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| Line-of-sight magnetic field, hmi.M, is computed from Doppler Velocity in two polarizations, as is done for MDI. | 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. |
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| Vector Field, hmi.B, will be computed from Stokes parameters derived from an independent set of polarized filtergrams. | 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. |
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| The possibility of combining filtergrams from the two cameras will be explored. | |
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| After launch the possibility of combining 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 |
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| The basic line-of-sight cadence is 45 seconds. The basic vector field cadence in 90 seconds. Vector field data products will be the following quantities and uncertainties on each . |B| - total flux . Filling factor . Inclination (gamma) to the line of sight . Azimuth (phi) relative to solar north . Magnetic line-of sight velocity |
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| ==== Science Data Products ==== Pipeline . 45 - second . Blos on full disk . Vlos on full disk . Continuum intensity on full disk |
==== 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) |
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| . Inverted vector B on full disk (TBD) . Disambiguated B in patches . 3 - hour . Disambiguated B on full disk |
. 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) |
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| . 3-second filtergram | . 3-second filtergrams |
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| . 90-second disambiguated patches . 90-second IQUV |
. 135-second disambiguated patches . 135-second Stokes Vectors |
HMI Magnetic Field 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