Search NASA⌕ Search

SEARCH · Search NASA

Results for “MAGNETOSPHERIC PHYSICS”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 685 records · Page 38
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Response of energetic particles to magnetospheric ultra-low-frequency waves

ULF waves in the space physics context are the lowest-frequency plasma waves propagating in the earth's magnetosphere. Although the propagation of the waves is explained in MHD theory, excitation of the waves involves not only MHD but also kinetic processes. This article describes how in situ magnetic field and particle measurements can be used to distinguish the basic properties of ULF waves, including the azimuthal wave number of the standing wave structure and the propagation direction. Examples are taken from observations with the AMPTE/CCE spacecraft.

Takahashi, Kazue↗
NASA NTRSDate not supplied

Energetic Particles in Geospace: Origin, Dynamics, and Modeling

This presentation explores the origins and dynamics of energetic particles—specifically solar energetic particles (SEPs) and galactic cosmic rays (GCRs) - within the heliosphere and Earth's magnetosphere. We will discuss the fundamental physical processes governing their transport and acceleration in the heliosphere, including interactions with the solar wind and the interplanetary magnetic field. The penetration of these particles into Earth's magnetosphere is examined, emphasizing how the geomagnetic field influences their propagation across the magnetosphere. Key phenomena such as the temporal trapping of SEPs in geospace, reductions in rigidity cutoff during geomagnetic storms, and the enhancement of atmospheric NOx and HOx concentrations - which affect the ozone balance through catalytic reactions—are discussed. The presentation also outlines contemporary numerical modeling techniques used to simulate SEPs and GCRs, providing insights into their complex behaviors under varying geomagnetic conditions.

solar energetic particles↗
NASA NTRS1968

Plasma in the magnetosphere.

Magnetosphere structure, thermal plasma in magnetosphere, energetic particles and waves in magnetosphere, noting relevance to plasma physics investigations

Scarf, F. L.↗
NASA NTRS1970

Large artificial plasma clouds in space

Large scale artificial plasma cloud experiments for magnetosphere, solar wind and cometary physics, discussing Ba ion and ice clouds released by satellites

Willis, R. G.↗
NASA NTRS1983

Galileo mission overview

The Galileo mission has three major and equally important scientific objectives: the investigation of the chemical composition and physical state of the Jupiter atmosphere, the study of the composition and state of the Jovian satellites, and the probing of the structure and physical dynamics of the Jovian magnetosphere. The Galileo spacecraft comprises an Orbiter and an atmospheric entry Probe, which will be released on a ballistic entry trajectory from the Orbiter about 150 days before Jupiter arrival. After Probe release, the Orbiter will overfly the Probe during entry in order to relay its data to earth. The Orbiter will then insert itself into a 200-day orbit around Jupiter. Attention is given to the radio science, remote sensing and fields and particles instruments to be carried for the mission.

Oneil, W. J.↗
NASA NTRS1984

A Shuttle free flyer qualification/acceptance program - Galileo

The next U.S. planetary mission, the Galileo Project, is to be launched in late spring 1986. Primary studies to be conducted are related to the chemical composition and physical state of Jupiter's atmosphere, the chemical composition and physical state of the Jovian satellites, and the structure and physical dynamics of the Jovian magnetosphere. The studies are to be performed with the aid of a planetary Orbiter and an atmospheric entry Probe. At launch and during the interplanetary cruise trip to Jupiter, the Orbiter and Probe will form an integrated spacecraft. The Shuttle will be employed in the launch of the spacecraft. A Centaur high energy upper stage is to transfer the spacecraft from the Shuttle parking orbit to the direct earth-to-Jupiter trajectory. Attention is given to Galileo environmental program special characteristics and major influencing factors.

Schlue, J. W.↗
NASA NTRS1989

Thermal design of the Galileo bus and Retro Propulsion Module

The Galileo spacecraft (S/C) consists of an Orbiter and Probe which have instruments to investigate the chemical composition and physical state of Jupiter's atmosphere, the Jovian satellites and the structure and physical dynamics of the Jovian magnetosphere. Galileo was at the Kennedy Space Center (KSC) preparing for a May 1986 launch at the time of the Challenger accident. The delay and an incraease in mission time has decreased the Radioisotope Thermoelectric Generator power output significantly. A change to the Inertial Upper Stage from the more powerful Centaur G-Prime has resulted in a trajectory that requires gravity assists once by Venus and twice by earth. The resulting peak solar intensity of this roundabout trajectory is more than twice the previous design value for the direct trajectory. Galileo was returned to the Jet Propulsion Laboratory (JPL) from KSC in February 1987 to begin the rework of the S/C thermal design. Verification of the thermal redesign was completed in the JPL 25' space simulator in August and November of 1988. This paper summarizes the thermal design and redesign of the Bus and Retro Propulsion Model.

