[en] Laser-driven shockwave experiments have been proposed for accurate determination of equation of state data in the multimegabar pressure range. This paper gives a quantitative analysis of the prospects for such experiments. In order to unambiguously interpret shockwave data, one requires a clean shock -- that is, a planar, steady shock wave entering cold material (without significant preheat perturbation). The problems of attaining sufficiently clean shocks at high pressure are examined and scaling relations which relate the pressure achieved to laser intensity, pulse energy, etc, are developed. It is shown that significantly higher pressures can be achieved when structured (layered) targets are used