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ORIGINAL RESEARCH article

Front. Astron. Space Sci.
Sec. Space Physics
Volume 11 - 2024 | doi: 10.3389/fspas.2024.1455400

Estimating the Wavelet Bispectrum of Multiband Whistler Mode Waves

Provisionally accepted
M. G. Shah M. G. Shah 1,2*D. Burgess D. Burgess 1
  • 1 Queen Mary University of London, London, United Kingdom
  • 2 Hajee Mohammad Danesh Science and Technology University, Dinajpur, Rangpur, Bangladesh

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

    Whistler mode waves are one of the dominant plasma emissions occurring in the Earth's magnetosphere. Using data from the Magnetospheric Multiscale (MMS) mission taken in the outer magnetosphere, we present observations of a multiband whistler event with multiple discrete frequency bands of whistler emission. A newly developed bispectral analysis method, the normalized wavelet bispectrum, is employed to explore the generation mechanism of such whistler mode waves. This method is useful for examining the time-evolving behaviour of coupled oscillatory systems. The wavelet bispectrum analysis of multiband whistlers suggests that the higher-frequency whistler band is possibly generated due to a nonlinear three-wave coupling involving the two lower-frequency whistler bands. The presence of other features such as rising tones provides evidence that multiband whistler events probably involve several different concurrent emission processes.

    Keywords: Earth's magnetosphere, Magnetospheric Multiscale mission, Multiband Whistlers, Wavelet bispectrum, Wave-wave coupling

    Received: 26 Jun 2024; Accepted: 23 Aug 2024.

    Copyright: © 2024 Shah and Burgess. 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: M. G. Shah, Queen Mary University of London, London, United Kingdom

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.