Particle acceleration in complex current-sheet-populated magnetic configurations
Abstract
In the MHD picture it has long been postulated that continued braiding of an initially smooth and continuous magnetic fields will eventually lead to the formation of localised current sheets. With a small amount of magnetic resistivity the free magnetic energy will be released through magnetic reconnection. Observations indicate that in such processes up to 50% of the released energy is transported away from the diffusion region by accelerated non-thermal particles. This physics is not covered by the MHD approach, and therefore to investigate the process of particle acceleration and its implications on the dynamical evolution of current sheets, one needs to adopt an approach that can handle this. Particle-in-cell simulations provide one such tool. Typically one associates this type of simulations with physics on a length scales that are very much smaller than the characteristic length scale of the dynamical systems in the solar atmosphere. But a different PIC approach can be adopted, where one takes the result from a large scale MHD simulation and focuses on a sub volume, of the experiment and exports it into a PIC simulation. We have developed a technique to perform such mixed MHD/PIC simulations, which allows us to investigate the dynamical evolution of the particles in and around current sheets, showing clear differences from the MHD picture. Information can be obtained on both the acceleration mechanism and changes to the general particle distribution function.
- Publication:
-
40th COSPAR Scientific Assembly
- Pub Date:
- 2014
- Bibcode:
- 2014cosp...40E.931G