Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “inner magnetosphere processes”

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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Modeling of Inner Magnetosphere Coupling Processes

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

Khazanov, George V.↗
NASA NTRS1998

Modeling the Plasmasphere

The plasmasphere, with its accumulation of H(+), He(+), and O(+), is both a strong influence on inner magnetospheric processes and a direct indicator or large and small scale convection electric fields which develop in this region. We will present our empirical and physical modeling of these plasmas and the data that drives them.

Gallagher, Dennis L.↗
NASA NTRS1992

Spacecraft design considerations for an Inner Magnetosphere Imager mission

Imaging the Earth's magnetosphere from space will enable scientists to better understand the global shape of the inner magnetosphere, its components and processes. The proposed Inner Magnetosphere Imager (IMI) mission will obtain the first simultaneous images of the component regions of the inner magnetosphere and will enable scientists to relate these global images to internal and external influences as well as local observations. NASA's Marshall Space Flight Center (MSFC) is performing a concept definition study of the proposed mission. As currently envisioned, the baseline mission calls for an instrument complement of approximately seven imagers to be flown in an elliptical Earth orbit with an apogee of seven Earth Radii (RE). Several spacecraft concepts have been examined for the mission. The baseline concept utilizes a spinning spacecraft with a despun platform, the second uses a three-axis stabilized spacecraft with a spinning platform, while the third option splits the instruments onto two small satellites; a spinning spacecraft and a complementary three-axis stabilized spacecraft. This paper will address the mission objectives, the rationale for using proven spacecraft designs, and the preliminary concept definition study team results for all three options.

Herrmann, Melody C.↗
DOE OSTI2025

Statistical Survey of Magnetic Flux Integral Quantities in Saturn's Magnetosphere

Magnetic flux integral quantities (e.g., flux tube entropy, flux tube content) are conserved quantities under the frozen-in assumption. The change of these quantities often indicates the violation of the frozen-in condition (e.g., interchange instability). In this study, we combine the Cassini CAPS and CHEMS moments data with a steady-state magnetic field model (i.e., the Caudal model) to estimate the flux tube mass and flux tube entropy in Saturn's magnetosphere. Our statistical survey found that the flux tube mass rapidly decreases with radial distance away from Saturn in the inner magnetosphere and roughly levels out in the middle magnetosphere. This indicates that the radial transport processes could occur via a double-reconnection process in the inner magnetosphere, while the radial transport processes appear to be more advective in the middle magnetosphere. Notice that Saturn's magnetosphere is stabilized by a radially increasing profile of flux tube entropy and destabilized by a radially decreasing profile of flux tube content. In this study, we also estimate the expected penetration location by using the flux tube interchange stability formalism developed by Southwood and Kivelson (1987, https://doi.org/10.1029/ja092ia01p00109). The results show that flux tube entropy can play a crucial role in braking the injections, while the flux tube content has a relatively smaller influence on the injected flux tube, being consistent with our previous case study by Wing et al. (2022, https://doi.org/10.3847/1538-4357/ac85b2).

Ma, Xuanye [Embry-Riddle Aeronautical University, ↗
NASA NTRS2021

Why Atmospheric Backscatter Is Important in the Formation of Electron Precipitation in the Diffuse Aurora

In addition to wave particle scattering in the magnetosphere, atmospheric backscatter of magnetospheric electrons is an important process that contributes to the formation of the precipitated electrons in the region of diffuse aurora. Two magnetically conjugate regions are involved in a complex magnetosphere-ionosphere (MI) particle and energy interplay. Based on synthesizing previous theoretical/modeling studies and experimental evidence, we demonstrate the need for improving the quantification of magnetospheric electrons backscatter processes that can affect inner magnetospheric electrodynamics, transport and loss in a way that is not easily predicted. We discuss how these complex and energy-dependent MI coupled processes can be treated in magnetospheric modeling.

diffuse aurora↗
NASA NTRS2010

FASTSAT-HSV01 Synergistic Observations of the Magnetospheric Response During Active Periods: MINI-ME, PISA and TTI

