HMI Magnetic Field Products
Synoptic Maps Available
- HMI synoptic maps are available. They are computed from the 720s line-of-sight magnetic field measurements and come in 3600*1440 and 720*360 sizes.
Line of sight synoptic map
hmi.Synoptic_Ml_720s
hmi.Synoptic_Ml_720s_small
Assumed Radial component of LoS map
hmi.Synoptic_Mr_720s
hmi.Synoptic_Mr_720s_small
General Description of HMI Magnetic Field Data Products
The line-of-sight magnetic field, hmi.M, is computed from the difference of the Doppler velocities observed in two circular polarizations, as was done for MDI. The filtergrams are obtained by the Doppler camera on HMI. The basic line-of-sight observing cadence is 45 seconds.
The vector magnetic field, hmi.B, is computed from Stokes parameters derived from an independent set of polarized filtergrams. The basic vector field observing cadence is currently 135 seconds and uses HMI's Magnetic camera. Most analysis is done with 720s averages.
The possibility of combining filtergrams from the two cameras will be explored.
Vector field data products include the following quantities (and at least 23 others, including uncertainties)
- |B| - total flux
- Inclination (gamma) to the line of sight
- Azimuth (phi) relative to 'up' on the CCD
- Magnetic line-of sight velocity
Data will be exported in a variety of coordinate systems: [Bx,By,Bz], [B_total,gamma,phi], and [Br,Btheta,Bphi]
More detail is provided at VectorMagneticField and LineofsightMagneticField and SpaceWeatherProducts.
Selected HMI Science Data Products
Standard Pipeline
- 45-second - full disk
- Blos (hmi.M_45s)
- Vlos (hmi.V_45s)
- Continuum intensity (hmi.Ic_45s), line depth (hmi.Ld_45s), and line width (hmi.Lw_45s)
- 12 - minute
- Line-of-sight magnetic field (hmi.M_720s)
- Doppler velocity (hmi.V_720s)
- Continuum intensity (hmi.Ic_720s), line depth (hmi.Ld_720s), and line width (hmi.Lw_720)
- Stokes vector (hmi.S_720s), the IQUV values at each of 5 wavelengths
- Inverted Vector Field (hmi.ME_720s) VFISV - Milne-Eddington Inversion (not yet released)
- Disambiguated Vector Field (patches), hmi.Bharp_720s (not yet released)
- 3 (TBD) - hour
- Disambiguated B on full disk, hmi.B (not yet released)
On Demand
- 3-second filtergrams
- 3-minute vector B on patches
- 6-minute disambiguated patches
- 12-minute full-disk disambiguated vector field
On Request
- 135-second disambiguated patches
- 135-second Stokes Vectors
- Anything else