Found 35 entries in the Bibliography.

Showing entries from 1 through 35


Raytracing Study of Source Regions of Whistler Mode Wave Power Distribution Relative to the Plasmapause

Abstract A comprehensive numerical raytracing study of whistler mode wave power with the inclusion of finite background electron and ion temperature is performed in order to investigate wave power distribution in relation to the plasmapause. Both Landau damping and linear growth of whistler mode waves are taken into account using a bi-Maxwellian hot electron distribution as well as an isotropic hot electron distribution. Isotropic and bi-Maxwellian distributions yield similar results of statistical spatial wave power for fre ...

Maxworth, A.; Gołkowski, M.; Malaspina, D.; Jaynes, A.;

YEAR: 2020     DOI: 10.1029/2019JA027154

hiss; plasmasphere; Warm Plasma; Raytracing; Magnetosphere; Van Allen Probes

Bayesian Inference of Quasi-Linear Radial Diffusion Parameters using Van Allen Probes

Abstract The Van Allen radiation belts in the magnetosphere have been extensively studied using models based on radial diffusion theory, which is derived from a quasi-linear approach with prescribed inner and outer boundary conditions. The 1D diffusion model requires the knowledge of a diffusion coefficient and an electron loss timescale, which is typically parameterized in terms of various quantities such as the spatial (L) coordinate or a geomagnetic index (e.g., Kp). These terms are typically empirically derived, not dire ...

Sarma, Rakesh; Chandorkar, Mandar; Zhelavskaya, Irina; Shprits, Yuri; Drozdov, Alexander; Camporeale, Enrico;

YEAR: 2020     DOI: 10.1029/2019JA027618

radial diffusion; Magnetosphere; Bayesian inference; Van Allen radiation belt; Van Allen Probes

Localization of the Source of Quasiperiodic VLF Emissions in the Magnetosphere by Using Simultaneous Ground and Space Observations: A Case Study

Abstract We study quasiperiodic very low frequency (VLF) emissions observed simultaneously by Van Allen Probes spacecraft and Kannuslehto and Lovozero ground-based stations on 25 December 2015. Both Van Allen Probes A and B detected quasiperiodic emissions, probably originated from a common source, and observed on the ground. In order to locate possible regions of wave generation, we analyze wave-normal angles with respect to the geomagnetic field, Poynting flux direction, and cyclotron instability growth rate calculated by ...

Demekhov, A.; Titova, E.; Maninnen, J.; Pasmanik, D.; Lubchich, A.; Santolik, O.; Larchenko, A.; Nikitenko, A.; Turunen, T.;

YEAR: 2020     DOI: 10.1029/2020JA027776

quasiperiodic VLF emissions; Cyclotron instability; wave propagation; Magnetosphere; whistler mode waves; Van Allen Probes

The Role of the Dynamic Plasmapause in Outer Radiation Belt Electron Flux Enhancement

Abstract The plasmasphere is a highly dynamic toroidal region of cold, dense plasma around Earth. Plasma waves exist both inside and outside this region and can contribute to the loss and acceleration of high energy outer radiation belt electrons. Early observational studies found an apparent correlation on long time scales between the observed inner edge of the outer radiation belt and the modeled innermost plasmapause location. More recent work using high-resolution Van Allen Probes data has found a more complex relationsh ...

Bruff, M.; Jaynes, A.; Zhao, H.; Goldstein, J.; Malaspina, D.; Baker, D.; Kanekal, S.; Spence, H.; Reeves, G.;

YEAR: 2020     DOI: 10.1029/2020GL086991

Plasmapause; outer radiation belt; Magnetosphere; chorus waves; Van Allen Probes


Rapid Precipitation of Relativistic Electron by EMIC Rising-Tone Emissions Observed by the Van Allen Probes

On 23 February 2014, Van Allen Probes sensors observed quite strong electromagnetic ion cyclotron (EMIC) waves in the outer dayside magnetosphere. The maximum amplitude was more than 14 nT, comparable to 7\% of the magnitude of the ambient magnetic field. The EMIC waves consisted of a series of coherent rising tone emissions. Rising tones are excited sporadically by energetic protons. At the same time, the probes detected drastic fluctuations in fluxes of MeV electrons. It was found that the electron fluxes decreased by more ...

