Spectral analysis and the two-dimensional distribution of physical parameters in a quiescent prominence

Abstract

The profiles of Hα and Ca ii K lines of a arch quiescent prominence on April 1, 1971 have been analyzed and the two-dimensional distributions of electron temperature T _e , micro-turbulence velocity v _t and the column number density of hydrogen along the line-of-sight N _H have been obtained. T _e , υ _t , and N _H are found to be 7500 K, 6 km s⁻¹ and 2.2 ^× 10¹⁸ cm⁻² on an average, respectively. The electron temperature at the central part of the prominence and along the two arcades are greater than that at the edges, while the distribution of the micro-turbulence velocity in these regions is opposite. There is no systematic variation in T _e and v _t , from the center to the periphery as described by Hirayama (1971). The column number density in the central region is lower than that at the two edges.

The contour lines of T _e , υ _t , and N _H are predominantly vertical rather than horizontal. This implies that the height-variation of physical parameters in filamentary structure is small. The arrangement of this structure in the prominence is likely to be arched and is probably in the direction of magnetic field lines.