# Subcritical convection in an internally heated layer

## TL;DR

This paper numerically investigates subcritical thermal convection in an internally heated horizontal layer with stress-free boundaries, relevant to liquid metal batteries, revealing the existence of 3D convection cells below the critical Rayleigh number.

## Contribution

It demonstrates the existence of three-dimensional convection cells at subcritical Rayleigh numbers in internally heated layers, advancing understanding of convection in liquid metal batteries.

## Key findings

- 3D convection cells exist at subcritical Rayleigh numbers
- Convection occurs in a horizontally layered system with internal heating
- Results are relevant for liquid metal battery design

## Abstract

Thermal convection in a horizontal layer with uniform internal heating and stress-free constant-temperature boundaries is analyzed numerically. The work is motivated by the questions arising in development of liquid metal batteries, in which convection is induced by the Joule heating of electrolyte. It is demonstrated that three-dimensional convection cells exist at subcritical Rayleigh numbers.