Distinct characteristics of asymmetric magnetic reconnections: Observational results from the exhaust region at the dayside magnetopause

Abstract

Magnetic reconnection plays a key role in the conversion of magnetic energy into the thermal and kinetic energy of plasma. On either side of the diffusion region in space plasma, the conditions for the occurrence of reconnections are usually not symmetric. Previous theoretical studies have predicted that reconnections under asymmetric conditions will bear different features compared with those of symmetric reconnections, and numerical simulations have verified these distinct features. However, to date, the features of asymmetric reconnections have not been thoroughly investigated using in situ observations; thus, some results from theoretical studies and simulations have not been tested with observations sufficiently well. Here, spacecraft observations are used in a statistical investigation of asymmetric magnetic reconnection exhaust at the dayside magnetopause. The resulting observational features are consistent with the theoretical predictions. The results presented here advance our understanding of the development of reconnections under asymmetric conditions.

MMS Observation of Magnetic Reconnection in the Turbulent Magnetosheath

“…A more detailed discussion of these intervals comes in the next sessions. The slopes and correlations for these intervals, except for the magenta line in Figure b, satisfy the usual conditions required for the Walén test (Zhang, ). A change in sign of the slopes can mean either the spacecraft are on the same side of the X line crossing the two boundaries of the same outflow successively or that the other side of the X line is crossed within the same hemisphere of the oppositely directed outflow (Øieroset et al, ).…”

Solar wind flow angle and geoeffectiveness of corotating interaction regions: First results

“…Hence, it was argued by them that the parameters in the solar wind decide the merging electric field. Recently, it has been experimentally observed [ Zhang , ] that the reconnection takes place in an asymmetric medium as the plasma parameters are not same on the bow shock and magnetopause side of the magnetosheath region. Therefore, depending on the local plasma processes, the merging can be different on some occasions even if the flow angle is well within 6°.…”

Electron Bernstein waves driven by electron crescents near the electron diffusion region

“…1, the neutral line is located at the time indicated by the red vertical line, determined by the B L zero-crossing point. On the magnetosheath side of the neutral line, MMS1 observes a strong increase in B M , which corresponds to the Hall magnetic field 5,28,29 . The magnetospheric separatrix is located at the time indicated by the blue vertical line, and is characterized by a fast electron flow along M direction (see Fig.…”