A 2D NUMERICAL STUDY OF RECURRENT DRIVEN RECONNECTION PROCESSES AT THE MAGNETOPAUSE

Two-dimensional (2D) compressible MHD simulations are performed to explore the time-dependence of driven reconnection process in the vicinity of the magnetopause. It is found that recurrent formation of magnetic islands/plasmoids occurs when the magnetic Reynolds number is sufficiently large (R(m) = 4000). This result is in line with the bursty reconnection model for the flux transfer events (FTEs) as advocated by Scholer (1988) and Southwood et al. (1988). Furthermore, the formation of magnetic islands in a multiple X-line configuration is also consistent with the Lee-Fu model (1985). In other words, the present results represent a new class of hybrid FTE model. With appropriate scalings, the characteristic time interval between the formation of magnetic islands is estimated to be on the order of 8 min. This time scale is compatible with the quasi-periodicity sometimes found in optical and/or radar ionospheric signatures which might be associated with FTEs.