Effects of inelastic collisions on Alfvn waves in partially ionized plasmas  

作　　者：Bing Li Ling Chen Dejin Wu 

机构地区：[1]Purple Mountain Observatory, Chinese Academy of Sciences [2]University of Chinese Academy of Sciences

出　　处：《Chinese Science Bulletin》2014年第8期740-746,共7页

基　　金：supported by the National Natural Science Foundation of China(10973043 and 41074107);National Basic Research Program of China(2006CB806302);Chinese Academy of Sciences(KJCX2-YW-T04)

摘　　要：Based on a three-component description of partially ionized plasmas(i.e.,electrons,ions,and neutral atoms),effects of inelastic collisions between ions(neutrals)and electrons on Alfve′n waves(AWs)in a partially ionized plasma are studied.It is shown that for a fixed ionizability(i)or a fixed inelastic collision parameter(v,i.e.,the ratio of the inelastic to elastic collision frequency),the damping rate of AWs has a peak value round kz vA/min*1,where kz is the parallel wavenumber of AWs,vA is the Alfve′n velocity,and min is the elastic collision frequency between ions and neutrals.On the other hand,the damping rate of AWs decreases monotonously with the ionizabilityi for a fixed inelastic collision parameter,but has a peak value when the inelastic collision parameter varies for sufficiently small ionizability(i\0:1).For sufficiently large ionizability(i[0:1),it is found that the damping rate decreases with the inelastic collision parameter.The results may help us to understand the physics of AWs in partially ionized plasmas.Based on a three-component description of partially ionized plasmas （i.e., electrons, ions, and neutral atoms）, effects of inelastic collisions between ions （neu- trals） and electrons on Alfven waves （AWs） in a partially ionized plasma are studied. It is shown that for a fixed ionizability （εi） or a fixed inelastic collision parameter （Z, i.e., the ratio of the inelastic to elastic collision frequency）, the damping rate of AWs has a peak value round kzVA/ vin -1, where kz is the parallel wavenumber of AWs, VA is the Alfven velocity, and vin is the elastic collision fre- quency between ions and neutrals. On the other hand, the damping rate of AWs decreases monotonously with the ionizability εi for a fixed inelastic collision parameter, but has a peak value when the inelastic collision parameter varies for sufficiently small ionizability （εi〈0.1）. For sufficiently large ionizability （εi 〉 0.1）, it is found that the damping rate decreases with the inelastic collision parameter. The results may help us to understand the physics of AWs in partially ionized plasmas.

关 键 词：非弹性碰撞 等离子体 阿尔芬波 电离度 碰撞频率 中性原子 碰撞参数 AWS 

分 类 号：O53[理学—等离子体物理]