太阳耀斑行星际激波传播中的追赶效应

NUMERICAL SIMULATION OF PROPAGATION AND OVERLAP OF INTERPLANETARY SHOCK

本文采用二维MHD模型对具有不同间隔时间的2个耀斑先后爆发,模拟研究它们所对应的行星际激波间的追赶效应,并和单个耀斑所产生的行星际激波相比较。研究结果表明,间隔时间一天以内的2个耀斑激波在行星际空间向外传播时,激波之间有明显的相互作用发生,间隔时间的长短决定了激波传播过程中追赶效应的强弱。根据数值试验结果,追赶效应可归纳为4类,(1)强追赶效应,(2)中等追赶效应,(3)弱追赶效应,(4)无追赶效应。属于强追赶效应的2个耀斑激波传播至1AU处,产生的行星际扰动非常相似于单个耀斑激波的扰动。

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.