Nakamura, S.; Omura, Y.; Kletzing, C.; Baker, D.;

YEAR: 2019     DOI: 10.1029/2019JA026772

EMIC waves; Magnetosphere; microburst; nonlinear; Radiation belt; Van Allen Probes; Wave-particle interaction

Variability of Quasilinear Diffusion Coefficients for Plasmaspheric Hiss

In the outer radiation belt, the acceleration and loss of high-energy electrons is largely controlled by wave-particle interactions. Quasilinear diffusion coefficients are an efficient way to capture the small-scale physics of wave-particle interactions due to magnetospheric wave modes such as plasmaspheric hiss. The strength of quasilinear diffusion coefficients as a function of energy and pitch angle depends on both wave parameters and plasma parameters such as ambient magnetic field strength, plasma number density, and co ...

Watt, C.; Allison, H.; Meredith, N.; Thompson, R.; Bentley, S.; Rae, I.; Glauert, S.; Horne, R.;

YEAR: 2019     DOI: 10.1029/2018JA026401

empirical; Magnetosphere; parameterization; stochastic; Van Allen Probes; wave-particle interactions

Empirical Modeling of the Geomagnetosphere for SIR and CME-Driven Magnetic Storms

During geomagnetic disturbances, the solar wind arrives in the form of characteristic sequences lasting from tens of hours to days. The most important magnetic storm drivers are the coronal mass ejections (CMEs) and the slow-fast stream interaction regions (SIRs). Previous data-based magnetic field models did not distinguish between these types of the solar wind driving. In the present work we retained the basic structure of the Tsyganenko and Andreeva (2015) model but fitted it to data samples corresponding to (1) SIR-drive ...

Andreeva, V.; Tsyganenko, N.;

YEAR: 2019     DOI: 10.1029/2018JA026008

Magnetic Storms; Magnetosphere; Modeling; Solar wind; spacecraft data; Van Allen Probes

Statistical Distribution of Whistler Mode Waves in the Radiation Belts With Large Magnetic Field Amplitudes and Comparison to Large Electric Field Amplitudes

We present a statistical analysis with 100\% duty cycle and non-time-averaged amplitudes of the prevalence and distribution of high-amplitude >50-pT whistler mode waves in the outer radiation belt using 5 years of Van Allen Probes data. Whistler mode waves with high magnetic field amplitudes are most common above L=4.5 and between magnetic local time of 0\textendash14 where they are present approximately 1\textendash6\% of the time. During high geomagnetic activity, high-amplitude whistler mode wave occurrence rises above 25 ...

Tyler, E.; Breneman, A.; Cattell, C.; Wygant, J.; Thaller, S.; Malaspina, D.;

YEAR: 2019     DOI: 10.1029/2019JA026913

Magnetosphere; magnetospheric chorus; Radiation belts; Van Allen Probes; whistler wave

Statistical Analysis of Transverse Size of Lower Band Chorus Waves Using Simultaneous Multisatellite Observations

Chorus waves are known to accelerate or scatter energetic electrons via quasi-linear or nonlinear wave-particle interactions in the Earth\textquoterights magnetosphere. In this letter, by taking advantage of simultaneous observations of chorus waveforms from at least a pair of probes among Van Allen Probes and/or Time History of Events and Macroscale Interactions during Substorms (THEMIS) missions, we statistically calculate the transverse size of lower band chorus wave elements. The average size of lower band chorus wave el ...

Shen, Xiao-Chen; Li, Wen; Ma, Qianli; Agapitov, Oleksiy; Nishimura, Yukitoshi;

YEAR: 2019     DOI: 10.1029/2019GL083118

Chorus wave; Magnetosphere; Scale size; Van Allen Probes


Eigenmodes of the transverse Alfv\ enic resonator at the plasmapause: a Van Allen Probes case study

A Pc4 ULF wave was detected at spacecraft B of the Van Allen Probes at the plasmapause. A distinctive feature of this wave is the strong periodical modulation of the wave. It is assumed that this modulation is a beating of oscillations close in frequency: at least two harmonics with frequencies of 15.3 and 13.6 MHz are found. It is shown that these harmonics can be the eigenmodes of the transverse resonator at the local maximum of the Alfv\ en velocity. In addition, the observed wave was in a drift resonance with energetic 8 ...