Understanding the complex processes within the inner magnetosphere of Earth particularly during storm periods requires coordinated observations of the particle and field environment using both in-situ and remote sensing techniques. In fact in order to gain a better understanding of our Heliophysics and potentially improve our space weather forecasting capabilities, new observation mission approaches and new instrument technologies which can provide both cost effective and robust regular observations of magnetospheric activity and other space weather related phenomenon are necessary. As part of the effort to demonstrate new instrument techniques and achieve necessary coordinated observation missions, NASA's Fast Affordable Science and Technology Satellite Huntsville 01 mission (FASTSAT-HSVOI) scheduled for launch in 2010 will afford a highly synergistic solution which satisfies payload mission opportunities and launch requirements as well as contributing iri the near term to our improved understanding of Heliophysics. NASA's FASTSAT-HSV01 spacecraft on the DoD Space Test Program-S26 (STP-S26) Mission is a multi-payload mission executed by the DoD Space Test Program (STP) at the Space Development and Test Wing (SDTW), Kirtland AFB, NM. and is an example of a responsive and economical breakthrough in providing new possibilities for small space technology-driven and research missions. FASTSAT-HSV is a unique spacecraft platform that can carry multiple small instruments or experiments to low-Earth orbit on a wide range of expendable launch vehicles for a fraction of the cost traditionally required for such missions. The FASTSAT-HSV01 mission allows NASA to mature and transition a technical capability to industry while increasing low-cost access to space for small science and technology (ST) payloads. The FASTSAT-HSV01 payload includes three NASA Goddard Space Flight Center (GSFC) new technology built instruments that will study the terrestrial space environment and potentially contribute to space weather research in a synergistic manner. MINI-ME, a neutral atom imager, will observe the neutral atom inputs to ionospheric heating which can be important during high levels of magnetospheric activity. PISA, a plasma impedance spectrometer, will measure simultaneously the local electron densities and temperatures as well as measure small scale density structure (500 m spatial scale) during these active periods. TTI, a thermospheric imager, will remotely determine the thermospheric temperature response to this magnetospheric activity. Together, these observations will contribute significantly to a comprehensive understanding of the flow of energy through and the response of the storm-time terrestrial magnetosphere.

Casas, Joseph C.↗
NASA NTRS1987

Plasma physics abstracts, 1 January - 31 December, 1986

Topics addressed include: ion-cyclotron waves; plasma waves; solar wind lithium releases; bow shock; Pi2 wave bursts; auroral kilometric radiation; ion energization; magnetic field corrections; electric fields; magnetospheric processes; electron acceleration; inner heliosphere; nightside auroral zone; computerized simulation; plasma wave turbulence; and magnetohydrodynamic waves in plasma sheets.

Gurnett, D. A.↗
NASA NTRS2000

Substorms At Jupiter: Galileo Observations of Transient Reconnection in The Near Tail

The magnetic flux content of the Jovian magnetosphere is set by the internal dynamo, but those magnetic field lines are constantly being loaded by heavy ions at the orbit of lo and dragged inexorably outward by the centrifugal force. Vasyliunas has proposed a steady state reconnecting magnetospheric model that sheds plasma islands of zero net magnetic flux and returns nearly empty flux tubes to the inner magnetosphere. The Galileo observations indicate that beyond 40 Rj the current sheet begins to tear and beyond 50 Rj on the nightside explosively reconnects as the tearing site reaches the low density lobe region above and below the current sheet. Small events occur irregularly but on average about every 4 hours and large events about once a day. The magnetic flux reconnected in such events amounts up to about 70,000 Webers/sec and is sufficient to return the outwardly convected magnetic flux to the inner magnetosphere. Since this process releases plasmoids into the jovian tail, as do terrestrial substorms; since this process involves explosive reconnection across the current sheet on the nightside of the planet, as do terrestrial substorms; and since the process is a key in closing the circulation pattern of the magnetic and plasma flux, as it is in terrestrial substorms; we refer to these events as jovian substorms.

Russell, C. T.↗
NASA NTRS2018

Inner Magnetospheric Physics

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

inner magnetosphere processes↗
NASA NTRSDate not supplied

Inner Magnetospheric Physics

- Historical Background - Main regions and transport processes - Ionosphere - Plasmasphere - Plasma sheet - Ring current - Radiation belt - Geomagnetic Activity - Storms - Substorm - Models

inner magnetosphere↗
NASA NTRS1981

Steady-state observations of geomagnetically trapped energetic heavy ions and their implications for theory

Data from the Heavy Ion Telescope on board Explorer 45 and the heavy ion channels on the ATS-6 spacecraft are used to describe the equatorial radial profiles of protons and He ions in the energy range of 0.1-1 MeV/nucleon. Measurements during a quiet period in June 1972 revealed that: fluxes of energetic protons and heavy ions inside L equals 4.5 are stable, with no observed decay; He ions of a given level are confined to the equatorial plane in a narrow L-range centered at Lmax; the equatorial differential flux ratio, compared on the basis of equal energy/ion, can exceed unity, indicating that He ion fluxes can be greater than equivalent energy proton fluxes; radial diffusion driven by variations of the magnetic field adequately models processes occurring in the inner magnetosphere for ion energies over 200 keV. The ATS-6 data from GEO found energetic heavy ions always present at L equals 6.6 and enhanced during magnetospheric substorms.

