The Relationship between Long-Duration Gamma-Ray Flares and Solar Cosmic Rays

Abstract

A characteristic pattern of solar hard X-ray emission, first identified in SOL1969-03-30 by Frost & Dennis (1971), turns out to have a close association with the prolonged high-energy gamma-ray emission originally observed by Forrestet al.(1985). This identification has become clear via the observations of long-duration γ-ray flares by theFermi/LAT experiment, for example in the event SOL2014-09-01. The distinctive features of these events include flat hard X-ray spectra extending well above 100 keV, a cha…