Data Description
The images show the Low-Latency (LL02) line-of-sight magnetic field
(Blos) and the continuum intensity (Icnt) obtained by the Full Disk
Telecope (FDT) of the Polarimetric and Helioseismic Imager onboard
Solar Orbiter (SO/PHI). LL02 data are produced from onboard-processed,
spectropolarimetric reconstructions of the Stokes profiles sampled at
6 points in the 617.3nm Fe-I absorption line and the nearby continuum.
LL02 are primarily produced as a support for Solar Orbiter's high-resolution
observation campaigns. However, given their unique value for space weather
predictions, they are now produced on a daily base, compatibly with
spacecraft operations.
Data Limitations
The LL are of lower quality than the regular SO/PHI science data in a
number of aspects. First, the LL02 are only roughly flat- and
dark-corrected. This may result in an imperfect calibration, and
residual artifacts. An example of such residual artifacts is a dust
grain that is often not properly removed: this can be easily
recognized as a black/white speck a few pixel wide in the continuum
image that has no correspondent magnetic field concentration. Second,
the inversion method that we use onboard for the LL02 data is a
center-of-gravity method rather than the Milne-Eddington inversion
that we use for science-grade data. Third, some of the methods to
remove optical artifacts that are available in the on-ground processing
pipeline are not yet available onboard (fringes, ghost, and cavity map
corrections). Last, the LL02 are often downlinked at high compression
rates for telemetry reason, which increases the noise with respect to
regular science data.
Data Usage
LL02 data are not of scientific quality and are provided in
good faith by the SO/PHI team for use
only in making real-time space weather predictions. More information
on regular, level2 (L2), released science-grade PHI data can be found
at https://www.mps.mpg.de/solar-physics/solar-orbiter-phi/data-releases.
Additional Information
For additional information on the SO/PHI
instruments (the Full disk Telescope and the High Resolution
Telescope), the available data, references, and acknowledgement
policy, please refer to the SO/PHI web page
https://www.mps.mpg.de/solar-physics/solar-orbiter-phi. Please,
address any question on SO/PHI observations to sophi_support@mps.mpg.de