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| == HMI Magnetic Field Products == | = HMI Magnetic Field Products = |
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| Line-of-sight magnetic field will be computed from Doppler Velocity in two polarizations, as is done for MDI. | ||<|3> http://jsoc.stanford.edu/data/hmi/images/latest/HMI_latest_Mag_256x256.gif|| There are four basic types of magnetic field products described below. || || Some data products suitable for space weather applications are available in near real time. || || More details are provided at VectorMagneticField, LineofsightMagneticField, ["HARPDataSeries"], and SpaceWeatherProducts. || |
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| Vector Field will be computed from Stokes parameters derived from an independent set of polarized filtergrams. | ===== Line-of-sight Magnetograms ===== . LineofsightMagneticField : 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 fastest line-of-sight observing cadence is 45 seconds in which twelve filtergrams from the HMI Doppler camera are combined, one in each circular polarization at each of six wavelengths. A lower noise version is calculated every 720s using selected filtergrams from nine 135s vector field sequences from the other HMI camera. . The latest HMI images are available at http://jsoc.stanford.edu/data/hmi/images/latest/ |
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| After launch the possibility of combining the two cameras will be explored. | ===== Vector Magnetic Field Image Data ===== . VectorMagneticField : 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 135 seconds and uses images from HMI's Magnetic camera. The 36 filtergrams measure six polarization states, I plus or minus Q,U,and V, at the same six wavelengths. All filtergrams are corrected for instrumental effects and interpolated to the proper time. Most analysis is done with weighted averages computed every 720s using data collected over 1215 seconds (nine 135s intervals). The processing happens in three steps. First Stokes parameters are computed. Then an inversion is performed to determine the field and other plasma parameters. Finally disambiguation is performed to determine the field angles. |
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| The basic line-of-sight cadence is 45 seconds. The basic vector field cadence in 90 seconds. | ===== Synoptic Maps ===== . SynopticMaps : Synoptic maps are computed from the 720s line-of-sight magnetograms. Standard charts are assembled by combining the 20 observations made nearest central meridian at each longitude. It takes approximately 27.27 days to complete a solar rotation. Synoptic maps are provided in two resolutions and as line-of-sight and inferred radial field. Daily update charts insert data observed within 60 degrees of central meridian averaged over a 4-hour interval into the most recent synopic chart. |
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| 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 (relative to solar north . Magnetic line-of sight velocity |
===== SHARP - HMI Active Region Patches with Space Weather Quantities ===== . ["HARPDataSeries"] : A HARP provides location information about a magnetic active region throughout its disk passage. Each 720s line-of-sight magnetogram is analyzed to generate a mask that indicates coherent regions of strong activity. The time series of masks is analyzed to identify persistent active regions. After the region rotates off the disk, a definitive time series is created that provides consistent geometric information about the HARP from before its first emergence to after its dissappearance. HARPs are often associated with one or more NOAA active regions. The SHARP data series collects the mapped data for the region along with computed space-weather quantities. |
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| === Links to Currently Available Magnetogram Data === | |
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| ===== Module Inputs ===== . List inputs here ===== Module Outputs ===== . List outputs here ===== Cadence ===== . Indicate nominal cadence on which module is run ===== Archive ===== . Indicate if/when products are archived ===== Options ===== . Indicate if there are any options when running the code ===== Overall Status of Module ===== . Indicate estimate of percentage complete for the module ===== Status of Code ===== . Name heritage or percent complete for Basic Code ===== Status of DRMS module ===== . Indicate status of DRMS module version of module ===== Issues needing resolution ===== * List issues that still need to be resolved * Describe as many as you like ===== Responsible scientist ===== . Give name of local coordinator for development of this module ===== Remarks ===== |
|| '''Magnetic Image Data''' |||| Links to lookdata || || Line of sight Magnetograms || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.M_720s hmi.M_720s] || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.M_45s hmi.M_45s] || || Stokes Parameters || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.S_720s hmi.S_720s] || || || VFISV Inversion - ME || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.ME_720s_fd10 hmi.ME_720s_fd10] || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.ME_720s_fd10_nrt hmi.ME_720s_fd10_nrt] || || Disambiguated Vector B || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.B_720s_e15w1332_cutout hmi.B_720s_e15w1332_cutout] || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.B_720s_e15w1332_CEA hmi.B_720s_e15w1332_CEA] || || Obscure Data Products|||| Summary Information about Some ObscureDataProducts || |
