On the nature of X-ray and ultraviolet radiations of solar flares

The origin of X-ray and UV radiations of the solar flares is investigated. The inconsistences in the explanation of the origin of hard X-ray bursts in the framework of the thick target model and the quasi-thermal model are pointed out. Both models imply the existence of anomalously high-energy fluxes from a source. The difficulty can be overcomed in the framework of the theory of thin pinched current layers. THe low-temperature current layers can act as quasistationary sources of soft X-ray and UV radiations. The pulse UV radiation of a solar is formed in thin transitional layers, which are formed due to pulse heating of the chromosphere by the flare heat fluxes and the fluxes of accelerated electrons. The qualitative model for the description of the observed dependence of the UV radiation burst intensity on the flare position on the surface of the Sun is proposed