Excitation kinetics of electronic states of hydrogen molecules in nonequilibrium discharges: Electronic ground state

Abstract

International audienceThis review offers an analysis of the vibrational kinetics of hydrogen molecules in the singlet ground state X 1∑ g + for various gas discharges. The measured quasi-stationary vibrational-level distribution functions of a hydrogen molecule in the electronic ground state at the corresponding vibrational temperatures of the first level and those calculated in the framework of a semiempirical level collisional–radiative model of low-temperature plasma in hydrogen, developed in this study, are compared. A database of the measured and calculated characteristics of kinetic processes involving vibrational-excited hydrogen molecules, as well as macro and microparameters of hydrogen low-temperature plasma, is created

Experimental benchmark of the NINJA code for application to the Linac4 H−ion source plasma

“…For the vibrational distribution in the H 2 ground state, the simulation demonstrates that a two-temperature distribution evolves [38], which is also observed in other low pressure discharges [39,40]. The cold temperature is in the range between 3500 and 4500K, which is in agreement with the measurement.…”

Experimental study of the evolution of H α line profile in a pulse hydrogen discharge

“…In fact, the fast atoms formation is due to twostep or three-step processes of dissociative ionization of v = 0 or vibrationally excited H 2 molecules. According to [30] the processes of vibrational redistribution of the ground molecular state of H 2 need some time to settle. A well-know fact is that the direct dissociation cross sections are affected by the vibrational population of the ground X 1 Σ + g state and an increase of vibrational energy decreases the threshold energy of the electron impact dissociation processes [31].…”

The role of secondary processes in kinetics of triplet states of a hydrogen molecule in an ECR discharge

“…In the model developed in [7] and used in this paper, the number of electronically excited states of a hydrogen molecule is significantly increased, compared with those described in [4][5][6], and the kinetic scheme is extended in the part of the collisional-radiative processes of interest for emission spectroscopy of hydrogen plasma. It additionally takes into account processes involving hydrogen molecules in singlet ( 1…”

“…Increasingly widespread in the diagnostics of the vibrational temperature of the ground state in hydrogen plasma are experimental-calculation techniques that are based on a combination of emission spectroscopy and collision-radiative plasma models [4][5][6][7]. A simplified coronal model is often used to process results of emission spectroscopy [8].…”