# Subcritical turbulent condensate in rapidly rotating Rayleigh-B\'enard convection

## TL;DR

This paper investigates the potential for subcritical transitions to large-scale vortex states in rapidly rotating Rayleigh-Bénard convection, revealing bistability and non-local energy transfer mechanisms in geostrophic turbulence.

## Contribution

It demonstrates that subcritical large-scale vortex formation can occur in rotating convection even without prior inverse cascade evidence, highlighting bistability in turbulent flows.

## Key findings

- Subcritical transition to large-scale vortices observed with finite amplitude initial conditions.
- Bistability exists between vortex dipole and turbulent states.
- Non-local inverse energy transfer can compete with direct cascade.

## Abstract

The possibility of subcritical behaviour in the geostrophic turbulence regime of rapidly rotating thermally driven convection is explored. In this regime a non-local inverse energy transfer may compete with the more traditional and local direct cascade. We show that, even for control parameters for which no inverse cascade has previously been observed, a subcritical transition towards a large-scale vortex state can occur when the system is initialized with a vortex dipole of finite amplitude. This new example of bistability in a turbulent flow, which may not be specific to rotating convection, opens up new avenues for studying energy transfer in strongly anisotropic three-dimensional flows.