G. Trottet¹, E. Rolli², and A. Magun²

1 Observatoire de Paris, Section de Meudon, DASOP, CNRS-UMR~8645, F-92195 Meudon, France

2 Institute of Applied Physics, University of Bern, Sidlerstrasse 5,CH-3092 Bern, Switzerland

We analyzed the multiwavelength observations of the X1.3/2B solar flare at 8 UTC on 1991 March 13. It was observed in Ha with the fast digital Ha-Camera at Locarno-Monti Switzerland, with the radiotelescopes in Bern and in hard X-rays (HXR) and gamma-rays (GR) by PHEBUS on board of the French-Russian GRANAT satellite. In this paper we present the analysis of the temporal and spatial evolution of this flare. It is found that the Ha emision arises from four kernels. The time evolution of each kernel comprises both a fast component which is well represented by the HXR time profile and a slow component which reflects the time integrated HXR emission. The relative intensity of both components varies from one kernel to another and with the different episodes of particle injection. In addition: there is some evidence of correlated Ha and HXR subsecond time structures during the first part of the HXR/GR event. These results are discussed in the framework of currents models of flares and particle acceleration.