A generalization of our old model that is based on the averaging of the two
-dimensional equations over the cross section of the tube and on using a lo
cal relationship between an electrical potential and an electrical charge a
nd that describes thr propagation of the ionizing waves near to light veloc
ity in long shielded tubes is given. The numerical modelling and the analyt
ical self-similar solutions of the problem of high-speed ionizing wave (FIW
) propagation in long shielded tubes are presented. Within the framework of
the new self-similar solution obtained using analytical formulae it is pos
sible to explain many experimental facts: dependence of the velocity of the
high-speed ionizing waves on the amplitude of the high-voltage potential a
nd on the building-up time of the high-voltage potential, on the effective
permeability of surrounding matter and, mainly, on the pressures of gases.
The analytical self-similar solution is obtained with an accuracy to only o
ne constant, that is the ionization threshold field. This constant is infer
red from fitting of the analytical dependence of the FIW's velocity on the
gas pressure to the experimental results of one point for each gas. The res
ults obtained correlate quantitatively with experimental results within the
accuracy of the experiments. The influence of the condensed particles on t
he propagation of the high-speed ionizing waves is analysed, these results
may be useful for the problem of high-speed ionizing wave propagation in sp
ecially produced channels in free atmosphere.