How small changes in the magnetopause current help trap the ring current population
Abstract
Particle energization is one of the open questions in heliophysics research, whether it pertains to coronal heating, polar wind outflow, or magnetospheric transport. The terrestrial magnetosphere acts as an efficient particle accelerator, as it can rapidly accelerate charged particles up to very high energies over relatively short times and distances. While the magnetic field topology is critical for understanding the particle drifts, knowing the source and structure of the electric field is crucial for interpreting the flow of particles in this region. Assessing the relative contribution of potential versus inductive electric fields at the energization of the hot ion population in the inner magnetosphere is only possible by thorough examination of the time varying magnetic field and current systems using global modeling of the entire system. Based on the Helmholtz vector decomposition of the motional electric field as calculated by the BATS-R-US model, we differentiate the electric field based on its source (electrostatic vs. inductive). Electric field coupling between the BATS-R-US and the Hot Electron and Ion Drift Integrator model reveals the crucial role of time varying magnetic fields, and hence the inductive electric field, in trapping of energetic particle and in the overall particle energization.
We show that inductive electric fields, even if not impulsive in nature, contribute significantly to the total field, and in the absence of strong dipolarizations, most of the contribution comes from the intensification of the magnetopause current. In addition, the inductive electric field acts to stabilize the ring current, and it plays a significant role in particle trapping. These results indicate a potential paradigm shift in our knowledge of particle energization in the context of ring current development and decay.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSM41D3272I
- Keywords:
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- 2730 Magnetosphere: inner;
- MAGNETOSPHERIC PHYSICS;
- 2774 Radiation belts;
- MAGNETOSPHERIC PHYSICS;
- 7807 Charged particle motion and acceleration;
- SPACE PLASMA PHYSICS;
- 7867 Wave/particle interactions;
- SPACE PLASMA PHYSICS