Mager, Pavel; Mikhailova, Olga; Mager, Olga; Klimushkin, Dmitri;

YEAR: 2018     DOI: 10.1029/2018GL079596

Magnetosphere; Plasmapause; poloidal Alfven waves; transverse resonator; ULF waves; Van Allen Probes; Wave-particle interaction

Energisation of the ring current by substorms

The substorm process releases large amounts of energy into the magnetospheric system, although where the energy is transferred to and how it is partitioned remains an open question. In this study, we address whether the substorm process contributes a significant amount of energy to the ring current. The ring current is a highly variable region, and understanding the energisation processes provides valuable insight into how substorm - ring current coupling may contribute to the generation of storm conditions and provide a sou ...

Sandhu, J.; Rae, I.; Freeman, M.; Forsyth, C.; Gkioulidou, M.; Reeves, G.; Spence, H.; Jackman, C.; Lam, M.;

YEAR: 2018     DOI: 10.1029/2018JA025766

BSPICE; HOPE; Magnetosphere; ring current; substorms; Van Allen Probes

Fast diffusion of ultra-relativistic electrons in the outer radiation belt: 17 March 2015 storm event

Inward radial diffusion driven by ULF waves has long been known to be capable of accelerating radiation belt electrons to very high energies within the heart of the belts, but more recent work has shown that radial diffusion values can be highly event-specific and mean values or empirical models may not capture the full significance of radial diffusion to acceleration events. Here we present an event of fast inward radial diffusion, occurring during a period following the geomagnetic storm of 17 March 2015. Ultra-relativisti ...

Jaynes, A.; Ali, A.; Elkington, S.; Malaspina, D.; Baker, D.; Li, X.; Kanekal, S.; Henderson, M.; Kletzing, C.; Wygant, J.;

YEAR: 2018     DOI: 10.1029/2018GL079786

Magnetosphere; radial diffusion; Radiation belts; ULF waves; Van Allen Probes


Conjugate Ground-Spacecraft Observations of VLF Chorus Elements

We present results of simultaneous observations of VLF chorus elements at the ground-based station Kannuslehto in Northern Finland and on board Van Allen Probe A. Visual inspection and correlation analysis of the data reveal one-to-one correspondence of several (at least 12) chorus elements following each other in a sequence. Poynting flux calculated from electromagnetic fields measured by the Electric and Magnetic Field Instrument Suite and Integrated Science instrument on board Van Allen Probe A shows that the waves propag ...

Demekhov, A.; Manninen, J.; ik, O.; Titova, E.;

YEAR: 2017     DOI: 10.1002/2017GL076139

ground-spacecraft observations; Magnetosphere; Van Allen Probes; VLF chorus

A Statistical Study of the Spatial Extent of Relativistic Electron Precipitation with Polar Orbiting Environmental Satellites.

Relativistic Electron Precipitation (REP) in the atmosphere can contribute significantly to electron loss from the outer radiation belts. In order to estimate the contribution to this loss, it is important to estimate the spatial extent of the precipitation region. We observed REP with the zenith pointing (0o) Medium Energy Proton Electron Detector (MEPED) on board Polar Orbiting Environmental Satellites (POES), for 15 years (2000-2014) and used both single and multi satellite measurements to estimate an average extent of th ...

Shekhar, Sapna; Millan, Robyn; Smith, David;

YEAR: 2017     DOI: 10.1002/2017JA024716

Magnetosphere; precipitation; Radiation belts; relativistic electrons; spatial scale of REP; Van Allen Probes; wave particle scattering

Location of intense electromagnetic ion cyclotron (EMIC) wave events relative to the plasmapause: Van Allen Probes observations

We have studied the spatial location relative to the plasmapause (PP) of the most intense electromagnetic ion cyclotron (EMIC) waves observed on Van Allen Probes A and B during their first full precession in local time. Most of these waves occurred over an L range of from -1 to +2 RE relative to the PP. Very few events occurred only within 0.1 RE of the PP, and events with a width in L of < 0.2 REoccurred both inside and outside the PP. Wave occurrence was always associated with high densities of ring current ions; plasma de ...

