Articles | Volume 32, issue 3
Ann. Geophys., 32, 223–230, 2014

Special issue: Dynamical processes in space plasmas II

Ann. Geophys., 32, 223–230, 2014

Regular paper 12 Mar 2014

Regular paper | 12 Mar 2014

Observation of shocks associated with CMEs in 2007

H. Aryan1, M. A. Balikhin1, A. Taktakishvili2, and T. L. Zhang3 H. Aryan et al.
  • 1Department of Automatic Control and Systems Engineering, University of Sheffield, Sheffield, UK
  • 2NASA Goddard Space Flight Center, Greenbelt, Maryland, USA
  • 3Space Research Institute, Austrian Academy of Sciences, Graz, Austria

Abstract. The interaction of CMEs with the solar wind can lead to the formation of interplanetary shocks. Ions accelerated at these shocks contribute to the solar energetic protons observed in the vicinity of the Earth. Recently a joint analysis of Venus Express (VEX) and STEREO data by Russell et al. (2009) have shown that the formation of strong shocks associated with Co-rotating Interaction Regions (CIRs) takes place between the orbits of Venus and the Earth as a result of coalescence of weaker shocks formed earlier. The present study uses VEX and Advanced Composition Explorer (ACE) data in order to analyse shocks associated with CMEs that erupted on 29 and 30 July 2007 during the solar wind conjunction period between Venus and the Earth. For these particular cases it is shown that the above scenario of shock formation proposed for CIRs also takes place for CMEs. Contradiction with shock formation resulting from MHD modelling is explained by inability of classical MHD to account for the role of wave dispersion in the formation of the shock.