Kinetic properties of collisionless magnetic reconnection in space plasma: in situ observations

Abstract

In collisionless plasmas, magnetic reconnection is widely recognized as one of the most important energy conversion and dissipation processes. Although reconnection is usually manifested as macroscopic effects, such as large-scale magnetic topology change and fast plasma flows, kinetic physics is the underlying process driving these macroscopic phenomena. This paper reviews the recent advances in understanding the kinetic physics in magnetic reconnection primarily on the basis of in situ satellite observations in the Earth's magnetosphere. We divide the reconnection into several sub-regions: the diffusion region, the outflow region and the separatrix region, and detail the kinetic process in these different regions. For these different regions, we start by reviewing the kinetic structure, and then discuss the particle kinetics and wave properties in these regions. Finally, we discuss some of the key unsolved questions.