太阳风动量涨落激发磁层亚暴的机制

<span style="color: rgb(0, 0, 0); font-family: verdana, Arial, Helvetica, sans-serif; font-size: 13px;">本文将太阳风涨落传输能量产生磁层亚暴的机制推广到无碰撞等离子体过程。太阳风的涨落在磁层顶激发压缩阿尔文波,并在磁尾的无碰撞等离子体中传播。尾瓣中满足条件β<<1,而等离子体片中β≥1,其中β为等离子体压力与磁压之比。这样,快磁声波在尾瓣中几乎不衰减,而在等离子体片中很快衰减,将波动能量耗散在等离子体片中使等离子体加热或者粒子加速。这种机制还表明,磁尾等离子体片中的高能粒子可以由太阳风涨落动能耗散而被加速,不一定是直接源于太阳。</span>

<span style="font-size: 13px; line-height: 19px;">In the present paper, the mechanism of magnetospheric substorm which is produced by the energy transportation from the fluctuation kinetic energy of solar wind is extended to the case of collisionless plasma process. The fluctuations of solar wind quantities at the magnetopause excite the compressed Alfven waves, which propagate through the collisionless plasma in the tail of magnetosphere. There is the condition β?1 in the tail lobe and β≥1 in the plasma sheet, where β is the ratio of plasma pressure and magnetic pressure. Hence, the fast magnetosonic waves dissipate very little in the tail lobe and decay rapidly in the plasma sheet, where the wave energies are converted into heat and kinetic energy of the particles. It is shown also that the energy particles in the plasma sheet may be produced by the dissipation o'f the energy from solar wind and are not necessarily originated from the solar wind directly.</span>