EDP Sciences
Free access
Volume 384, Number 3, March IV 2002
Page(s) 1098 - 1106
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20020092

A&A 384, 1098-1106 (2002)
DOI: 10.1051/0004-6361:20020092

On the association between type II radio bursts and CMEs

H. T. Claßen and H. Aurass

Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
    e-mail: tclassen@aip.de

(Received 23 July 2001 / Accepted 20 December 2001 )

Ground-based observations of metric (coronal) type II radio bursts are compared with observations of coronal mass ejections (CMEs) obtained by the LASCO coronagraph aboard SOHO and with decametric (interplanetary) type II bursts recorded by the WAVES instrument aboard Wind. The basic data sample comprises 63 metric type II radio bursts observed during different phases of the solar cycle, i.e., 20 events in 1997 and 43 events in 1999/2000. Our analysis is based on temporal coincidence and velocity data derived from height-time plots of CMEs and frequency drift rates of type II radio bursts, respectively. The results suggest that there are three scenarios leading to metric type II burst excitation: The radio emission is generated either at flare-related blast wave shocks (class 1), at shocks driven by the leading edge of the CME (class 2), or at shocks driven by internal parts or the flanks of the CME (class 3). This classification is supported by an analysis of the association with H $\alpha$ flare sites. The first class of events comprises 19 events (30%), the second 19 events (30%), and the third 18 events (29%). 7 events (11%) were not classified. Furthermore, we notice a possible solar cycle dependence of the relative occurrence of the different scenarios.

Key words: Sun: radio radiation -- coronal mass ejections (CMEs) -- shock waves

Offprint request: T. Claßen, tclassen@aip.de

© ESO 2002

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access.

An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account.
    In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.