Export And Metrics Reference

Export Metrics

Metric	Output Key(s)	Description
j	j	Current-density magnitude |J|.
j_vec	j_vec	Current-density vector.
alpha	alpha	Force-free alpha, computed as (J . B) / |B|^2.
b_nabla_bz	b_nabla_bz	Vertical magnetic tension-related derivative.
energy	energy	Magnetic energy density.
energy_gradient	energy_gradient	Cartesian vertical magnetic-energy gradient.
spherical_energy_gradient	spherical_energy_gradient	Spherical radial magnetic-energy gradient.
free_energy	free_energy	Cartesian free magnetic energy density using the default potential-field method.
free_energy_fft	free_energy_fft	Free magnetic energy density using the Cartesian FFT potential field.
free_energy_direct	free_energy_direct	Free magnetic energy density using the direct potential-field method.
magnetic_helicity	magnetic_helicity	Magnetic helicity diagnostic.
los_trv_azi	los_trv_azi	LOS/transverse/azimuth field components.
squashing_factor	squashing_factor, twist	Squashing factor and twist diagnostics.

Quality Metrics

Metric	Description
mean_abs_divB	Mean absolute divergence in G/Mm.
rms_divB	Root-mean-square divergence in G/Mm.
mean_abs_divB_over_B	Mean |div B| / |B| in 1/Mm.
rms_divB_over_B	Root-mean-square |div B| / |B| in 1/Mm.
theta_J	Current-weighted angle between J and B in degrees.
sigma_J	Current-weighted sine of the J-B angle.
CWsin	Alias for sigma_J used in NLFF comparisons.
mean_force_free_residual	Mean |J x B| / |B|.
rms_force_free_residual	Root-mean-square |J x B| / |B|.
E_tot	Total magnetic energy.
E_free	Free magnetic energy. Cartesian uses the FFT potential-field reference.
E_pot	Potential magnetic energy estimate E_tot - E_free.
E_free_over_E_tot	Free-energy fraction.
mean_B	Mean magnetic-field strength.
max_B	Maximum magnetic-field strength.