scholarly journals Radiation belt electron acceleration by chorus waves during the 17 March 2013 storm

2014 ◽  
Vol 119 (6) ◽  
pp. 4681-4693 ◽  
Author(s):  
W. Li ◽  
R. M. Thorne ◽  
Q. Ma ◽  
B. Ni ◽  
J. Bortnik ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Electron Acceleration ◽  
Chorus Waves

Radiation belt electron acceleration during periods of low plasma density

2021 ◽  
Author(s):  
Hayley Allison ◽  
Yuri Shprits ◽  
Irina Zhelavskaya ◽  
Dedong Wang ◽  
Artem Smirnov
Keyword(s):  
Plasma Density ◽  
Cold Plasma ◽  
Radiation Belt ◽  
Electron Acceleration ◽  
Number Density ◽  
Chorus Waves ◽  
Radiation Belt Electrons ◽  
Plasma Depletion

<p>Electrons in the Van Allen radiation belts can have energies in excess of 7 MeV. We present a unique way of analyzing phase space density data which demonstrates that local acceleration is capable of heating electrons up to 7 MeV. The Van Allen Probes mission not only provided unique measurements of ultra-relativistic radiation belt electrons, but also simultaneous observations of plasma waves that allowed for the routine inference of total plasma number density. Based on long-term observations, we show that the underlying plasma density has a controlling effect over local acceleration to ultra-relativistic energies, which occurs only when the plasma number density drops down to very low values (~10 cm<sup>-3</sup>). The VERB-2D model is used to simulate ultra-relativistic electron acceleration during an event which exhibits an extreme cold plasma depletion. The results show that a reduced electron plasma density allows chorus waves to efficiently resonate with electrons up to ultra-relativistic energies, producing enhancements from 100s of keV up to >7 MeV via local diffusive acceleration. We analyse statistically the observed chorus wave power during ultra-relativistic enhancement events, considering the contribution from both upper and lower band chorus waves. The PINE density model allows for the investigation of global magnetospheric density changes. We analyze the how the global cold plasma density changes during ultra-relativistic enhancement events and compare to in-situ point measurements of the plasma density.</p>

scholarly journals Rapid Electron Acceleration in Low‐Density Regions of Saturn's Radiation Belt by Whistler Mode Chorus Waves

2019 ◽  
Vol 46 (13) ◽  
pp. 7191-7198 ◽  
Author(s):  
E. E. Woodfield ◽  
S. A. Glauert ◽  
J. D. Menietti ◽  
T. F. Averkamp ◽  
R. B. Horne ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Electron Acceleration ◽  
Low Density ◽  
Whistler Mode ◽  
Chorus Waves

Chorus acceleration of relativistic electrons in extremely low L-shell during geomagnetic storm

2020 ◽  
Author(s):  
Zhenxia Zhang ◽  
Lunjin Chen ◽  
Si Liu ◽  
Ying Xiong ◽  
Xinqiao Li ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Radiation Belt ◽  
Electron Acceleration ◽  
Acceleration Process ◽  
Relativistic Electrons ◽  
Chorus Waves ◽  
Van Allen Probes ◽  
New Finding ◽  
First Time ◽  
Shell Region

<p>Based on data from the Van Allen Probes and ZH-1 satellites, relativistic electron enhancements in extremely low L-shell Regions (reaching L~3) were observed during major geomagnetic storm (minimum Dst`-190 nT).  Contrary to what occurs in the outer belt, such an intense and deep electron penetration event is rare and more interesting. Strong whistler-mode (chorus and hiss) waves, with amplitudes 81-126 pT, were also observed in the extremely low L-shell simultaneously (reaching L~2.5) where the plasmapause was suppressed. The bounce-averaged diffusion coefficient calculations support that the chorus waves can play a significantly important role in diffusing and accelerating the 1-3 MeV electrons even in such low L-shells during storms. This is the first time that the electron acceleration induced by chorus waves in the extremely low L-shell region is reported. This new finding will help to deeply understand the electron acceleration process in radiation belt physics.</p>

Simulations of the Relativistic Radiation Belt Electrons Using the VERB-3D Code

2021 ◽  
Author(s):  
Dedong Wang ◽  
Yuri Shprits ◽  
Alexander Drozdov ◽  
Nikita Aseev ◽  
Irina Zhelavskaya ◽  
...  
Keyword(s):  
Space Weather ◽  
Radiation Belt ◽  
Model Performance ◽  
Dynamic Evolution ◽  
Relativistic Electrons ◽  
Outer Radiation Belt ◽  
Chorus Waves ◽  
Van Allen Probes ◽  
Radiation Belt Electrons ◽  
Simulation Results

<p>Using the three-dimensional Versatile Electron Radiation Belt (VERB-3D) code, we perform simulations to investigate the dynamic evolution of relativistic electrons in the Earth’s outer radiation belt. In our simulations, we use data from the Geostationary Operational Environmental Satellites (GOES) to set up the outer boundary condition, which is the only data input for simulations. The magnetopause shadowing effect is included by using last closed drift shell (LCDS), and it is shown to significantly contribute to the dropouts of relativistic electrons at high $L^*$. We validate our simulation results against measurements from Van Allen Probes. In long-term simulations, we test how the latitudinal dependence of chorus waves can affect the dynamics of the radiation belt electrons. Results show that the variability of chorus waves at high latitudes is critical for modeling of megaelectron volt (MeV) electrons. We show that, depending on the latitudinal distribution of chorus waves under different geomagnetic conditions, they cannot only produce a net acceleration but also a net loss of MeV electrons. Decrease in high‐latitude chorus waves can tip the balance between acceleration and loss toward acceleration, or alternatively, the increase in high‐latitude waves can result in a net loss of MeV electrons. Variations in high‐latitude chorus may account for some of the variability of MeV electrons. </p><p>Our simulation results for the NSF GEM Challenge Events show that the position of the plasmapause plays a significant role in the dynamic evolution of relativistic electrons. We also perform simulations for the COSPAR International Space Weather Action Team (ISWAT) Challenge for the year 2017. The COSPAR ISWAT is a global hub for collaborations addressing challenges across the field of space weather. One of the objectives of the G3-04 team “Internal Charging Effects and the Relevant Space Environment” is model performance assessment and improvement. One of the expected outputs is a more systematic assessment of model performance under different conditions. The G3-04 team proposed performing benchmarking challenge runs. We ‘fly’ a virtual satellite through our simulation results and compare the simulated differential electron fluxes at 0.9 MeV and 57.27 degrees local pitch-angle with the fluxes measured by the Van Allen Probes. In general, our simulation results show good agreement with observations. We calculated several different matrices to validate our simulation results against satellite observations.</p>

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