SO/PHI Data Releases

April 11, 2024

Author: Jonas Sinjan

This page contains the history of the official data releases to the Solar Orbiter Archive (SOAR) and information for publishing.

Publishing Information

Description: The following paragraphs contain information for those preparing publications wherein SO/PHI data contributes in any way.

If any publications are produced to which SO/PHI data contribute in any way, we would be request you to cite the relevant instrument paper:

Solanki, S. K., del Toro Iniesta, J. C., Woch, J., et al. 2020, A&A, 642, A11, DOI: 10.1051/0004-6361/201935325;

For papers including SO/PHI-HRT data, please also add:

Gandorfer, A. M., Grauf, B., Staub, J., et al. 2018, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Vol. 10698, Space Tele-scopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave,1403–1415, DOI: 10.1117/12.2311816.

Please also add the following acknowledgment:

“Solar Orbiter is a space mission of international collaboration between ESA and NASA, operated by ESA. We are grateful to the ESA SOC and MOC teams for their support. The German contribution to SO/PHI is funded by the BMWi through DLR and by MPG central funds. The Spanish contribution is funded by AEI/MCIN/10.13039/501100011033/ and European Union “NextGenerationEU”/PRTR” (RTI2018-096886-C5, PID2021-125325OB-C5, PCI2022-135009-2, PCI2022-135029-2) and ERDF “A way of making Europe”; “Center of Excellence Severo Ochoa” awards to IAA-CSIC (SEV-2017-0709, CEX2021-001131-S); and a Ramón y Cajal fellowship awarded to DOS. The French contribution is funded by CNES.”

The data are public and there is no requirement to include SO/PHI team members as co-authors. However, we appreciate if key members of the PHI team are included on publications based to a significant extent on SO/PHI data.

We also would appreciate receiving a copy of any publication you produce that profits from SO/PHI data.

We would be glad if you can report to us about any problem or issue encountered in using SO/PHI data. Please contact sophi_support [at] mps.mpg.de

Further information is given at: https://www.mps.mpg.de/solar-physics/solar-orbiter-phi

An overview of the released data, including quick look thumbnails and information about the quality of each released data set, is available here. We suggest consulting that web site before using the data set for scientific applications.

HRT (High Resolution) Data

1^st Data Release: December 2022

Description: All available HRT observations of RSW 1 and RSW 2, L2 data level, version 01.

General information about the RSW 1 and 2 can be found in the Solar Orbiter Confluence webpage.

The version of the HRT Pipeline is: v1.5 September 2nd 2022.

The data are fully reduced (see Sinjan et al., 2022) and corrected for optical aberrations (see Kahil et al., 2022, 2023). However, reconstruction for diffraction at the entrance pupil is not applied. Only L2 data are released, more info about them can be found in Data Format.

Notes: ISS is off, HRT polarization images are co-registered before demodulation.

2^nd Data Release: July 2023

Description: L2 SO/PHI-HRT datasets from RSW 3, 4, and 5 (version 1).

General information about the RSW 3-5 can be found in the Solar Orbiter Confluence webpage.

The data are fully reduced (see Sinjan et al., 2022). The version of the HRT Pipeline is: v1.7.0 May 15th 2023.

All datasets are corrected for optical aberration, however, reconstruction for diffraction at the entrance pupil is not applied. The quality of the correction is variable, depending on the availability of suitable phase-diversity calibration files (not always available mostly due to off-pointing). In some cases, improvement to processing is to be expected from forthcoming acquisitions of new calibration datasets and updated observational procedures (see Kahil et al., 2023).

For the above reason, at this point in time only part of the data is released to SOAR. The criteria for SOAR upload is that either data are properly calibrated, or it is not expected that the calibration will improve in the near future. Nevertheless, the data are in a state suitable for scientific exploitation. The datasets uploaded to SOAR are part of the following SOOPs:

RSW 3: Nanoflare, Polar (first instance), AR_Long_Term
RSW 4: RS_ Bursts (both instances), Connection_Mosaic
RSW 5: AR_Long_Term

The remaining data, including the whole RSW 6, will be uploaded to SOAR as soon as better calibrations are attained.

