Quasi-isentropic experiment based on Shen Guang-III prototype laser facility with laser direct drive illumination

Abstract

Quasi-isentropic compression technique is very useful for new material, shock wave physics, and earth physics. With shaping pulse laser, the quasi-isentropic compression technique is provided. For the designed experimental condition, the high energy density of shaping lasers can be used to generate shockless loading on the solid material to reach a high compression rate state with low temperature, which cannot be obtained with shock compression and isentropic compression technique. Then a new way to study the material can be provided. In this paper, the isentropic compression experiment with laser direct-drive illumination based on Shen Guang-III prototype laser facility is conducted. The theoretical model, target designing, experimental results, key technique, experimental characteristics and experimental data are analyzed in detail. The compression pressure above 400 GPa on the loading surface is obtained with experimental data and processing program, which is the highest pressure achieved to date. After comparing the apparent particle velocity with the true particle velocity, the dynamic correction curve can be obtained to achieve the real particle velocity, which is more accurate. The improving direction is provided, which will provide the important information. The experimental data and design will give the valuable reference for the study in this field.

Ramp-Wave Compression Experiment with Direct Laser Illumination on ShenGuang-III Prototype Laser Facility

“…3), the interface would accelerate into the LiF window, and the interface velocity history 𝑢 for each layer was recorded with a line-imaging velocity interferometer (VISAR). [13,14] A typical VISAR data recorded (Fig. 4) has a spatial resolution of ∼4 µm over 500 µm at the target, a temporal resolution 0.01 ns over an 20 ns window, and a minimum velocity per fringe of 2.87 km/s with the fringe position determined to less than 2% of a fringe.…”

“…Figure 1 shows the schematic diagram of our experiment. The four laser beams (energy 1300 J, wavelength 351 nm) to form a 𝜑2 mm focus shape from an x-ray pinhole camera (XPHC) illuminated on the Al layer of the target, and the line-imaging velocity interferometer (VISAR) [13,14] with a probe laser (𝜆 = 532 nm) received the reflected signal from the 500-µm-thick LiF window. Three targets of Al/LiF with the 20 µm/30 µm/40 µm-thick Al are the main targets.…”