The work described in this paper is a combination of plasma focus electrical parameters and plasma sheath axial phase dynamics. 4 kJ plasma focus device of Mather type, is powered by two modules capacitor bank of 61.68 μF capacity, has been constructed for this course of study. The discharge takes place in helium gas with an operating pressure ranging from 0.5 to 1.5 Torr (1 Torr=133.3224 Pa). The experiments are conducted with charging voltages changes from 8 to 12 kV. The work described in this paper is a combination of plasma focus electrical parameters and plasma sheath axial phase dynamics. 4 kJ plasma focus device of Mather type, is powered by two modules capacitor bank of 61.68 μF capacity, has been constructed for this course of study . The discharge takes place in helium gas with an operating pressure ranging from 0.5 to 1.5 Torr (1 Torr = 133.3224 Pa). The experiments are conducted with a voltage change from 8 to 12 kV.