Electrohydrodynamic surface instabilities: role of porous lining at the ablative surface of laser-driven inertial fusion energy target

Abstract

Recent progress in surface instabilities of the Rayleigh-Taylor type at the ablative surface of laser-driven inertial fusion energy (IFE) target is reviewed with the objective of increasing the efficiency of IFE by reducing the growth rate of Rayleigh-Taylor Instability (RTI) using the following two mechanisms: (i) porous lining in the absence of electric force at the ablative surface of the IFE target, i.e. hydrodynamics and magnetohydrodynamics and (ii) porous lining of smart materials of nanostructure in the presence of electric force at the ablative surface of the IFE target, i.e. electrohydrodynamics. The former mechanism deals with two cases. Case 1 is the study of linear and nonlinear RTIs in an ordinary viscous fluid past a densely packed porous lining considering combined lubrication and Stokes approximations. Case 2 deals with RTI considering only Stokes approximation. Mechanism (ii) deal with RTI in a poorly conducting fluid in the presence of the transverse electric field called eletrohydrodynamic RTI (ERTI). IN both case a simple theory based on replacing the no-slip condition with Saffman condition with and without thermal radiation is proposed. Both analytical and numerical techniques are used to study RTI. It is shown in both mechanisms, that the porous lining reduce the ratio of growth rates by about 80% compared to about 45% predicted in the literature, over the value that it would have if the target shell is bounded by an impermeable boundary. This finding is useful in the effective extraction of IFE by reducing the asymmetry caused by laser radiation in fusing deuterium-tritium in thr target. These mechanisms are also useful in biomedical engineering problems in controlling the effects of plaques in coronary artery diseases and in trachea (i.e. wind in the body).