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

11-20A 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) properties of the m- and DH-type II bursts for class I and class II; and ii) 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

Analysis of type II and type III radio bursts associated with SEPs from non-interacting/interacting radio-loud CMEs

We analyze radio bursts observed in events with interacting/non-interacting CMEs that produced major SEPs (Ip $>$ 10 MeV) fromApril 1997 to December 2014.We compare properties of meter (m), deca-hectometer (DH) type II as well as DH type III bursts, and time lags for interacting-CME-associated (IC) events and non-interacting-CME-associated (NIC) events. About 70\% of radio emissions were observed in events of both types from meters to kilometers. We found high correlations between the drift rates and mid-frequencies of type II radio bursts calculated as the mean geometric between their starting and ending frequencies for both NIC and IC-associated events (Correlation coefficient \textit{R}$^{2}$ = 0.98, power-law index $\varepsilon$ = 1.68 $\pm$ 0.16 and \textit{R}$^{2}$ = 0.93, $\varepsilon$ = 1.64 $\pm$ 0.19 respectively).We also found a correlation between the frequency drift rates of DH type II bursts and space speeds of CMEs in NIC-associated events. The absence of such correlation for IC-associated events confirms that the shock speeds changed in CME--CME interactions. For the events with western source locations, the mean peak intensity of SEPs in IC-associated events is four times larger than that in NIC-associated SEP events. From the mean time lags between the start times of SEP events and the start of m, DH type II, and DH type III radio bursts, we inferred that particle enhancements in NIC-associated SEP events occurred earlier than in IC-associated SEP events. The difference between NIC events and IC events in the mean values of parameters of type II and type III bursts is statistically insignificant.Comment: 15 pages, 4 figures, 2 table