On a method to determine the effective extension, visibility of the Balmer continuum, and the effective mass in solar flares

Abstract

A method to determine the emission measure and hence the effective extension of solar flares is described. The conditions for the Balmer continuum to be visible in disk flares is also considered. The concept of the effective mass is introduced and it is shown that this mass is a little less than that of a plasma filling the whole spectroscopic volume and including thin and dense filaments and the intervals between them as well. In this connection it is necessary to have high energy electron fluxes. It is assumed that these electrons maintian a high temperature in the interval volume; being a source of powerful X-rays, such hot intervals can heat cool filaments and they in their turn reradiate in the visible and ultraviolet regions of the flare spectrum. Taking one flare as an example, we give curves of the emission measure, effective mass and numbers of hydrogen atoms in the second quantum state versus time. These curves agree qualitatively with the light curve characteristics for most of the flares.