Laser-driven plasma loader and solid matter ramp compression experiments on SG-II Laser

¹ Institute of Fluid Physics, PO Box 919-113, Mianyang, Sichuan 621900, China
² Shanghai Institute of Laser Plasma, PO Box 800-229, Shanghai 201800, China

Abstract

Laser-driven plasma loader for shockless compression provides a new approach to study the rapid compression response of materials. But little information about the “plasma piston” can be obtained. The objective of the current study tried to map out a whole procedure of laser-driven plasma jet and shockless compression of solid materials. The experiment was performed using the Shenguang-II Nd: glass laser. Shock wave transmitting in reservoir, and Al/LiF interface velocity history both are recorded by a 2-channel line VISAR. Streaked and separated shade graph of plasma jet from rear surface of reservoir gave the 2D configuration and front speed (about 28 km/s to 60 km/s). A coaxial M-Z interferometer system is used for plasma density diagnostic. The density distribution is downward bulge near front of plasma jet, which is an important characteristic that determines shockless compression. Shockless compression of 30/40μ m Al step backed by 1mm LiF presented smooth pressure history up to 20GPa. The strain rate can reach 10^7∼8/s.