELECTRON DIFFUSION, MAGNETIC FIELD RECONNECTION, MATHEMATICAL...
Extracting information from coronal features above flares has become more reliable with the availability of increasingly higher spatial- and temporal-resolution data in recent decades. We are now able to sufficiently probe the region high above long-duration flaring active regions where reconnection is expected to be continually occurring. Flows in the supra-arcade region, first observed with Yohkoh/SXT, have been theorized to be associated with newly-reconnected outflowing loops. High...
Topics: NASA Technical Reports Server (NTRS), PARTICLE ACCELERATION, SOLAR FLARES, MAGNETIC FIELD...
No abstract available
Topics: NASA Technical Reports Server (NTRS), SOLAR FLARES, CORONAL MASS EJECTION, HELIOSPHERE, MAGNETIC...
We investigate observations of intense bursts of electromagnetic waves in association with magnetic reconnection in the turbulent magnetosheath. These structured, broadband bursts occur above 80-Hz, often displaying features reminiscent of absorption bands and are observed at local minima in the magnetic field. We present detailed analyses of these intense bursts of electromagnetic waves and quantify their proximity to X- and O-nulls.
Topics: NASA Technical Reports Server (NTRS), ELECTROMAGNETIC RADIATION, MAGNETIC FIELD RECONNECTION,...
An analytical treatment has been developed to study some of the axisymmetric vortex breakdown and reconnection fluid dynamic processes underlying body-vortex interactions that are frequently manifested in rotorcraft and propeller-driven fixed-wing aircraft wakes. In particular, the presence of negative vorticity in the inner core of a vortex filament (one example of which is examined in this paper) subsequent to "cutting" by a solid body has a profound influence on the vortex...
Topics: NASA Technical Reports Server (NTRS), AIRCRAFT CONFIGURATIONS, VORTEX BREAKDOWN, VORTICES, VORTEX...
The primary purpose of the Theory and Modeling Group meeting was to identify scientists engaged or interested in theoretical work pertinent to the Max '91 program, and to encourage theorists to pursue modeling which is directly relevant to data which can be expected to result from the program. A list of participants and their institutions is presented. Two solar flare paradigms were discussed during the meeting -- the importance of magnetic reconnection in flares and the applicability of...
Topics: NASA Technical Reports Server (NTRS), ASTRONOMICAL MODELS, SOLAR FLARES, SOLAR PHYSICS,...
Two Dual Ion Spectrometer flight units of the Fast Plasma Instrument Suite (FPI) for the Magnetospheric Multiscale Mission (MMS) have returned to MSFC for flight testing. Anticipated to begin on June 30, tests will ensue in the Low Energy Electron and Ion Facility of the Heliophysics and Planetary Science Office (ZP13), managed by Dr. Victoria Coffey of the Natural Environments Branch of the Engineering Directorate (EV44). The MMS mission consists of four identical spacecraft, whose purpose is...
Topics: NASA Technical Reports Server (NTRS), MASS SPECTROMETERS, MAGNETIC FIELD RECONNECTION, PLASMAS...
Supra-arcade downflows (SADs) observed above flaring active regions during long-duration events are theorized to be signatures of magnetic reconnection. Observations of SADs strongly indicate an association with shrinking reconnected flux tubes characterized by a specific magnetic topology. Plasmoids comprise another proposed group of observational reconnection signatures. While some plasmoids occur under nearly the same conditions as SADs, the magnetic configuration of the two phenomena are...
Topics: NASA Technical Reports Server (NTRS), ASTROPHYSICS, SOLAR FLARES, PLASMAS (PHYSICS), MAGNETIC FIELD...
404
404
May 23, 2011
05/11
by
Bahcall, John; Fisher, Karl; Miralda-Escude, Jordi; Strauss, Michael; Weinberg, Davi
texts
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This grant supported research by the investigators through summer salary support for Strauss and Weinberg, support for graduate students at Princeton University and Ohio State University, and travel, visitor, and publication support for the investigators. The grant originally had a duration of 1 year, and it was extended (without additional funding) for an additional year. The impact of the grant was considerable given its relatively modest duration and funding level, in part because it...
Topics: CURRENT DENSITY, DYNAMIC RESPONSE, POLARITY, CORONAS, MAGNETIC FIELD CONFIGURATIONS, MAGNETIC...
