Characteristics of type II solar radio bursts in the meter and deca-hectometer wavelengths

Abstract

A detailed investigation on type II radio bursts pairs in the meter and deca-hectometer wavelength ranges (herein after m-and DH-type II bursts) and their associated flares and CMEs observed during the period 2000-2005 has been presented. Out of 38 events, only 27 events have been selected, which are the CMEs following the associated flares (AF-CMEs). The selected events are divided into two classes using the drift plots: class I, where DH-type II bursts are not continuation of m-type II bursts; and class II, where DH-type II bursts are extensions of m-type II bursts. The study consists of: i)<b style=""> </b>properties of the m- and DH-type II bursts for class I and class II; and ii)<b style=""> </b>characteristics of type II bursts and their associated flares and CMEs. It has been found that there are significant differences in class I and class II type II bursts pairs and they are associated with flares and CMEs (duration, ending frequency, m-type II speed). The class I m-type II bursts have speeds much slower than the class II events. The correlation between the starting frequencies and flare start-CME onset delay times of m- and DH-type II bursts has been found. Out of 27 type II bursts pairs, 26% are associated with class I events, i.e. the DH-type II is not continuous of m-type II burst, which is consistent with two types of coronal shocks model. The remaining 74% of class II events (DH-type II bursts is extension of m-type II bursts) are associated with single shocks model. From these results, it is concluded that the class I type II bursts pairs (m- and DH-type II bursts) tend to be related with flares and CMEs and class II events tend to be related with CMEs.