Generation and characterization of a pulsed dense plasma with helium

This contribution is about the characterization of a Lorentz-drift based plasma accelerator in preparation for a colliding plasma experiment. The aim is to investigate the basics of a high energy density collision zone by accelerating two or more plasma sheets simultaneously against each other. Possible applications for this device are UV/VUV backlighting and the production of high densities for plasma stripping. Additionally the device is eligible for basic research of stopping energy. The experimental setup has a total capacitance of 27 μF at maximum voltages of 10 kV. The maximum discharge current of 147 kA is switched by a thyratron. Due to the low total inductance of the setup of 130nH high current slew rates in the 10
¹¹
A/s range are achieved. All measurements have been performed in a vacuum chamber at 3 to 100mbar pressures with a 2% hydrogen in helium gas mixture. For dynamic characterization and optimization of the acceleration process velocity and kinetic energy of the plasma sheet have been investigated. Up to 80 km/s velocities have been determined by a photodiode array and images of a fast framing camera. Moreover the images show the shape of the plasma sheet. Due to the Stark broadening of the H
_β
-line electron densities in the 10
¹⁵
cm
^-3
range have been determined by a 0.5 m monochromator. The mean temperature has been estimated via He I and Hell line intensities. Electron density and temperature of the single accelerator are of great interest for the upcoming comparison to the collision experiment.