Efficiency Of Energy Dissipation At A Magnetic X-point
Abstract
Magnetic reconnection at a current sheet is believed to release stored magnetic energy by decreasing the net current carried by the sheet. The current change will affect magnetic field throughout the coronal volume, not just on field lines transferred across the current sheet. This global effect results from a fast magnetosonic rarefaction wave launched by the reconnection, which carries away the excess current and converts free magnetic energy to kinetic energy through the volume. The present work demonstrates, in a simplified model, how reflection of this wave from the photospheric boundary determines the total energy dissipation possible. Previous investigations by Craig and McClymont (1991) and Hassam (1992) assumed one-hundred percent of the reflected wave returned to the dissipation region (the X-point), and thereby concluded that all of the stored energy could be dissipated eventually. The present investigation uses a more realistic geometry to show that only a fraction of the stored magnetic energy could be directly dissipated, at least within the dissipation region. The remaining energy continues to propagate as a fast magnetosonic wave.
- Publication:
-
American Astronomical Society Meeting Abstracts #220
- Pub Date:
- May 2012
- Bibcode:
- 2012AAS...22020423L