scholarly journals Modeling gradual diffusion changes in radiation belt electron phase space density for the March 2013 Van Allen Probes case study

2014 ◽  
Vol 119 (10) ◽  
pp. 8396-8403 ◽  
Author(s):  
Zhao Li ◽  
Mary Hudson ◽  
Allison Jaynes ◽  
Alexander Boyd ◽  
David Malaspina ◽  
...  
Keyword(s):  
Phase Space ◽  
Radiation Belt ◽  
Phase Space Density ◽  
Space Density ◽  
Van Allen Probes

Substorm Injections as a Source of Relativistic Electrons in Earth’s Outer Radiation Belt

2020 ◽  
Author(s):  
Drew Turner ◽  
Ian Cohen ◽  
Kareem Sorathia ◽  
Sasha Ukhorskiy ◽  
Geoff Reeves ◽  
...  
Keyword(s):  
Phase Space ◽  
Plasma Sheet ◽  
Radiation Belt ◽  
Energetic Electron ◽  
Local Source ◽  
Relativistic Electrons ◽  
Phase Space Density ◽  
Outer Radiation Belt ◽  
Space Density ◽  
Van Allen Probes

<p>Earth’s magnetotail plasma sheet plays a crucial role in the variability of Earth’s outer electron radiation belt. Typically, injections of energetic electrons from Earth’s magnetotail into the outer radiation belt and inner magnetosphere during periods of substorm activity are not observed exceeding ~300 keV.  Consistent with that, phase space density radial distributions of electrons typically indicate that for electrons below ~300 keV, there is a source of electrons in the plasma sheet while for electrons with energies above that, there is a local source within the outer radiation belt itself.  However, here we ask the question: is this always the case or can the plasma sheet provide a direct source of relativistic (> ~500 keV) electrons into Earth’s outer radiation belt via substorm injection? Using phase space density analysis for fixed values of electron first and second adiabatic invariants, we use energetic electron data from NASA’s Van Allen Probes and Magnetospheric Multiscale (MMS) missions during periods in which MMS observed energetic electron injections in the plasma sheet while Van Allen Probes concurrently observed injections into the outer radiation belt. We report on cases that indicate there was a sufficient source of up to >1 MeV electrons in the electron injections in the plasma sheet as observed by MMS, yet Van Allen Probes did not see those energies injected inside of geosynchronous orbit.  From global insight with recent test-particle simulations in global, dynamic magnetospheric fields, we offer an explanation for why the highest-energy electrons might not be able to inject into the outer belt even while the lower energy (< ~300 keV) electrons do. Two other intriguing points that we will discuss concerning these results are: i) what acceleration mechanism is capable of producing such abundance of relativistic electrons at such large radial distances (X-GSE < -10 RE) in Earth’s magnetotail? and ii) during what conditions (if any) might injections of relativistic electrons be able to penetrate into the outer belt?</p>

Phase Space Density matching of relativistic electrons using the Van Allen Probes: REPT results

2013 ◽  
Vol 40 (18) ◽  
pp. 4798-4802 ◽  
Author(s):  
S. K. Morley ◽  
M. G. Henderson ◽  
G. D. Reeves ◽  
R. H. W. Friedel ◽  
D. N. Baker
Keyword(s):  
Phase Space ◽  
Relativistic Electrons ◽  
Phase Space Density ◽  
Space Density ◽  
Van Allen Probes

Magnetopause Shadowing Characteristics in Phase Space Density Measurements

2021 ◽  
Author(s):  
Frances Staples ◽  
Jonathan Rae ◽  
Adam Kellerman ◽  
Kyle Murphy ◽  
Jasmine Sandhu ◽  
...  
Keyword(s):  
Phase Space ◽  
Radiation Belt ◽  
Interplanetary Space ◽  
Phase Space Density ◽  
Electron Dynamics ◽  
Rapid Loss ◽  
Space Density ◽  
Ulf Wave ◽  
The Earth ◽  
Flux Increase

