A model of so-called `Zebra' emissions in type IV radio bursts
  A simple mechanism for the generation of electromagnetic Zebra pattern emission is proposed. The mechanism is based on the generation of an ion-ring distribution in a magnetic mirror geometry in the presence of a properly directed field-aligned electric potential field. The ion-cyclotron maser then generates a number of electromagnetic ion-cyclotron harmonics which modulate the electron maser emission. The mechanism is capable of switching the emission on and off or amplifying it quasi-periodically which is a main feature of the observations. 
R. A. Treumann, R. Nakamura, and W. Baumjohann
physics.space-ph astro-ph.SR physics.geo-ph