Inhomogeneity in laboratory plasma discharges and Stark shift measurement

Several examples of Stark spectral line shifts from different laboratory plasma experiments are presented. The difference is outlined between the Stark shift caused by the micro field of charged particles on one side and the Stark shift caused by macroscopic electric field occurring in plasma sheaths on the other. In the first case the shift is used for testing of the Stark shifting theory and/or measurement of density of electrons while in the second it is used for measurement of macroscopic electric field strength. It is shown that inhomogeneity of the plasma can be used to provide the reference nonshifted lines for exact evaluation of the shift magnitude.