Fritz, T. A.↗
NASA NTRS1987

Limits on the extent of Saturn's hydrogen cloud

The 30-day reports from the Voyager Ultraviolet Spectrometer team characterize the atomic hydrogen observed near Saturn as a torus with a half width of 7 Saturnian radii. The atomic processes occurring in the inner magnetosphere are modelled, including sputtering, ionization, charge exchange, ion-atom interchange, recombination, and transport, and a neutral hydrogen source is added to test the proposal that a hydrogen cloud exists in this region. Plasma observations in the inner magnetosphere are found to be inconsistent with the presence of a dense atomic hydrogen cloud. Thus, it is concluded that the hydrogen cloud must be a torus as originally reported, and that the cloud does not extend inward to the orbits of the inner satellites of Saturn.

Richardson, John D.↗
NASA NTRSDate not supplied

Inner Magnetospheric Physics

A brief overview of inner magnetospheric physics will be given. As a discipline, magnetospheric physics is a young science. Its earliest experimental beginnings were in the 1950s with the study of low frequency radio waves originating from lightning and later with the first orbiting satellite, Explorer 1. The solar wind drives the coupled magnetospheric system from the ionosphere-thermosphere, plasmasphere, ring current, radiation belts, out through the region of interface to interplanetary space, the magnetosheath and bow shock. The basic plasma systems, their motions, and responses to the driving solar wind will be mentioned. These highlights of the magnetospheric system are intended only to provide points of reference for further more in-depth study.

inner magnetosphere, physical processes↗
NASA NTRS1985

Particle behavior in the magnetosphere

The Rice Convection Model deals with large-scale processes in the earth's inner and middle magnetosphere, including coupling to the ionosphere. Starting from appropriate initial and boundary conditions, the model computes the following physical parameters: ionospheric electric fields and currents; magnetospheric particle distributions, electric fields, and electric currents; and magnetic-field-aligned (Birkeland) currents connecting the two regions. This paper evaluates work on the model, with emphasis on the assumptions made, the basic equations, and the numerical methods. The theoretical basis of the model is compared and contrasted with standard magnetohydrodynamics. The limitations imposed by the major assumptions are discussed. Model inputs and boundary conditions are listed, and the methods of specifying them discussed. Some physical conclusions and insights that have been gained from the model are listed and described very briefly. References are given to published discussions of the major points of physics.

Wolf, R. A.↗
NASA NTRS1979

Expected charge states of energetic ions in the magnetosphere

Major developments in magnetospheric heavy ion physics during the period 1974-1977 are reviewed with emphasis on charge state aspects. Particular attention is given to the high energy component at energies above tens of keV per ion. Also considered are charge exchange processes with application to the inner magnetosphere, a comparison between theory and measurements, and a survey of heavy ion and charge state observations in the outer magnetosphere, magnetosheath and the surrounding space.

Spjeldvik, W. N.↗
NASA NTRS1980

Particle energization in the inner, nonazimuthally symmetric magnetospheres of neutron stars

The energization process of magnetic pumping, a combination of time dependent magnetic mirror fields with pitch-angle scattering, is applied to trapped charged particles drifting in corotating, azimuthally nonsymmetric neutron star magnetospheres. When particle energization is balanced by synchrotron radiation loss, it is found that protons, rather than electrons, reach considerable kinetic energies and radiate, in the X-ray regime, at rates up to the 10 to the 6th power MeV/proton/sec.

Borovsky, J. E.↗
NASA NTRS1987

Magnetospheric environments of outer planet rings - Influence of Saturn's axially symmetric magnetic field

Saturn's main rings exist within a zone of negligible magnetospheric losses and surface alteration effects, substantially due to the solid-body absorption of inwardly diffusing magnetospheric particles. This process is presently shown to be especially efficient in the inner magnetosphere of Saturn, due to the near-axial symmetry of the planetary magnetic field relative to the equatorial rotation plane; under the assumption of comparable diffusion rates, the inward magnetospheric particle transport is far more inhibited in the inner Saturnian magnetosphere than in the same regions of Jupiter and Uranus, even when only rings of comparable widths and depths are considered. In light of this, ring particle surface exposure to the ion fluxes of the radiation belt remains a prepossessing rationale for low Uranian ring albedos.

Hood, L. L.↗