Temporal aspects and frequency distributions of solar soft X-ray flares

¹ Institut für Geophysik, Astrophysik & Meteorologie, Universität Graz, Universitätsplatz 5, 8010 Graz, Austria
² Sonnenobservatorium Kanzelhöhe, 9521 Treffen, Austria
³ Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34131 Trieste, Italy

Corresponding author: A. Veronig, asv@igam.uni-graz.at

Received: 13 September 2001
Accepted: 15 November 2001

Abstract

A statistical analysis of almost 50 000 soft X-ray (SXR) flares observed by GOES during the period 1976–2000 is presented. On the basis of this extensive data set, statistics on temporal properties of soft X-ray flares, such as duration, rise and decay times with regard to the SXR flare classes is presented. Correlations among distinct flare parameters, i.e. SXR peak flux, fluence and characteristic times, and frequency distributions of flare occurrence as function of the peak flux, the fluence and the duration are derived. We discuss the results of the analysis with respect to statistical flare models, the idea of coronal heating by nanoflares, and elaborate on implications of the obtained results on the Neupert effect in solar flares.