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The Effect of Equatorial noise on the Proton Density Structure of the Inner Van Allen Belt
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  • Jayasri Joseph,
  • Allison Jaynes,
  • Gregory Howes,
  • David Hartley,
  • Maria Usanova
Jayasri Joseph
University of Iowa

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Allison Jaynes
University of Colorado at Boulder
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Gregory Howes
Department of Physics and Astronomy, University of Iowa
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David Hartley
University of Iowa
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Maria Usanova
University of Alberta
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We present evidence of damping of equatorial noise due to Finite-Larmor-radius (FLR) effect in the inner Van Allen belt. Detail observation of the FLR phenomenon in the inner belt region has not been reported until now. Waves primarily damped by the FLR mechanism can influence the energy dependent proton density structure. We analyze a typical case recorded by the Van Allen probe that involves FLR damping of equatorial noise, which was propagating radially towards the Earth, at L-shell ~1.7. As a result of this damping, protons in the energy range of ~18 – 21 MeV at L-shell ~1.7 – 2 get energized. This kind of wave-particle interaction should be included in the future models of the inner Van Allen belt. This phenomenon may also account for the unknown proton loss mechanism reported in Selesnick and Albert (2019).