117 / 2023-04-14 10:55:18

Growth of the ablative Rayleigh-Taylor instability induced by time-variant heat flux fluctuations

ablative Rayleigh-Taylor instability,time-variant heat flux fluctuations,smoothing by spectral dispersion

辐射和流体力学 > 流体力学不稳定性-海报

The evolution of ablative Rayleigh-Taylor instability (ARTI) induced by single-mode stationary and time-variant heat flux fluctuations is numerically studied in two dimensions. For the stationary cases, the shorter-wavelength modes grow substantially later than the longer-wavelength modes, while the linear growth rate can still be well predicted by the self-consistent linear theories. Compared with the stationary cases, time-variant heat flux fluctuations can mitigate the ARTI growths due to the enhanced thermal smoothing effect induced by wave-like traveling heat fluxes. A resonance is found to be formed when the phase velocity of the heat flux fluctuation matches the averaged sound speed in the ablation regions. In the resonant regime, the coherent density and temperature fluctuations would enhance the electron thermal conduction in the ablation region and lead to larger ablation pressures and effective accelerations, which consequently yield higher linear growth rates and saturated bubble velocities. The enhancement of effective acceleration can both facilitate increasing implosion velocities and compromise the integrity of ICF shells by causing faster ARTI growths.