Moving radio bursts associated with solar flares detected by XSM onboard Chandrayaan-2

Abstract Solar radio bursts and associated solar flares play an important role in investigating the solar eruptive events occurring in the solar atmosphere. Radio bursts serve as precise indicators of electron acceleration, plasma processes, and coronal mass ejections, generally observed at low frequencies below a few hundred MHz. We investigated the temporal correlation of such radio bursts with solar flares observed by X-ray Solar Monitor (XSM) on board Chandrayaan-2. For this investigations, we choose moving radio bursts which are type II and type IVm; as these bursts are strongly associated with large scale eruptive events. We identified such 36 events of moving radio bursts out of which 23 are type IIs and 13 type IVm bursts within november 2019 to september 2022 timerange. We found strong positive pearson correlation coefficient for both onset (r ≈ 0.99) and end time delays (r ≈ 0.99) of type II radio bursts with respect to flare onset while for type IVm bursts, onset time correlation coefficient found to be (r ≈ 0.99) and (r ≈ 0.95) for end time. We found a variation for onset delays of type II radio bursts across associated B, C and M classes. In the onset analysis we observed that small scale flares (B class) showing large onset delays of about ≈ 27 min while moderate to strong flares (C and M) showed very short onset delays which interprets that bursts associated with stronger energetic flare introduces rapid coronal shock formation. Type II bursts showed increasing negative delays (11 − 26 min) with increasing flare energy that indicated more energetic flare ending very faster before flare decay. Type IVm bursts found to be associated with C and M class solar flares, showing onset delays of 13.5 min and 15.4 min respectively while end time delays found to be increasing with flare energy class with more variability. Additionally, we analysed the onset to peak times for both moving radio bursts and found that most of the flares peaked below +20 min time; and this suggested that +20 min window can be used for detection and prediction of eruptive events associated with moving solar radio bursts. Non-uniform decrease in delay observed with increasing flare energy with a few outlier events; this given idea that not only flare energetics but also magnetic environment, plasma conditions, and radio bursts production influences eruptive events to occur.