Shock Ignition: A New Approach to High Gain Inertial Confinement Fusion on the National Ignition Facility

Shock ignition, an alternative concept for igniting thermonuclear fuel, is explored as a new approach to high gain, inertial confinement fusion targets for the National Ignition Facility (NIF). Results indicate thermonuclear yields of $\sim 120–250\mathrm{MJ}$ may be possible with laser drive energies of 1–1.6 MJ, while gains of $\sim 50$ may still be achievable at only $\sim 0.2\mathrm{MJ}$ drive energy. The scaling of NIF energy gain with laser energy is found to be $G\sim 126E(\mathrm{MJ}{)}^{0.510}$. This offers the potential for high-gain targets that may lead to smaller, more economic fusion power reactors and a cheaper fusion energy development path.

Figure 1

(a) Schematic laser pulse shape for shock ignition (solid curve) relative to that for conventional indirect or direct drive (dotted curve), (b) spherical radial build of a candidate NIF shock-ignition target.

Figure 2

(a) NIF shock-ignition fusion yield and (b) target energy gain, versus total NIF laser drive energy. Corresponding values for the NIF indirect-drive baseline ignition target are shown for comparison, together with gain predictions for NIF targets operating under conventional direct drive (DD) and polar direct drive (PDD).

Figure 3

Characteristic implosion parameters for NIF shock-ignited targets: In-flight aspect ratio (IFAR), convergence ratio (CR) and peak implosion velocity (V). Corresponding values for the NIF indirect-drive baseline ignition target are shown for comparison.

Figure 4

Peak laser powers for the main assembly drive and the shock-ignition pulse (solid lines) together with peak laser intensity for the shock pulse (dashed line).