<p>Loss mechanisms act independently or in unison to drive rapid loss of electrons in the radiation belts. Electrons may be lost by precipitation into the Earth’s atmosphere, or through the magnetopause into interplanetary space. Whilst this magnetopause shadowing is well understood to produce dropouts in electron flux, it is less clear if shadowing continues to remove particles in tandem with electron acceleration processes, limiting the overall flux increase. </p><p>We investigate the contribution of shadowing to overall radiation belt fluxes throughout a geomagnetic storm in early September 2017. We use new, multi-spacecraft phase space density calculations to decipher electron dynamics during each storm phase and identify features of magnetopause shadowing during both the net-loss and the net-acceleration storm phases. We also highlight two distinct types of shadowing; ‘Indirect’, where electrons are lost through ULF wave driven radial transport towards the magnetopause boundary, and ‘direct’, where electrons are lost as their orbit intersects the magnetopause. </p>

Phase Space Density Analysis of Outer Radiation Belt Electron Energization and Loss during Geoeffective and Nongeoeffective Sheath Regions

2021 ◽  
Author(s):  
Milla M. H. Kalliokoski ◽  
Emilia Kilpua ◽  
Adnane Osmane ◽  
Allison N Jaynes ◽  
Drew L. Turner ◽  
...  
Keyword(s):  
Phase Space ◽  
Radiation Belt ◽  
Phase Space Density ◽  
Outer Radiation Belt ◽  
Space Density ◽  
Density Analysis

Reanalysis of radiation belt electron phase space density using various boundary conditions and loss models

2011 ◽  
Vol 48 (8) ◽  
pp. 1327-1334 ◽  
Author(s):  
M. Daae ◽  
Y.Y. Shprits ◽  
B. Ni ◽  
J. Koller ◽  
D. Kondrashov ◽  
...  
Keyword(s):  
Phase Space ◽  
Boundary Conditions ◽  
Radiation Belt ◽  
Phase Space Density ◽  
Space Density ◽  
Various Boundary Conditions ◽  
Loss Models

scholarly journals Early-Time Non-Equilibrium Pitch Angle Diffusion of Electrons by Whistler-Mode Hiss in a Plasmaspheric Plume Associated with BARREL Precipitation

2021 ◽  
Vol 8 ◽  
Author(s):  
R. M. Millan ◽  
J.-F. Ripoll ◽  
O. Santolík ◽  
W. S. Kurth
Keyword(s):  
Phase Space ◽  
Pitch Angle ◽  
Particle Interaction ◽  
Phase Space Density ◽  
Angle Distribution ◽  
Loss Cone ◽  
Linear Diffusion ◽  
Whistler Mode ◽  
Space Density ◽  
Van Allen Probes

In August 2015, the Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) observed precipitation of energetic (<200 keV) electrons magnetically conjugate to a region of dense cold plasma as measured by the twin Van Allen Probes spacecraft. The two spacecraft passed through the high density region during multiple orbits, showing that the structure was spatial and relatively stable over many hours. The region, identified as a plasmaspheric plume, was filled with intense hiss-like plasma waves. We use a quasi-linear diffusion model to investigate plume whistler-mode hiss waves as the cause of precipitation observed by BARREL. The model input parameters are based on the observed wave, plasma and energetic particle properties obtained from Van Allen Probes. Diffusion coefficients are found to be largest in the same energy range as the precipitation observed by BARREL, indicating that the plume hiss waves were responsible for the precipitation. The event-driven pitch angle diffusion simulation is also used to investigate the evolution of the electron phase space density (PSD) for different energies and assumed initial pitch angle distributions. The results show a complex temporal evolution of the phase space density, with periods of both growth and loss. The earliest dynamics, within the ∼5 first minutes, can be controlled by a growth of the PSD near the loss cone (by a factor up to ∼2, depending on the conditions, pitch angle, and energy), favored by the absence of a gradient at the loss cone and by the gradients of the initial pitch angle distribution. Global loss by 1-3 orders of magnitude (depending on the energy) occurs within the first ∼100 min of wave-particle interaction. The prevalence of plasmaspheric plumes and detached plasma regions suggests whistler-mode hiss waves could be an important driver of electron loss even at high L-value (L ∼6), outside of the main plasmasphere.

scholarly journals On the storm-time evolution of relativistic electron phase space density in Earth's outer radiation belt

2013 ◽  
Vol 118 (5) ◽  
pp. 2196-2212 ◽  
Author(s):  
D. L. Turner ◽  
V. Angelopoulos ◽  
W. Li ◽  
M. D. Hartinger ◽  
M. Usanova ◽  
...  
Keyword(s):  
Phase Space ◽  
Relativistic Electron ◽  
Time Evolution ◽  
Radiation Belt ◽  
Phase Space Density ◽  
Outer Radiation Belt ◽  
Space Density
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