HMI Vector Magnetic Field Data Products

The HMI instrument collects filtergrams in various wavelengths and polarizations sufficient to determine the Stokes parameters, I, Q, U, & V, every 90 seconds. The Stokes parameters are averaged in time and space to reduce the noise. Inversion is first performed to determine the magnetic field parameters, B-Total, Filling Factor, Inclination, and 180-degree Azimuth relative to the line of sight along with uncertainties on each quantity. These data are disambiguated to fully determine the azimuth. The method of computation may differ for quick-look and final data products and for full-disk and selected patches. Routines will be provided to export the data in useful heliographic coordinates, either rectilinear Bx, By, Bz for patches or for full-disk observations spherical coordinates, either Br, Btheta, Bphi or Br, inclination, and azimuth.

Vector Magnetic Field Modules