Characteristics of vibrational temperature of hydrogen molecules in detached plasma

The ground-state vibrational temperature of hydrogen molecules, Tvib, is observed in detached plasma using a VUV spectrometer on a linear plasma device, TPD-SheetIV. Tvib was deduced by applying the corona equilibrium model by using the electron impact excitation rate and the spontaneous emission coefficient, taking into account the cascade contribution of E,F1Σg+ and the radiation trapping. Tvib can be found which results in a fit to the observed relative intensities of VUV spectrum in the range from 90 to 150 nm. With increasing gas pressure P, Tvib gradually decreases from 5000 to 3000 K and remains nearly constant at around 1000 K in detached plasma at discharge current of 50 A.