Laser-driven inertial confinement fusion (ICF) is an important approach in confinement research. All prevailing ICF laser facilities, such as the National Ignition Facility (NIF) in the United States, the Laser Mega Joule (LMJ) in France, and the ShenGuang laser facility in China, use a pulsed xenon flashlamp as the pump source. As an important optical component of a large high-power laser amplifier, a high-power pulsed xenon lamp can convert electrical energy into light energy in an energy-storage system to pump Nd∶glass, thus affecting the stability of the laser output. In this study, a scheme is proposed to effectively improve the peak trigger voltage of a xenon flashlamp at a constant operating voltage. The experimental results show that the peak trigger voltage of the xenon flashlamp increases by 7.1 kV, i.e., an increment of 26.4%, thus effectively improving the discharge reliability of the xenon flashlamp.

The operating voltage of the xenon flashlamp, which determines the energy released by the energy-storage capacitor to the flashlamp, is one of the main physical parameters in amplifier design. It must satisfy the pump-energy requirement of the amplifier but cannot be overly high to avoid decreasing the spectral efficiency of the pump light or increasing the explosion coefficient of the xenon flashlamp. The peak trigger voltage significantly affects the reliable breakdown of xenon flashlamps. The higher the peak voltage, the greater is the discharge reliability of the xenon flashlamp, the more reliable is the amplifier, and the less susceptible it is to output energy fluctuations caused by the discharge failure of the xenon flashlamp. Historical data pertaining to amplifier operation were calculated. The data show that the discharge failure of a xenon flashlamp with a shorter leading-cable length is greater. Increasing the operating voltage of the xenon flashlamp can improve the peak trigger voltage, thereby effectively improving the discharge success rate. To improve the discharge reliability of the xenon flashlamp under a fixed operating voltage, the peak trigger voltage was increased by extending the length of the leading cable and connecting suitable resistors and capacitors in parallel in the discharge circuit. The peak trigger voltages under different circuit configurations were measured, and the discharge success rate after increasing the peak trigger voltage was calculated.

The variation in the peak trigger voltage was measured as the operating voltage was increased under leading-cable lengths of 10 m and 20 m, as shown in the inset of Fig. 6. When the operating voltage is 14 kV, an increase in the leading-cable length increases the peak trigger voltage by 2.2 kV, i.e., an increment of 8.1%. The experimental results show that a longer leading-cable length facilitates an increase in the peak trigger voltage. The variation in the peak trigger voltage was measured as the operating voltage was increased under shunt resistances of 1 kΩ and 20 kΩ, as shown in the inset of Fig. 7. At an operating voltage of 14 kV, an increase in the leading-cable length increases the peak trigger voltage by 3.1 kV, i.e., an increment of 11.5%. The experimental results show that the peak trigger voltage can be effectively increased by increasing the shunt resistance. Additionally, the ignition after the peak trigger voltage increases was calculated. The experimental results show that the threshold operating voltage required to achieve discharge from the xenon flashlamp is successfully reduced, and that the discharge success rate of the xenon flashlamp can be effectively improved by optimizing the peak trigger voltage. The peak trigger voltage was measured when the leading-cable length, parallel resistance, and capacitance were increased simultaneously, as shown in the inset of Fig. 10. When the operating voltage is 14 kV, the peak trigger voltage increases by 7.1 kV, i.e., an increment of 26.4%.

Herein, a method for improving the discharge reliability of a xenon flashlamp by increasing the peak trigger voltage without affecting the operating voltage of the amplifier was investigated experimentally. The results show that the peak trigger voltage can be effectively increased by increasing the leading-cable length, paralleling the resistor at the inductor in the discharge loop, and paralleling the small capacitor at the two poles of the xenon flashlamp without changing the operating voltage, thus improving the discharge reliability of the xenon flashlamp. Additionally, three optimization methods were adopted, and the peak trigger voltage corresponding to the 14 kV operating voltage of the amplifier increases from 26.9 kV before optimization to 34 kV after optimization, i.e., a relative increase of 26.4%; meanwhile, the discharge success rate of the xenon flashlamp can reach 100%. This method has been applied to a high-power laser facility, which effectively improved the discharge reliability of xenon flashlamps and ensured the stable operation of the amplifier.