抄録
Loeb’s condition for the onset of a positive burst pulse corona was applied to the case of point-to-point electrodes arrangement and a formula, which gives relations between the field strength to pressure ratio, ratio of ionizing photons to electrons in an avalanche and the effective absorption coefficient for this ionizing radiation, was obtained.
From the measured starting potential versus pressure curve the limitting value of the field strength to pressure ratio for the case of indefinitely high pressure was obtained by extrapolation, and from this value the effective absorption coefficient μ for the burst pulse forming radiation was estimated.
The estimated values for the effective absorption coefficients at 760 Torr are 3700 cm−1 for air, 2375 cm−1 for nitrogen and 2200 cm−1 for oxygen. As these values are of the same order of magnitude as for the radiations in the range of the resonance bands in the ionization continua, the wavelength of the ionizing radiations effective in the positive burst pulse corona formation might be assumed to be in the range of the ionization continua. Moreover the ratios of the numbers of ionizing photons to those of electrons in a burst forming avalanche were deduced. They are approximately 1.6∼1.8 for air, 1.4∼1.5 for nitrogen and 1.8∼1.9 for oxygen.