The Geospace Dynamics Observatory (GDO) mission observes the near-Earth region in space called Geospace with unprecedented resolution, scale and sensitivity. At a distance of 60 Earth Radii (Re) in a near-polar circular orbit and at approximately 27-day period, GDO images the earth's full disk with: (1) a three-channel far ultraviolet imager, (2) an extreme ultraviolet imager of the plasmasphere, and (3) a spectrometer in the near to far ultraviolet range that probes any portion of the disk and...
Topics: NASA Technical Reports Server (NTRS), AERONOMY, MAGNETIC FIELD RECONNECTION, SOLAR WIND, COUPLING,...
The question of whether the micro scale controls the macroscale or vice-versa remains one of the most challenging problems in plasmas. A particular topic of interest within this context is collisionless magnetic reconnection, where both points of views are espoused by different groups of researchers. This presentation will focus on this topic. We will begin by analyzing the properties of electron diffusion region dynamics both for guide field and anti-parallel reconnection, and how they can be...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELD RECONNECTION, MATHEMATICAL MODELS, PLASMAS...
The following describes a list of errata in our paper, "A simple, analytical model of collisionless magnetic reconnection in a pair plasma." It supersedes an earlier erratum. We recently discovered an error in the derivation of the outflow-to-inflow density ratio.
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELD RECONNECTION, MATHEMATICAL MODELS, CORRECTION,...
The NASA Magnetospheric Multiscale (MMS) mission will fly four spinning spacecraft in formation in highly elliptical orbits to study the magnetosphere of the Earth. This paper describes the development of an MMS launch window tool that uses the orbitaveraged Variation of Parameter equations as the basis for a semi-analytic quantification of the dominant oblateness and lunisolar perturbation effects on the MMS orbit. This approach, coupled with a geometric interpretation of all of the MMS...
Topics: NASA Technical Reports Server (NTRS), LAUNCH WINDOWS, MAGNETIC FIELD RECONNECTION, EARTH...
A new analytic model describing a family of vortices has been developed to study some of the axisymmetric vortex breakdown and reconnection fluid dynamic processes underlying body-vortex interactions that are frequently manifested in rotorcraft and propeller-driven fixed-wing aircraft wakes. The family of vortices incorporates a wide range of prescribed initial vorticity distributions -- including single or dual-core vorticity distributions. The result is analytical solutions for the vorticity...
Topics: NASA Technical Reports Server (NTRS), VORTICES, WAKES, ROTARY WING AIRCRAFT, MAGNETIC FIELD...
The polar fields on the Sun are directly related to solar cycle variability. Recently there has been interest in studying an important characteristic of the polar fields: the timing of the polar field reversals. However this characteristic has been poorly defined, mostly due to the limitations of early observations. In the past, the reversals have been calculated by averaging the flux above some latitude (i.e. 55deg or 75deg). Alternatively, the reversal could be defined by the time in which...
Topics: NASA Technical Reports Server (NTRS), POLARITY, SOLAR MAGNETIC FIELD, SOLAR CYCLES, TRANSPORT...
A revolutionary opportunity to explore the consequences of reconnection in the ionosphere as never before will be presented. It is a revolutionary opportunity to explore key Aeronomy emissions on a global scale with spatial and temporal resolution not possible today. For example, observations of the signature of dayside merging and nightside reconnection that are reflected in the auroral oval evolution during disturbed periods and quiet times, will be described; observations that will open a...
Topics: NASA Technical Reports Server (NTRS), AERONOMY, MAGNETIC FIELD RECONNECTION, SOLAR WIND, EARTH...
Fast magnetic reconnection refers to annihilation or topological rearrangement of magnetic fields on a timescale that is independent (or nearly independent) of the plasma resistivity. The resistivity of astrophysical plasmas is so low that reconnection is of little practical interest unless it is fast. Yet, the theory of fast magnetic reconnection is on uncertain ground, as models must avoid the tendency of magnetic fields to pile up at the reconnection layer, slowing down the flow. In this...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELD RECONNECTION, MATHEMATICAL MODELS, SPACE...
Flux Transfer Events (FTEs) are magnetopause signatures that result from the passage of flux ropes produced by transient bursts of reconnection. They exhibit bipolar signatures in the component of the magnetic field normal to the magnetopause and transient increases or crater-like structures in the magnetic field strength. We use the bipolar magnetic field signatures and magnetic field strength variations observed by all four Cluster spacecrafts during the years of 2002 and 2003 to determine...
