OBSERVATIONS OF AN INTERPLANETARY INTERMEDIATE SHOCK ASSOCIATED WITH A MAGNETIC RECONNECTION EXHAUST

Abstract

ABSTRACT Two intermediate shocks (ISs) in interplanetary space have been identified via one spacecraft observation. However, Feng et al. suggested that the analysis using a single spacecraft observation based only on the Rankine–Hugoniot (R-H) relations could misinterpret a tangential discontinuity (TD) as an IS. The misinterpretation can be fixed if two spacecraft observations are available. In this paper, we report an IS-like discontinuity associated with a magnetic reconnection exhaust, which was observed by Wind on 2000 August 9 at 1 au. We investigated this discontinuity by fitting the R-H relations and referring to the Advanced Composition Explorer (ACE) observations. As a result, we found that the observed magnetic field and plasma data satisfy the R-H relations well, and the discontinuity satisfies all the requirements of the type IS. Although the discontinuity cannot be identified strictly by using two spacecraft observations, in light of the ACE observations we consider that the discontinuity should be an IS rather than a TD.