Coronal type II radio bursts in 2002

Type II radio bursts are produced near the local plasma frequency and its harmonic by fast electrons accelerated by a shock wave moving through the corona and solar wind with a typical speed of ~1000km/s. The coronal bursts have dynamic spectra with frequency gradually falling with time and durations of several minutes.

This Letter presents a new method developed to detect type II coronal radio bursts automatically and describes its implementation in an extended Automated Radio Burst Identification System (ARBIS 2). Preliminary tests of the method with spectra obtained in 2002 show that the performance of the current implementation is quite high, ~80%, while the probability of false positives is reasonably low, with one false positive per 100-200hr for high solar activity and less than one false event per 10000hr for low solar activity periods.