Investigation of electric discharge in gas of superhigh density with preliminary adiabatic compression

A powerful electric discharge in high-density hydrogen is investigated in a two-stage facility. The initial experimental conditions are as follows: the energy stored in a capacitive storage, $140$–$300$ kJ; the discharge current, $90$–$220$ kA; the current rise rate $dI/dt\sim10^8$ A/s; the charging voltage, $4.0$–$6.0$ kV. The maximal concentration of hydrogen molecules $n$, achieved after adiabatic compression of gas (immediately before the discharge), is $3.3\times10^{22}$ cm$^{-3}$. The electrical parameters of the discharge and the gas pressure are measured in the experiments. The temperature, the concentration of charged particles, and the discharge channel radius are calculated using the results of these measurements. The estimates reveal that, under the given initial conditions, the arc channel temperature is $(1.3-1.8)\times10^5$ K, the concentration of charged particles is $(0.7-1.2)\times10^{20}$ cm$^{-3}$, and the channel radius is $0.14$–$0.20$ cm.