Numerical studies of tearing mode instability and magnetic reconnection inanisotropic plasma

The tearing mode instability and magnetic reconnection process in an anisot ropic plasma (P-perpendicular to not equal P-// , T-perpendicular to not eq ual T-//) are numerically studied by a two-dimensional three-component time -dependant compressible MHD simulation. It is found that the instability te nds to become nonlinear saturation after, a short period of linear growth. The growth rate will increase when the intensity of pressure anisotropy / P -perpendicular to/P-// / increases, while it will decrease with the decreas e of the plasma beta and the augment in the y component B-y of magnetic fie ld. In case of a large perpendicular anisotropy (P-perpendicular to > P (// )), when the magnetic island formed in the current sheet by magnetic reconn ection becomes nonlinear saturation, there will be cavity structures formed near the X points. The cavities become larger gradually while the magnetic islands become smaller and vanish at last. In the plasma with a parallel a nisotropy (P-perpendicular to < P-//), the fire hose instability can only b e excited in the central region of current sheet, and large magnetic island can't be formed in the current sheet.