Intensity scaling of hot electron energy coupling in cone-guided fast ignition

A critical issue for the fast ignition of inertial fusion targets, where compressed fuel is ignited by injection of an intense short laser pulse, is whether the hot electrons produced in the interaction are in an energy range conducive to efficient heating of the core. This work presents the first comprehensive two-dimensional kinetic simulation of the cone-guided approach to fast ignition. Simulation results predict the hot electron temperature to be much lower than previously expected, which indicates the possibility of using them for optimum core heating. Furthermore, the roles of collisional versus kinetic processes for transport and heating mechanisms of the core plasmas are clarified. The core heating efficiency scales linearly with intensity at ranges of 1019–1020W∕cm2, but falls below this range due to deflection of hot electrons in strong magnetic filaments behind the cone target.

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