In general, all standard observables are released, as described in https://www.mps.mpg.de/solar-physics/solar-orbiter-phi/data

Some artefacts may impact significantly in particular on vlos. In such cases, vlos is not released at this point in time.

3^rd Data Release: September 2024

Description: L2 SO/PHI-HRT datasets from RSW 7, 8, 10, 11, and 12 (version 1).

General information about the RSW 7-8 can be found in the Solar Orbiter Confluence webpage.

General information about the RSW 10-12 can be found in the Solar Orbiter Confluence webpage.

The data are fully reduced (see Sinjan et al., 2022). The version of the HRT Pipeline is: v1.8.7 August 29th 2024.

The on-ground processing pipeline includes correction for optical aberration. However, reconstruction for diffraction at the entrance pupil is not applied. The quality of the correction is variable, depending on the availability of suitable phase-diversity calibration files (not always available, mostly due to off-pointing) and on the status of the instrument across the orbit (see Kahil et al., 2023 and Bailén et al., 2024). Only the continuum is used for the flat field correction, while a cavity-map based wavelength correction is applied and a cross-talk correction which allows a variation of the cross-talk along the image (2D plane) to account for a gradient over the field of view (FoV). The RTE inversion is applied with different input parameters and polarimetric weights depending on whether the pixel is considered magnetically active or not.

At this point in time almost all, but not quite all of the data is released to SOAR. The criteria for SOAR upload is that either data are properly calibrated, or it is not expected that the calibration will improve in the near future. Nevertheless, the data are in a state suitable for scientific exploitation. The datasets uploaded to SOAR belong to the following SOOPs:

RSW 7: Full Disk Mosaic, Composition Mosaic, RS-burst, Slow Wind Connection
RSW 8: Nanoflares (4 instances), Bright Points, Sunspot Oscillations, RS-burst (2 instances), Connection Mosaic
RSW 10: RS-burst (2 instances), Connection Mosaic, Fast Wind
RSW 11: AR_Long_Term, Polar Observation, Atmospheric Dynamics Structure, CH Boundary Expansion
RSW 12: Fast Wind, Full Disk Mosaic, AR Heating (5 instances), Sunspot Oscillations, Bright Points, Polar Observation

The remaining data will be uploaded to SOAR as soon as better calibrations are attained. This includes the Polar Observation (RSW 7), Probe Quadrature (RSW 10), Earth Quadrature (RSW 10) SOOPs.

All standard observables are released, as described in https://www.mps.mpg.de/solar-physics/solar-orbiter-phi/data

FDT (Full Disk) Data

1st Data Release: October 2023

Description: L2 SO/PHI-FDT datasets from 31 January 2022 until 20 September 2022 and 27 October until 11 December 2022.

All datasets have been processed with the on-ground FDT pipeline, and are corrected for ghost and fringe artefacts. In addition, a polarimetric crosstalk correction that allows a variation of the crosstalk along the image (2D plane), to account for a gradient over the disk, was applied. In spite of these corrections, weak residual signatures of ghost and fringe artefacts, which are most pronounced in Stokes U, remain. In some cases a ringing around active regions in Stokes Q leads to slightly stronger fringes in the azimuth and in rare cases in the B field magnitude. In B, a remnant of the filtergraph cavity map affects all datasets. Finally, depending on the available calibration observations, it is not always possible to remove the effect of a dust grain present in the optical path and defects of the Etalon (mostly showing as dots in the continuum images).

For the above reason, at this point in time only the continuum intensity (observable identifier: icnt, computed by the RTE inversion) and the longitudinal magnetic field (observable identifier: blos, computed from magnitude and inclination) data are released to SOAR. The criteria for release to SOAR is that the data are of high enough quality to be suitable for scientific exploitation.

The other observables, including the measured continuum as well as the full vector magnetic field data and the Stokes L2 parameters of the released time range, need to be treated with caution for scientific studies.

