Characteristics and Roles of ESW Observed in the Separatrix of Reconnection in the Magnetotail

Abstract Magnetic reconnection plays a key role in the energy release and transformation in geospace. Though Electrostatic Solitary Wave (ESW) is widely observed in space, direct observations in the vicinity of reconnection site are rare, which makes it ambiguous of the characteristics of ESW associated with reconnection. Here we present a reconnection event for which ESW is ample in the separatrix of the reconnection diffusion region. Characteristics of the ESW associated with reconnection are studied and the effect of ESW to reconnection is discussed. The result shows that the ESW observed in the separatrix of reconnection which takes place during a substorm is more solitary and more nonlinear than that in other regions. The ESW observed associated with reconnection can propel the reconnection process via presenting a parallel electric field and accelerate electron.