Global magnetospheric dynamics with reduced kinetic models
Abstract
Global models of solar wind-magnetosphere interaction based on simplified magnetohydrodynamics description of the plasma have been successful at capturing the large scale structure and dynamics of the magnetosphere. However, these approaches are limited by their lack of the microscopic physics, which is known to be important for many processes, such as solar wind-magnetosphere mass and energy transfer, substorm onset and dynamics, and wave-particle interactions. On the other hand, large spatial and temporal scale separation typical of magnetospheric plasmas limits the use of kinetic models to isolated, small regions of near-Earth space. The development of new methods that can bridge the scale gap to successfully handle coupling of large-scale dynamics and microscopic process remains a major challenge and a very active area of research. In this presentation, we describe a new simulation technique to study this problem, which is based on solving kinetic equation using an expansion of the plasma distribution function in a set of basis functions. When suitable choice of the basis is made, the low-order terms describe the large-scale dynamics of the system in a manner similar to fluid models. The microscopic physics can be retained by adding more terms to the expansion, which is conceptually equivalent to increasing velocity space-resolution. Such a method is ideally suited for problems involving fluid-kinetic coupling, since the number of expansion terms could be adapted in space and time. This general approach has been implemented in the SpectralPlasmaSolver (SPS) code. We will present several applications of the method to various problems, including solar wind-magnetosphere interaction.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSM13F3362K
- Keywords:
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- 1910 Data assimilation;
- integration and fusion;
- INFORMATICS;
- 1942 Machine learning;
- INFORMATICS;
- 2753 Numerical modeling;
- MAGNETOSPHERIC PHYSICS;
- 7924 Forecasting;
- SPACE WEATHER