The role of mixing in astrophysics

The role of hydrodynamic mixing in astrophysics is reviewed, emphasizing its connections with laser physics experiments and inertial confinement fusion. Computer technology now allows us to use two-dimensional simulations, with complex microphysics, of stellar hydrodynamics and evolutionary sequences, and it holds the promise of simulations in three dimensions. Careful validation of astrophysical methods by laboratory experiment, by the critical comparison of numerical and analytical methods and by observation are necessary for the development of simulation methods with reliable predictive capabilities. The recent and surprising results from isotopic patterns in presolar grains, from two-dimensional hydrodynamic simulations of stellar evolution, and from laser tests and computer simulations of Richtmeyer-Meshkov and Rayleigh-Taylor instabilities will be discussed in relation to stellar evolution and supernovae.