Bayesian Identification of Chorus Sub-Packets from the Van Allen Probes
Abstract
Whistler mode chorus is a quasi-coherent emission that occurs in wave-packets that quickly grow to a large amplitude above the background fluctuations. It has a frequency that changes (typically rising) on a time-scale that is comparable to the time-scale of amplitude variation. The wave-packet is broken up into sub-packets, which are seen as large amplitude fluctuations. All of these features are thought to be due to nonlinear self-consistent wave-particle interactions with source electrons in the KeV range. In this work we develop a Bayesian model comparison framework to compare semi-Empirical models of individual sub-packets using six-dimensional time-domain waveform data (three orthogonal electric field measurements and three orthogonal magnetic field measurements) from the EMFISIS instrument on board the Van Allen Probes. The model comparison framework calculates the relative probability of the different models being tested given the observed data. We also apply this technique to simulated data from electromagnetic particle-in-cell simulations, self-consistent whistler-mode Hamiltonian models, and laboratory data of bursting Langmuir modes interacting with an electron beam. The model parameters extracted from the waveforms allow for an assessment of the formation of the sub-packets and whether the sub-packets observed in simulations and laboratory experiments are similar to the natural emissions.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSM51H3263C
- Keywords:
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- 2730 Magnetosphere: inner;
- MAGNETOSPHERIC PHYSICS;
- 2752 MHD waves and instabilities;
- MAGNETOSPHERIC PHYSICS;
- 2772 Plasma waves and instabilities;
- MAGNETOSPHERIC PHYSICS;
- 2774 Radiation belts;
- MAGNETOSPHERIC PHYSICS