Review of the current status of fast ignition research at the IAPCM

Abstract

We review the present status and future prospects of fast ignition (FI) research of the theoretical group at the IAPCM (Institute of Applied Physics and Computational Mathematics, Beijing) as a part of the inertial confinement fusion project. Since the approval of the FI project at the IAPCM, we have devoted our efforts to improving the integrated codes for FI and designing advanced targets together with the experimental group. Recent FI experiments [K. U. Akli et al., Phys. Rev. E 86, 065402 (2012)] showed that the petawatt laser beam energy was not efficiently converted into the compressed core because of the beam divergence of relativistic electron beams. The coupling efficiency can be improved in three ways: (1) using a cone-wire-in-shell advanced target to enhance the transport efficiency, (2) using external magnetic fields to collimate fast electrons, and (3) reducing the prepulse level of the petawatt laser beam. The integrated codes for FI, named ICFI, including a radiation hydrodynamic code, a particle-in-cell (PIC) simulation code, and a hybrid fluid-PIC code, have been developed to design this advanced target at the IAPCM. The Shenguang-II upgraded laser facility has been constructed for FI research; it consists of eight beams (in total 24 kJ/3ω, 3 ns) for implosion compression, and a heating laser beam (0.5-1 kJ, 3-5 ps) for generating the relativistic electron beam. A fully integrated FI experiment is scheduled for the 2014 project.

Ultrahigh-Density Spin-Polarized H and D Observed via Magnetization Quantum Beats

“…The 10 19 cm −3 SPD or SPD densities allow new applications: the demonstration and study of polarized laser fusion [13,17] using several >5 kJ pulses offered at several laser facilities [10][11][12]; polarized ion acceleration with SPH densities of 10 19 − 10 21 cm −3 for wavelengths of 10-1 µm, respectively; maximizing the production of spin-polarized molecules in the NMR detection volume, for signal enhancement requiring gas densities of >10 19 cm −3 .…”

“…Polarized laser fusion, using densities of at least 10 19 SPD cm −3 and 10 20 cm −3 of polarized 3 He, and at least 5 kJ/pulse focused to ∼10 µm [10][11][12], will yield well above 10 4 neutrons for the D-3 He and D-D fusion reactions, needed for polarized fusion studies; well above 10 6 neutron will be produced using the 2MJ/pusle NIF laser [13].…”

Mitigating the hosing instability in relativistic laser-plasma interactions

“…To accomplish this, a DT capsule is first compressed to ∼400 g cm -3 with an areal density of ∼2 g cm -2 . Ignition is then triggered by an additional short-duration (∼10-20 ps) petawatt laser pulse isochorically heating the compressed target to ∼10 keV [23,24]. Upon hitting the critical surface of the coronal plasma formed during the compression phase, this high-power laser pulse then produces fast electrons of energies ∼1-3 MeV that travel through the remaining plasma and deposit their energy in the dense core [25].…”