Surges, Magnetic Flux Cancellations, and UV Brightenings around an Emerging Flux Region
Abstract
Surge activities, which are observed in Hα images, have been studying for a long time. Many authors noticed that cancellations of magnetic flux was an important factor for surge activities and proposed the models based on magnetic reconnection. But there are not many observations which have enough cadence for comparison changes of magnetic field with surge activities. So the correlation between surges and magnetic flux cancellations is not clear yet. (ex. Zhang et al. 2001) We studied the temporal and spatial relations between surge activities and other phenomena which may be accompanied by surge activities. The data we used here are from coordinated observation with Swedish Vacuum Solar Telescope on La Palma, TRACE and SOHO/MDI. So high cadence images for the same target are available in various wavelengths. MDI, for example, took magnetogram data every one minutes with high resolution mode at that time. The main results from this study are as follows: (1) We can not find any large time lag between the onset of the surge and of the magnetic fields cancellation. This is a conflict result against the one in Zhang et al. (2) There were UV brightenings which correlated well with rapid cancellation of magnetic fields. (3) The UV brightenings located just on neutral lines with some displacement from the region where rapid magnetic cancellation occurred. These observational fact can be explained by magnetic reconnection model.
- Publication:
-
Multi-Wavelength Observations of Coronal Structure and Dynamics
- Pub Date:
- January 2002
- Bibcode:
- 2002mwoc.conf...99Y