Plasma jets generated from conical-wire arrays driven by a 1-kJ pulsed-power system*

Plasma jets were generated by using conical-wire arrays driven by a pulsed-power system. The pulsed-power system was built for studying space sciences, particularly in simulating solar winds. The pulsed-power system consisted of twenty $1$-${\rm \mu F}$ capacitors, two rail-gap switches, two parallel plate transmission lines, and a cylindrical vacuum chamber orientated vertically. Two capacitors were first connected in series forming a brick. Five bricks were connected in parallel forming a wing. Finally, two wings were connected in parallel forming the whole capacitor bank, i.e., $5\;{\rm \mu F}$ in total. The system was charged to $20\;{\rm kV}$ storing total energy of $1\;{\rm kJ}$. When it was discharged, a peak current of $110\pm20\;{\rm kA}$ with a rise time of $1.4\pm0.2\;{\rm \mu s}$, i.e., a peak power of $\sim 700\;{\rm MW}$, was provided. The conical-wire array was formed by four tungsten wires with a diameter of $20\;{\rm \mu m}$. The opening angle and the smaller radius of the conical-wire arrays were $30^{{\rm o}}$ and $5\;{\rm mm}$, respectively. Images of the implosions were taken by an x-ray pinhole camera with an exposure time of $1\;{\rm \mu s}$, i.e., temporal-integrated images of the implosions. Images of the implosion will be shown.