Improvement of Absorption and Hydrodynamic Efficiency by Using a Double-Foil Target with a Pinhole

Abstract
The improvement of absorption and hydrodynamic efficiency was experimentally investigated by using a double-foil target with a pinhole for laser beam. The behavior of the accelerated target is reasonably consistent with a cannonball-acceleration model. The absorption coefficient and the hydrodynamic efficiency increased by factors of 14 and 7, respectively, in comparison with a single foil target under the same irradiation condition.