In collaboration with Thomas Gastine (IPGP) we are developing forward models of strongly-driven, rapidly-rotating convection, in a spherical shell geometry relevant for the regime expected in Earth's core. The velocity field is assumed quasi-geostrophic, so the horizontal components of the flow are invariant parallel to rotation axis. The temperature field is fully 3D and there is also a coupling to a 3D magnetic field.
Strongly-driven, rapidly rotating convection
Above: An example of quasi-geostrophic convection showing axial vorticity in the equatorial plane. Control parameters: Ek=1e-8, Pr=1e-2, Ra=5e10 (approx 80xRa_crit)
A first example of hybrid QG-3D core convection with a magnetic field
We have carried out initial simulations of quasi-geostrophic convection together with the 3D magnetic induction they produce. An example is shown below for Ek=1e-5, Pr=1e0, Pm=9e-1, Ra=5000e8 (approx 20x Ra_crit). Snapshots of the 3D temperature field, QG axial vorticity and zonal flow (including thermal wind) and magnetic field (meridional section of azimuthally-averaged azimuthal field and radial field at the outer boundary). This is a first proof-of-concept example.
3D temperature field
QG vorticity in equatorial plane plus azimuthal flow including the 3D thermal wind
3D magnetic field: B_phi (top) and Br at the CMB (bottom)
