scholarly journals Thermal electron acceleration by electric field spikes in the outer radiation belt: Generation of field-aligned pitch angle distributions

2015 ◽  
Vol 120 (10) ◽  
pp. 8616-8632 ◽  
Author(s):  
I. Y. Vasko ◽  
O. V. Agapitov ◽  
F. S. Mozer ◽  
A. V. Artemyev
Keyword(s):  
Electric Field ◽  
Pitch Angle ◽  
Radiation Belt ◽  
Electron Acceleration ◽  
Thermal Electron ◽  
Outer Radiation Belt

scholarly journals Field-aligned chorus wave spectral power in Earth's outer radiation belt

2015 ◽  
Vol 33 (5) ◽  
pp. 583-597 ◽  
Author(s):  
H. Breuillard ◽  
O. Agapitov ◽  
A. Artemyev ◽  
E. A. Kronberg ◽  
S. E. Haaland ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Radiation Belt ◽  
Spectral Power ◽  
Peak Frequency ◽  
Wave Power ◽  
Outer Radiation Belt ◽  
Substantial Impact ◽  
Wide Range ◽  
Frequency Variations ◽  
Chorus Wave

Abstract. Chorus-type whistler waves are one of the most intense electromagnetic waves generated naturally in the magnetosphere. These waves have a substantial impact on the radiation belt dynamics as they are thought to contribute to electron acceleration and losses into the ionosphere through resonant wave–particle interaction. Our study is devoted to the determination of chorus wave power distribution on frequency in a wide range of magnetic latitudes, from 0 to 40°. We use 10 years of magnetic and electric field wave power measured by STAFF-SA onboard Cluster spacecraft to model the initial (equatorial) chorus wave spectral power, as well as PEACE and RAPID measurements to model the properties of energetic electrons (~ 0.1–100 keV) in the outer radiation belt. The dependence of this distribution upon latitude obtained from Cluster STAFF-SA is then consistently reproduced along a certain L-shell range (4 ≤ L ≤ 6.5), employing WHAMP-based ray tracing simulations in hot plasma within a realistic inner magnetospheric model. We show here that, as latitude increases, the chorus peak frequency is globally shifted towards lower frequencies. Making use of our simulations, the peak frequency variations can be explained mostly in terms of wave damping and amplification, but also cross-L propagation. These results are in good agreement with previous studies of chorus wave spectral extent using data from different spacecraft (Cluster, POLAR and THEMIS). The chorus peak frequency variations are then employed to calculate the pitch angle and energy diffusion rates, resulting in more effective pitch angle electron scattering (electron lifetime is halved) but less effective acceleration. These peak frequency parameters can thus be used to improve the accuracy of diffusion coefficient calculations.

scholarly journals Thermal electron acceleration by localized bursts of electric field in the radiation belts

2014 ◽  
Vol 41 (16) ◽  
pp. 5734-5739 ◽  
Author(s):  
A. V. Artemyev ◽  
O. V. Agapitov ◽  
F. Mozer ◽  
V. Krasnoselskikh
Keyword(s):  
Electric Field ◽  
Electron Acceleration ◽  
Radiation Belts ◽  
Thermal Electron

scholarly journals Statistical model of electron pitch angle diffusion in the outer radiation belt

2012 ◽  
Vol 117 (A8) ◽  
pp. n/a-n/a ◽  
Author(s):  
A. Artemyev ◽  
O. Agapitov ◽  
V. Krasnoselskikh ◽  
H. Breuillard ◽  
G. Rolland
Keyword(s):  
Statistical Model ◽  
Pitch Angle ◽  
Radiation Belt ◽  
Outer Radiation Belt

scholarly journals Generation of nonlinear electric field bursts in the outer radiation belt through the parametric decay of whistler waves

2015 ◽  
Vol 42 (10) ◽  
pp. 3715-3722 ◽  
Author(s):  
O. V. Agapitov ◽  
V. Krasnoselskikh ◽  
F. S. Mozer ◽  
A. V. Artemyev ◽  
A. S. Volokitin
Keyword(s):  
Electric Field ◽  
Radiation Belt ◽  
Whistler Waves ◽  
Outer Radiation Belt ◽  
Parametric Decay

