WALL RECOMBINATION IN LOW-PRESSURE DISCHARGES

The effects on wall charges and wall recombination of the positive column of a low-pressure discharge not being steady and uniform, of magnetic fields being applied, and of negative ions being present have been examined. Removal of the restrictions leaves the conditions opposite plasmas essentially the same. It is not certain, however, how the space-charges between the plasmas of striations affect the wall charges and the ion sheaths between the plasmas and the wall. Whatever the patterns of the wall charges and wall recombination processes in striated discharges, their fundamental wavelength, and, if they are moving, their fundamental frequency, will be the same as the fundamental wavelength and frequency of the striations, but the harmonic components will have different relative amplitudes and phases. Investigation of time-varying discharges could give new quantitative information about surface processes, as could that of the wall contribution to discharge noise.