Naslov
Type-II Bursts in Meter and Deca – Hectometer Wavelengths and Their Relation to Flares and CMEs: II

Autori
Prakash, O. ; Umapathy, S. ; Shanmugaraju, A. ; Pappa Kalaivani, P. ; Vršnak, Bojan

Izvornik
Solar physics (0038-0938) 266 (2010), 1; 135-147

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Coronal mass ejections · Solar flares · Type-II bursts

Sažetak
A study of the relationship between 38 type-II bursts recorded in meter and decahectometer (hereinafter m and DH) wavelength range and the associated flares and CMEs observed during the years 2000 – 2005 was carried out by Prakash et al. (2009). These events were divided into two classes: i) Class I, representing events where DH-type-II bursts are not a continuation of m-type-II bursts and ii) Class II, where DH-type-II bursts are a continuation of m-type-II bursts. In the present work, we extend the analysis of this sample of 38 events in three different steps: i) statistical properties of m- and DH-type-II bursts ; ii) analysis of time lags between onsets of flares and CMEs associated with type-II bursts ; and iii) statistical properties and relation between flares and CMEs of Class I and Class II events.We found a significant difference between the properties of m- and DH-type-II bursts of Class I and Class II events. For example, there are significant differences in starting and ending frequencies, bandwidth and speed. From the time delay analysis, we found the following. i) In 64% of Class I events, flares start after the onset of CMEs and the remaining 36% of flares start before the onset of CMEs. On the other hand, in the case of Class II events, the values are 83% and 17%, respectively. ii) The difference between the mean values of delay between flare start and DH start has high statistical significance (probability P of null hypothesis < 1%). The time delays between the start of m-type-II burst and the CME onset are considerably larger for Class I events (P = 7%) than Class II events. iii) There are notable differences in: (a) delay between the flare and CME onset times (P <1%) ; (b) flare rise time of Class I and Class II events (P <5%). iv) While the flare rise time is well correlated with the lag between the flare start and the CME onset in Class I events, there is no such correlation for Class II events.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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