Plasma diffusion across inhomogeneous magnetic fields

This paper reports experimental studies on plasma diffusion across inhomogeneous magnetic fields. Plasma created in a multicusp bucket source is allowed to diffuse across inhomogeneous magnetic fields formed by two different arrangements of permanent magnets. Two-dimensional measurements near the magnetic sheath shows the existence of a shear in electric field and plasma turbulence. The plasma turbulence is localized in the region of a magnetic filter. The observed features of turbulence near the magnetic field can be best explained by electron–ion hybrid modes at the lower hybrid frequencies, which exploit free energy from electron E×B drift, in the background of unmagnetized ions. These results lead to a clear model for the earlier observation of a decrease in electron temperature of the plasma across an inhomogeneous magnetic field.