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| === Links to Synoptic Maps === . HMI synoptic maps provide a composite view of the entire observable solar surface. They are computed from the 720s line-of-sight magnetic field measurements and come in 3600*1440 and 720*360 sizes. ||||||Standard HMI Photospheric Field Carrington Synoptic Maps || || Line of sight synoptic map || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Synoptic_Ml_720s hmi.Synoptic_Ml_720s] || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Synoptic_Ml_720s_small hmi.Synoptic_Ml_720s_small] || || Assumed Radial component of LoS map || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Synoptic_Mr_720s hmi.Synoptic_Mr_720s] || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Synoptic_Mr_720s_small hmi.Synoptic_Mr_720s_small] || ||||||DailySynopticMaps|| || Daily Update LoS Synoptic Map || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Mldailysynframe_720s hmi.Mldailysynframe_720s] || Soon: [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Mldailysynframe_720s_small hmi.Mldailysynframe_720s_small] || || Daily Update Radial Synoptic Map || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Mrdailysynframe_720s hmi.Mrdailysynframe_720s] || Soon: [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Mrdailysynframe_720s_small hmi.Mrdailysynframe_720s_small] || ||||||Daily NRT Synoptic Maps|| || Daily Update NRT Los Synoptic Map || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Mldailysynframe_720s_nrt hmi.Mldailysynframe_720s_nrt] || Soon: [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Mldailysynframe_720s_nrt_small hmi.Mldailysynframe_720s_nrt_small] || || Daily Update NRT Radial Synoptic Map || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Mrdailysynframe_720s_nrt hmi.Mrdailysynframe_720s_nrt] || Soon: [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Mrdailysynframe_720s_nrt_small hmi.Mrdailysynframe_720s_nrt_small] || === HMI Active Region Patches === A HARP (short for HMI Active Region Patch) is an enduring, coherent magnetic structure at the size scale of a solar active region. The primary purpose of the HARP data series is to provide the practical geometric information needed to follow an evolving region as it crosses the solar disk. A HARP is initially identified automatically in a sequence of HMI line-of-sight magnetograms. HARPs are typically observed over several days (possibly as long as a disk passage) and tracked from one image to the next. At each time step, the rectangular HARP bounding box is provided and a BITMAP that characterizes the pixels of the HARP is recorded. The bounding box encloses the maximum heliographic extent of the region during its life time. The BITMAP indicates which pixels in the box are part of the HMI active region patch and can be applied to an HMI image. Keywords provide summary information about the patch (e.g. the total line-of-sight magnetic flux) as well as geometric and heliographic specifics. The HARP information is being used to determine regions of interest for vector field inversion processing, both for past data (hmi.ME_720s_fd10) and for near real time processing (hmi.ME_720s_fd10_nrt). Near real time HARPs (hmi.Mharp_720s_nrt) are a little different than definitive HARPs because the entire history or each region is not known; NRT and definitive HARP numbers differ. See ["HARPDataSeries"] for details. || HARP Data Series || Definitive || NRT || || [http://sun.stanford.edu/~turmon/data/tracker-movies-notes/ Movie Description] ||[http://jsoc.stanford.edu/data/hmi/HARPs_movies/definitive Monthly Movies]||[http://jsoc.stanford.edu/data/hmi/HARPs_movies/nrt Daily Movies]|| || Line of Sight || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Mharp_720s hmi.Mharp_720s] ||[http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Mharp_720s_nrt hmi.Mharp_720s_nrt] || || Vector - ME || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.ME_720s_fd10 hmi.ME_720s_fd10] || [http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.ME_720s_fd10_nrt hmi.ME_720s_fd10_nrt] || |
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| * Back to ["HMIModuleTable"] | * Back to ["Lev1Doc"] |
HMI Magnetic Field Products
http://jsoc.stanford.edu/data/hmi/images/latest/HMI_latest_Mag_256x256.gif |
There are four basic types of magnetic field products described below. |
Some data products suitable for space weather applications are available in near real time. |
|
More details are provided at VectorMagneticField, LineofsightMagneticField, ["HARPDataSeries"], and SpaceWeatherProducts. |
Line-of-sight Magnetograms
LineofsightMagneticField : 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 fastest line-of-sight observing cadence is 45 seconds in which twelve filtergrams from the HMI Doppler camera are combined, one in each circular polarization at each of six wavelengths. A lower noise version is calculated every 720s using selected filtergrams from nine 135s vector field sequences from the other HMI camera.