Tetrick, S.; Engebretson, M.; Posch, J.; Olson, C.; Smith, C.; Denton, R.; Thaller, S.; Wygant, J.; Reeves, G.; MacDonald, E.; Fennell, J.;

YEAR: 2017     DOI: 10.1002/2016JA023392

EMIC waves; Magnetosphere; Plasmapause; Van Allen Probes


Local time variations of high-energy plasmaspheric ion pitch angle distributions

Recent observations from the Van Allen Probes Helium Oxygen Proton Electron (HOPE) instrument revealed a persistent depletion in the 1\textendash10 eV ion population in the postmidnight sector during quiet times in the 2 < L < 3 region. This study explores the source of this ion depletion by developing an algorithm to classify 26 months of pitch angle distributions measured by the HOPE instrument. We correct the HOPE low energy fluxes for spacecraft potential using measurements from the Electric Field and Waves (EFW) instrum ...

Sarno-Smith, Lois; Liemohn, Michael; Skoug, Ruth; Larsen, Brian; Moldwin, Mark; Katus, Roxanne; Wygant, John;

YEAR: 2016     DOI: 10.1002/2015JA022301

algorithm; Magnetosphere; pitch angles; plasmasphere; spacecraft potential corrections; Van Allen Probes

Compressional ULF wave modulation of energetic particles in the inner magnetosphere

We present Van Allen Probes observations of modulations in the flux of very energetic electrons up to a few MeV and protons between 1200 - 1400 UT on February 19th, 2014. During this event the spacecraft were in the dayside magnetosphere at L*≈5.5. The modulations extended across a wide range of particle energies, from 79.80 keV to 2.85 MeV for electrons and from 82.85 keV to 636.18 keV for protons. The fluxes of π/2 pitch angle particles were observed to attain maximum values simultaneously with the ULF compressional mag ...

Liu, H.; Zong, Q.-G.; Zhou, X.-Z.; . Y. Fu, S; Rankin, R.; Wang, L.-H.; Yuan, C.; Wang, Y.; Baker, D.; Blake, J.; Kletzing, C.;

YEAR: 2016     DOI: 10.1002/2016JA022706

Compressional ULF wave; energetic particles; Magnetosphere; Mirror effect; Modulation; relativistic electrons; Van Allen Probes

Electron butterfly distribution modulation by magnetosonic waves

The butterfly pitch angle distribution is observed as a dip in an otherwise normal distribution of electrons centered about αeq=90\textdegree. During storm times, the formation of the butterfly distribution on the nightside magnetosphere has been attributed to L shell splitting combined with magnetopause shadowing and strong positive radial flux gradients. It has been shown that this distribution can be caused by combined chorus and magnetosonic wave scattering where the two waves work together but at different local times. ...

Maldonado, Armando; Chen, Lunjin; Claudepierre, Seth; Bortnik, Jacob; Thorne, Richard; Spence, Harlan;

YEAR: 2016     DOI: 10.1002/2016GL068161

butterfly; electron; magnetosonic; Magnetosphere; Van Allen Probes; wave particle interaction


Internal Charging Hazards in Near-Earth Space During Solar Cycle 24 Maximum: Van Allen Probes Measurements

The Van Allen Probes mission provides an unprecedented opportunity to make detailed measurements of electrons and protons in the inner magnetosphere during the weak solar maximum period of cycle 24. The MagEIS suite of sensors measures energy spectra and fluxes of charged particles in the space environment. The calculations show that these fluxes result in electron deposition rates high enough to cause internal charging. We use omnidirectional fluxes of electrons and protons to calculate the dose under varying materials and ...

Skov, Tamitha; Fennell, Joseph; Roeder, James; Blake, Bernard; Claudepierre, Seth;

YEAR: 2015     DOI: 10.1109/TPS.2015.2468214

artificial satellites; dielectric materials; electrons; Energy measurement; MAGEis; Magnetosphere; particle detectors; protons; Van Allen Probes

A statistical study of EMIC waves observed by Cluster: 1. Wave properties

Electromagnetic ion cyclotron (EMIC) waves are an important mechanism for particle energization and losses inside the magnetosphere. In order to better understand the effects of these waves on particle dynamics, detailed information about the occurrence rate, wave power, ellipticity, normal angle, energy propagation angle distributions, as well as local plasma parameters are required. Previous statistical studies have used in situ observations to investigate the distribution of these parameters in the MLT-L frame within a li ...

