Magnetized Turbulent Combustion

The deflagration-to-detonation transition (DDT) is a critical mechanism in Type Ia supernovae

(SNe Ia), enabling the transition from subsonic burning to a detonation wave in a turbulent white

dwarf environment. While existing models, such as the data-driven subgrid-scale approach by Gusto

(2022), focus on the role of turbulence in plasma preconditioning within the Zel’dovich gradient

mechanism, the precise energy sources that facilitate this transition remain an open question.

A growing body of evidence suggests that localized ignition clusters regions of hot plasma with

short ignition times play a crucial role in triggering detonation. The survival of these clusters depends

on their ability to remain isolated from turbulence and avoid rapid mixing, allowing nuclear burning

to accelerate and eventually lead to full ignition. However, the mechanisms that sustain these ignition

kernels and supply the necessary energy remain unclear.

In this study, we investigate magnetic reconnection as a potential source of energy release that

could influence DDT conditions. Magnetic reconnection, a fundamental process in high-energy plas

mas, facilitates the rapid conversion of magnetic field energy into plasma thermal energy, leading

to localized heating and turbulence. This process may significantly impact hotspot formation and

thermonuclear runaway in the pre detonation phase.

To explore this hypothesis, we use the FLASH code to perform a series of computational experi

ments simulating reconnection driven energy release in burning dense stellar plasmas. Our approach

builds on the reconnection analysis techniques of Servidio et al. (2009), which utilize magnetic field

topology to identify reconnection regions, and we compare these results with the recently proposed

method by Wang et al. (2024). The Wang approach, which avoids a potentially sensitive to numerical errors eigen analysis of the magnetic field Hessian.