Type II radio bursts and their association with coronal mass ejections in solar cycles 23 and 24

Abstract

Context. Meter-wavelength type II solar radio bursts are thought to be the signatures of shock-accelerated electrons in the corona. Studying these bursts can give information about the initial kinematics, dynamics, and energetics of coronal mass ejections (CMEs) in the absence of white-light observations. Aims. We investigate the occurrence of type II bursts in solar cycles 23 and 24 and their association with CMEs. We also explore whether type II bursts might occur in the absence of a CME. Methods. We performed a statistical analysis of type II bursts that occurred between 200 and 25 MHz in solar cycles 23 and 24 and determined the temporal association of these radio bursts with CMEs. We categorized the CMEs based on their linear speed and angular width and studied the distribution of type II bursts with fast (≥500 km s−1), slow (< 500 km s−1), wide (≥60°), and narrow (< 60°) CMEs. We explored the dependence of type II bursts occurrence on the phases of the solar cycle. Results. Our analysis shows that during solar cycles 23 and 24, 768 and 435 type II bursts occurred, respectively. Of these, 79% were associated with CMEs in solar cycle 23, and 95% were associated with CMEs in solar cycle 24. However, only 4% and 3% of the total number of CMEs were accompanied by type II bursts in solar cycle 23 and 24, respectively. Most of the type II bursts in both cycles were related to fast and wide CMEs (48%). We also determined the typical drift rate and duration for type II bursts, which is 0.06 MHz s−1 and 9 min. Our results suggest that type II bursts dominate at heights ≈1.7 − 2.3 ± 0.3 R⊙. A clear majority have an onset height around 1.7 ± 0.3 R⊙ assuming the four-fold Newkirk model. Conclusions. The results indicate that most of the type II bursts had a white-light CME counterpart, but a few type II bursts lacked a clear CME association. There were more CMEs in cycle 24 than in cycle 23. However, cycle 24 contained fewer type II radio bursts than cycle 23. The onset heights of type II bursts and their association with wide CMEs reported in this study indicate that the early lateral expansion of CMEs may play a key role in the generation of these radio bursts.

Metric type-II radio bursts and space weather phenomena: A statistical study

“…The exact distributions, also over the remaining SN configurations and the split into for m-II only and m+IP type II bursts, are shown in the Table 1. Kumari et al (2023) also investigated the correlation between number of SNs and type-II radio bursts and the reported correlations are consistent with our results.…”

“…These findings are represented in Figures 7 and 8, respectively. The number of type II events associated with CMEs is 316/429 (74%), which is consistent with Kumari et al (2023) for SC 23 where they found 79% association, however, they report this association to be 95% in SC 24. In our list, among the 316 CME-associated type IIs, m-IIs are 54% (231/429 or 73% as a fraction of the entire CME smaple, 231/316), whereas the m+IP-II events are only 20% (85/429, or 27%, 85/316).…”

“…A well-known classifier for SFs is according to the peak in soft Xrays (SXRs), termed A (the weakest), B, C, M and X-class (the extreme We calculated the ratio and obtain an upper limit for the association between CMEs and the IP-IIs of slightly less than 2% in both SCs and only ∼1% in SC 24. A recent study by Kumari et al (2023) reports 3% for the association between CMEs and m-IIs in SCs 23 and 24. There are several studies in literature where the association between CMEs and type II radio bursts (both m and DH) is investigated in detail (Kahler et al, 1986;Gopalswamy et al, 2012Gopalswamy et al, , 2015bKharayat, Joshi, and Chandra, 2021, and references cited therein).…”

“…In contrast to our study, Kumari et al (2023) investigated the relationship between the observatory reports on m-IIs from https://www.swpc.noaa.gov/pr oducts/solar-and-geophysical-event-reports and CMEs from various databases for the last two solar cycles. For the same period of our analysis, SC 24, they found very similar number of m-IIs in the reports ( 435), compared to our study (429) which is based on visual identifications.…”

Predicting the Arrival Time of an Interplanetary Shock Based on DSRT Spectrum Observations for the Corresponding Type II Radio Burst and a Blast Wave Theory

“…During their eruptions, CMEs can travel at speeds ranging from several tens to even thousands of kilometers per second (Yashiro et al 2004;Webb & Howard 2012), potentially carrying mass from 10 13 to 10 16 g and releasing energy from 10 27 to 10 32 erg (Vourlidas et al 2000(Vourlidas et al , 2010. Their occurrence rates depend on the corresponding solar activity level (Yashiro et al 2008;Lamy et al 2019;Song et al 2021;Kumari et al 2023), which increases from roughly 0.5 day −1 during solar minimum to 6 day −1 during solar maximum (Gopalswamy et al 2003). CMEs originate primarily near the equatorial region during solar minimum, whereas they are ejected from all latitudes during solar maximum (Yashiro et al 2004).…”