LAUSR

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 B Pappa Kalaivani [email protected] Prakash [email protected] Shanmugaraju [email protected] Li Feng [email protected] Lei Lu [email protected] Weiqun Gan [email protected] Michalek [email protected] 1 Department of Physics, Ultra College of Engineering and Technology for Women, Ultra Nagar, Madurai 625 104, Tamil Nadu, India 2 Department of Physics, Sethu Institute of Technology, Pulloor, Kariapatti,Viruthunagar, Tamil Nadu – 626 115, India 4 Department of Physics, Arul Anandar College, Karumathur, Madurai -625514, India 3 Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing – 210008, Jiangsu, China 5 Astronomical Observatory of Jagiellonian University, Cracow, Poland Astrophysics: Astro_example_6.tex; 22 July 2021; 0:45; p. 1 Pappa Kalaivani et al. events (Correlation coefficient R = 0.98, power-law index ε = 1.68 ± 0.16 and R = 0.93, ε = 1.64 ± 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.