Dopplergrams are maps of solar surface velocity. The HMI (Camera 2) instrument takes 72 filtergrams to construct a single dopplergram. Six filtergrams are taken in six positions across the nominal 6173.3 Å spectral line; each filtergram is taken in two polarization states (right circularly polarized (RCP), or Stokes I-V, and left circularly polarized (LCP), or I+V). Assuming that the absorption line is a Gaussian and that the HMI filter transmission profiles are delta functions, the Fourier coefficients can be calculated and are then used to estimate the line-of-sight magnetic field strength B.
Version:2.7.1
Version:2.7.1
Dopplergrams are maps of solar surface velocity. The HMI (Camera 2) instrument takes 72 filtergrams to construct a single dopplergram. Six filtergrams are taken in six positions across the nominal 6173.3 Å spectral line; each filtergram is taken in two polarization states (right circularly polarized (RCP), or Stokes I-V, and left circularly polarized (LCP), or I+V). Assuming that the absorption line is a Gaussian and that the HMI filter transmission profiles are delta functions, the Fourier coefficients can be calculated and are then used to estimate the line-of-sight magnetic field strength B.
| Role | Person | StartDate | StopDate | Note | |
|---|---|---|---|---|---|
| 1. | PrincipalInvestigator | spase://SMWG/Person/Philip.H.Scherrer | |||
| 2. | GeneralContact | spase://SMWG/Person/Rick.Bogart |
The HelioData dataset page provides an overview of the dataset with access links, associated variables, and more.
Change the date and the time to find the HMI data.
VSO path to JSOC-resident SDO HMI data files
Line-of-sight velocity
Array size: 4096x4096
Pixel Resolution: 0.504 arcsec