Fu Sizu

Optimization of 4.7-keV X-ray titanium sources driven by 100-ps laser pulses

An experiment with thin titanium foils irradiated by two pulses delayed in time is conducted on the Shenguang-II laser facility. A prepulse induces an underdense plasma, 2-ns later a main pulse (λL = 0.35 μm, EL ≈ 120 J, τL ≈ 100 ps) is injected into the underdense plasma and produces strong line emission from the titanium K shell (i.e., Heα at 4.7 keV). Data show that the intensity of 4.7-keV X-ray emission with the prepulse is approximately twice more than without the prepulse, and can be used as a backlighting source satisfying the diagnostic requirements for dense plasma probing. High-quality plasma images are obtained with the backlighting 4.7-keV X-rays in a Rayleigh—Taylor hydrodynamic instability experiment.

Experimental Diagnosis of Plasma Jets by Using X-Ray Laser

The supersonic jets and the interaction of strong shock waves are ubiquitous features of the nonlinear hydrodynamics of inertial-confinement fusion, astrophysics, and related fields of high energy-density science, so it is very important of laboratory studies on it. In this paper, a laboratory experimental study is reported. The jets were created by a ns laser pulse irradiating a specific target, and the shadow of jets were measured by an x-ray laser probe with wavelength of 13.9nm. The legible images of jets were recorded, and the experimental results and theory simulation were qualitative agreement.

Tending to Saturated Gain of Soft X-Ray Laser at 23.2 and 23.6Nm

We proposed a design named “Four-Target Series Coupling” to work, on soft x-ray laser in Ne-like Ge plasma. The total length for four targets is up to 5.6cm. The gain length product (GL) for small signal is up to about 18 for both lines at 23.2 and 23.6nm , and the effective GL is 16.4 and 15.7 for these two lines respectively. These two lines are obviously tending to saturation. The divergence of X-ray laser beam is about 3 ˜ 4 mrad. Before experiments, we developed a series of codes to simulate these experiments, got the parameters about the distance and angle between the targets in order to get best coupling.