A Guide to Sunspot Magnetic Field Configuration
This guide is focused on sunspots observed using the Helioseismic and Magnetic Imager (HMI) instrument aboard the Solar Dynamics Observatory (SDO). There are eight magnetic field configurations in Hale Classification of sunspots/magnetic field configurations. In the first column are example images of sunspots from 2023-2024; on the left hand side are HMI Continuum (yellow) for sunspot images and on the right hand side are the HMI Magnetogram (grey) showing the magnetic field configuration images of the sunspots. The second column contains information on a description/identification and any additional information of each sunspot class.
Solar Magnetic Field Configuration
- α -- Alpha : Unipolar magnetic field sunspot group
White Light image | Magnetogram | Note |
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NOAA 13251 |
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NOAA 13294 |
 |
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NOAA 13571 |
- β -- Beta : Bipolar (negative-positive) magnetic fields with simple division between polarities
White Light image | Magnetogram | Note |
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NOAA 13251 |
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NOAA 13294 |
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NOAA 13571 |
- γ -- Gamma :
Complex region where positive and negative polarities are not clearly divided to the point where the configuration is not considered bipolar.
White Light image | Magnetogram | Note |
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NOAA 13251 |
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NOAA 13294 |
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NOAA 13571 |
- β-γ -- Beta-Gamma : A bipolar sunspot group
that has enough complexity where a clear division cannot be drawn.
White Light image | Magnetogram | Note |
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NOAA 13251 |
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NOAA 13294 |
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NOAA 13571 |
- δ -- Delta : Sunspot umbrae of opposite polarity shares
the same penumbra. Delta spots are rarely designated by itself.
Usually designated in the form like beta-delta spots or beta-gamma-delta spots.
- β-δ -- Beta-Delta :
General beta configuration with a sunspot or two with delta configuration.
White Light image | Magnetogram | Note |
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NOAA 13251 |
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NOAA 13294 |
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NOAA 13571 |
- β-γ-δ -- Beta-Gamma-Delta :
Complex sunspot beta-gamma group with delta sunspots (most prone to high level flaring)
White Light image | Magnetogram | Note |
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NOAA 13251 |
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NOAA 13294 |
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NOAA 13571 |
- γ-δ -- Gamma-Delta :
Unorganized magnetic configuration with delta sunspot regions. These regions are also rare with this one designated recently, then tracking back to 2000 for the next most recent designation.
White Light image | Magnetogram | Note |
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NOAA 13883 |
(29-Jan-2025, initial version by Rhiannon Fleming)
(06-Mar-2025, modified to this hand written version by Aki Takeda)