First demonstration of laser engagement of 1-Hz-injected flying pellets and neutron generation

Abstract

Pellet injection and repetitive laser illumination are key technologies for realizing inertial fusion energy. Numerous studies have been conducted on target suppliers, injectors, and tracking systems for flying pellet engagement. Here we for the first time demonstrate the pellet injection, counter laser beams' engagement and neutron generation. Deuterated polystyrene (CD) bead pellets, after free-falling for a distance of 18 cm at 1 Hz, are successfully engaged by two counter laser beams from a diode-pumped, ultra-intense laser HAMA. The laser energy, pulse duration, wavelength, and the intensity are 0.63 J per beam, 104 fs, and 811 nm, 4.7 × 10 ¹⁸ W/cm ², respectively. The irradiated pellets produce D(d,n) ³ He-reacted neutrons with a maximum yield of 9.5 × 10 ⁴/4 π sr/shot. Moreover, the laser is found out to bore a straight channel with 10  μm-diameter through the 1-mm-diameter beads. The results indicate potentially useful technologies and findings for the next step in realizing inertial fusion energy.