Supertransient magnetohydrodynamic turbulence in Keplerian shear flows

TL;DR

This study investigates the transition to turbulence in magnetized Keplerian shear flows using numerical simulations, revealing a supertransient behavior where turbulence lifetime grows exponentially with magnetic Reynolds number.

Contribution

It demonstrates that the transition to sustained turbulence follows a supertransient law, providing new insights into turbulence dynamics in magnetized shear flows.

Findings

Turbulence lifetime increases exponentially with Rm.

No clear transition to sustained turbulence observed.

Turbulence exhibits supertransient behavior.

Abstract

A subcritical transition to turbulence in magnetized Keplerian shear flows is investigated using a statistical approach. Three-dimensional numerical simulations of the shearing box equations with zero net magnetic flux are employed to determine the transition from decaying to sustained turbulence as a function of the magnetic Reynolds number Rm. The results reveal no clear transition to sustained turbulence as the average lifetime of the transients grows as an exponential function of Rm, in accordance with a type-II supertransient law.