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2022 Coronal Magnetic Field Plane-of-Sky (POS) maps from MLSO UCoMP Observations

kolinski — Mon, 28 Apr 2025 15:47:19 +0000

2022 Coronal Magnetic Field Plane-of-Sky (POS) maps from MLSO UCoMP Observations kolinski Mon, 04/28/2025 - 09:47

Courtesy of Zihao Yang

Description

Yang et al. 2024 used the Mauna Loa Upgraded Coronal Multi-Channel Polarimeter (UCoMP) observations to construct 8 months of plane-of-sky (POS) coronal magnetic field maps to determine the coronal magnetic field distribution with height and quantify the strength of the magnetic field over heights of 1.5 to 1.6 solar radii. Spherical distributions of the field were also constructed over different heights in the atmosphere. They found the field strength between 1.05 and 1.6 solar radii varies from < 1 to ~20 gauss. They also found a signature of active longitudes in the coronal magnetic field maps.

The Mauna Loa Upgraded Coronal Multi-Channel Polarimeter (UCoMP) observes full Stokes polarimetry (IQUV) in up to 9 coronal emission lines, including the 1074.7 nm and 1079.8 nm lines of FeXIII. UCoMP has a field-of-view (FOV) from 1.05 to 1.6 solar radii in the north-south direction and 1.05 to 2.0 solar radii in the east-west direction.

Click on movie to open full-res MP4 file.

Movie from Yang et al. 2024

UCoMP provides a daily ‘waves’ program (weather permitting) that acquires 3 wavelengths across the FeXIII 1074.7 nm line for 1 hour at 30-second cadence to produce a Doppler velocity product used to track waves in the corona (shown in this figure) and determine their plane-of-sky (POS) phase speed. The FeXIII linear polarization provides the direction of the magnetic field in the POS. The waves are compared with the POS direction of the field to identify waves moving along the magnetic field (e.g. Alfven waves, kink waves).

POS Coronal Magnetic Field Map and POS Direction

Click on movie to open full-res MP4 file.

Movie from Yang et al. 2024

The POS density is found from the ratio of 1074.7 and 1079.8 FeXIII line pair. The density and wave phase speed are used to derive the strength of the magnetic field in the POS. This is combined with the POS field direction from the linear polarization to produce a POS B-field map (shown in the figure above). Note that all quantities are integrated along the observer’s line-of-sight, as are all remote-sensing observations of the optically thin solar corona.

Evolution and Height Variation of the Magnetic Field

Feb 21, 2022 data from (A) SDO AIA 193 Å, (B) UCoMP POS magnetic field, (C) UCoMP POS magnetic field direction.

Adapted from Fig 1 Yang et al. 2024

Yang et al. combined UCoMP, AIA and HMI observations to study the evolution and height variation of the magnetic field over 5 Carrington rotations. Fig 2 from Yang et al. (below) shows the photospheric magnetic field from HMI with UCoMP POS magnetic field and AIA intensity from 1.1 to 1.15 Rsun and from 1.20 to 1.25 Rsun.

Fig 2 from Yang et al. 2024

Spherical Construction of Magnetic Field with Height

Movie showing the variation of magnetic field strength with height from the photosphere in HMI (left) into the low corona from UCOMP. Active longitudes are visible in the movie. Click on movie to open full-res MP4 file.

Yang et al. 2024

For more info see the paper and supplemental file with movies

Zihao Yang, Hui Tian, Steven Tomczyk, Xianyu Liu, Sarah Gibson, Richard J. Morton, Cooper Downs, Observing the evolution of the Sun’s global coronal magnetic field over 8 months, 2024, Science, 386, pp 76-82

Full text from Publisher: https://www.science.org/doi/10.1126/science.ado2993

Preprint: arXiv:2410.16555: https://arxiv.org/abs/2410.16555

SUBMIT Science Nuggets Using MLSO observations to: mlso_data_requests@ucar.edu

1998-08-24: Chromospheric Wave

kolinski — Thu, 03 Mar 2022 17:58:40 +0000

1998-08-24: Chromospheric Wave kolinski Thu, 03/03/2022 - 10:58

A chromospheric wave caused by a filament eruption as seem by PICS in H-alpha. The same event as seen by the CHIP Helium-I imager is discussed in the figure to the right.

PICS H-alpha

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CHIP He-I sequence

A time sequence of images from the Mauna Loa Helium-I (CHIP) instrument showing the progression of a chromospheric wave associated with a filament eruption and an X-level flare on August 24, 1998. The event had a good association with the severe geomagnetic storm at Earth on August 27.

