Converging geometry Rayleigh–Taylor instability and central ignition of inertial confinement fusion targets

Abstract

The Rayleigh-Taylor instability (RTI) of the inner surface of an inertial confinement fusion shell is studied through high-resolution two-dimensional numerical simulations. The instability is seeded by a mass displacement introduced in the simulations at the end of the implosion coasting stage. Analysis of single-mode, small-amplitude perturbations confirms that ablation caused by electron conduction and fusion alpha-particles causes significant growth reduction of all modes and stabilization of high-l modes. Different measures of the instability are discussed and compared with modified Takabelike expressions. Large-amplitude multi-mode simulations are performed to study the effects of RTI on ignition and burn. RTI perturbations reduce the size of the central hot spot and delay ignition. For a few different perturbation spectra the dependence of fusion yield on the initial perturbation root mean square amplitude is studied.

Compact neutron source from head-on collision of high energy density plasma jets

“…Based on the original FLASH code, the thermonuclear reaction module has been extended. It is known that the neutron generation rate per volume for D-D thermonuclear reaction is expressed as dY n /dt 1 2 n 2 D 〈σv〉, where 〈σv〉 is an averaged reactivity based on Maxwellian velocity distribution [35]. In thermal equilibrium, the reactivity can be written as…”

Viscous effects on the Rayleigh-Taylor instability with background temperature gradient

“…The results can be qualitatively compared with previous results related to the ICF coasting. [31][32][33]45 . These studies include the effect of ablation, however they do not account for the presence of viscosity.…”

Role of electron inertia and electron/ion finite Larmor radius effects in low-beta, magneto-Rayleigh-Taylor instability

“…The Rayleigh-Taylor instability (RTI) is an instability of a fluid interface appropriately oriented in the presence of an acceleration. Conventional hydrodynamic 1,2 and magnetohydrodynamic (MHD) 3 simulations have been performed to study the growth of this instability for regimes ranging from space and astrophysical plasmas 4,5 to fusion plasmas 6,7 . The single-fluid MHD model does not alter the growth rate of 2-dimensional RTI when a purely out-of-plane magnetic field is present except due to large thermal conduction and diffusion mechanisms.…”