Laboratory modeling of MHD accretion disks

TL;DR

This review summarizes two decades of laboratory experiments on magnetohydrodynamic phenomena in accretion disks, focusing on MRI, turbulence, and angular momentum transport, providing new insights and constraints for theoretical models.

Contribution

It compiles and analyzes experimental results on MRI and turbulence in laboratory settings, advancing understanding of accretion disk dynamics and informing astrophysical theories.

Findings

Demonstrated MRI generation in liquid metal experiments.

Linked laboratory turbulence to angular momentum transport in disks.

Provided constraints on turbulence levels in protoplanetary disks.

Abstract

This review article summarizes two decades of laboratory research aimed at understanding the dynamics of accretion disks, with particular emphasis on magnetohydrodynamic experiments involving liquid metals and plasmas. First, the Taylor-Couette experiments demonstrated the generation of magnetorotational instability (MRI) in liquid metals, and highlighted how this instability is critically influenced by boundary conditions and the geometry of the applied magnetic field. These experiments also highlight the nonlinear transition to turbulence in accretion disks, and their link with other MHD instabilities in centrifugally-stable flows. A complementary approach, involving laboratory experiments with volumetric fluid driving rather than rotating boundaries, enables a quantitative study of angular momentum transport by Keplerian turbulence. Collectively, these various laboratory studies offer new constraints on the theoretical models designed to explain the dynamics of accretion disks. This is particularly true with regard to the role of Keplerian turbulence in protoplanetary disks, where recent observations from the ALMA telescope have considerably revised previously expected values of the magnitude of the turbulent fluctuations. Finally, the paper discusses outstanding questions and future prospects in laboratory modeling of accretion disks.