Dispersion relation of ionizing waves in positive columns

The dispersion relations for the ionization, ion-acoustic and electron plasma waves are numerically calculated from the basic equations which consist of the continuity and momentum equations for electrons and ions, the energy balance equation for electrons and the current equation. Only the ionization wave among the three waves are detectable at the gas pressure of a few Torr. It is confirmed that the values calculated by the present method for the real part of the frequency agree well with the experimental one but its imaginary part shows some discrepancy. (Auth.)