SELF

30

and S.B. Karavashkin

When we yielded this new type of oscillograms, we have set ourselves to the question, do there exist the peaks of the opposite polarity. This has been fully corroborated when we reversed the polarity of source E ₂   (Fig. 6) and shifted downwards the screen the line of oscillograph beam return. The typical oscillogram registering the peaks of reverse polarity is shown in Fig. 9.

Fig. 9. Showering arc under inverse feeding voltage at the studied contacts

We can see in the shown oscillogram that when the feeding source was applied in reverse polarity, the sections of parasitic capacitance charging also inverted, but there between them have been revealed the same sections of voltage surges as in oscillograms with previous polarity of the source. The registered process of a negative part of relaxation also consists of two stages - monotonous and surge-like that is finished by luminous points at the tops .

It was long time impossible to see the surges of both polarities at once, retaining the full pattern of process, since under necessary attenuation of signal in 10⁴  times, the monotonous sections practically merged with each other and with zero line. But this type of oscillograms has a great value for the purpose of understanding the physics of processes in showering arcs, because, if this fact was corroborated, we would may speak for certain that relaxation has an oscillating pattern. Proceeding from this, we went on in this trend. In order monotonous sections in the oscillograms to be not merging, we increased the parasitic capacitance up to utmost possible value; this decreased the number of showering arcs and lengthened the monotonous sections. The results of these experiments are shown in Fig. 10.

Fig. 10. The oscillogram of showering arcs with registered surges of both polarities at the ends of monotonous sections

Just as it was premised, the span in voltage of positive and negative polarity is practically the same: positive - in limits of  2500 V and negative - in limits of 2000 V. But the main, their synchronous position between the monotonous sections unambiguously corroborates the formed pattern with two-stage process consisting of low-voltage monotonous section in limits of 500 V and high-amplitude section with the two-sided span in limits (2000 - 2500) V.