© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.
A model of so-called "Zebra" emissions in solar flare radio burst continua
1Department of Geophysics and Environmental Sciences, Munich University, Munich, Germany
2Department of Physics and Astronomy, Dartmouth College, Hanover NH 03755, USA
3Space Research Institute, Austrian Academy of Sciences, Graz, Austria
*visiting: International Space Science Institute, Bern, Switzerland
Abstract. A simple mechanism for the generation of electromagnetic "Zebra" pattern emissions is proposed. "Zebra" bursts are regularly spaced narrow-band radio emissions on the otherwise broadband radio continuum emitted by the active solar corona. 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. Such ion-rings or ion-conics are well known from magnetospheric observations. Under coronal conditions they may become weakly relativistic. In this case the ion-cyclotron maser 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.