SIMULATION STUDY ON STOCHASTIC RECONNECTION AT THE MAGNETOPAUSE

A two-dimensional MHD simulation model is presented to study stochasti c reconnection at the magnetopause. the simulation indicates that in a n open system with strong velocity shear and large Reynolds and magnet ic Reynolds number (R and R(m)), stochastic reconnection can take plac e in the magnetopause current sheet when the interplanetary magnetic f ield has a southward component, leading to the appearance of irregular mesoscale and small-scale structures (IMSSSs). The larger the R and R (m) are, the more IMSSSs are produced. The stronger the flow shear int ensity is, the faster IMSSSs occur. Mesoscale and small-scale structur es can coalesce to form large-scale ones if R and R(m) are midranged ( 10 to 200), while large and mesoscale structures can break into smalle r ones if R and R(m), increase. It is expected that stochastic reconne ction plays an important role in the solar wind-magnetosphere coupling .