Emission of Fast Hydrogen Atoms in a Low Density Gas Discharge—The Most “Natural” Mirror Laboratory

Abstract

In this work, we present a new application for the line shapes of emission induced by reflected hydrogen atoms. Optical properties of the solids in contact with the plasma could be effectively measured at the wavelength of Balmer lines: time-resolved measurements of reflectance and polarization properties of mirrors are performed using the wavelength separation of the direct and reflected signals. One uses the Doppler effect of emission of atoms excited by collisions with noble gases, primarily with Ar or with Kr. In spite of a new application of line shapes, the question of the source of the strong signal in the case of Ar exists: the emission observed in the case of the excitation of H or D atoms by Ar exceeds the signal induced by collisions with Kr atoms by a factor of five, and the only available experimental data for the ground state excitation show practically equal cross-sections for both gases in the energy range of 80–200 eV.

Emission of fast hydrogen atoms at a plasma–solid interface in a low density plasma containing noble gases

“…The experimental data show that this assumption is probably correct, as the agreement for all targets is rather good, e.g. the emission of fast atoms occurs after ions collide with the target surface [44]. Energy onset for the red-shifted wavelengths interval depends also on the material of the target used.…”