Poloidal magnetic field potential at CMB

The cmb outputs controls the output of poloidal field potential coefficients at the CMB \(b_{\ell m}(r=r_o)\): B_coeff_cmb.TAG up to a maximum spherical harmonic degree l_max_cmb.

Note

This calculation is only enabled when l_cmb_field=.true. or when l_dt_cmb_field=.true..

Specific inputs

  • l_cmb_field (default l_cmb_field=.false.) is a logical. It needs to be turned on to get cmb files computed.

  • l_dt_cmb_field (default l_dt_cmb_field=.false.) is a logical. When set to .true., it allows the calculation of the secular variation of the magnetic field at the CMB.

  • l_max_cmb (default l_max_cmb=14) is an integer. This is the maximum spherical harmonic degree \(\ell\) stored in B_coeff_cmb.TAG, i.e. only \(\ell \leq \ell_{maxcmb}\) are stored. For example, the following input parameter means that the B_coeff_cmb.TAG file is stored up to a spherical harmonic degree of \(\ell\):

    l_cmb_field = .true.,
l_max_cmb   = 20,

Standard inputs

  • n_cmb_step (default n_cmb_step=0) is an integer. This is the number of timesteps between two cmb outputs.

  • n_cmbs (default n_cmbs=0) is an integer. This is the number of cmb outputs to be written.

  • t_cmb (default t_cmb=-1.0 -1.0 ...) is real array, which contains the times when cmb outputs are requested.

  • dt_cmb (default dt_cmb=0.0) is a real, which defines the time interval between cmb outputs.

  • t_cmb_start (default t_cmb_start=0.0) is a real, which defines the time to start writing cmb outputs.

  • t_cmb_stop (default t_cmb_stop=0.0) is a real, which defines the time to stop writing cmb outputs.

Poloidal and toroidal potentials at several depths

The coeff_r# outputs controls the output of the poloidal and toroidal potential coefficients at several depths up to a maximum spherical harmonic degree l_max_r. The files B_coeff_r#.TAG and V_coeff_r#.TAG are written when l_r_field=.true.. The file T_coeff_r#.TAG is written when l_r_fieldT=.true..

Note

This calculation is only enabled when l_r_field=.true. or when l_r_fieldT=.true..

Specific inputs

  • l_r_field (default l_r_field=.false.) is a logical. It needs to be turned on to get r_field files computed.

  • l_max_r (default l_max_r=l_max) is an integer. This is the maximum spherical harmonic degree \(\ell\) stored in the r_field file, i.e. only \(\ell \leq \ell_{maxcmb}\) are stored.

There are two ways to specify the radial grid points where you want to store the [B|V|T]_coeff_r#.TAG files. You can either specify a stepping n_r_step: in that case 5 coeff_r#.TAG files will be stored at 5 different radial levels every n_r_step grid point:

l_r_field = .true.,
n_r_step  = 6,
l_max_r   = 30,

This will produces 5 files that contain the poloidal and toroidal potentials up to spherical harmonic degree \(\ell=30\):

  • [B|V|T]_coeff_r1.TAG corresponds to the radial grid point with the index nR=6.

  • [B|V|T]_coeff_r2.TAG to nR=12.

  • [B|V|T]_coeff_r3.TAG to nR=18.

  • [B|V|T]_coeff_r4.TAG to nR=24.

  • [B|V|T]_coeff_r5.TAG to nR=30.

  • n_r_step (default n_r_step=2) is an integer. This specifies the number of radial levels between two consecutive [B|V|T]_coeff_r#.TAG files.

Alternatively, the input array n_r_array can be used to specify the radial grid points you exactly want to store:

l_r_field = .true.,
n_r_array = 8, 24, 47,
l_max_r   = 10,

This will produces 3 files that contain the poloidal and toroidal potentials up to spherical harmonic degree \(\ell=10\):

  • [B|V|T]_coeff_r1.TAG corresponds to the radial grid point with the index nR=8.

  • [B|V|T]_coeff_r2.TAG to nR=24.

  • [B|V|T]_coeff_r3.TAG to nR=47.

  • n_r_array (default n_r_array=0 0 0 ...) an array of integers. You can specify the radial grid points (starting from n_r_cmb=1) where you want to store the coefficients.

Standard inputs

  • n_r_field_step (default n_r_field_step=0) is an integer. This is the number of timesteps between two r_field outputs.

  • n_r_fields (default n_r_fields=0) is an integer. This is the number of r_field outputs to be written.

  • t_r_field (default t_r_field=-1.0 -1.0 ...) is real array, which contains the times when r_field outputs are requested.

  • dt_r_field (default dt_r_field=0.0) is a real, which defines the time interval between r_field outputs.

  • t_r_field_start (default t_r_field_start=0.0) is a real, which defines the time to start writing r_field outputs.

  • t_r_field_stop (default t_r_field_stop=0.0) is a real, which defines the time to stop writing r_field outputs.