H-alpha flare spectra

Abstract

More than 1000 H-alpha flare profiles from 24 solar flares of Class 1 or brighter recorded with the multislit spectrograph of the Lockheed Solar Observatory are examined. It is found that the profiles can be classified in terms of whether or not they show central self-reversals, whether or not they have extended wings, and whether or not they are asymmetric. The profile groupings are not correlated with the size (class) of the flares, nor do they seem to be correlated with the type of chromospheric flare structure from which they are emitted. Although different flare points within the same overall event may show profiles of different types, any given element (bright patch) can usually be described in terms of a single combination of the profile descriptors.