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Backward-propagating source as a component of rising tone whistler-mode chorus generation
- Source :
- Frontiers in Astronomy and Space Sciences, Vol 9 (2022)
- Publication Year :
- 2022
- Publisher :
- Frontiers Media S.A., 2022.
-
Abstract
- Whistler-mode chorus waves in the magnetosphere play a crucial role in space weather via wave–particle interactions. The past two decades have observed tremendous advances in theory and simulations of chorus generation; however, several details of the generation mechanism are still actively contended. To simulate chorus generation, a new envelope particle-in-cell code is introduced. The model produces a rising tone chorus element in a parabolic geomagnetic field. The initial chorus element “embryo” frequency is shown to initialize near the equator at the frequency of maximum linear growth. A backward resonant current is then observed to propagate upstream of the equator. The trajectory of the backward current follows that of a freely falling electron that has been de-trapped at the equator superimposed with forward motion at the group velocity. The backward current iteratively radiates a rising tone element where the highest frequency components are generated furthest upstream. The work provides new advancements in modeling chorus and corroborates other recent work that has also demonstrated a backward-moving source during the generation of coherent whistler-mode waves.
Details
- Language :
- English
- ISSN :
- 2296987X
- Volume :
- 9
- Database :
- Directory of Open Access Journals
- Journal :
- Frontiers in Astronomy and Space Sciences
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.f94ddd1137c47f5a3ed41a280825ff6
- Document Type :
- article
- Full Text :
- https://doi.org/10.3389/fspas.2022.981949