# Detonability of white dwarf plasma: turbulence models at low densities

## TL;DR

This study investigates the conditions under which turbulent, low-density white dwarf plasma can produce self-sustained detonations, emphasizing the role of compressive turbulence and the formation of stable detonation kernels.

## Contribution

It introduces a new detonation mechanism driven by highly compressible turbulence, supported by 3D simulations showing the formation of stable kernels at unresolved scales.

## Key findings

- Compressively driven turbulence increases detonation kernel formation.
- Detonation kernels are centrally condensed with low curvature.
- High-resolution simulations suggest a higher likelihood of detonations in white dwarf mergers.

## Abstract

We study the conditions required to produce self-sustained detonations in turbulent, carbon-oxygen degenerate plasma at low densities. We perform a series of three-dimensional hydrodynamic simulations of turbulence driven with various degrees of compressibility. The average conditions in the simulations are representative of models of merging binary white dwarfs. We find that material with very short ignition times is abundant in the case that turbulence is driven compressively. This material forms contiguous structures that persist over many ignition times, and that we identify as prospective detonation kernels. Detailed analysis of prospective kernels reveals that these objects are centrally-condensed and their shape is characterized by low curvature, supportive of self-sustained detonations. The key characteristic of the newly proposed detonation mechanism is thus high degree of compressibility of turbulent drive. The simulated detonation kernels have sizes notably smaller than the spatial resolution of any white dwarf merger simulation performed to date. The resolution required to resolve kernels is 0.1 km. Our results indicate a high probability of detonations in such well-resolved simulations of carbon-oxygen white dwarf mergers. These simulations will likely produce detonations in systems of lower total mass, thus broadening the population of white dwarf binaries capable of producing Type Ia supernovae. Consequently, we expect a downward revision of the lower limit of the total merger mass that is capable of producing a prompt detonation. We review application of the new detonation mechanism to various explosion scenarios of single, Chandrasekhar-mass white dwarfs.