Mantle and Inner Core Namelists

Mantle Namelist

This namelist defines mantle properties

  • conductance_ma (default conductance_ma=0.0) is a real that defines the conductance (dimensionless) of the mantle in the limit of a thin conductinglayer.

  • nRotMa (default nRotMa=0) is an integer that defines the rotation of the mantle:

nRotMa=-1

Mantle rotates with prescribed rate (see omega_ma1 and omega_ma2 below)

nRotMa=0

Fixed, non-rotating mantle

nRotMa=1

Mantle rotates according to torques

  • rho_ratio_ma (default rho_ratio_ma=1) is a real which gives the density of the mantle in terms of that of the outer core.

  • omega_ma1 (default omega_ma1=0.0) is a real which defines a mantle rotation rate (used when nRotMa=-1).

  • omegaOsz_ma1 (default omegaOsz_ma1=0.0) is a real which prescribes the oscillation frequency of the mantle rotation rate. In this case, omega_ma1 is the amplitude of the oscillation.

  • tShift_ma1 (default tShift_ma1=0.0) is a real which defines the time shift of the mantle rotation rate omega_ma1.

  • omega_ma2 (default omega_ma2=0.0) is a real which defines a second mantle rotation rate.

  • omegaOsz_ma2 (default omegaOsz_ma2=0.0) is a real which defines the oscillation frequency of the second mantle rotation rate omega_ma2.

  • tShift_ma2 (default tShift_ma2=0.0) is a real which defines the time shift for omega_ma2.

The resultant prescribed mantle rotation rate is computed as:

omega_ma = omega_ma1*cos(omegaOsz_ma1*(time+tShift_ma1)) + &
           omega_ma2*cos(omegaOsz_ma2*(time+tShift_ma2))

  • ellipticity_cmb (default ellipticity_cmb=0.0) is a real which defines the ellipticity of the outer boundary. This is used together with omega_ma1 and omegaOsz_ma1 to represent the effect of a librating ellipsoidal boundary using a radial flow boundary condition.

The following defines the parameters when one wants to excite inertial modes in the system artificially using a method similar to Rieutord et. al 2012 .

  • amp_mode_ma (default amp_mode_ma=0.0) is a real which defines the amplitude of forcing on the outer boundary.

  • omega_mode_ma (default omega_mode_ma=0.0) is a real which defines the frequency of forcing on the outer boundary.

  • m_mode_ma (default m_mode_ma=0) is an integer which defines the wavenumber of the forced mode.

  • mode_symm_ma (default mode_symm_ma=0) is an integer which defines the symmetry of the forced mode. 0 is for an equatorially anti-symmetric mode while 1 is for an equatorially symmetric mode.

Inner Core Namelist

This namelist defines properties of the inner core

  • sigma_ratio (default sigma_ratio=0.0) is a real that defines the conductivity of the inner core with respect to the value of the outer core. sigma_ratio=0 thus corresponds to a non-conducting inner core.

  • nRotIc (default nRotIc=0) is an integer that defines the rotation of the inner core. Behaves the same way as nRotMa (above).

  • rho_ratio_ic (default rho_ratio_ic=1.0) is a real which defines the density of the inner core in terms of that of the outer core.

  • gammatau_gravi (default gammatau_gravi=0.0) is a real. It defines the amplitude of the gravitational torque between the mantle and the inner core following \(\Gamma_g = -\Gamma\tau(\omega_{ic}-\omega_{ma})\). When this is non zero the torque with the opposite sign is exerted on the mantle side.

  • BIC (default BIC=0.0) is a real which gives the imposed dipole field strength at the Inner Core Boundary. Having BIC > 0 implies that the inner core acts as a dipole magnet - as implemented in the DTS experiment at Grenoble, France.

  • Variables prescribing rotation rate of inner core The following variables are used to prescribe rotation rate of the inner core. They behave in the same way as the corresponding variables for the mantle. They are usd only when nRotIC=0.

As with the mantle, the resultant prescribed rotation rate for the inner core is computed as:

omega_ic = omega_ic1*cos(omegaOsz_ic1*(time+tShift_ic1)) + &
           omega_ic2*cos(omegaOsz_ic2*(time+tShift_ic2))

  • ellipticity_icb (default ellipticity_cmb=0.0) is a real which defines the ellipticity of the inner boundary. This is used together with omega_ic1 and omegaOsz_ic1 to represent the effect of a librating ellipsoidal boundary using a radial flow boundary condition.

The following, as for the mantle namelist, is for artificially exciting inertial modes in the spherical shell, but for the inner boundary.

  • amp_mode_ic (default amp_mode_ic=0.0) is a real which defines the amplitude of forcing on the inner boundary.

  • omega_mode_ic (default omega_mode_ic=0.0) is a real which defines the frequency of forcing.

  • m_mode_ic (default m_mode_ic=0) is an integer which defines the wavenumber of the forced mode.

  • mode_symm_ic (default mode_symm_ic=0) is an integer which defines the symmetry of the forced mode. 0 is for an equatorially anti-symmetric mode while 1 is for an equatorially symmetric mode.