Abstract
Downstream structures of interplanetary fast shocks associated with coronal mass ejections
National Institute of Information and Communications Technology, Tokyo, Japan
National Institute of Information and Communications Technology, Tokyo, Japan
National Institute of Information and Communications Technology, Tokyo, Japan
National Institute of Information and Communications Technology, Tokyo, Japan
National Institute of Information and Communications Technology, Tokyo, Japan
We investigate 17 coronal mass ejection (CME) events identified by the ACE spacecraft during solar cycle 23, focusing upon the fine structures of the sheath region between the CME and its associated shock to find their dependence on the shock parameters. We observe the planar magnetic structure (PMS) downstream of a quasi-perpendicular shock when the Alfvén Mach number >2.0. Here, the PMS is characterized by the magnetic fields changing directions abruptly and intermittently within a plane parallel to the shock plane. The downstream PMS does not form when a magnetic cloud with β value <0.05 exists just upstream of a shock with Alfvén Mach number <2.0. The sheath magnetic fields become highly turbulent when the shock angle is <60 and/or the upstream β value is >0.5 and the upstream is dominated by Alfvenic fluctuations.
Received 21 February 2005; accepted 20 May 2005; published 18 June 2005.
Citation: (2005), Downstream structures of interplanetary fast shocks associated with coronal mass ejections, Geophys. Res. Lett., 32, L12103, doi:10.1029/2005GL022777.
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