Understanding the Physics of Shock Breakout*

The early emission from a supernova blastwave breaking out of its progenitor star provides key insight into the nature of the supernova explosion and its progenitor.  Asymmetries in the supernova engine, inhomogeneities in the stellar envelope and stellar wind, and the structure of the transition region between the stellar envelope and wind all contribute to the emission from this initial shock breakout.  The importance of inhomogeneous radiation-flow (and its subsequent shock-heating) spans many disciplines, leading to the design of a growing number of laboratory experiments to better understand this physics.  In this talk, I will review the astrophysical problem of early-time shock emission, upcoming NASA missions designed to measure it and the laboratory experiments designed to better understand the physics driving this emission.