Allen, R.; Zhang, J.; Kistler, L.; Spence, H.; Lin, R.; Klecker, B.; Dunlop, M.; e, Andr\; Jordanova, V.;

YEAR: 2015     DOI: 10.1002/2015JA021333

Cluster; EMIC waves; Magnetosphere; Shabansky orbits

Multipoint observations of the open-closed field line boundary as observed by the Van Allen Probes and geostationary satellites during the November 14 th 2012 geomagnetic storm

The twin Van Allen Probes spacecraft witnessed a series of lobe encounters between 0200 and 0515 UT on November 14th 2012. Although lobe entry had been observed previously by the other spacecraft, the two Van Allen Probe spacecraft allow us to observe the motion of the boundary for the first time. Moreover, this event is unique in that it consists of a series of six quasi-periodic lobe entries. The events occurred on the dawn flank between 4 and 6.6 local time and at altitudes between 5.6 and 6.2 RE. During the events Dst dr ...

Dixon, P.; MacDonald, E.; Funsten, H.; Glocer, A.; Grande, M.; Kletzing, C.; Larsen, B.; Reeves, G.; Skoug, R.; Spence, H.; Thomsen, M.;

YEAR: 2015     DOI: 10.1002/2014JA020883

Lobes; Magnetosphere; Modelling; Open/closed field line boundary; Van Allen Probes

Solar cycle dependence of ion cyclotron wave frequencies

Electromagnetic ion cyclotron (EMIC) waves have been studied for decades, though remain a fundamentally important topic in heliospheric physics. The connection of EMIC waves to the scattering of energetic particles from Earth\textquoterights radiation belts is one ofmany topics that motivate the need for a deeper understanding of characteristics and occurrence distributions of the waves. In this study, we show that EMIC wave frequencies, as observed at Halley Station in Antarctica from 2008 through 2012, increase by approxim ...

Lessard, Marc; Lindgren, Erik; Engebretson, Mark; Weaver, Carol;

YEAR: 2015     DOI: 10.1002/2014JA020791

EMIC waves; Ion cyclotron; Magnetosphere; plasma waves; Radiation belts; solar cycles

What frequencies of standing surface waves can the subsolar magnetopause support?

It is has been proposed that the subsolar magnetopause may support its own eigenmode, consisting of propagating surface waves which reflect at the northern/southern ionospheres forming a standing wave. While the eigenfrequencies of these so-called Kruskal-Schwartzschild (KS) modes have been estimated under typical conditions, the potential distribution of frequencies over the full range of solar wind conditions is not know. Using models of the magnetosphere and magnetosheath applied to an entire solar cycle\textquoterights w ...

Archer, M.; Plaschke, F.;

YEAR: 2015     DOI: 10.1002/2014JA020545

magnetopause; magnetosheath; Magnetosphere; Ulf; waves


Imaging the plasmasphere with ground based GPS TEC observations and comparisons with in situ plasmaspheric observations with Van Allen Probes

For over a decade, incoherent scatter radar observations of the mid and auroral-latitude ionosphere combined with ground based GPS observations of total electron content (TEC) have been used to study the intense storm enhanced density (SED) plumes that form over the Americas during major geomagnetic storms [1]. Magnetic field mapping of the ionospheric observations to magnetospheric heights revealed close correspondence between the SED and plasmasphere erosion plumes observed from space in EUV imagery by the IMAGE satellite ...

Foster, J;

YEAR: 2014     DOI: 10.1109/URSIGASS.2014.6929943

magnetic fields; Magnetic resonance imaging; Magnetosphere; Van Allen Probes

Initial observations of plasma waves in the sub-auroral polarization stream with the Van Allen Probes

The Sub-Auroral Polarization Stream (SAPS) is a geospace boundary layer phenomenon associated with the interaction of the warm plasma of the magnetospheric ring current with the cold ions and electrons of the outer plasmasphere [1]. Driven by ring current enhancements during magnetospheric disturbances, SAPS location, intensity, and characteristics are greatly influenced by the underlying ionosphere. Strong M-I coupling by means of field-aligned currents creates a high-speed (>1000 m/s) westward plasma flow channel in the io ...

