Simulated enhancement of solar type II radio bursts during the collision of two shocks associated with coronal mass ejections

Free access article

Issue		A&A Volume 454, Number 3, August II 2006


Page(s)		983 - 988
Section		The Sun
DOI		http://dx.doi.org/10.1051/0004-6361:20065130

A&A 454, 983-988 (2006)
DOI: 10.1051/0004-6361:20065130

Simulated enhancement of solar type II radio bursts during the collision of two shocks associated with coronal mass ejections

J. I. Sakai¹, T. Mori¹, S. Saito¹, Y. Tanaka¹ and H. Aurass²

¹ Laboratory for Plasma Astrophysics, Faculty of Engineering, University of Toyama, 3190, Gofuku, Toyama 930-8555, Japan
e-mail: sakaijun@eng.u-toyama.ac.jp
² Astrophysical Institute Potsdam, An der Sternwarte 16a, 14482 Potsdam, Germany

(Received 2 March 2006 / Accepted 3 April 2006 )

Abstract
Aims.We investigate how solar type II radio bursts can be enhanced when two fast magnetosonic shocks associated with coronal mass ejections (CMEs) collide. This work was motivated by recent observations showing that the radio signature is in the form of intense continuum-like radio emission following an interplanetary type II burst, when a fast CME overtakes a slow CME.
Methods. We used a 2D3V fully relativistic, electromagnetic particle-in-cell (PIC) simulation.
Results. We found that during the collision between a fast shock with Alfvén Mach $M_{\rm A}=3$ and a slow wave with Alfvén Mach $M_{\rm A}=0.75$ , the radio emission with a broad band can be enhanced with an amplitude about ten times larger than for the undisturbed type II burst. We also found that when a fast shock with Alfvén Mach $M_{\rm A}=3$ overtakes a slow shock with Alfvén Mach $M_{\rm A}=1.5$ , the enhancement of the radio emission is about five times greater than the undisturbed type II burst.

Key words: plasmas -- radiation mechanisms: non-thermal -- shock waves -- methods: numerical -- Sun: radio radiation

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.