Time delay between γ-ray lines and hard X-ray emissions during the 23 July 2002 solar flare interpreted by a trap plus precipitation model

LESIA, Observatoire de Paris, 92195 Meudon Cedex, France e-mail: cyril.dauphin@obspm.fr

Received: 14 August 2006
Accepted: 6 January 2007

Abstract

Context.The 23 July 2002 event was the first γ-ray flare observed by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). Analysis of the time profiles of the hard X-ray and gamma-ray radiations of this flare shows a time delay between hard X-ray at 150 keV and gamma ray line emissions.

Aims.We aim to interpret this delay in terms of transport of the particles accelerated during the flare.

Methods.In this paper, we focus on the interpretation of this delay in the context of a trap plus precipitation model for energetic particles.

Results.The time profiles of hard-X-ray and prompt gamma-ray line fluxes can be reproduced given that electrons and ions are injected and partially trapped in different coronal loop systems with slightly different characteristics such as density and length, and that the energetic electron-to-ion ratio varies from peak to peak during the flare.

Conclusions.The results obtained from this analysis are discussed with respect to the constraints provided by the X-ray and gamma-ray images previously obtained, as well as with previously published analysis of the same event