  The potential for laser-produced plasmas to yield fundamental insights into
high energy density physics (HEDP) and deliver other useful applications can
sometimes be frustrated by uncertainties in modeling the properties and
behavior of these plasmas using radiation-hydrodynamics codes. In an effort to
overcome this and to corroborate the accuracy of the HEDP capabilities in the
publicly available FLASH radiation-hydrodynamics code, we present detailed
code-to-code comparisons between FLASH and the HYDRA code developed at Lawrence
Livermore National Laboratory using previously published HYDRA simulations from
Grava et al. (2008). That study describes a laser experiment that produced a
jet-like feature that the authors compare to astrophysical jets. Importantly,
the Grava et al. (2008) experiment included detailed x-ray interferometric
measurements of electron number densities and a time-integrated measurement of
the soft x-ray spectrum. Despite markedly different methods for treating the
computational mesh, and different equation of state and opacity models, the
FLASH results resemble the results from HYDRA and, most importantly, the
experimental measurements of electron density. Having validated the FLASH code
in this way, we use the code to further investigate and understand the
formation of the jet seen in the Grava et al. (2008) experiment and discuss its
relation to the Wan et al. (1997) experiment at the NOVA laser.
