181 / 2023-04-15 15:10:01

Transport of laser-accelerated fast-electron beams in solid-density matters guided by laser-driven pulsed magnetic fields

laser-plasma interactions,fast-ignition,magnetic field,innertial confinement fusion,fast-electrons

惯性约束聚变物理学 > 其他ICF途径和脉冲功率技术-I

Laser-accelerated fast-electron beams promise fast-heating of compressed high-density plasma to hot spark necessary for nuclear reactions, particularly in the concepts of the fast-ignition and double-cone ignition schemes. However, the large angular and spectral spread of fast-electron beams means that only a small portion of kinetic energy can be deposited in the core region of the fuel. In this study, we demonstrate experimentally that pulsed magnetic fields generated by laser-driven capacitor-coils with a strength of hundreds of Tesla show guiding effects on fast-electron beams generated from conical targets. We employed dual layered Cu tracers with a graphite transport layer in between, to observe the electron generation and transmission characteristics through a Cu-K_α monochromatic imager. Our results show that the introduction of the magnetic field has increased the concentration of fast electrons by about tenfold, as indicated by the K_α photon excitation. Furthermore, the gyration of electrons due to the Lorentz force led to more efficient kinetic energy deposition. These findings offer insights into the designs to increase the laser-to-core coupling efficiency in ignition schemes with fast-electron heating.