Low frequency Type II radio bursts from CMEs related solar flares

Abstract:

We present a study of 11 type II radio bursts observed at starting frequency of 1MHz and solar flares related coronal mass ejections (CMEs) phenomena. The time durations of these type II radio bursts are ranges between 5 min to 2020 min. On investigation of 11 type II radio bursts and associated CMEs, solar flares and coronal holes (CHs) data we have found that 4 type II radio bursts were observed when there were CHs and solar flares within 10 degree and 5 type II radio bursts were observed when there were CHs and solar flares within 20 degree, respectively. Earlier Verma and Pande (1989) and Verma (1998, 2002) presented a view that the CMEs may have been produced by some mechm, in which the mass ejected by solar flares or active prominences, gets connected with the open magnetic lines of CHs (source of high speed solar wind streams) and moves along them to appear as a halo CMEs. The each low frequency type II radio bursts and other solar events observed are analyzed separately to understand the origin of low frequency type II radio bursts from the Sun in view in view of recent scenario of solar Heliophysics.

References:

Verma, V. K. & Pande, M. C. 1989, in Proc. IAU Colloq. 104 " Solar and Stellar Flares" (Poster Papers), Stanford University, Stanford, USA, p.239

Verma, V. K. 1998, Journal of Indian Geophysical Union, 2, 65

Verma, V. K. 2002, COSPAR Colloquia Series(Elsevier Science Ltd), 13, 319