Unstable discharge phenomena, which are known as moving striations or ionization waves, occurring in the dischage tube filled with low pressure rare gas and saturated mercury vapor were investigated. They appeared within a positive column when the discharge tubes were operated on the commercial ballast applied for 50 or 60 Hz frequency and under the room temperature. It was found that these spontaneously generated moving striations showed the different behaviors from artificial ones according to research on the dispersive plane between angular frquency ω and wave number
k depending on the ambient temperature and the filling pressure of rare gas. As a result, natural moving striations showed the positive gradient contrary to the negative slope of ω/
k based on artificially generated ionization waves.
The relatioship between phase angle of discharge current and spectral line intensity ratio of rare gas/Hg in moving striations was investigated using a multi-channel spectrometer. The results suggest that the average kinetic energy of electrons
kBTe after reignitions was increased until the excitation levels of rare gas. It was confirmed that the solution of rate and energy balance equations introduced by taking into account the non-Maxwellian distributuion function for energetic electrons supports the experimental results.
View full abstract