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
Moving Striations in Arc Discharge
In the same manner as in glow discharge, the moving striations are observed in arc discharge. From the patterns of light oscillation, a light intensity wave travelling towards the cathode is obtained. The phenomenon of the moving striations is one manifestation of the light intensity wave which occurs due to an interaction between the following two waves, a space charge wave travelling towards the cathode and an electron density wave. The former changes the electron emission of the cathode, and this produces the latter. The stationary striations observed in the positive column also seem to be one aspect of the light intensity wave.
Oscillatory Phenomena of Arc in Hot Cathode Discharge Tube (2) Theoretical (Mechanism of Oscillation)
In regard to the mechanism of the oscillatory arc in a hot cathode discharge tube like fluorescent lamp, the circumstances was made clear as follows. The oscillations occur in the following cases. That is, (1). The quantity of the positive ions generated by ionization in the anode fall is greater than that necessary to sustain the arc, and (2) the arc current is smaller than the saturated electron current determined by the cathode temperature. Accordingly the existence of the excess ions is the cause of the oscillations. Ionization and diffusion occur alternately. Therfore the characteristic of oscillation is determined by the quantity of excess ions. But in this case it is also influenced by the space charge in front of the cathode, that is, by the thermoionic emission of cathode. And generally a fraction of the excess ions will be employed to reduce the anode fall stationarily, if the electron emission becomes to be limited by its saturation value or by the negative space charge in front of the cathode.