The Madison plasma dynamo experiment: a facility for studying laboratory plasma astrophysics

Abstract

The Madison plasma dynamo experiment (MPDX) is a novel, versatile, basic plasma research device designed to investigate flow driven magnetohydrodynamic (MHD) instabilities and other high-$\beta$ phenomena with astrophysically relevant parameters. A 3 m diameter vacuum vessel is lined with 36 rings of alternately oriented 4000 G samarium cobalt magnets which create an axisymmetric multicusp that contains $\sim$14 m${}^3$ of nearly magnetic field free plasma that is well confined and highly ionized $(>50\%)$. At present, 8 lanthanum hexaboride (LaB${}_6$) cathodes and 10 molybdenum anodes are inserted into the vessel and biased up to 500 V, drawing 40 A each cathode, ionizing a low pressure Ar or He fill gas and heating it. Up to 100 kW of electron cyclotron heating (ECH) power is planned for additional electron heating. The LaB${}_6$ cathodes are positioned in the magnetized edge to drive toroidal rotation through $\mathbf{J}\times \mathbf{B}$ torques that propagate into the unmagnetized core plasma. Dynamo studies on MPDX require a high magnetic Reynolds number $Rm>1000$, and an adjustable fluid Reynolds number $10<Re<1000$, in the regime where the kinetic energy of the flow exceeds the magnetic energy ($M_A^2=($v$/$v${}_A{)}^2>1$). Initial results from MPDX are presented along with a 0-dimensional power and particle balance model to predict the viscosity and resistivity to achieve dynamo action.

14 pages, 13 figures

References in corpus (4)

• Stirring Unmagnetized Plasma
• Optimized boundary driven flows for dynamos in a sphere
• Resistive and ferritic-wall plasma dynamos in a sphere
• Fast dynamos in spherical boundary-driven flows

Cited by in corpus (25)

• Dynamo theories
• Development of magnetic liquid metal suspensions for magnetohydrodynamics
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• The Wisconsin Plasma Astrophysics Laboratory
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• The dynamo effect in decaying helical turbulence
• Chiral Exact Relations for Helicities in Hall Magnetohydrodynamic Turbulence
• A nonlinear structural subgrid-scale closure for compressible MHD Part II: a priori comparison on turbulence simulation data
• Comparative statistics of selected subgrid-scale models in large eddy simulations of decaying, supersonic MHD turbulence
• Flow dynamics and magnetic induction in the von-Karman plasma experiment
• Weakly magnetized, Hall dominated plasma Couette flow
• Nonlinear closures for scale separation in supersonic magnetohydrodynamic turbulence
• Taylor-Couette Flow of Unmagnetized Plasma
• Coexistence of weak and strong wave turbulence in incompressible Hall magnetohydrodynamics
• The Mochi.LabJet experiment for measurements of canonical helicity injection in a laboratory astrophysical jet
• Prospects for observing the magnetorotational instability in the Plasma Couette Experiment
• Characterization of fast magnetosonic waves driven by compact toroid plasma injection along a magnetic field
• Formation of Transient High-$\beta$ Plasmas in a Magnetized, Weakly Collisional Regime
• Ion heating and flow driven by an Instability found in Plasma Couette Flow
• Magnetic field dynamos and magnetically triggered flow instabilities
• Parametric instability in periodically perturbed dynamos
• Laboratory experiments and numerical simulations on magnetic instabilities
• Effect of electromagnetic boundary conditions on the onset of small-scale dynamos driven by convection
• Numerical simulations for the DRESDYN precession dynamo