Foster, John; Erickson, Philip;

YEAR: 2014     DOI: 10.1109/URSIGASS.2014.6929852

Ionosphere; Magnetosphere; Van Allen Probes

Progress on understanding chorus emissions from data of the electric and magnetic field instrument suite and integrated science (EMFISIS) on the Van Allen Probes

The physics of the creation, loss, and transport of radiation belt particles is intimately connected to the electric and magnetic fields which mediate these processes. A key wave-particle interaction important to both acceleration and loss in the radiation belts is the of whistler-mode chorus interacting with energetic electrons. To measure this important radiation belt interaction, the two-satellite Van Allen Probes mission utilizes one of the most complete sets of measurements ever made in the inner magnetosphere. As part ...

Kletzing, Craig;

YEAR: 2014     DOI: 10.1109/URSIGASS.2014.6929872

Instruments; Magnetic field measurement; magnetic fields; Magnetometers; Magnetosphere; Van Allen Probes

Prompt energization of relativistic and highly relativistic electrons during a substorm interval

On 17 March 2013, a large magnetic storm significantly depleted the multi-MeV radiation belt. We present multi-instrument observations from the Van Allen Probes spacecraft Radiation Belt Storm Probe A and Radiation Belt Storm Probe B at \~6 Re in the midnight sector magnetosphere and from ground-based ionospheric sensors during a substorm dipolarization followed by rapid reenergization of multi-MeV electrons [1]. A 50\% increase in magnetic field magnitude occurred simultaneously with dramatic increases in 100 keV electron f ...

Foster, John; Erickson, Philip;

YEAR: 2014     DOI: 10.1109/URSIGASS.2014.6929876

Magnetic flux; Magnetosphere; Van Allen Belts; Van Allen Probes

Radiation belt losses observed from multiple stratospheric balloons over Antarctica

Relativistic electrons, trapped by Earth\textquoterights magnetic field, have received increasing attention since increasing numbers of commercial and research spacecraft traverse regions of high radiation flux. The Van Allen probes were launched into Earth\textquoterights radiation belts in September 2012, making comprehensive measurements of charged particle fluxes and electromagnetic fields, with the objective of a better understanding of the processes that modulate radiation belt fluxes. Because losses of radiation belt ...

McCarthy, Michael; Millan, Robyn; Sample, John; Smith, David;

YEAR: 2014     DOI: 10.1109/URSIGASS.2014.6929960

Extraterrestrial measurements; Loss measurement; Magnetosphere; Van Allen Probes

Estimates of the power per mode number of broadband ULF waves at geosynchronous orbit

In studies of radial diffusion processes in the magnetosphere it is well known that ultralow frequency (ULF) waves of frequency mωd can resonantly interact with particles of drift frequency ωd, where m is the waves\textquoteright azimuthal mode number. Due to difficulties in estimating m, an oversimplifying assumption is often made in simulations, namely that all ULF wave power is located at a single mode number. In this paper a technique is presented for extracting information on the distribution of ULF power in a range o ...

Sarris, T.;

YEAR: 2014     DOI: 10.1002/2013JA019238

Magnetosphere; mode number; radial diffusion; Radiation belts; ULF waves; ultralow frequency

The Energetic Particle Detector (EPD) Investigation and the Energetic Ion Spectrometer (EIS) for the Magnetospheric Multiscale (MMS) Mission

The Energetic Particle Detector (EPD) Investigation is one of 5 fields-and-particles investigations on the Magnetospheric Multiscale (MMS) mission. MMS comprises 4 spacecraft flying in close formation in highly elliptical, near-Earth-equatorial orbits targeting understanding of the fundamental physics of the important physical process called magnetic reconnection using Earth\textquoterights magnetosphere as a plasma laboratory. EPD comprises two sensor types, the Energetic Ion Spectrometer (EIS) with one instrument on each o ...

