Two- and three-dimensional numerical simulations of the core helium flash

The effects arising from the time-dependent interaction of convection and the thermonuclear runaway of the core helium flash found previously with coarsely zoned two-dimensional calculations are studied with much more finely zoned two-dimensional and with three-dimensional calculations. These effects include: (1) a cyclic behavior in the strength of both the thermonuclear runaway and convection caused by the failure of convection to adjust instantaneously to the runaway, (2) extensive convective overshooting across the strong temperature innversion into the inner core, (3) the rapid convective heating of the inner core, (4) large (more than a few percent) nonspherical temperature variations, and (5) the eventual failure of convection to contain the runaway. All of these effects are confirmed by the more refined calculations. Implications of these effects are discussed.