Description
Magnetic reconnection is of particular importance in space plasmas because of its role in controlling magnetic topology and releasing stored magnetic energy. In situ observations of reconnection complement remote sensing and simulations by directly quantifying the local properties of reconnection as well as providing ground truth of the plasma physical mechanisms of heating and acceleration. Whilst the majority of in situ measurements have been made in and near the Earth’s magnetosphere, new observations from the inner heliosphere are showing that magnetic reconnection is prevalent in the Heliospheric Current Sheet (HCS) close to the Sun, and this provides a new laboratory to study magnetic reconnection physics. More specifically, reconnection is observed in regimes that may be relevant for understanding solar wind formation, for example below the Alfven transition region where the solar wind is sub-Alfvenic. In this contribution we present Parker Solar Probe observations of reconnection in the HCS made during perhelion encounters, including below the Alfven surface. We examine the nature of the reconnection energy fluxes during HCS reconnection, and assess the existence and properties of other transient structure such as flux ropes and islands. The implications of these observations for both our basic understanding of reconnection in large scale current sheets, and for the energisation of plasma deeper in the corona are discussed.
