Current sheets in magnetic configurations with singular X-lines

The possibility of the formation of current sheets in 3D magnetic configurations with singular X-lines was studied experimentally. It is shown that a sheet can be formed in the presence of the longitudinal magnetic-field component directed along the X-line, in which case the longitudinal component can exceed the transverse component everywhere inside the plasma. Characteristic of the CS formation in 3D magnetic configurations with X-lines are an increase in the longitudinal magnetic-field component inside the sheet and a decrease in the plasma compression ratio as compared to 2D configurations with null-lines. If the longitudinal component exceeds a certain critical value, a sheet cannot be formed: instead of a sheet, there appear two sheaths separated by a cavity with a local minimum in the electron density.