  This research focuses on interaction of ionization waves (IW) generated in
long discharge tubes (1 m length and 1.5 cm in diameter) filled with neon or
argon under pressure about 1 Torr and, in particular, on simplest case of such
interference which is collision of the opposite directed IW of positive
polarity. The waves were triggered from two electrodes of the tube by
simultaneous application of the same high voltage pulse and propagated toward
the tube center until their collision. Space and time stability of the
collisions was achieved via decreasing time delay of the initial breakdowns
which trigger IW by employment of both memory effect and photo-desorption of
wall surface electrons. Significant memory effect occurred for the pulse
repetition rate over 100Hz. Multiple IW transition from the electrode forms
specific one-electrode discharge; as a result the problem of IW collision was
transformed into the observation of two opposite one-electrode discharges
interaction. Patterns of IW interfering were registered via deviation of their
kinematic characteristics (x-t diagrams) from ones for non-collided wave. This
method shows that two ionization waves travel toward each other with decreasing
speeds and subsequent degradation of the emission. An area near the tube center
where IWs emission was not detected was considered as the IW suppression zone.
The zone width depends on voltage amplitude, gas type and pressure.