Topics: NASA Technical Reports Server (NTRS), FLUX TRANSFER EVENTS, MOTION, MAGNETOPAUSE, MAGNETIC...
Gamma-ray burst statistics are best explained by a source population at cosmological distances, while spectroscopy and intensity histories of some individual bursts imply an origin on Galactic neutron stars. To resolve this inconsistency I suggest the presence of two populations, one at cosmological distances and the other Galactic. I build on ideas of Shemi and Piran (1990) and of Rees and Mesozaros (1992) involving the interaction of fireball debris with surrounding clouds to explain the...
Topics: NASA Technical Reports Server (NTRS), COSMOLOGY, GAMMA RAY BURSTS, MAGNETIC FIELD RECONNECTION,...
Flux transfer events (FTEs) are ropes of interconnected magnetosheath and magnetospheric magnetic field lines generated by bursty reconnection at the dayside magnetopause. Theory predicts that the combined pressure gradient and magnetic curvature forces should determine the speed at which the events move and the locations where they can be observed. We present results indicating that events form on the dayside magnetopause for both northward and southward IMF orientations, but that the events...
Topics: NASA Technical Reports Server (NTRS), MAGNETOSHEATH, FLUX TRANSFER EVENTS, MAGNETIC FIELD...
363
363
May 29, 2011
05/11
by
Kleyner, I.; Katz, R.; Tiggeler, H
texts
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This paper presents a methodology and a tool set which implements automated generation of moderate-size blocks of customized intellectual property (IP), thus effectively reusing prior work and minimizing the labor intensive, error-prone parts of the design process. Customization of components allows for optimization for smaller area and lower power consumption, which is an important factor given the limitations of resources available in radiation-hardened devices. The effects of variations in...
Topics: SOLAR CORONA, IMAGE RESOLUTION, IMAGING TECHNIQUES, NONTHERMAL RADIATION, HEATING, SOLAR ACTIVITY,...
Disconnection event (DE) in cometary plasma physics is the regular loss of the entire plasma tail and the growth of the new one. Analysis of a sequence of DEs that occurred 13-18 April, 1986 shows that they correlate well with a magnetic, sector-boundary crossing and a complex magnetic structure in the solar wind with polarity reversals that occurred about one day later. These events are entirely consistent with sunward, magnetic reconnection as the DE mechanism.
Topics: NASA Technical Reports Server (NTRS), COMET TAILS, HALLEY'S COMET, MAGNETIC FIELD CONFIGURATIONS,...
A revolutionary opportunity to explore the consequences of reconnection in the ionosphere as never before will be presented. It is a revolutionary opportunity to explore key Aeronomy emissions on a global scale with spatial and temporal resolution not possible today. For example, observations of the signature of dayside merging and nightside reconnection that are reflected in the auroral oval evolution during disturbed periods and quiet times, will be described; observations that will open a...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELD RECONNECTION, AERONOMY, AURORAS, SOLAR WIND,...
We present RHESSI observF5oss of three homologous flares, which occurred between April 14 and 16, 2002. We find that the RHESSI images of all three flares at energies between 6 and 25 keV had some common features: (1) A. separate coronal source up to approx. 30 deg. above the flare loop appeared in the early impulsive phase and stayed stationary for several minutes. (2) Before the flare loop moved upward; previously reported by others, the flare loop-top centroid moved downward for 2-4 minutes...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELD RECONNECTION, SOLAR FLARES, CORONAS,...
We investigate observations of intense bursts of electromagnetic wave energy in association with the thin current layers of turbulent magnetosheath reconnection. These observed emissions - typically detected in the layers immediately outside of the current layer proper - form two distinct types: (i) broadband emissions that extend continuously to lOs of Hertz; and (ii) structured bursts of emitted energy that occur above 80-Hz, often displaying features reminiscent of absorption bands and are...
Topics: NASA Technical Reports Server (NTRS), ELECTROMAGNETIC RADIATION, MAGNETIC FIELD RECONNECTION,...
The aim of the project is to establish how much of the magnetotail's total potential is due to flow bursts and how much of this potential maps to the ionosphere. In order to quantify these contributions, we need to develop a reliable method to measure the total cross-polar cap potential and the total reconnection rate across the entire polar cap boundary. This was the goal achieved in the first year of the grant. In the following section, we describe in more detail the activities leading to...