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2006-12-06: Chromospheric Wave

kolinski — Thu, 03 Mar 2022 17:32:26 +0000

2006-12-06: Chromospheric Wave kolinski Thu, 03/03/2022 - 10:32

This animation shows a chromospheric wave, also known as a Moreton wave or solar tsunami, as seen by MLSO's CHIP instrument (which images the Sun's chromosphere in the Helium line). Waves like these affect the structure of the chromosphere and may contribute to the heating of both the chromosphere and higher lying regions. They have characteristic speeds of around 1000 kilometers per second. This particular wave was initiated by an X6.5 flare.

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2010-07-11: Moon In Corona

kolinski — Thu, 03 Mar 2022 16:40:31 +0000

2010-07-11: Moon In Corona kolinski Thu, 03/03/2022 - 09:40

In this movie, you can see the Moon passing through the bottom of the Sun's corona. On the right is a composite image from the total solar eclipse that day (credit: NASA/ESA/Williams College Eclipse Expedition)

Mk4 coronameter

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Eclipse composite

Composite image for July 11, 2010 total solar eclipse

NASA/ESA/Williams College Eclipse Expedition

2012-06-05: Transit of Venus

kolinski — Thu, 03 Mar 2022 15:50:52 +0000

2012-06-05: Transit of Venus kolinski Thu, 03/03/2022 - 08:50

The Mauna Loa Solar Observatory took images during the transit of Venus on June 5th, 2012. The example shown here is the silhouette of Venus moving through the corona as imaged by MLSO's CoMP instrument.

Visit the MLSO Venus Transit page for movies of the event in many of our instruments.

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2014-10-23: Moon In Corona

kolinski — Wed, 02 Mar 2022 22:13:26 +0000

2014-10-23: Moon In Corona kolinski Wed, 03/02/2022 - 15:13

While the partial solar eclipse was not visible from Mauna Loa, the Moon came close enough to be seen in the corona in K-Cor data.

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2016-05-09: Transit of Mercury

kolinski — Wed, 02 Mar 2022 21:47:23 +0000

2016-05-09: Transit of Mercury kolinski Wed, 03/02/2022 - 14:47

Mercury transited the Sun on May 9th, 2016. The tiny planet (only 3,032 miles across) was observed passing in front of the corona in K-Cor data.

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2017-08-21: The Great American Eclipse

kolinski — Wed, 02 Mar 2022 21:35:35 +0000

2017-08-21: The Great American Eclipse kolinski Wed, 03/02/2022 - 14:35

The Great American Eclipse that took its path through the middle of the United States on August 21st was also visible as a partial eclipse from the Mauna Loa Solar Observatory. This data was taken by the K-Cor Coronagraph.

K-Cor Movie times: 17:13 to 18:34 UT

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2019-11-11: Transit of Mercury

kolinski — Mon, 07 Feb 2022 19:19:35 +0000

2019-11-11: Transit of Mercury kolinski Mon, 02/07/2022 - 12:19

Mercury transited the Sun on November 11, 2019. The tiny planet (only 3,032 miles across) was observed passing in front of the corona in K-Cor data. Although small, it is visible going left to right just above the center of this animation.

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2020-06-03: Venus Inferior Solar Conjunction

kolinski — Mon, 07 Feb 2022 18:47:10 +0000

2020-06-03: Venus Inferior Solar Conjunction kolinski Mon, 02/07/2022 - 11:47

The planet Venus was at inferior conjunction on June 3rd, 2020, when it passed between the Sun and the Earth. This occurs once in every synodic cycle of the planet (584 days), and marks the end of Venus's appearance in the evening sky and its transition to become a morning object over the next few weeks. You can see it in this K-Cor movie as a black silhouette against the corona above the occulted disk of the Sun (it is more clear in the linked larger animation). When the Sun, Venus, and the Earth are perfectly aligned, Venus will pass through the disk of the Sun. This is called a transit, which K-Cor observed in 2012.

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The silhouette of Venus passes in front of the corona on June 3rd, 2020. It can be seen about 1/3 of the way from the top of the image moving from left to right.

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2022 Coronal Magnetic Field Plane-of-Sky (POS) maps from MLSO UCoMP Observations

Description

POS Coronal Magnetic Field Map and POS Direction

Evolution and Height Variation of the Magnetic Field

Spherical Construction of Magnetic Field with Height

For more info see the paper and supplemental file with movies

SUBMIT Science Nuggets Using MLSO observations to: mlso_data_requests@ucar.edu

Category

1998-08-24: Chromospheric Wave

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2006-12-06: Chromospheric Wave

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2010-07-11: Moon In Corona

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2012-06-05: Transit of Venus

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2014-10-23: Moon In Corona

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2016-05-09: Transit of Mercury

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2017-08-21: The Great American Eclipse

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2019-11-11: Transit of Mercury

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2020-06-03: Venus Inferior Solar Conjunction

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