In order to access the observables currently not released to SOAR we warmly invite you to get in touch with the PHI team (sophi_support@mps.mpg.de).

The datasets uploaded to SOAR are part of the synoptics programs, which had been run in LTP 6 (before and after the RSWs), LTP 7, LTP 8, and LTP 9 (see here for details on LTPs). In addition, the uploaded data is part of the following SOOPs of LTP9:

RSW 5: CH_Boundary_Expansion
RSW 6: Eruption Watch, AR heating

2^nd Data Release: April 2024

Description: L2 SO/PHI-FDT datasets from 26 December 2022 until 31 December 2023.

All datasets have been processed with the on-ground FDT pipeline, and are corrected for ghost and fringe artefacts. In addition, a polarimetric crosstalk correction that allows a variation of the crosstalk along the image (2D plane), to account for a gradient over the disk, was applied. In spite of these corrections, weak residual signatures of ghost and fringe artefacts, which are most pronounced in Stokes U, remain. In some cases, a ringing around active regions in Stokes Q leads to slightly stronger fringes in the azimuth and in rare cases in the B field magnitude. In B and the LOS velocity maps, a remnant of the filtergraph cavity map affects all datasets.

SO/PHI is the only magnetograph on a deep space mission. The artefacts that affect data until the end of January 2023 are the result of the extreme physical conditions that SO/PHI experiences during high radial S/C velocity. In most cases, the main visible effects are a shift of the spectral line and the appearance of small round artefacts in the filtergraph, particularly visible in the LoS velocity. Although not unforeseen, the detailed way in which orbital conditions affect observations could be quantified only in flight. In the meantime, countermeasures to limit such negative effects have been put in place, and we do not expect to have such strong artefacts in the forthcoming data. The presence of two dust grains in Icnt cannot be corrected completely.

For the above reasons, at this point in time only the continuum intensity (observable identifier: icnt, computed by the RTE inversion) and the longitudinal magnetic field (observable identifier: blos, computed from magnitude and inclination) data are released to SOAR. The criteria for release to SOAR is that the data are of high enough quality to be suitable for scientific exploitation.

The other observables, including the measured continuum as well as the full vector magnetic field data, the LOS velocity maps and the Stokes L2 parameters of the released time range, need to be treated with caution for scientific studies. Therefore, in case of interest, we warmly invite you to get in touch with the PHI team (sophi_support@mps.mpg.de) in order to access the observables currently not released to SOAR.

The datasets uploaded to SOAR are part of the synoptic programs which had been run in Long Term Plannings (LTPs) 10 to 13 (see here for details on LTPs), as well as during the encompassed Remote Sensing Windows (RSWs) 7 to 9 and 10 to 12.

3rd Data Release: January 2025

Description: L2 SO/PHI-FDT datasets from 1 January 2024 until 28 December 2024.

All datasets have been processed with the on-ground FDT pipeline, and are corrected for ghost and fringe artefacts. In addition, a polarimetric crosstalk correction that allows a variation of the crosstalk along the image (2D plane), to account for a gradient over the disk, was applied. In spite of these corrections, weak residual signatures of ghost and fringe artefacts, which are most pronounced in Stokes U, remain. In some cases, a ringing around active regions in Stokes Q leads to slightly stronger fringes in the azimuth and in rare cases in the B field magnitude. In B and the LOS velocity maps, a remnant of the filtergraph cavity map affects all datasets.

SO/PHI is the only magnetograph on a deep space mission, and, as such, it is affected by severe telemetry limitations. This, in combination with the extreme variation of observing conditions on the highly elliptical orbit of SO, makes it challenging to have suitable calibration information for all datasets. As a result, some datasets are still affected by the imperfect removal of artifacts, such as dust grains or etalon cavity residuals.

The datasets uploaded to SOAR are part of the synoptic programs which had been run in Long Term Plannings (LTPs) 14 to 17 (see here for details on LTPs), as well as during the encompassed Remote Sensing Windows (RSWs) 13 to 15 and 16 to18.