The expansion of a laser-produced aluminum plasma and the heat penetration in multi-layered targets

H-like and He-like Al lines and their satellites are obtained from Al and polyethylene layered targets irradiated by a Nd:glass laser at a power flux of 2*10¹³ W cm^-2 on target. Two-dimensional spatial resolution is achieved using a flat crystal spectrograph incorporating a wire shadow technique. Expansion profiles in the lateral direction as a function of the Al layer location are measured and interpreted in terms of the temporal history of the interaction. By varying the location of the Al layer, the penetration depth of the heat wave front is also determined. It is found that in this power flux range, heat conduction can be explained by classical mechanisms.