Axial magnetic field restriction of plasma sheath in a coaxial discharge

The study deals with the effect of an applied axial magnetic field on the dynamics and parameters of the plasma sheath and the expanded plasma in a coaxial discharge. Experimental investigations were carried out with a 3 kJ coaxial discharge device of a Mather geometry. The discharge takes place in Hydrogen gas with base pressure of 1 torr. The experiments were conducted with a 10 kV bank voltage, which corresponds to 100 kA discharge currents. The investigations have shown that the maximum axial plasma sheath velocity is decreased by 20% when applying the external axial magnetic field along the coaxial electrodes of intensity 2.6 kG. The experimental results of axial magnetic field intensity Bz along the coaxial electrodes indicated that the application of external axial magnetic field causes an increases of Bz ∼ 40% at a mid-distance between the breech and the muzzle and a decrease by 75% at the muzzle. The experimental results of expanded plasma electron temperature Te and density ne cleared that when the axial magnetic field is applied the maximum Te is decreased by 2.6 and 3 times, while the maximum ne is increased by 2.8 and 2 times for the first and second half cycles respectively. (author)