Magnetic Reconnection on the Sun and in the Earth’s Magnetosphere

Abstract

Observational evidence for magnetic reconnection in the Sun?s atmosphere and in the Earth?s magnetosphere is reviewed. On the Sun reconnection is inferred from observations of high speed flows derived from motion of X-ray or EUV features, from the identification of structures in the soft X-ray images, and from the observation of energetic particle events in hard X-ray images. In particular the soft X-ray images during flares are supposed to exhibit the large scale magnetic field structure. In the Earth?s magnetosphere in situ observations by satellites at a particular location reveal magnetic field and flow variations. To these one can apply conservation laws and verify whether boundaries, like the magnetopause, have a normal magnetic field component, i.e., are rotational discontinuities. In the magnetotail the magnetic field structure can be deduced from the temporal variation of the magnetic field during high speed flow events.