%0 Journal Article
%T Two-dimensional collisionless magnetic reconnection with initial asymmetric density distribution<br>密度非对称的二维无碰撞磁场重联
%A HUANG Jun
%A MA Zhi-Wei
%A <br>黄俊
%J 地球物理学报
%D 2008
%I 
%X Collisionless magnetic reconnections with different initial temperature gradients across the current sheet are studied through two-dimensional Darwin Particle-in-cell simulations.Due to asymmetric properties of the temperature and density,it is found that the plasma flow,electric field,and magnetic field structures as well as the reconnection dynamical process exhibit significant differences from that in the symmetric case.Through the case studies,the results can be concluded:(1)In the asymmetric cases,electrons drift from the high density region to the low density region,which leads to form a current loop along the saperatrix in out-flow region;(2) Intense charge separation appears near the edge of the magnetic island in the high temperature and low density region and results in a large perpendicular electric field structure.The amplitude and the scale of the electric field are linearly proportional and inverse to the temperature gradient, respectively,For the case T_m/T_s=5,where T_m and T_s represent the temperature in magnetospheric side and magnetosheath side respectively,the amplitude of E_z will be 0.71 and the scope is of the same order of the electron inertial length d_e,which are in good agreement with the observations;(3)the reconnection rate will decrease with increase of the temperature ratio.
%K Magnetopause
%K Collisionless magnetic reconnection
%K PIC simulation
%K Asymmetric current sheet
%K Temperature gradient
%K Reconnection rate
%K Perpendicular electric field<br>磁层顶
%K 无碰撞磁场重联
%K 粒子模拟
%K 非对称电流片
%K 温度梯度
%K 重联率
%K 垂直电场
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=E62459D214FD64A3C8082E4ED1ABABED5711027BBBDDD35B&cid=1E44AE713D8A6DE0&jid=14DC41C59CBF6770055A7D610D53AE46&aid=CC53C4466E7A07FF2BB948D39E8B3152&yid=67289AFF6305E306&vid=987EDA49D8A7A635&iid=E158A972A605785F&sid=40700C9CB4E84E3B&eid=F131C0ADC94A25CF&journal_id=0001-5733&journal_name=地球物理学报&referenced_num=1&reference_num=17