Plasma uniformity enhancement in a single-core ferromagnetic inductor coupled plasma source

We describe the phenomenon of plasma uniformity enhancement in the recently developed simple version of the ferromagnetic inductor coupled plasma source in which a single thin ferromagnetic core having a large diameter (ferroinductor) was fully immersed in plasma. The plasma appeared due to the gas discharge driven by a comparatively low ac voltage (<= 350 V) applied to the primary winding of this core. Under certain circumstances the plasma nonuniformity did not exceed a few per cent in the radial direction as well as in the axial direction while the plasma density reached almost 10(13) cm(-3). A qualitative explanation of such uniformity enhancement is suggested.