On capture and acceleration of heavy ions (a-particle) in high-speed solar wind

The α-particles and other heavy ions, as well es a few protons are observed to be faster than the main part of protons by about the local Alfven speed in the high-speed solar wind. It is suggested that when the velocity of the solar wind is equal to the local Alfven velocity, another Iow-frequency kinetic Alfvan wave will be excitated, and trap ail the α-particles and a few protons, so these ions have a local Alfven velocity faster than the other parts of the solar wind. The undamping kinetic Alfven waves change into Iow-frequency Alfven solitons in the solar wind. This model can explain the observation and give the conditions of wave excitated and ions trapped.     

太阳风高速流中重离子(α粒子)的捕获加速机制

观测表明,太阳风高速流中重离子(α粒子)的速度高于太阳风整体速度,而且大约高出一个Alfven波速;同时还有少量质子也是如此. 提出当太阳风高速流被加速到Alfven速度时,动力Alfven波二次激发,捕获全部的α粒子和部分质子并形成Alfven孤波. 这一机制可以解释上述观测结果. 数值计算给出波激发捕获条件.     

太阳风中的Alfvén孤波和中间激波 *

提出中间激波由动力Alfv啨ｎ波经波形连续变陡演化而成 .由动力Alfv啨ｎ波的色散作用形成Alfv啨ｎ孤波再进而演化成为激波 .由导出的非线性自治方程组计算出各种稳态结构 .它们分别对应中间激波(I_b 类) ,Switch-on激波和Alfvén孤波 .另有一类由稀疏孤波演化成的稀疏型间断面 .由于方程中没有强耗散机制 ,所得到的激波峰面上残留着孤波系列 .