Topics: NASA Technical Reports Server (NTRS), GEOMAGNETIC TAIL, PLANETARY MAGNETOTAILS, MAGNETIC ISLANDS,...
Signatures of reconnection in major CME (coronal mass ejection)/flare eruptions and in coronal X-ray jets are illustrated and interpreted. The signatures are magnetic field lines and their feet that brighten in flare emission. CME/flare eruptions are magnetic explosions in which: 1. The field that erupts is initially a closed arcade. 2. At eruption onset, most of the free magnetic energy to be released is not stored in field bracketing a current sheet, but in sheared field in the core of the...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELD RECONNECTION, SOLAR FLARES, CURRENT SHEETS,...
The engine that drives the jovian magnetosphere is the mass added to the Io ion torus, accelerated to corotational velocities by field-aligned currents that couple the Io torus to the jovian ionosphere. The mass of the torus builds up to an amount that the magnetic forces cannot contain and the plasma, first slowly and then more rapidly, drifts outward. Numerous authors have treated this problem based first on the observations of the Pioneer 10 and 11 flybys; then on Voyager 1 and 2, and...
Topics: NASA Technical Reports Server (NTRS), IO, PLANETARY MAGNETIC FIELDS, TORUSES, PLANETARY...
It has yet to be established why ordinary stars possess X-ray coronas. Detailed observations of the Sun make it doubtful that the X-ray corona is produced by the dissipation of Alfven waves. The uniform X-ray brightness over all scales from 10,000 to 100,000 km simply does not look like a resonance phenomenon. It is demonstrated that the arbitrary winding patterns introduced into the bipolar magnetic fields of X-ray corona produce discontinuities within the field. It is suggested that the...
Topics: NASA Technical Reports Server (NTRS), SOLAR LIMB, SOLAR MAGNETIC FIELD, SOLAR X-RAYS, STELLAR...
Collisionless magnetic reconnection is often associated with time-dependent behavior. Specifically, current layers in the diffusion region can become unstable to tearing-type instabilities on one hand, or to instabilities with current-aligned wave vectors on the other. In the former case, the growth of tearing instabilities typically leads to the production of magnetic islands, which potentially provide feedback on the reconnection process itself, as well as on the rate of reconnection. The...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELD RECONNECTION, STABILITY, TEARING, TIME...
Magnetic reconnection is arguably the most effective energy conversion and transport process in plasmas. Reconnection is subject to topological considerations in two ways. First, the process itself involves a change in topology of the combined plasma-magnetic field system. This change in topology transcends that of the magnetic field alone and accounts for flux transport relative to the motion of the plasma in the system under investigation. The second way topology is important to magnetic...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELD RECONNECTION, ENERGY CONVERSION, TRANSPORT...
A revolutionary opportunity to explore the consequences of reconnection in the ionosphere as never before will be presented. It is a revolutionary opportunity to explore key Aeronomy emissions on a global scale with spatial and temporal resolution not possible today. For example, observations of the signature of dayside merging and nightside reconnection that are reflected in the auroral oval evolution during disturbed periods and quiet times, will be described; observations that will open a...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELD RECONNECTION, AERONOMY, AURORAS, SOLAR WIND,...
No abstract available
Topics: NASA Technical Reports Server (NTRS), MISSION PLANNING, SATELLITE CONSTELLATIONS, FORMATION FLYING,...
Magnetic reconnection is often referred to as the primary source of energy release during solar flares. Directly observing reconnection occurring in the solar atmosphere, however, is not trivial considering that the scale size of the diffusion region is magnitudes smaller than the observational capabilities of current instrumentation, and coronal magnetic field measurements are not currently sufficient to capture the process. Therefore, predicting and studying observationally feasible...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELD RECONNECTION, SOLAR MAGNETIC FIELD, SOLAR...
Using two-dimensional particle-in-cell (PIC) together with magnetohydrodynamic (MHD) Q1 simulations of magnetotail dynamics, we investigate the evolution toward onset of reconnection and the subsequent energy transfer and conversion. In either case, reconnection onset is preceded by a driven phase, during which magnetic flux is added to the tail at the high-latitude boundaries, followed by a relaxation phase, during which the configuration continues to respond to the driving. The boundary...
Topics: NASA Technical Reports Server (NTRS), MAGNETIC FIELD RECONNECTION, MAGNETOHYDRODYNAMICS, ENERGY...
