Experimental Study Of High Density Plasma Source With Hollow Cathode

High-density plasmas are indispensable in many applications such as material processing,electromagnetic protection and plasma stealth.Hollow cathode discharge(HCD)is one of the most popular methods to generate high-density plasma due to the unique hollow cathode effect(HCE).HCE is well known phenomenon which indicates the pendulum motion of the electrons inside the cathode.So the ionization rate and electron density can be increased significantly.In this thesis,producing high-density plasma outside the cathode cavity with magnetic field confinements were studied.The effects of operating parameters on the plasma,were also investigated.Driven by DC(direct current)and pulse power supply,the characteristics of hollow cathode discharge in argon were obtained experimentally.The V-I curve,plasma density,light emission image of discharge plasma are measured under various conditions.The results show that with DC high voltage,the hollow cathode discharge is operated in abnormal glow mode.While HCD is operated in enhanced glow mode when driven by a pulsed supply.At different voltage pulse widths,a current fluctuation of?100m A in amplitude and?100?s in width is found in each voltage pulse.The light emission images indicate that the current fluctuation during the voltage pulse is important for the glow region to expand out the cathode hole,which results in a long high density plasma column.At argon pressure p=0.5 Torr,hollow cathode inner diameter d=10 mm,hollow cathode depth h=3 mm and magnetic field B=200 Gauss,the maximum density of plasma column is on the order of 10¹¹cm^-3.