A new discharge scheme of a prepulse plus two main pulses for capillary-discharge soft-x-ray laser

Reducing the capillary-discharge current is one way of possibly decreasing the pumping power requirement. We examine the influence of various discharge currents on laser intensity and determine the suitable pre-discharge condition for a 46.9-nm discharge-pumped Ne-like Ar soft-x-ray amplifier. The experimental results show that a high additional pre-pulse current at amplitude of several kA and with a very short duration of several tens of nanosecond can effectively decrease the amplitude of the main discharge current at the lasing time. We propose a new discharge scheme of a pre-pulse plus two main pulses which appears to significantly decrease the requirement for discharge current. This in turn may decrease the pumping power requirement for the capillary discharge laser and can greatly increase laser efficiency.