PROFILES OF SELF-REVERSED PROMINENCE LINES INTERPRETED USING A 3-LAYERED MODEL FOR THE VARIATIONS OF THE SOURCE FUNCTION

It is known that the self-reversal of a prominence line is related to the variation of the source function along the line of sight. In this paper, the variable source function represented by a three-layered mod el has been used to probe the relation between the changing form of th e source function and the self-reversal of the prominence line. It is found that: (1) the source function of self-reversed Ha lines increase s from the surface towards the center of the prominence, and the sourc e functions at the center are in theory > 1.0 times those on the bound ary of the prominence; (2) when the total optical depth at the line ce nter (taulambda0) is not very thick, the self-reversal cannot appear a t the line center, although the source function increases from the sur face toward the center of the prominence; and (3) with the increase of taulambda0 and the coefficient of the source function, the profile va riations follow this order: shallow self-reversal and then deep self-r eversal.