Instabilities elucidate dynamics of supernovae blasts

Supernova remnants encapsulate information about stellar evolution and the formation of heavy elements. Modeling supernovae is extremely difficult because it requires an in-depth understanding of complex physical processes, such as fluid instabilities and interfacial mixing.

Abarzhi et al. used group theory to explore fluid instabilities in supernovae, revealing that the dynamics at early and late times are strongly influenced by initial conditions.

“We want to work backward from the supernova remnant to the underlying explosion to provide insights into the event and reveal the star’s birth, life, and death,” said author Snezhana Abarzhi. “So, we need to know the details of what explodes at microscopic scales, quantify the explosion’s conditions at macroscopic scales, and reveal the information imprinted in astronomical observations.”

To accomplish this, the team analyzed Rayleigh-Taylor (RT) and Richtmyer-Meshkov (RM) instabilities. The former develops at the interface between two liquids with distinct densities when they are accelerated against the density gradient.

“In everyday life, we observe RT instability when watching water flowing from an overturned cup. The heavy fluid on the top is water, while the light fluid on the bottom is air and the acceleration is gravity,” said Abarzhi. “RM instability develops when the acceleration is impulsive. A supernova’s blast causes the development of RT and RM instabilities and intense interfacial mixing.”

The researchers were able to directly link the conservation laws of RT and RM dynamics to a symmetry-based momentum model. In doing so, they found that, from a fluid dynamics perspective, supernovae can be regarded as an astrophysical initial value problem.

These results will inform high energy density plasma experiments and astronomical observations.

Source: “Fluid dynamic mathematical aspects of supernova remnants,” by Snezhana I. Abarzhi, Desmond L. Hill, Kurt C. Williams, Jiahe T. Li, Bruce A. Remington, David Anthony Martinez, and W. David Arnett, Physics of Fluids (2023). The article can be accessed at https://doi.org/10.1063/5.0123930 .