Saturation Ion Current Densities in Inductively Coupled Hydrogen Plasma Produced by Large-Power Radio Frequency Generator

An experimental investigation of the saturation ion current densities(Jions) in hydrogen inductively coupled plasma(ICP) produced by a large-power(2-32 kW) radio frequency(RF) generator is reported,then some reasonable explanations are given out.With the increase of RF power,the experimental results show three stages:in the first stage(2-14 kW),the electron temperature will rise with the increase of RF power in the ICP,thus,the J_(ions) increases continually as the electron temperature rises in the ICR In the second stage(14-20 kW),as some H~- ions lead to the mutual neutralization(MN),the slope of J_(ions) variation firstly decreases then increases.In the third stage(20-32 kW),both the electronic detachment(ED) and the associative detachment(AD) in the ICP result in the destruction of H~- ions,therefore,the increased amplitude of the J_(ions) in the third stage is weaker than the one in the first stage.In addition,with the equivalent transformer model,we successfully explain that the J_(ions) at different radial locations in ICP has the same rule.Finally,it is found that the J_(ions) has nothing to do with the outer/inner puffing gas pressure ratio,which is attributed to the high-speed movement of hydrogen molecules.