Sheet Plasma Produced by Hollow Cathode Discharge

A sheet plasma is produced by a hollow cathode discharge under an axial magnetic field. The plasma is about 40 cm in length, 4 cm in width and 1 cm in thickness. The electron density is about 10⁸cm^-3. The hollow cathode is made to be shallow with a large opening, which is different from the ordinary deep hollow cathode. A Langmuir probe is used to detect the plasma. The electron density and the spatial distribution of the plasma changed when the voltage, the pressure and the magnetic field vary. A peak and a data fluctuation at about 200 G-300 G are observed in the variation of electron density (or thickness of the sheet plasma) with the magnetic field. Our work will be helpful to characterize the sheet plasma and make the production of dense sheet plasma more controllable.