In order to develop a high repetition rate X-ray lasers, the longitudinal-pumped transient collisional excitation (TCE) X-ray laser is one of the most effective pumping schemes. The high directive Ni-like Mo 18.9 nm soft X-ray laser pumped by modest laser energy has already been demonstrated by using the tabletop size Ti:sapphire/Nd:glass laser system that delivering energy of 150 mJ in 475 fs at the center wavelength of 1054 nm. The total energy in the pre-pulse and the main pulse was 150 mJ, which will make possible multi-hertz operation. To pursue the high repetition rate of the laser-driven TCE X-ray laser, we have designed a new 20 TW Ti:Sapphire laser system (600 mJ, 30 fs, 10 Hz). Special attention was paid to improve the contrast ratio, control of pulse shape as well as phase by an acoustic optic programmable dispersive filter (AOPDF) and 1 kHz preamplifier. Preliminary data have shown good laser characteristics. As the preliminary experiments, we have investigated high order harmonics generation from low-density laser plasma by using the solid target irradiated by a femtosecond laser pulse. The highest order was the 51st. harmonic at wavelength of 15.61 nm.

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We study the process of a laser-supported combustion wave (LSCW) when an aluminum alloy is irradiated by a millisecond pulse laser based on the method of laser shadowgraphy. Under the condition of different laser parameters, the obtained results include the velocity, ignition threshold of LSCW and the variation law. The speed of LSCW increases with the laser energy under the same irradiation laser pulse width, and the speed of LSCW reduces with the increase of the laser pulse width under the same irradiation laser energy. Moreover, the ignition time of LSCW becomes shorter by increasing the laser number of the pulse and is not effected by changing the frequencies, when keeping the laser pulse width and energy unchanged. The results of the study can be applied in the laser propulsion technology and metal surface laser heat treatment, etc.

In this paper, the energy transmission of a laser-supported combustion wave (LSCW) is numerically studied, which includes inverse bremsstrahlung, thermal conduction and convection. A physical model is established to simulate an LSCW induced by millisecond-pulsed laser on aluminum alloy. This physical model is a 2D axis-symmetric numerical model of radiation gas dynamics. Moreover, the simulation focuses on the interaction process in different laser conditions such as various pulse widths and peak energies. As a result, the speed of the LSCW increases by increasing the laser energy while keeping the laser pulse constant, whereas the speed is reduced by increasing the laser pulse width while keeping the laser energy constant. After a comparison of the theoretical, numerical and experimental results, analyses are performed while the experimental results are explained reasonably. Furthermore, the consistency between the numerical and experimental results implies that the numerical calculation model used in this paper can describe the motion of the LSCW of the millisecond-pulsed laser on aluminum alloy very well.