Study the formation mechanism of plasma effluent gas turbulence and its dynamics at different plasma configurations help to manipulate and optimize the plasma for relevant applications. In this article, the dynamics of the turbulent front (TF) of the jet plasma effluent gas at three-electrode configuration driven by pulsed dc and ac power sources was studied experimentally for the first time. The TF formed by helium plasma jet was imaging by Schlieren technics. Moreover, the high-speed camera was utilized to capture the time evolution of the TF formation, and the contribution of ac and pulsed dc on the turbulent formation was studied and repeated for different initial phases of ac sinusoidal waveform. The results show that the pulsed dc is more effective on diminishing the laminar length, whereas ac power affects on laminar fluctuations which is resulted from the formation of trains of the fast TF. The transverse turbulent is also observed resulted from the speed change of consecutive TF. The study of the bullet propagation at different initial phases of ac power showed that although bullet propagation dynamics alters drastically due to changes of electric field distribution, there is no experimental evidence observed to prove that TF fluctuations follow the bullet propagation dynamics.
