X-ray Phase Contrast Imaging of a Strong Shock in a Dense Plasma*

X-ray phase contrast imaging (XPCI) relies on gradients in an object's phase, rather than absorption, to produce image contrast, and requires sufficient propagation distances to optimize the contrast for a given x-ray source size and wavelength. We report initial experimental results using the TRIDENT 200-TW laser to produce bright K-$\alpha$ x-rays with a source size $\sim$ 12-$\mu$m using Mo or Ag wire targets. This is used as a point backlighter to radiograph static or dynamic targets in the phase contrast regime. For the dynamic experiments, a strong spherical shock is launched in a low-Z target using a 200-J, 1.2 nsec laser focused on the target, which is diagnosed using XPCI with a few psec time resolution. Initial experimental results and comparison to theory will be reported.