The Magnetorotational Instability Experiment

    The Magnetorotational Instability (MRI) Experiment is a small laboratory experiment located at the Princeton Plasma Physics Laboratory (PPPL), in collaboration with Department of Astrophysical Sciences, Princeton University. The goal of MRI Experiment is to investigate physics of MRI in liquid gallium. Click to learn more about the physics of MRI and to find out our publications and results.

    The experimental apparatus has been constructed, and here is a movie: "First spin" movie (11/10/04). Subsequently, high-speed water experiments have been carried out, and here is a movie: water experiment using Laser Doppler Velocimetry (10/20/05).

    Our hydrodynamic results have been published in "Nature": "Hydrodynamic turbulence cannot transport angular momentum effectively in astrophysical disks", Nature 444, 343 (2006). (see paper from Nature website or its reprint, introduction by S. Balbus, news story at "" or "life, and the universe").

    We have discovered a "Shercliff Layer Instability" when a sufficiently strong magnetic field is imposed on otherwise stable flows. The results have been published as a Physical Review Letter and here is a movie of the observed instability at the mid plane measured by Ultrasonic Doppler Velocimetry.

    We have published an introductory review article in "Physics Today": "Angular momentum transport in astrophysics and in the lab", Physics Today 66, 27 (2013). Here is the paper in the pdf format.

    We have upgraded the apparatus by using electrically conducting axial boundaries to increase the saturation level of the MRI, in order to unambiguously detect the standard form of MRI in any real systems for the first time. We have successfully confirmed the effectiveness of conducting axial boundaries, both experimentally and numerically.

    Finally, after more than 20 years of continued effort, observation of magnetorotational instability or MRI have been reported from our liquid metal experiment. On September 7, 2022, a letter paper titled "Observation of Axisymmetric Standard Magnetorotational Instability in the Laboratory," by Y. Wang, E. Gilson, F. Ebrahimi, J. Goodman, and H. Ji, has been published in Physical Review Letters. Interestingly, a non-axisymmetric mode has been also reported in a paper published on August 9, 2022 in Nature Communications: "Identification of a non-axisymmetric mode in laboratory experiments searching for standard magnetorotational instability" by Y. Wang, E. Gilson, F. Ebrahimi, J. Goodman, K. Caspary, H. Winarto, and H. Ji. Click here for a news story by APS and click here for a news story by physicsworld. Also, here is a news story by Princeton University, another version of it by PPPL, as well as how does it work and its long history.

    A concise review titled "Taylor-Couette flow for astrophysical purposes" has been published in Phil. Trans. Roy. Soc. A in March 2023. Here is the link to the article.

    Separately, we have successfully demonstrated the standard MRI mechanism with a spring-mass analogue and the results have been published in Nature's Communications Physics journal in 2019.

    The MRI Experiment is currently jointly supported by NSF, NASA, and DoE.



Last Revised on 5/19/23
by Hantao Ji