The energy transport in cone-guided low-$Z$ targets has been studied for laser intensities on target of $2.5\times {10}^{20}\text{W}{\text{cm}}^{-2}$. Extreme ultraviolet (XUV) imaging and transverse optical shadowgraphy of the rear surfaces of slab and cone-slab targets show that the cone geometry strongly influences the observed transport patterns. The XUV intensity showed an average spot size of $65\pm 10\mu \text{m}$ for slab targets. The cone slabs showed a reduced spot size of $44\pm 10\mu \text{m}$. The shadowgraphy for the aforementioned shots demonstrate the same behavior. The transverse size of the expansion pattern was $357\pm 32\mu \text{m}$ for the slabs and reduced to $210\pm 30\mu \text{m}$. A transport model was constructed which showed that the change in transport pattern is due to suppression of refluxing electrons in the material surrounding the cone.

• Received 3 February 2009

DOI:https://doi.org/10.1103/PhysRevE.80.045401