Low-frequency waves in magnetic reconnection  

作　　者：CHAI LiHui LI Yi WANG Shui SHEN Chao 

机构地区：[1]School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China [2]National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China

出　　处：《Chinese Science Bulletin》2012年第12期1461-1466,共6页

基　　金：supported by the National Natural Science Foundation of China(41074120,40974101);the Chinese Academy of Sciences(KJCX2-YW-N28);the Fundamental Research Funds of State Key Laboratory of Space Weather;the National Basic Research Program of China(2011CB811404)

摘　　要：The characteristics of low-frequency waves in magnetic reconnection are studied using two-dimensional hybrid simulation code. In a coordinate system moving with fluid,the time series of a magnetic field perpendicular to the magnetic reconnection plane,By, is transformed into the power spectrum via fast Fourier transformation,while the wave propagation direction and polarization are determined by minimum variance analysis of the electric field.The results show that low-frequency Alfvén ion-cyclotron waves dominate the reconnection area.These waves have frequencies 0-1Ωp(where Ωp is the local proton gyro frequency)and all are left-handed circularly polarized.Among these waves,large-amplitude turbulence,with frequencies of 0-0.6Ωp and isotropic propagation,dominates the outflow regions.This can cause the reversal of By in the quadrupole structure.In the inflow regions, dominant waves,propagating mainly parallel to the ambient magnetic field,have higher frequencies and smaller amplitudes.The frequency of the main peak of wave energy is usually higher than 0.5Ωp.The characteristics of low-frequency waves in magnetic reconnection are studied using two-dimensional hybrid simulation code. In a coordinate system moving with fluid, the time series of a magnetic field perpendicular to the magnetic reeonnection plane, By, is transformed into the power spectrum via fast Fourier transformation, while the wave propagation direction and polarization are determined by minimum variance analysis of the electric field. The results show that low-frequency Alfven ion-cyclotron waves dominate the reconnection area. These waves have frequencies 0-1Ωp （where Ωp is the local proton gyro frequency） and all are left-handed circularly polarized. Among these waves, large-amplitude turbulence, with frequencies of 0-0.6Ωp and isotropic propagation, dominates the outflow regions. This can cause the reversal of By in the quadrupole structure. In the inflow regions, dominant waves, propagating mainly parallel to the ambient magnetic field, have higher frequencies and smaller amplitudes. The frequency of the main peak of wave energy is usually higher than 0.5Ωp.

关 键 词：磁场重联 低频波 快速傅立叶变换 传播方向 离子回旋波 混合模拟 坐标系统 时间序列 

分 类 号：P318[天文地球—固体地球物理学]