Monday, April 30, 20121:00 PM - 2:00 PMCNLS Conference Room (TA-3, Bldg 1690)|
From a water experiment to supernova theory
The explosive death of massive stars as supernovae, observed every night in distant galaxies, is believed to start with the collapse of the stellar core into a neutron star. One major difficulty is to understand how the inward motion of the infalling envelope turns into an explosion. Computer simulations over the last decade taught us that the simplest spherical scenario fails to explode stars heavier than 10 solar masses. Transverse motions induced by hydrodynamical instabilities seem to be the key to an asymmetric explosion mechanism. This would also explain the natal kick of neutron stars. I will show that the complex dynamics of core-collapse can be enlightened using the analogy between acoustic waves in a gas and surface waves in shallow water. The first experiment of this kind, named SWASI, has been developed at CEA-Saclay. It is one million times smaller and hundred times slower than its astrophysical analogue. It demonstrates the physical nature of instabilities discovered in numerical simulations and confirms that asymmetric explosions are a robust outcome of fluid mechanics.
Host: Casey Meakin, LANL T-2