Study of a continuous spectrum of low pressure glow discharge in hydrogen and helium in a longitudinal magnetic field

Abstract

The influence of a longitudinal magnetic field on electron temperature and density and on the continuous spectral radiance of a negative glow discharge in the visible spectrum range was studied. The electron temperature and density were determined by the double probe method. It was found that the discharge is compressed to a narrow column under the action of the magnetic field and its glow intensity increases by ∼100 times. This is accompanied by an increase in the electron temperature and density. The total voltage at the discharge decreases by two or three times. The study of the influence of a longitudinal magnetic field on the spectral radiance of the continuous spectrum is of greatest interest in this work. For the given conditions of the studied glow discharge (low pressure and small degree of ionization ∼10⁻⁶), bremsstrahlung radiation was shown to make the largest contribution to continuous spectral radiance upon electron scattering on a neutral particle. The measured quantity of the continuous spectral radiance of the discharge was compared with the calculated quantity of bremsstrahlung radiation for neutral particles. The measured quantity was found to be larger than the calculated one by 10²–10³ times, and the largest discrepancy was observed in the absence of the magnetic field. A hypothesis is proposed to explain such a strong discrepancy between the measured and calculated spectral radiance of the continuum spectrum.