Understanding IRIS Observations of Explosive Events in Terms of Magnetic Reconnection Mechanisms
Abstract
The explosive events (here after mentioned as EEs) are thought to be driven by small-scale reconnection in the transition region. The reconnection processes take place in scales that are far below the resolution limit of existing imaging telescopes. Nevertheless, the spectral observations from the IRIS mission have the potential to reveal convolved information of density, temperature and velocity of a reconnection site; because reconnection mechanisms, e.g. Sweet-Parker, Petschek and the plasmoid instability, have reconnection sites with very different density and velocity structures and presumably spectral line profiles of different shapes. In our numerical experiments, we trigger different kinds of reconnection, produce synthetic line profiles of the reconnection sites and manage to build connections between reconnection mechanisms with shapes of line profiles. Subsequently, by comparing the observed line profiles of EEs with the synthetic line profiles from simulation, we could probe the reconnection processes that could not be directly observed on the Sun. We find that the observed spectra during EEs can be reproduced by a reconnection site with multiple magnetic islands and null points (or X points) that characterize the plasmoid instability but not by bi-directional jets that characterize the Sweet-Parker or the Petschek mechanism. This result suggests that if EEs are small-scale reconnection sites, then the reconnection proceeds via the plasmoid instability, rather than the Sweet-Parker or Petschek mechanism.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFMSH42B..06G
- Keywords:
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- 7599 General or miscellaneous;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMYDE: 7899 General or miscellaneous;
- SPACE PLASMA PHYSICSDE: 7999 General or miscellaneous;
- SPACE WEATHER