  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 ${\bf J}\times{\bf B}$ 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.
