磁层亚暴时环电流的局部加速机制

本文讨论了一种使环电流增强的局部湍流发电机过程。由于磁层内部的磁场很强,其位形基本满足无作用力磁场近似。另一方面,磁场的涨落值与其平均值相当。当涨落场电动势局部增强时,可以使平均场以及平均电流密度增强,形成环电流的增强。这时,亚暴过程中维持环电流所需要的能量是由湍流或波动的涨落场提供的,这是一种使粒子局部加速的过程。本文还具体讨论了一种α2湍流发电机模型,求出了具有随时间增长特性的本征模式。将分析结果应用于讨论亚暴时的环电流过程,并进行了定量估计。 

THE MECHANISM OF ACCELERATION OF RING CURRENT DURING A SUBSTORM OF MAGNETOSPHERE

Aprocess of turbulent dynamo action which leads to the growth of ring current is described in this peper.Owing to the strong magnetic field in the magnetosphere,the magnetic field configuration essentially satisfies the approximation of the force-free field.On the other hand,the fluctuating value of magnetic field is comparable to the mean value,When the electromotive force of the fulctuating field grows,the mean field and current density may grow in such a way that ring current is increased.Obviously,the turbulent or fluctuating field supplies the energy which keeps ring current during a substorm.This is a process of the acceleration of particles.Amodel of α2-turbulent dynamo is discussed specifically in this paper,and an eigenmodel of exponential growth of time is obtained The results of analysis have been used in discussing the process of ring current during a substorm,and a quantitative estimate has been made.