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:10.1007/978-1-4614-3673-7_11

Cited by 99 publications

(121 citation statements)

References 9 publications

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“…Here, by means of a set of 45 s cadence full-disk continuum intensity images and 12 min cadence vector magnetograms taken by the Helioseismic and Magnetic Imager (HMI)25 telescope on board the Solar Dynamic Observatory (SDO), we characterize the sudden reversal in the rotation of a part of a sunspot during an X1.6 flare. Moreover, the azimuthal component of the horizontal field in the sunspot is found to significantly increase over the course of the flare.…”

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confidence: 99%

Observation of a reversal of rotation in a sunspot during a solar flare

Jiang

Yang

et al. 2016

Nat Commun

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The abrupt motion of the photospheric flux during a solar flare is thought to be a back reaction caused by the coronal field reconfiguration. However, the type of motion pattern and the physical mechanism responsible for the back reaction has been uncertain. Here we show that the direction of a sunspot's rotation is reversed during an X1.6 flare using observations from the Helioseismic and Magnetic Imager. A magnetic field extrapolation model shows that the corresponding coronal magnetic field shrinks with increasing magnetic twist density. This suggests that the abrupt reversal of rotation in the sunspot may be driven by a Lorentz torque that is produced by the gradient of twist density from the solar corona to the solar interior. These results support the view that the abrupt reversal in the rotation of the sunspot is a dynamic process responding to shrinkage of the coronal magnetic field during the flare.

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confidence: 99%

Observation of a reversal of rotation in a sunspot during a solar flare

Jiang

Yang

et al. 2016

Nat Commun

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“…We extracted all the event reports from the Heliophysics Event Knowledgebase (HEK) during the years 2014 to 2017 for Active Region and Coronal Holes events. We selected the reports from the Helioseismic and Magnetic Imager (HMI) instrument [23] for active regions, and SPoCA module [24] for coronal holes. As a pre-filtering step, we excluded the event reports which had a bounding box outside of the solar limb.…”

Section: A Event Record Collectionmentioning

confidence: 99%

Solar Event Tracking with Deep Regression Networks: A Proof of Concept Evaluation

Sarker

Banda

2019

2019 IEEE International Conference on Big Data (Big Data)

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With the advent of deep learning for computer vision tasks, the need for accurately labeled data in large volumes is vital for any application. The increasingly available large amounts of solar image data generated by the Solar Dynamic Observatory (SDO) mission make this domain particularly interesting for the development and testing of deep learning systems. The currently available labeled solar data is generated by the SDO mission's Feature Finding Team's (FFT) specialized detection modules. The major drawback of these modules is that detection and labeling is performed with a cadence of every 4 to 12 hours, depending on the module. Since SDO image data products are created every 10 seconds, there is a considerable gap between labeled observations and the continuous data stream. In order to address this shortcoming, we trained a deep regression network to track the movement of two solar phenomena: Active Region and Coronal Hole events. To the best of our knowledge, this is the first attempt of solar event tracking using a deep learning approach. Since it is impossible to fully evaluate the performance of the suggested event tracks with the original data (only partial ground truth is available), we demonstrate with several metrics the effectiveness of our approach. With the purpose of generating continuously labeled solar image data, we present this feasibility analysis showing the great promise of deep regression networks for this task.

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“…I also combined the TIP observations with those from the Helioseismic and Magnetic Imager (HMI; Schou et al, ) as well as the Atmospheric Imaging Assembly (AIA; Lemen et al, ). The HMI data consist of continuum intensity filtergrams and LOS magnetograms having a cadence of 45 s, while the AIA observations comprise filtergrams in the He II 304 Å and Fe IX 171 Å bands having a cadence of 1 min.…”

Section: Observations and Data Analysismentioning

confidence: 99%

Investigation of a Confined C‐Class Flare in an Arch Filament System Close to a Regular Sunspot

Louis

2019

JGR Space Physics

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A moderate C1.1 class confined flare is investigated here, which occurred on 24 September 2013 at 22:56 UT, in an arch filament system close to a regular, unipolar sunspot. Spectropolarimetric observations from the Tenerife Infrared Polarimeter at the 70-cm German Vacuum Tower Telescope were combined with data from the Helioseismic Magnetic Imager and the Atmospheric Imaging Assembly to identify the processes that triggered the flare. The legs of this arch filament were anchored in the leading sunspot and the network flux region of opposite polarity. The flare was driven by small-scale, flux cancellation at the weak neutral line underlying the arch filament, which resulted in two small flaring events within an hour of the C1.1 flare. Flux cancellation was facilitated by the moat flow from the leading sunspot wherein small-scale magnetic fragments stream toward patches of preexisting flux. The cancellation of flux led to the destabilization of the arch filament, which was seen as an increase in the twist along the arch filament. The horizontal fields across the weak neutral line decay rapidly, which cannot prevent the filament from rising that results in a two-ribbon flare at the neutral line. The arch filament unwinds as it rises but is confined by the higher, overlying fields between the two polarities of the active region that decay much more slowly.Unlike PIL filaments, arch filament systems (AFSs) are a bunch of dark filament threads crossing the PIL and connecting the regions of opposite polarity, sometimes extending into sunspots (Bruzek, 1967;Weart & Zirin, 1969;Zwaan, 1985). The arches in the AFS exhibit an upward motion of about 10-15 km/s and downwflows of about 10-50 km/s along their legs. Flares occurring in AFS arise from reconnection with

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

Cited by 99 publications

References 9 publications

Observation of a reversal of rotation in a sunspot during a solar flare

Observation of a reversal of rotation in a sunspot during a solar flare

Solar Event Tracking with Deep Regression Networks: A Proof of Concept Evaluation

Investigation of a Confined C‐Class Flare in an Arch Filament System Close to a Regular Sunspot

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