THE CHARACTERISTICS OF SOLAR X-RAY EMISSION FOR PROTON FLARES AND PROTON EVENT WARNING

Studying the characteristics of solar X-ray emission for proton flare will provide an important way and method for proton event warning. The observational data of proton flares and relevant X-ray emission obtained by GOES and SMMsatellites during the 21st Solar Maximum are analysed in this paper. It shows that, for most proton flares, the hard X-ray emission has following properties: the peak flux F_HX≥10^{4c/s, duration time T_n≥103sec, maximum X-ray photon energy E_x≥300 keV, average spectral index<3.5, high energy time delay T_L> 10 sec, integral flux F₀>106counts, rising time T_R>102sec. By using these characteristic parameters to warn the proton events, the a correct prediction rate of 94% and a false prediction rate of 40% are obtained respectively.}