  We analyze complex zebra patterns and fiber bursts during type-IV solar radio
bursts on August 1, 2010. It was shown that all of the main details of sporadic
zebra patterns can be explained within the model of zebra patterns and fiber
bursts during the interaction of plasma waves with whistlers. In addition, it
was shown that the major variations in the stripes of the zebra patterns are
caused by the scattering mechanism of fast particles on whistlers, which leads
to the transition of whistler instability from the normal Doppler effect to an
anomalous one.
