Analysis of hard X- and gamma-rays and microwave emissions during the flare of July 18, 2002

The Nobeyama Radioheliograph observation results and data from the KONUS-Wind spectrometer mounted at the Wind and RHESSI satellites on several solar flares are jointly analyzed. The analysis results for data on the flare of July 18, 2002 are described. The hard X-rays were measured in the 18 keV-15 MeV range (KONUS-Wind), and spectroheliograph measurements were carried out in the radio range at frequencies of 17 and 34 GHz. Spatial distributions of the radio brightness were calculated for the flare of July 18, 2002; they show the presence of two sources at the footpoints and one source at the top of the supposed flaring loop. The energy spectra of hard X-rays, energy flux, and the total number of accelerated electrons were found from the KONUS spectrometer data. The number of accelerated X-ray emitted electrons was estimated as N ≥ 10 36 , and the maximum X-ray energy flux was estimated as ∼5 × 10 −6 erg cm −2 s −1 . The spectrum index varies in time from −4.6 to −3.6, i.e., the soft-hard-harder trend is implemented. The spectral index of the radio waves is α ≈ −0.3 at the flare start, attains the value α ≈ −0.5 at the flux maximum, and even change the sign further. The accelerated electron transport model in the flare loop plasma is suggested for interpretation of relationships between parameters of the radio emission and hard X-rays.