Dynamic stabilization of the isolated internal defect in the presence of a temporally modulated laser prepulse

Hydrodynamic instabilities seeded by isolated internal defects remain a critical performance-limiting factor in inertial confinement fusion experiments. Here we extend the concept of dynamic stabilization via temporally modulated laser pulses from the main drive [K. G. Zhao et al., Phys. Rev. E 109, 025213 (2024)2470-004510.1103/PhysRevE.109.025213] to the prepulse stage, which stabilizes the hydrodynamic evolution of perturbations seeded by micrometer-scale (low-density) internal defects. Analysis of the unperturbed ablative flow generated by the modulated laser prepulse indicates that the periodic oscillatory configuration has the potential to stabilize the instability growth from such defects. A single defect under the modulated laser prepulse is compared with that in the unmodulated case. The results show that the modulated laser prepulse reduces the bubble penetration depth and vorticity generation. This stabilization arises from a phase difference between the density and pressure gradients, which induces a reversal of the baroclinic term in the vorticity transport equation. Moreover, the results show that the stabilization effect of the modulated laser prepulse is more significant for shallower defects and diminishes progressively with increasing defect depth.