Mauk, B.; Blake, J.; Baker, D.; Clemmons, J.; Reeves, G.; Spence, H.; Jaskulek, S.; Schlemm, C.; Brown, L.; Cooper, S.; Craft, J.; Fennell, J.; Gurnee, R.; Hammock, C.; Hayes, J.; Hill, P.; Ho, G.; Hutcheson, J.; Jacques, A.; Kerem, S.; Mitchell, D.; Nelson, K.; Paschalidis, N.; Rossano, E.; Stokes, M.; Westlake, J.;

YEAR: 2014     DOI: 10.1007/s11214-014-0055-5

Magnetic reconnection; Magnetosphere; Magnetospheric multiscale; NASA mission; Particle acceleration; Space plasma

Photoelectron-mediated spacecraft potential fluctuations

Electric field fluctuations such as those due to plasma waves in Earth\textquoterights magnetosphere may modulate photoelectrons emitted from spacecraft surface, causing fluctuations in spacecraft potential. We experimentally investigate such photoelectron-mediated spacecraft potential fluctuations. The photoelectric charge of a spacecraft model is found to increase with increasing applied electric field as more photoelectrons escape the spacecraft model surface and dissipates with a decrease in the electric field through co ...

Wang, X.; Malaspina, D.; Ergun, R.; M., Hor\;

YEAR: 2014     DOI: 10.1002/2013JA019502

chorus waves; electric field; Magnetosphere; photoelectrons; plasma density; spacecraft potential fluctuations

One year of on-orbit performance of the Colorado Student Space Weather Experiment (CSSWE)

The Colorado Student Space Weather Experiment is a 3-unit (10cm \texttimes 10cm \texttimes 30cm) CubeSat funded by the National Science Foundation and constructed at the University of Colorado (CU). The CSSWE science instrument, the Relativistic Electron and Proton Telescope integrated little experiment (REPTile), provides directional differential flux measurements of 0.5 to >3.3 MeV electrons and 9 to 40 MeV protons. Though a collaboration of 60+ multidisciplinary graduate and undergraduate students working with CU professo ...

Palo, Scott; Gerhardt, David; Li, Xinlin; Blum, Lauren; Schiller, Quintin; Kohnert, Rick;

YEAR: 2014     DOI: 10.1109/USNC-URSI-NRSM.2014.6928087

artificial satellites; atmospheric measuring apparatus; Ionosphere; Magnetic Storms; Magnetosphere; Van Allen Probes


Dynamics of the Earth\textquoterights Radiation Belts and Inner Magnetosphere

Trapped by Earth\textquoterights magnetic field far above the planet\textquoterights surface, the energetic particles that fill the radiation belts are a sign of the Sun\textquoterights influence and a threat to our technological future. In the AGU monograph Dynamics of the Earth\textquoterights Radiation Belts and Inner Magnetosphere, editors Danny Summers, Ian R. Mann, Daniel N. Baker, and Michael Schulz explore the inner workings of the magnetosphere. The book reviews current knowledge of the magnetosphere and recent rese ...

Schultz, Colin;

YEAR: 2013     DOI: 10.1002/eost.v94.5210.1002/2013EO520007

aurora; Magnetosphere; Radiation belts; Van Allen Probes


Radiation belt 2D and 3D simulations for CIR-driven storms during Carrington Rotation 2068

As part of the International Heliospheric Year, the Whole Heliosphere Interval, Carrington Rotation 2068, from March 20 to April 16, 2008 was chosen as an internationally coordinated observing and modeling campaign. A pair of solar wind structures identified as Corotating Interaction Regions (CIR), characteristic of the declining phase of the solar cycle and solar minimum, was identified in solar wind plasma measurements from the ACE satellite. Such structures have previously been determined to be geoeffective in producing e ...

Hudson, M.; Brito, Thiago; Elkington, Scot; Kress, Brian; Li, Zhao; Wiltberger, Mike;

YEAR: 2012     DOI: 10.1016/j.jastp.2012.03.017

Magnetosphere; Modeling; Radiation belts; Solar wind

Weak turbulence in the magnetosphere: Formation of whistler wave cavity by nonlinear scattering

We consider the weak turbulence of whistler waves in the in low-β inner magnetosphere of the earth. Whistler waves, originating in the ionosphere, propagate radially outward and can trigger nonlinear induced scattering by thermal electrons provided the wave energy density is large enough. Nonlinear scattering can substantially change the direction of the wave vector of whistler waves and hence the direction of energy flux with only a small change in the frequency. A portion of whistler waves return to the ionosphere with a ...

Crabtree, C.; Rudakov, L.; Ganguli, G.; Mithaiwala, M.; Galinsky, V.; Shevchenko, V.;

YEAR: 2012     DOI: 10.1063/1.3692092

Whistler waves; Magnetosphere