The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Optimization of the Spectral Line Inversion Code

Centeno, R.; Schou, J.; Hayashi, Keiji; Norton, A. A.; Hoeksema, J. T.; Liu, Y.; Leka, K. D.; Barnes, G.

doi:10.1007/s11207-014-0497-7

Cited by 107 publications

(113 citation statements)

References 17 publications

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“…The fd10 version of the code described in this article and in more detail in Centeno et al (2013) has been run on all HMI full-disk vector field data since 1 May 2010.…”

Section: Discussionmentioning

confidence: 99%

“…The Very Fast Inversion of the Stokes Vector (VFISV) is a ME spectral line inversion code specifically designed to infer the vector magnetic field of the solar photosphere from HMI Stokes measurements Centeno et al, 2013). VFISV uses a Levenberg-Marquardt least-squares minimization (Press et al, 1992) of a χ 2 function.…”

Section: Milne-eddington Inversionmentioning

confidence: 99%

“…The HMI team has derived optimal settings for the pipeline processing to improve the speed and general performance of the code. These changes to the original VFISV code are described in detail in Centeno et al (2013). Some of the significant changes include a) a regularization term added to the χ 2 minimization merit function to bias the solution towards the more physical solution when encountering two nearly degenerate minima, b) an adjustment to the relative weighting applied to the Stokes parameters I Q U V, c) implementation of tailored iteration and exit criteria that results in an average of ∼ 30 iterations per pixel, d) use of a spectral line synthesis module that computes the full radiative transfer solution only for the inner wavelength range of the HMI spectral line, and e) a simpler initial-guess scheme that does not use a neural net.…”

Section: Milne-eddington Inversionmentioning

confidence: 99%

“…The current data that are generated are labeled fd10. Section 4 of this article gives a brief description of the fd10 pipeline processing, but an in-depth description can be found in Centeno et al (2013) and Barnes et al (2014). This Appendix briefly summarizes the differences between the processing that generated the e15w1332 data and the current pipeline that generates the fd10 and SHARP data:…”

Section: A4 Data Segment Disambigmentioning

confidence: 99%

“…Such an inversion can be computationally intensive. Section 4 briefly describes how the fd10 version of the VFISV code Centeno et al, 2013) based on a relatively simple Milne-Eddington atmosphere has been adapted and optimized for use in the HMI pipeline. All images since 1 May 2010 have been processed using a version of fd10 (data series: hmi.ME_720s_fd10).…”

Section: Introductionmentioning

confidence: 99%

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The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Overview and Performance

et al. 2014

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The Helioseismic and Magnetic Imager (HMI) began near-continuous full-disk solar measurements on 1 May 2010 from the Solar Dynamics Observatory (SDO). An automated processing pipeline keeps pace with observations to produce observable quantities, including the photospheric vector magnetic field, from sequences of filtergrams. The basic vector-field frame list cadence is 135 seconds, but to reduce noise the filtergrams are combined to derive data products every 720 seconds. The primary 720 s observables were released in mid-2010, including Stokes polarization parameters measured at six wavelengths, as well as intensity, Doppler velocity, and the line-of-sight magnetic field. More advanced products, including the full vector magnetic field, are now available. Automatically identified HMI Active Region Patches (HARPs) track the location and shape of magnetic regions throughout their lifetime.The vector field is computed using the Very Fast Inversion of the Stokes Vector (VFISV) code optimized for the HMI pipeline; the remaining 180 • azimuth ambiguity is resolved with the Minimum Energy (ME0) code. The Milne-Eddington inversion is performed on all full-disk HMI observations. The disambiguation, until recently run only on HARP regions, is now implemented for the full disk. Vector and scalar quantities in the patches are used to derive active region indices potentially useful for forecasting; the data maps and indices are collected in the SHARP data series, hmi.sharp_720s. Definitive SHARP processing is completed only after the region rotates off the visible disk; quick-look products are produced in near real time. Patches are provided in both CCD and heliographic coordinates.HMI provides continuous coverage of the vector field, but has modest spatial, spectral, and temporal resolution. Coupled with limitations of the analysis and interpretation techniques, effects of the orbital velocity, and instrument performance, the resulting measurements have a certain dynamic range and sensitivity and are subject to systematic errors and uncertainties that are characterized in this report.

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“…The fd10 version of the code described in this article and in more detail in Centeno et al (2013) has been run on all HMI full-disk vector field data since 1 May 2010.…”

Section: Discussionmentioning

confidence: 99%

Section: Milne-eddington Inversionmentioning

confidence: 99%

Section: Milne-eddington Inversionmentioning

confidence: 99%

Section: A4 Data Segment Disambigmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Overview and Performance

et al. 2014

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Inferring Currents from the Zeeman Effect at the Solar Surface

Barnes

Leka

2018

Electric Currents in Geospace and Beyond

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The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: SHARPs – Space-Weather HMI Active Region Patches

et al. 2014

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A new data product from the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) called Space-weather HMI Active Region Patches (SHARPs) is now available. SDO/HMI is the first space-based instrument to map the fulldisk photospheric vector magnetic field with high cadence and continuity. The SHARP data series provide maps in patches that encompass automatically tracked magnetic concentrations for their entire lifetime; map quantities include the photospheric vector magnetic field and its uncertainty, along with Doppler velocity, continuum intensity, and line-of-sight magnetic field. Furthermore, keywords in the SHARP data series provide several parameters that concisely characterize the magnetic-field distribution and its deviation from a potential-field configuration. These indices may be useful for active-region event forecasting and for identifying regions of interest. The indices are calculated per patch and are available on a twelveminute cadence. Quick-look data are available within approximately three hours of observation; definitive science products are produced approximately five weeks later.

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The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Optimization of the Spectral Line Inversion Code

Cited by 107 publications

References 17 publications

The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Overview and Performance

The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Overview and Performance

Inferring Currents from the Zeeman Effect at the Solar Surface

The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: SHARPs – Space-Weather HMI Active Region Patches

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