Avila, A.↗
NASA NTRS1989

Shuttle Atlantis to deploy Galileo probe toward Jupiter

The objectives of Space Shuttle Mission STS-34 are described along with major flight activities, prelaunch and launch operations, trajectory sequence of events, and landing and post-landing operations. The primary objective of STS-34 is to deploy the Galileo planetary exploration spacecraft into low earth orbit. Following deployment, Galileo will be propelled on a trajectory, known as Venus-Earth-Earth Gravity Assist (VEEGA), by an inertial upper stage (IUS). The objectives of the Galileo mission are to study the chemical composition, state, and dynamics of the Jovian atmosphere and satellites, and investigate the structure and physical dynamics of the Jovian magnetosphere. Secondary STS-34 payloads include the Shuttle Solar Backscatter Ultraviolet (SSBUV) instrument; the Mesoscale Lightning Experiment (MLE); and various other payloads involving polymer morphology, the effects of microgravity on plant growth hormone, and the growth of ice crystals.

Source record↗
NASA NTRS1992

Auroral mapping during substorms

A discussion on auroral mapping during substorms is presented. The mapping of auroral displays into space along magnetic field lines can provide invaluable clues to the nature of the physical processes involved in many magnetospheric phenomena. Unfortunately, there are no representations of the Earth's magnetic field which adequately model the large time variations that occur during magnetospheric substorms. These time variations are believed to be due, in part, to current systems that flow across the near Earth magnetotail and then arch along field lines to the ionosphere where they contribute to the auroral electrojets. Even after the challenge of modeling the typical substorm magnetic field variations has been met, it can be expected that ad hoc adjustments will be needed to match the variations observed during each actual event. Precise determination of what point within a narrow auroral arc is pierced by the field line from spacecraft in the magnetotail will clearly be difficult.

Mcilwain, Carl E.↗
NASA NTRS1995

Evolution of Photon and Particle Spectra in Compact, Luminous Objects

Physical conditions in the radiating plasma in the cores of radio-strong quasars and active galactic nuclei cannot be derived from observations until the effects of relativistic aberration are understood. This requires determining both the bulk flow speeds and any wave or signal speed in the parsec-scale nuclear jets. In this project we studied several aspects of such waves. We considered constraints on jet deceleration by mass pickup, and found that bolometric luminosities of the active nuclei cannot constrain core jet speeds usefully. We also simulated observations of ballistic, helical trajectories and helical waves moving directly outwards along the jet. We found that ballistic trajectories are not allowed by the data; the helical features seen are very likely to be helical waves. We believe these are waves propagating in the jet plasma. To this end, we studied waves propagating in relativistic pair plasma jets. In particular, we undertook a program whose goal was to determine the nature of waves which can propagate in relativistic pair plasmas, and how such waves propagating in streaming jet plasma would be observed by an external observer. We developed the possibility of using pulsars as test cases for our models; this takes advantage of new technology in pulsar observations, and the similarity of the physical conditions in the pulsar magnetosphere to the dense, relativistic pair plasmas which exist in radio-strong quasars.

Eilek, Jean A.↗
DOE OSTI2015

X-ray perspective of the twisted magnetospheres of magnetars

Anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs) are recognized as the most promising magnetar candidates, as indicated by their energetic bursts and rapid spin-downs. It is expected that the strong magnetic field leaves distinctive imprints on the emergent radiation both by affecting the radiative processes in atmospheres of magnetars and by scattering in the upper magnetospheres. We construct a self-consistent physical model that incorporates emission from the magnetar surface and its reprocessing in the three-dimensional (3D) twisted magnetosphere using a Monte Carlo technique. The synthetic spectra are characterized by four parameters: surface temperature kT, surface magnetic field strength B, magnetospheric twist angle Δϕ, and the normalized electron velocity β. We also create a tabular model (STEMS3D) and apply it to a large sample of XMM-Newton spectra of magnetars. The model successfully fits nearly all spectra, and the obtained magnetic field for 7 out of the 11 sources are consistent with the values inferred from the spin-down rates. We conclude that the continuum-fitting by our model is a robust method to measure the magnetic field strength and magnetospheric configuration of AXPs and SGRs. Investigating the multiple observations of variable sources, we also study the mechanism of their spectral evolution. Our results suggest that the magnetospheres in these sources are highly twisted (Δϕ>1), and the behavior of magnetospheric twisting and untwisting is revealed in the 2002 outburst of 1E 2259+586.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2007

Magnetospheric Multiscale Mission SpaceWire Implementation

This viewgraph presentation reviews the use of SpaceWire in the Magnetospheric Multiscale Mission (MMS). The Science Objectives of the are to Discover the fundamental plasma physics process of reconnection in the Earth's magnetosphere using temporal scales of milliseconds to seconds and spatial scales of 10s to 100s of km. MMS should be the first NASA mission to fly several new Spacewire protocols including: - Remote Memory Access Protocol - Distributed interrupt Protocol - Standardized Backplane These are briefly reviewed in the presentation.

