Changes of the electron dynamics in hydrogen inductively coupled plasma

Changes of the electron dynamics in hydrogen(H2)radio-frequency(RF)inductively coupled plasmas are investigated using a hairpin probe and an intensified charged coupled device(ICCD).The electron density,plasma emission intensity,and input current(voltage)are measured during the E to H mode transitions at different pressures.It is found that the electron density,plasma emission intensity,and input current jump up discontinuously,and the input voltage jumps down at the E to H mode transition points.And the threshold power of the E to H mode transition decreases with the increase of the pressure.Moreover,space and phase resolved optical emission spectroscopic measurements reveal that,in the E mode,the RF dynamics is characterized by one dominant excitation per RF cycle,while in the H mode,there are two excitation maxima within one cycle.