  We present laboratory measurements of the interaction between thermoelectric
currents and turbulent magnetoconvection. In a cylindrical volume of liquid
gallium heated from below and cooled from above and subject to a vertical
magnetic field, it is found that the large scale circulation (LSC) can undergo
a slow axial precession. Our experiments demonstrate that this LSC precession
occurs only when electrically conducting boundary conditions are employed, and
that the precession direction reverses when the axial magnetic field direction
is flipped. A novel thermoelectric magnetoconvection (TEMC) model is developed
that successfully predicts the zeroth-order magnetoprecession dynamics. Our
TEMC magnetoprecession model hinges on thermoelectric current loops at the top
and bottom boundaries, which create Lorentz forces that generate horizontal
torques on the overturning large-scale circulatory flow. The thermoelectric
torques in our model act to drive a precessional motion of the LSC. This model
yields precession frequencies predictions that are in good agreement with the
experimental observations. We postulate that thermoelectric effects in
convective flows, long argued to be relevant in liquid metal heat transfer and
mixing processes, may also have applications in planetary interior
magnetohydrodynamics.
