NUMERICAL SIMULATION OF PROPAGATION AND OVERLAP OF INTERPLANETARY SHOCK

A time dependent,two-dimensional magn:tohydrodynamic model is used to simulate the flare-associated shock waves and their subsquent disturbances in equatorial plane between 0.1 AU and 1.1 AU.It is simulated that the shocks associated with a disturbed interplanetary medium by two flares,erupted one after with a delay of several hours.The result shows that interactions between shocks depends on the time interval of the two flares.These interactions can be classified into four types,(1) strong interaction,(2) middle interaction,(3) weak interaction,(4) no interaction,according to the interval of flares.Computations are carried out in two cases,(1) the shock wave associated with a single flare,(2) the shock wave associated with two flares which belong to strong interaction.The result shows that interplanetary magnetic fields in first case are similar to those in the second case,44 hours after the introduction of disturbances.The parameters of the solar wind measured at 1.0 AU,along the flare normal also have the similar time profiles in the two cases.