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Bursty Bulk Flow Turbulence as a Source of Energetic Particles to the Outer Radiation Belt
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  • Maria E. Usanova,
  • R E Ergun,
  • D L Turner,
  • J E Stawarz
Maria E. Usanova
LASP

Corresponding Author:[email protected]

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R E Ergun
University of Colorado
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D L Turner
Johns Hopkins University
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J E Stawarz
Imperial College London
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Abstract

We report observations of a Bursty Bulk Flow (BBF) penetrating to the outer edge of the radiation belt. The turbulent BBF braking region is characterized by ion velocity fluctuations, magnetic field (B) variations, and intense electric fields (E). In this event, energetic (>100 keV) electron and ion fluxes are appreciably enhanced. Importantly, fluctuations in energetic electrons and ions suggest that they are locally energized. Using correlation distances and other observed characteristics of turbulent E, test-particle simulations support that local energization by E favors higher-energy electrons and leads to an enhanced energetic shoulder and tail in the electron distributions. The energetic shoulder and tail can be amplified to MeV energies by adiabatic transport into the radiation belt where |B| is higher. This analysis suggests that turbulence generated by BBFs can, in part, supply energetic particles to the outer radiation belt and that turbulence can be a significant contributor to particle acceleration.