Problems in the optical measurement of dense plasma heating in laser shock wave compression

Experimental results on the heating of matter carried out in a study on laser-driven shock waves in aluminium are discussed. The measured temporal evolution of the 'colour' temperature of the rear surface of the target is compared with that computed by numerical codes. We show how the target preheating can substantially affect optical signals recorded from the rear side of the target, and consequently influence the accuracy of temperature and pressure measurements of the material behind the shock wavefront.