Two-dimensional multi-parameter fields of a limb flare loop system
Yunnan Observatory, CAS, Kunming 650011 and National Astronomical Observatories, CAS, Beijing 100012, PR China
2 United Laboratory of Optical Astronomy, CAS, Shanghai 200030, PR China
Corresponding author: Xiao Ma Gu, email@example.com
Accepted: 7 August 2001
The 2D H spectral data of the post-flare loop system (PFLs) of August 17, 1989 are obtained and analyzed quantitatively. Four physical parameters (the line-of-sight velocity V//, column number density of the hydrogen atoms at the second level along the line-of-sight direction N2, the excitation temperature Tex and the micro-turblence velocity Vt) and their 2D distributions are derived. The 2D fields of V//, N2, Tex and Vt exhibit inhomogeneous and asymmetric properties in two loop legs. Red-shift velocities in the south leg are smaller than those of blue shift in the north leg where the velocity reaches 60 km s-1. The values of N2 and Tex in the south leg are all much higher than those in the north leg, N2 ranges between 0.5 to cm-2, while Tex ranges from 0.8 to K, lower at the top part than in the two legs. A high temperature region is located in the middle of the south leg. Vt at the top part is greater than that in the two legs, with the average being 30~40 km s-1. Electron density ne and electron pressure Pe are estimated at 0.2~ cm-3 and at 0.04~0.12 dyn cm-2, respectively. These results are compared with those obtained from the PFLs of 1984 February 18.
Key words: Sun: flares / Sun: fundamental parameters
© ESO, 2001