# Theory of combustion in disordered media

## TL;DR

This paper develops a theoretical framework for combustion in disordered media, revealing a universal phase transition behavior influenced by hot spot interactions and disorder, applicable across dimensions and interaction types.

## Contribution

It introduces a model showing that hot spot systems undergo a phase transition, which can be first or second order, with a universal phase diagram across various conditions.

## Key findings

- Hot spot systems exhibit a dynamic phase transition.
- The transition can be first or second order, separated by a tri-critical point.
- The phase diagram is universal across dimensions and interaction types.

## Abstract

The conventional theory of combustion describes systems where all of the parameters are spatially homogeneous. On the other hand, combustion in disordered explosives has long been known to occur after local regions of the material, called "hot spots", are ignited. In this article we show that a system of randomly distributed hot spots exhibits a dynamic phase transition, which, depending on parameters of the system can be either first or second order. These two regimes are separated by a tri-critical point. We also show that on the qualitative level the phase diagram of the system is universal. It is valid in two and three dimensions, in the cases when the hot spots interact either by heat or sound waves and in a broad range of microscopic disorder models.