Observation of Molecular and Atomic Ions in Recombination Plasma

Abstract

Measurements of the densities of the molecular and atomic ions (n H + , n H2 + , n H3 + ) were carried out in hydrogen recombination plasma in the linear divertor plasma simulator, TPD-SheetIV. The molecular and atomic ion currents were detected using an omegatron mass analyzer. The ground-state vibrational temperature of hydrogen molecules T vib is obtained by measurement with VUV emission spectroscopy. Taking into account of T vib , a zero-dimensional model using the relevant rate balance equations was found to predict the observed dominant ion.

Observation and Modeling of Molecular and Atomic Ions in Hydrogen Plasma

“…However, the role of molecular ions in the hydrogen plasma is still under discussion and various conclusions have been derived from the analysis of different experiments. [3][4][5][6] On the other hand, it has been pointed out that even the contribution of recombination is not critical for a reduction in ion flux. 7) Recently, it has been reported that in a typical high-density plasma, H 2 (v) molecules assist dissociation (MAD) and ionization (MAI) before they contribute to recombination.…”

“…In this study, we have carried out the experimental observation and modeling of molecular ions in hydrogen plasma in a linear plasma device, TPD-SheetIV. 5,6) Measurements of the densities of molecular and atomic ions were carried out in hydrogen plasma with a hydrogen gas puff. The molecular and atomic ion currents were detected using an ''omegatron'' mass analyzer, while the electron density and temperature were measured using a Langmuir probe and a double probe.…”

Characteristics of vibrational temperature of hydrogen molecules in detached plasma

“…[9,14,15] uniform magnetic field up to 0.1 T in the experimental region. The hydrogen plasma was generated at a hydrogen gas flow of 75 sccm, with a discharge current of 30-100 A.…”

“…In high neutral density such as detached divertor plasma, it is necessary to take into account of radiation trapping to experimental investigation of the VUV spectroscopy [9,18]. In case of the consideration of radiation trapping, the brightness of line will be in the ratio of their spontaneous emission coefficients.…”

“…On the other hands, vacuum ultraviolet (VUV) emission spectroscopy in the spectral range 80-180 nm are investigated for basic research in laboratory experiments [7][8][9] VUV emission intense line spectrum is observed at the Lyman (B 1 R þ u ! X 1 R þ g ) and Werner (C 1 P u !…”