• VectorMagneticField

HMI Vector Magnetic Field Data Products

Overview of Vector Field Pipeline

The HMI instrument collects filtergrams in various wavelengths and polarizations sufficient to determine the Stokes parameters, I, Q, U, & V, as rapidly as every 90 seconds. Level1 filtergrams are interpolated in time and corrected for solar rotation as they are averaged in time to reduce 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, for full-disk and selected patches, and for strong and weak field regions. A module will exist to merge the various methods. Routines will be provided to export the data in useful heliographic coordinates, either in rectilinear {Bx, By, Bz} for patches or for full-disk observations in spherical coordinates, either {Br, Btheta, Bphi} or {Br, inclination, and azimuth}. Data can also be exported after remapping to standard synoptic or synchronic map coordinates. Averaging vector field maps in time and/or space can also be accomplished.

These data will be combined to produce Carrington charts, synoptic maps, and synchronic frames of the vector field components. A long-term estimate of the polar field will be available for applications requiring global coverage.

From the photospheric data various products and models will be computed, including local and global harmonic coefficients, global potential field - source surface models, global and local magnetostatic models (including NLFFF on patches), global and local MHD models of various types.

Methods for tracking surface features will include local correlation tracking, ILCT, and DAVE4M. Interfaces to other models will be provided as practical.

Near real time SpaceWeatherProducts will be produced from quick look data. These will include indices calculated for the full disk and patches of interest.

Status of various modules can be found in the ["HMIModuleTable"]

Vector Magnetic Field Modules

• ["TimeAverage_IQUV"]

• ["StokesInversion"]

• ["FieldDisambiguation"]

• ["MergingPatches"]

• ["BxByBzTransform"]

• ["BrBtBpTransform"]

• ["BrInAzTransform"]

• ["VectorB_Remap"]
• ["VectorBSpatialAverage"]
• ["VectorBTemporalAverage"]

• ["CarringtonSynopticChart"]

• ["SynchronicFrame"]

• ["DailySynchronicUpdate"]

• ["VectorSynchronicMap"]

• ["PolarFieldExtrapolation"]

• ["MagneticHarmonicCoefficients"]

• ["PotentialField-SourceSurface"]

• ["PotentialField-Local"]

• ["NonLinearForceFreeField"]

• ["InferredHorizontalFlow-Local"]

• ["InferredHorizontalFlow-Global"]

• ["SolarWindModel"]

• ["ModelDynamicActiveRegions"]

• ["ModelDynamicCorona"]

• ["ModelHeliosphericConditions"]

• ["Model3DARField"]

• ["SpaceWeatherProducts-Local"]

• ["SpaceWeatherProducts-Global"]

Associated HMI Pipeline Modules

• ["FeatureRecognition"]

• ["SpatialAverage"]

Line of Sight Magnetic Field Modules

• ["B_LOS-Stokes"]
• ["B_LOS-Average"]
• ["B_LOS-Remap"]
• ["B_LOS-Remap_and_Average"]

• ["B_LOS-CarringtonMap"]

• ["B_LOS-SynchronicFrame"]

• ["B_LOS-DailySynchronicMap"]

• ["B_LOS-MDI_Emulation"]

• ["HMI_MeanField"]

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