Interplanetary type II radio bursts and their association with CMEs and flares

Shanmugaraju, A.; Suresh, K. A.; Vasanth, V.; Selvarani, G; Umapathy, Siva

doi:10.1007/s10509-018-3345-7

Cited by 5 publications

(1 citation statement)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In their analysis of type II burst end frequencies, Vasanth et al (2015) concluded that the lower the emission end frequency, the higher the possibility of having a strong geomagnetic storm near Earth. Shanmugaraju et al (2018) divided the type II bursts into groups by their end frequency: (A) higher than 1 MHz, (B) intermediate, between 1 MHz and 100 kHz, and (C) lower than 100 kHz. Their analysis indicated that there was a correlation between the observed CME height and the estimated type II burst height for groups B and C, but no correlation for group A.…”

Section: Introductionmentioning

confidence: 99%

Formation of Isolated Radio Type II Bursts at Low Frequencies

Pohjolainen

Sheshvan

2021

Sol Phys

View full text Add to dashboard Cite

The first appearance of radio type II burst emission at decameter-hectometer (DH) waves typically occurs in connection, and often simultaneously, with other types of radio emissions. As type II bursts are signatures of propagating shock waves that are associated with flares and coronal mass ejections (CMEs), a rich variety of radio emissions can be expected. However, sometimes DH type II bursts appear in the dynamic spectra without other or earlier radio signatures. One explanation for them could be that the flare-CME launch happens on the far side of the Sun, and the emission is observed only when the source gets high enough in the solar atmosphere. In this study we have analysed 26 radio type II bursts that started at DH waves and were well-separated (‘isolated’) from other radio emission features. These bursts were identified from all DH type II bursts observed in 1998 – 2016, and for 12 events we had observations from at least two different viewing angles with the instruments on board Wind and the Solar Terrestrial Relations Observatory (STEREO) satellites. We found that only 30% of the type II bursts had their source origin on the far side of the Sun, but also that no bursts originated from the central region of the Sun (longitudes E30 – W40). Almost all of the isolated DH type II bursts could be associated with a shock near the CME leading front, and only few were determined to be shocks near the CME flank regions. In this respect our result differs from earlier findings. Our analysis, which included inspection of various CME and radio emission characteristics, suggests that the isolated DH type II bursts could be a special subgroup within DH type II bursts, where the radio emission requires particular coronal conditions to form and to die out.

show abstract

Section: Introductionmentioning

confidence: 99%