AMPTE observations of steady-state reconnection at the dayside magnetopause

Abstract

Since the introduction of magnetic reconnection into magnetospheric physics by Dungey /1/, the argument over its existence at the dayside magnetopause has raged back - and - forth. Much indirect evidence for dayside reconnection has been compiled. For example, the dependence of magnetospheric processes on the IMF Bz component /2/ and IMF control of energetic solar particle access to the polar cap /3/. However, analysis of IMP6 /4/ and HEOS2 data /5/ failed to find any evidence of high speed ion flows at the magnetopause, an expected signature of magnetic reconnection /6/. It was thus left to the ISEE - 1 and - 2 spacecraft to provide the most powerful evidence for the existence of dayside reconnection. In particular, the observations of high speed plasma flows /7/, which have been shown to be consistent with reconnection models /8/, provide strong evidence. Recently, observations from the AMPTE spacecraft provide further evidence for steady - state reconnection and promise to further our knowledge of the reconnection process.