Application of Langmuir Probe for Study of Recombination of D[sub 3]+] Ions with Electrons in He-Ar-D2 Stationary and Flowing Afterglow Plasma

Abstract

We report measurements of the rate coefficient for recombination of D3+ and D5+ with electrons in He‐Ar‐D2 plasma. Two afterglow experiments, flowing afterglow and stationary afterglow were used to cover large extent of pressures of He buffer gas (2–10 Torr) and large extent of partial number densities of D2 (5×1010−3×1015cm−3). Langmuir probes and mass spectrometers were used to monitor decay of the plasma during the afterglow. The observed rate coefficient is dependent on the deuterium number density indicating that third‐body‐assisted recombination is efficient and significantly contributes to recombination when sufficient number density of deuterium is present. At low D2 number densities the ions D3+ dominate the ion composition and electron density decay is controlled by recombination of D3+ with recombination rate coefficient α(D3+). At higher D2 number densities and lower temperatures D5+ are formed and electron density decay is controlled by recombination of D5+ ions with recombination rate coeffi...