Dependence of the Properties of Moving Striations in the Plasma of the Positive Column on Some External and Internal Parameters
Dependence of the Properties of Moving Striations in the Plasma of the Positive Column on Some External and Internal Parameters
Factors affecting the self-excitation of low-frequency oscillations in an electric discharge
The influence of the individual factors affecting the production of low-frequency oscillations connected with moving striations in a discharge is analysed and experimentally verified. From the conception of two mechanisms of feedback, which leads to self-excitation of these oscillations, it follows that the following influence the production of oscillations: 1) the tendency of the plasma to stratification, 2) the length of the positive column, 3) processes in regions at the electrodes, 4) the external electric circuit.The measurements confirm the influence of all these factors. It is shown that the main factor conditioning the production of oscillations is the property of the plasma of the positive column — its tendency to stratification. The plasma of a glow discharge in neon — in the region of low pressures and currents investigated — has a very strong tendency to stratification with the exception of a small interval in the neighbourhood of the pressure of 4 mm Hg and current 3 тА. Low-frequency oscillations and moving striations are therefore very often present in a discharge in neon.The influence of the external circuit on the oscillations investigated was also experimentally proved, but it is very weak.
On the Moving Striations in a Neon Tube
The following paper is the continuation of the account of experiments on the moving striations in neon tubes already communicated. In the previous experiments the discharge was excited by an induction coil, but in these direct current was used and the magnitude of the current was under control. Three Geissler tubes (A, B, C) were used, diameters of the capillary arts were respectively 2⋅2 mm., 1⋅41 mm. and 1⋅27 mm., their lengths being 10⋅8 cm., 7 cm. and 8⋅5 cm. These tubes (A and B) had auxiliary platinum wire electrodes at the ends of the capillary parts of the tubes to measure the drop of potential along that part.