Design and Ground Calibration of the Helioseismic and Magnetic Imager (HMI) Instrument on the Solar Dynamics Observatory (SDO)

Schou, J.; Scherrer, P. H.; Bush, R. I.; Wachter, R.; Couvidat, S.; Rabello-Soares, M. C.; Bogart, R. S.; Hoeksema, J. T.; Liu, Y.; Duvall, T. L.; Akin, D. J.; Allard, B. A.; Miles, John W.; Rairden, R. L.; Shine, R. A.; Tarbell, T. D.; Title, A. M.; Wolfson, C. J.; Elmore, D.; Norton, A. A.; Tomczyk, S.

doi:10.1007/s11207-011-9842-2

Cited by 1,744 publications

(773 citation statements)

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“…The HMI instrument design and planned processing scheme are described by Schou et al (2012b) and Scherrer et al (2012). The SDO mission, launched 11 February 2010, is described by Pesnell, Thompson, and Chamberlin (2012).…”

Section: The Hmi Instrument and Data Flowmentioning

confidence: 99%

“…To perform this conversion the polarimetric model described in Schou et al (2012b) is used, including the corrections that depend on the front window temperature and the polarization selector temperature. At each point in the image a least-squares fit is then performed to derive I Q U V from the six observed polarization states.…”

Section: Stokes Vector Processing Descriptionmentioning

confidence: 99%

“…The Helioseismic and Magnetic Imager (HMI, Schou et al, 2012b) provides the first uninterrupted time series of space-based, full-disk, vector magnetic field observations of the Sun with a 12-minute cadence. This report summarizes the HMI vector magnetic field analysis pipeline, provides an assessment of the quality of the vector data, and characterizes some of the known uncertainties and systematic errors.…”

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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Section: The Hmi Instrument and Data Flowmentioning

confidence: 99%

Section: Stokes Vector Processing Descriptionmentioning

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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“…Figure 1(a) shows the G-band image of the region taken with Hinode/SOT. Contours in Figure 1(b) indicate the line-of-sight magnetic fields observed with Helioseismic and Magnetic Imager (HMI; Schou et al, 2012) onboard the Solar Dynamic Observatory (SDO; Pesnell, Thompson, and Chamberlin, 2011) superposed on the continuum image from SDO/HMI. It can be seen that the preceding sunspot had a negative polarity and the following sunspot groups had a positive polarity.…”

Section: Observation and Analysismentioning

confidence: 99%

FISS Observations of Vertical Motion of Plasma in Tiny Pores

et al. 2013

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Pores can be exploited for the understanding of the interaction between smallscale vertical magnetic field and the surrounding convective motions as well as the transport of mechanical energy into the chromosphere along the magnetic field. For better understanding of the physics of pores, we investigate tiny pores in a new emerging active region (AR11117) that were observed and the Ca II 8542 Å line simultaneously taken by the FISS. The coordinated observation reveals that the pores are filled with plasma which moves down slowly and are surrounded by stronger downflow in the photosphere. In the lower chromosphere, we found that the plasma flows upwards inside the pores while the plasma in the SMCs is always moving down. Our inspection of the Ca II 8542 Å line from the wing to the core shows that the upflow in the pores slows down with height and turns into downflow in the upper chromosphere while the downflow in the SMCs gains its speed. Our results are in agreement with the numerical studies which suggest that rapid cooling of the interior of the pores drives a strong downflow, which collides with the dense lower layer below and rebounds into an upflow.

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“…Because there is a possibility − even if the event has no WL enhancements from the SOT data − that WL emission may exist out of the SOT field of view, we also checked the continuum data from the Helioseismic and Magnetic Imager (HMI) [29,30] onboard the Solar Dynamics Observatory (SDO) [31]. We found that both events had WL emission observed simultaneously by both instruments.…”

Section: Event Selectionmentioning

confidence: 99%

Capability of the accelerated protons as the origin of white-light emission of solar flare

Watanabe¹,

Masuda²,

Ohno³

2017

Proceedings of 35th International Cosmic Ray Conference — PoS(ICRC2017)

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In association with strong solar flares, we sometimes observe enhancements of visible continuum radiation, which is known as a "white-light flare". As most white-light (WL) events show close correlations in time and location with hard X-rays and/or radio emission, there is some consensus that WL emission originates from accelerated particles, especially non-thermal electrons. One model proposes that WL is emitted near the photosphere; however, non-thermal electrons are thermalized in the chromosphere and cannot reach the photosphere. Thus, there is a problem: how can the energy of non-thermal electrons − and/or other accelerated particles such as high-energy protons − propagate to the photosphere and produce WL emission? In the present study, we investigate the possibility that accelerated protons may produce the WL emission of solar flares. We found 51 WL events observed by Hinode/SOT. Among them, gamma-rays with energies greater than 1 MeV were observed only in the X1.8-class flare on October 23, 2012 and in the M7.9-class flare on June 25, 2015. Focusing on these flare events, we compare the energetics of WL emission and of accelerated ion fluxes. We find that it is difficult for accelerated ions to provide sufficient energy to account for WL emission.

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Design and Ground Calibration of the Helioseismic and Magnetic Imager (HMI) Instrument on the Solar Dynamics Observatory (SDO)

Abstract: The Helioseismic and Magnetic Imager (HMI) investigation (Solar Phys.

Cited by 1,744 publications

References 9 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

FISS Observations of Vertical Motion of Plasma in Tiny Pores

Capability of the accelerated protons as the origin of white-light emission of solar flare

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