Kelvin-Helmholtz stability of reconnection exhausts in the solar wind

Abstract

Three solar wind reconnection exhaust events observed by the Wind satellite are compared to the analytical solution of the Riemannian decay of a current sheet due to reconnection of skewed magnetic fields. This process leads to high speed flows inside an exhaust region which is bounded not only by Alfvénic and slow mode waves but also, to a large extent, by tangential discontinuities (TDs). The TD portions of the exhaust boundary expand with distance from the X-line and therefore a long exhaust does not necessarily imply a long X-line. In some cases, portions of the exhaust show oscillations which might be connected to a Kelvin-Helmholtz instability in agreement with analytical estimates. Copyright 2012 by the American Geophysical Union.