Time-resolved plasma temperature measurements in a laser-triggered hydrogen-filled capillary discharge waveguide

Temporally resolved, spatially integrated measurements of the temperature of the plasma channel formed by a hydrogen-filled discharge capillary waveguide are presented. Plasma temperatures of 4–7 eV are measured for peak discharge currents between 80 and 150 A. It is demonstrated that laser-triggering the capillary discharge enables capillary discharges with a peak current as low as 23 A to be driven, reducing the plasma temperature to approximately 3 eV. This plasma temperature meets the requirements of a recently proposed soft x-ray recombination laser.