Memory Effects of the Ionization Wave Generated by an Atmospheric‐Pressure Helium Plasma Jet in Air

ABSTRACT

This work investigates competing memory effects associated with surface‐charge‐induced electric field enhancement and residual‐space‐charge‐induced field shielding in a helium atmospheric‐pressure plasma jet (APPJ) using numerical simulations validated by experiments. A numerical model integrating a 2D axisymmetric plasma fluid model with a gas flow model is developed to capture the dynamics of the ionization wave generated. The simulated results of charge‐removal numerical experiments indicate that surface charges dominate the discharge ignition in the positive HP, whereas residual space charges suppress discharge formation due to the shielding of the electric field in the negative HP, leading to the observed asymmetric discharge current. These findings provide physical insight into polarity‐dependent memory effects and discharge control in APPJs.