The latest HMI images are available at http://jsoc.stanford.edu/data/hmi/images/latest/
Vector Magnetic Field Image Data
VectorMagneticField : 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 135 seconds and uses images from HMI's Magnetic camera. The 36 filtergrams measure six polarization states, I plus or minus Q,U,and V, at the same six wavelengths. All filtergrams are corrected for instrumental effects and interpolated to the proper time. Most analysis is done with weighted averages computed every 720s using data collected over 1215 seconds (nine 135s intervals). The processing happens in three steps. First Stokes parameters are computed. Then an inversion is performed to determine the field and other plasma parameters. Finally disambiguation is performed to determine the field angles.
Synoptic Maps
SynopticMaps : Synoptic maps are computed from the 720s line-of-sight magnetograms. Standard charts are assembled by combining the 20 observations made nearest central meridian at each longitude. It takes approximately 27.27 days to complete a solar rotation. Synoptic maps are provided in two resolutions and as line-of-sight and inferred radial field. Daily update charts insert data observed within 60 degrees of central meridian averaged over a 4-hour interval into the most recent synopic chart.
SHARP - HMI Active Region Patches with Space Weather Quantities
- ["HARPDataSeries"] : A HARP provides location information about a magnetic active region throughout its disk passage. Each 720s line-of-sight magnetogram is analyzed to generate a mask that indicates coherent regions of strong activity. The time series of masks is analyzed to identify persistent active regions. After the region rotates off the disk, a definitive time series is created that provides consistent geometric information about the HARP from before its first emergence to after its dissappearance. HARPs are often associated with one or more NOAA active regions. The SHARP data series collects the mapped data for the region along with computed space-weather quantities.
Links to Currently Available Magnetogram Data
Magnetic Image Data
Links to lookdata
Line of sight Magnetograms
[http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.M_720s hmi.M_720s]
[http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.M_45s hmi.M_45s]
Stokes Parameters
[http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.S_720s hmi.S_720s]
VFISV Inversion - ME
[http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.ME_720s_fd10 hmi.ME_720s_fd10]
[http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.ME_720s_fd10_nrt hmi.ME_720s_fd10_nrt]
Disambiguated Vector B
[http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.B_720s_e15w1332_cutout hmi.B_720s_e15w1332_cutout]
[http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.B_720s_e15w1332_CEA hmi.B_720s_e15w1332_CEA]
Obscure Data Products
Summary Information about Some ObscureDataProducts
Links to Synoptic Maps
- HMI synoptic maps provide a composite view of the entire observable solar surface. They are computed from the 720s line-of-sight magnetic field measurements and come in 3600*1440 and 720*360 sizes.
HMI Active Region Patches
A HARP (short for HMI Active Region Patch) is an enduring, coherent magnetic structure at the size scale of a solar active region. The primary purpose of the HARP data series is to provide the practical geometric information needed to follow an evolving region as it crosses the solar disk. A HARP is initially identified automatically in a sequence of HMI line-of-sight magnetograms. HARPs are typically observed over several days (possibly as long as a disk passage) and tracked from one image to the next. At each time step, the rectangular HARP bounding box is provided and a BITMAP that characterizes the pixels of the HARP is recorded. The bounding box encloses the maximum heliographic extent of the region during its life time. The BITMAP indicates which pixels in the box are part of the HMI active region patch and can be applied to an HMI image. Keywords provide summary information about the patch (e.g. the total line-of-sight magnetic flux) as well as geometric and heliographic specifics.
The HARP information is being used to determine regions of interest for vector field inversion processing, both for past data (hmi.ME_720s_fd10) and for near real time processing (hmi.ME_720s_fd10_nrt). Near real time HARPs (hmi.Mharp_720s_nrt) are a little different than definitive HARPs because the entire history or each region is not known; NRT and definitive HARP numbers differ.
See ["HARPDataSeries"] for details.
HARP Data Series
Definitive
NRT
[http://sun.stanford.edu/~turmon/data/tracker-movies-notes/ Movie Description]
[http://jsoc.stanford.edu/data/hmi/HARPs_movies/definitive Monthly Movies]
[http://jsoc.stanford.edu/data/hmi/HARPs_movies/nrt Daily Movies]
Line of Sight
[http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Mharp_720s hmi.Mharp_720s]
[http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.Mharp_720s_nrt hmi.Mharp_720s_nrt]
Vector - ME
[http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.ME_720s_fd10 hmi.ME_720s_fd10]
[http://jsoc.stanford.edu/ajax/lookdata.html?ds=hmi.ME_720s_fd10_nrt hmi.ME_720s_fd10_nrt]