Compared to the TIG arc, the constricted plasma arc has a much lower divergence, i.e.,
much larger changes in arc length can be tolerated. Thus, for example, a 20 % increase
of arc cross-section corresponds to a ten times larger length of the plasma arc than of the
TIG arc. This explains the relative insensitivity of the plasma arc to surface unevenness
(Figure 4201.03.03).