Temporal evolution of electron density in anomalously dense non-equilibrium argon plasma

This study investigates generating a dense non-equilibrium plasma states in high presure (up to 10 bar) Argon. Initially, electric discharges are generated using high voltage nanosecond pulses (10 kV, 20ns) and then a relatively low energy picosecond laser (\textasciitilde 1 mJ) is applied for the further ionization of the initial dischage plasma. The electrode configuration consists of a pin-to-pin geometry with short gap (\textasciitilde 200 um). The temporal evolution of electron density during one cycle (\textasciitilde 100 ns) is measured by optical emission spectroscopy with 10 picosecond-resolution streak camera. The electron density is inferred from the Stark broadening of H \begin{figure}[htbp] \centerline{\includegraphics[width=0.09in,height=0.17in]{150620181.eps}} \label{fig1} \end{figure} line (656.2nm) and Ar I (2p-1s) line (696.5 nm).