Low-density plasma as a key catalyst for electron acceleration in the Van Allen radiation belts

Abstract The near-Earth space environment is populated by the most energetic electrons with velocities very close to the speed of light, reaching ultra-relativistic energies. These electrons present a serious hazard to the Earth-orbiting spacecraft and are referred to as the Van Allen radiation belt...

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Main Authors: Yuri Y. Shprits, Bernhard Haas, Dedong Wang
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Communications Physics
Online Access:https://doi.org/10.1038/s42005-025-02223-w
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author Yuri Y. Shprits
Bernhard Haas
Dedong Wang
author_facet Yuri Y. Shprits
Bernhard Haas
Dedong Wang
author_sort Yuri Y. Shprits
collection DOAJ
description Abstract The near-Earth space environment is populated by the most energetic electrons with velocities very close to the speed of light, reaching ultra-relativistic energies. These electrons present a serious hazard to the Earth-orbiting spacecraft and are referred to as the Van Allen radiation belts. The question of how these particles are accelerated to such energies is still unanswered. Examining the 20 April 2017 geostorm, we show that such acceleration is achievable only under extremely low plasma density conditions. The global model of radiation belts with a statistical model of plasma density fails to produce the acceleration to such high energies, whereas the model with observed plasma density variations accurately reproduces the observed acceleration at all radial locations and energies. This study demonstrates that electrons are accelerated to multi-MeV by taking energy from plasma waves when the conditions for such acceleration are preferential. It also reveals the intricate interplay between cold plasma and the enhancements of ultra-relativistic electrons that are millions of times more energetic than plasma particles. Similar acceleration may occur in planetary radiation belts, for lab plasmas, at exoplanets, and in other magnetized astrophysical objects.
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spelling doaj-art-cab06e06a7b74f59a1686152ead3148f2025-08-20T04:02:57ZengNature PortfolioCommunications Physics2399-36502025-07-01811710.1038/s42005-025-02223-wLow-density plasma as a key catalyst for electron acceleration in the Van Allen radiation beltsYuri Y. Shprits0Bernhard Haas1Dedong Wang2GFZ German Research Centre for GeosciencesGFZ German Research Centre for GeosciencesGFZ German Research Centre for GeosciencesAbstract The near-Earth space environment is populated by the most energetic electrons with velocities very close to the speed of light, reaching ultra-relativistic energies. These electrons present a serious hazard to the Earth-orbiting spacecraft and are referred to as the Van Allen radiation belts. The question of how these particles are accelerated to such energies is still unanswered. Examining the 20 April 2017 geostorm, we show that such acceleration is achievable only under extremely low plasma density conditions. The global model of radiation belts with a statistical model of plasma density fails to produce the acceleration to such high energies, whereas the model with observed plasma density variations accurately reproduces the observed acceleration at all radial locations and energies. This study demonstrates that electrons are accelerated to multi-MeV by taking energy from plasma waves when the conditions for such acceleration are preferential. It also reveals the intricate interplay between cold plasma and the enhancements of ultra-relativistic electrons that are millions of times more energetic than plasma particles. Similar acceleration may occur in planetary radiation belts, for lab plasmas, at exoplanets, and in other magnetized astrophysical objects.https://doi.org/10.1038/s42005-025-02223-w
spellingShingle Yuri Y. Shprits
Bernhard Haas
Dedong Wang
Low-density plasma as a key catalyst for electron acceleration in the Van Allen radiation belts
Communications Physics
title Low-density plasma as a key catalyst for electron acceleration in the Van Allen radiation belts
title_full Low-density plasma as a key catalyst for electron acceleration in the Van Allen radiation belts
title_fullStr Low-density plasma as a key catalyst for electron acceleration in the Van Allen radiation belts
title_full_unstemmed Low-density plasma as a key catalyst for electron acceleration in the Van Allen radiation belts
title_short Low-density plasma as a key catalyst for electron acceleration in the Van Allen radiation belts
title_sort low density plasma as a key catalyst for electron acceleration in the van allen radiation belts
url https://doi.org/10.1038/s42005-025-02223-w
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