强磁场扰动对宇宙线调制的统计研究

对1978─1982太阳活动高年时发生的激波、强磁场扰动及激波与强磁场扰动共存这三类事件引起的宇宙线变化进行了统计研究,得到如下结果:(1)激波与强磁场扰动共存时引起的宇宙线强度下降最为显着;只有激波或强磁场扰动时,宇宙线的强度变化相对较小;(2)标志速度间断的激波是产生宇宙线Forbush下降的重要因素;(3)速度间断在强磁场扰动对宇宙线的调制中可能起一个触发的作用。

STATISTICAL STUDY OF CSOMIC RAY MODULATION PRODUCED BY INTERPLANETARY STRONG MAGNETIC FIELD DISTURBANCE

Three categories of interplanetary disturbances have been chosen from the period 1978--1982 when solar activity was high. They are:(i)shock wave;(ii)strong magnetic field disturbance;(iii)strong magnetic field disturbance behind shock wave. The cosmic ray variations produced by them have been studied statistically.The following results are obtained:(1)cosmic ray decrease resulted from the strong magnetic field disturbance is very obvious when there is a shock wave before it,but the cosmic ray decrease is relatively small when only shock wave or strong magnetic disturbance exists;(2)the shock wave which indicates the speed discontinuity is a vital factor resulting the Forbush decrease;(3)the speed discontinuity may take a role of trigger in the process of the cosmic ray modulation produced by the strong magnetic field disturbance.