Robust fuel target in heavy ion inertial fusion

Abstract

Uniformity of heavy ion beam (HIB) illumination is one of the key issues in HIB inertial confinement fusion (HIF): deviation from fuel implosion symmetry should be less than a few percent in order to compress a fuel sufficiently and release fusion energy effectively. In this paper, a new mitigation method of the Rayleigh–Taylor (R-T) instability growth is presented in order to make a HIF target robust against a non-uniform implosion. In this study a new mitigation method of R-T instability growth is proposed based on an oscillating perturbed acceleration, which can be realized by a rotating or oscillating HIB illumination onto a fuel pellet. The R-T instability analyses and fluid simulations demonstrate that the oscillating acceleration reduces the R-T instability growth significantly. In this paper a baseline steady acceleration g 0 is perturbed by a perturbed oscillating acceleration δg, which is spatially non-uniform and oscillates in time ( g 0⪢ δg). An example result shows 84% reduction of the R-T instability growth.