The Plasmasphere During Major Geomagnetic Storms: Analysis Of Trapped Particles In The Outer Radiation Belt

2020 ◽  
Author(s):  
Jessy Matar ◽  
Benoit Hubert ◽  
Stan Cowley ◽  
Steve Milan ◽  
Zhonghua Yao ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Geomagnetic Field ◽  
Radiation Belt ◽  
Ring Current ◽  
Geomagnetic Storms ◽  
Outer Radiation Belt ◽  
Trapped Particles ◽  
The Earth ◽  
Field Lines

<p> The coupling between the Earth’s magnetic field and the interplanetary magnetic field (IMF) transported by the solar wind results in a cycle of magnetic field lines opening and closing generally known as the Dungey substorm cycle, mostly governed by the process of magnetic reconnection. The geomagnetic field lines can therefore have either a closed or an open topology, i.e. lower latitude field lines are closed (map from southern ionosphere to the northern), while higher latitude field lines are open (map from one polar ionosphere into interplanetary space). Closed field lines can trap electrically charged particles that bounce between mirror points located in the North and South hemispheres while drifting in longitude around the Earth, forming the plasmasphere, the radiation belts and the ring current. The outer boundary of the plasmasphere is the plasmapause. Its location is mostly driven by the interplay of the corotation electric field of ionospheric origin, and the convection electric field that results from the interaction between the IMF and the geomagnetic field. At times of prolonged intense coupling between these fields, the response of the magnetosphere becomes global and a geomagnetic storm develops. The ring current created by the motion of the trapped energetic particles intensifies and then decays as the storm abates. This study aims to find a possible relationship between the evolution of the trapped population and the process of magnetic reconnection during storm times. The EUV instrument on board the NASA-IMAGE spacecraft observed the distribution of the trapped helium ions (He+) in the plasmasphere. We consider several cases of intense geomagnetic storms observed by the IMAGE satellite. We identify the plasmapause location (Lpp) during those cases. We find a strong correlation between the Dst index and Lpp. The ring current and the trapped particles are expected to vary during storms. We use the Tsyganenko magnetic field model to map the electric potential between the Heppner-Maynard boundary (HMB) in the ionosphere and the magnetosphere and estimate the voltage and electric field in the vicinity of the plasmapause. The ionospheric electric field is deduced from the ionospheric convection velocity measured by the SuperDARN (SD) radar network at high latitudes. The tangential electric field component of the moving plasmapause boundary is estimated from IMAGE-EUV observations of the plasmasphere and is compared with expectations based on the SD data. We combine measurements of the trapped population from IMAGE-EUV and IMAGE-FUV observations of the aurora to better understand and quantify the variability of the Earth's outer radiation belt during strong storms. The auroral precipitation at ionospheric latitude is studied using FUV imaging and compared to the He+ response during the storms.</p>

scholarly journals Favored regions for chorus-driven electron acceleration to relativistic energies in the Earth's outer radiation belt

2003 ◽  
Vol 30 (16) ◽  
Author(s):  
Nigel P. Meredith ◽  
Richard B. Horne ◽  
Richard M. Thorne ◽  
Roger R. Anderson
Keyword(s):  
Radiation Belt ◽  
Electron Acceleration ◽  
Outer Radiation Belt

scholarly journals REPAD: An empirical model of pitch angle distributions for energetic electrons in the Earth's outer radiation belt

2014 ◽  
Vol 119 (3) ◽  
pp. 1693-1708 ◽  
Author(s):  
Yue Chen ◽  
Reiner H. W. Friedel ◽  
Michael G. Henderson ◽  
Seth G. Claudepierre ◽  
Steven K. Morley ◽  
...  
Keyword(s):  
Empirical Model ◽  
Pitch Angle ◽  
Radiation Belt ◽  
Outer Radiation Belt ◽  
Energetic Electrons
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