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ORIGINAL RESEARCH article

Front. Astron. Space Sci.
Sec. Space Physics
Volume 11 - 2024 | doi: 10.3389/fspas.2024.1446194
This article is part of the Research Topic The Loss and Acceleration Mechanisms of Energetic Electrons in the Earth’s Outer Radiation Belt View all 7 articles

Magnetosonic Wave Instability by Proton Ring and Shell Distributions

Provisionally accepted
Xu Liu Xu Liu 1*Lunjin Chen Lunjin Chen 1Xueyi Wang Xueyi Wang 2
  • 1 The University of Texas at Dallas, Richardson, United States
  • 2 Auburn University, Auburn, Alabama, United States

The final, formatted version of the article will be published soon.

    Both proton ring and shell distributions, providing a positive gradient along the perpendicular direction, can trigger ion Bernstein instabilities and excite magnetosonic (MS) waves in the Earth's inner magnetosphere. A thorough comparison of the ion Bernstein instability due to the proton ring and shell distributions has not been performed. In this study, we perform and compare the MS wave instabilities under different wave normal angles and parameters of ring and shell distributions. We find that (1) compared to shell-driven MS waves, ring-driven MS waves have narrower frequency and wavenumber ranges. (2) The peak growth rates of shell-driven MS waves are always near the first peaks of the square of first-kind Bessel function Jn2. While, The peak growth rates of ring-driven MS waves are near the first peaks of Jn2, and shift to the cold plasma dispersion relation as ring velocity or wave normal angle increases. (3) MS wave growth rates increase as first peaks of Jn2 approach the cold plasma dispersion in frequency-wavenumber domain. This result can be used to explain dependences on ring (shell) velocity and wave normal angle. (4) The MS wave frequency range and growth rates decrease with increasing ring or shell temperature.

    Keywords: MS waves, ring and shell distributions, ring and shell parameters, Wave instability, Earth's inner magnetosphere

    Received: 10 Jun 2024; Accepted: 26 Aug 2024.

    Copyright: © 2024 Liu, Chen and Wang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Xu Liu, The University of Texas at Dallas, Richardson, United States

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