?quidensitometrie—eine methode zur beurteilung der struktur von plasmen—X. Untersuchung der zeitlichen und r?umlichen Teilchenverteilung in unipolaren Bogenplasmen1

The axial distribution of the emission and the particle densities of chemical elements was investigated in a pulsed, unipolar arc. The following parameters were varied: polarity and position of the electrodes, electrode gap, ionization potential by using different elements, and the absence or presence of the easily ionizable element Li (as the carbonate). As the method of investigation the authors used poly- and monochromatic photography in connection with photographic equidensitometry. In addition some plasma parameters, such as temperature and electron pressure, were determined. The evaluation was performed partly using photographs that covered integrations over a long period of time and partly with photographs pertaining to separate pulses. A detailed discussion is given of the results, which clearly demonstrate that the directed motion of the ions in the electric field principally governs the axial particle density distribution.