Formation of zebra patterns of solar microwave bursts as a result of propagation of radio waves through the inhomogeneous corona

Abstract

The geoefficiency of solar bursts is diagnosed using the dynamic radio emission spectrum. At certain time intervals, the spectrum exhibits nearly parallel narrow-band emission strips termed the zebra pattern. Although there are many hypotheses of its origin, all of them do not take into account changes in the signal parameters upon signal propagation through the solar corona. Our analysis shows that the propagation effects form a dynamic spectrum that contains a zebra pattern. The properties of the modeled spectrum are shown to coincide with the basic properties of the observed spectrum. It is clarified that the spike structure of strips is a natural consequence of the interference of radio waves, and the occurrence of this structure is considered to be evidence in favor of the interference nature of the zebra pattern formation. Consequently, the zebra pattern can be formed not in the radiation source itself, but rather can arise as a result of propagation of radio waves through an inhomogeneous refracting medium of the solar corona.