INTERACTION OF WEAK SHOCK-WAVES WITH CURRENT SHEETS IN AN ACTIVE-REGION TO PRODUCE NANOFLARES AND CHAINS OF TYPE-I RADIO-BURSTS

Interaction of weak shock waves with a current sheet is investigated b y a two-dimensional numerical magnetohydrodynamic model. In accordance with solar coronal conditions, a ratio of thermal to magnetic pressur es of 0.1 and a shock Alfven Mach number slightly above 1 are consider ed. It is found that even weak shock waves trigger magnetic field reco nnection in current sheets. Based on this result, it is suggested that drifting chains of type I radio bursts are radio manifestations of th e interactions of weakly super-Alfvenic shock waves with pre-existing current sheets distributed in an active region. This model of type I n oise storms is then discussed in connection with the concept of nanofl ares (localized reconnections) and the heating of the solar corona.