Jackson, George↗
DOE OSTI2017

PIC simulations of wave-particle interactions with an initial electron velocity distribution from a kinetic ring current model

Whistler wave-particle interactions play an important role in the Earth inner magnetospheric dynamics and have been the subject of numerous investigations. By running a global kinetic ring current model (RAM-SCB) in a storm event occurred on Oct 23–24 2002, we obtain the ring current electron distribution at a selected location at MLT of 9 and L of 6 where the electron distribution is composed of a warm population in the form of a partial ring in the velocity space (with energy around 15 keV) in addition to a cool population with a Maxwellian-like distribution. The warm population is likely from the injected plasma sheet electrons during substorm injections that supply fresh source to the inner magnetosphere. These electron distributions are then used as input in an implicit particle-in-cell code (iPIC3D) to study whistler-wave generation and the subsequent wave-particle interactions. Here, we find that whistler waves are excited and propagate in the quasi-parallel direction along the background magnetic field. Several different wave modes are instantaneously generated with different growth rates and frequencies. The wave mode at the maximum growth rate has a frequency around 0.62ω ce , which corresponds to a parallel resonant energy of 2.5 keV. Linear theory analysis of wave growth is in excellent agreement with the simulation results. These waves grow initially due to the injected warm electrons and are later damped due to cyclotron absorption by electrons whose energy is close to the resonant energy and can effectively attenuate waves. The warm electron population overall experiences net energy loss and anisotropy drop while moving along the diffusion surfaces towards regions of lower phase space density, while the cool electron population undergoes heating when the waves grow, suggesting the cross-population interactions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
NASA NTRS1982

Magnetospheres of Jupiter and Saturn

During the time from 1973 to 1981, the giant planets, Jupiter and Saturn, have been studied with the aid of the spacecraft Pioneers 10, 11, and Voyagers 1 and 2. The present investigation is concerned with the study of the magnetospheres of these planets, taking into account the immediate region of their environment in which the planetary magnetic field is the dominant physical force, and the boundary of the magnetospheres which is formed by the interaction with the solar wind. Attention is given to the recent results obtained by the Voyagers. It is found that the basic features of the magnetospheres of Jupiter and Saturn are similar to those of the earth. There are, however, also differences with the earth which relate to the large amount of entrapped low energy plasmas that form a magnetodisk and an Io associated torus at Jupiter, while at Saturn there is a Titan torus and a substantial ring current.

Ness, N. F.↗
NASA NTRS2016

Rippled Quasiperpendicular Shock Observed by the Magnetospheric Multiscale Spacecraft

Collisionless shock nonstationarity arising from microscale physics influences shock structure and particle acceleration mechanisms. Nonstationarity has been difficult to quantify due to the small spatial and temporal scales. We use the closely spaced (subgyroscale), high-time-resolution measurements from one rapid crossing of Earths quasiperpendicular bow shock by the Magnetospheric Multiscale (MMS) spacecraft to compare competing nonstationarity processes. Using MMSs high-cadence kinetic plasma measurements, we show that the shock exhibits nonstationarity in the form of ripples.

Johlander, A.↗
DOE OSTI2019

Effects of the guide field on electron distribution functions in the diffusion region of asymmetric reconnection

Crescent electron distribution functions in the electron diffusion region in asymmetric reconnection with a guide field (strength less than 50% of the upstream magnetic field) are investigated by theory and fully kinetic simulations. Electron motion in the electron diffusion region is a combination of meandering across the current sheet and gyration around the guide field. Combining the two canonical momentum conservation laws in a one-dimensional model with the energy conservation law, we derive the shape of crescent electron distribution functions in both velocity planes: perpendicular to the magnetic field and coplanner with the magnetic field. There are two major effects of the guide field on crescent distribution functions: (1) widening the opening angle of the crescent in a reduced distribution function and (2) the linear cut-off of a distribution function nonparallel to the magnetic field. We also discuss a translational mapping (perpendicular to the linear cut-off) of distribution functions between the X-line and another position. In addition, considering the gyration due to the normal magnetic field, we predict the shape of distribution functions in general positions in the electron diffusion region. Finally, the predictions will be useful to identify features of magnetic reconnection in a guide field by satellite observations.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