A Guide to Sunspot Magnetic Field Configuration
Sunspots are regions of the sun where magnetic fields are especially potent, creating dark spots in certain observing filters (such as H-alpha). These spots are also known as active regions, bright and dynamic areas made of loops of magnetic field and solar material, in other observing filters. This guide is specifically focused on sunspots observed using the Helioseismic and Magnetic Imager (HMI) instrument aboard the Solar Dynamics Observatory (SDO), but does use the Michelson Doppler Imager (MDI) instrument aboard the Solar and Heliospheric Observatory (SOHO) .
There are eight magnetic field configurations in Hale Classification of sunspots/magnetic field configurations (1). In the first column are example images of sunspots mainly from 2023-2025, exceptions noted; 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 |
 |
 |
NOAA 14046 |
 |
 |
NOAA 13571 |
 |
 |
NOAA 13217 (center) and NOAA 13220 (left) |
- β -- Beta : Bipolar (negative-positive) magnetic fields with simple division between polarities
White Light image | Magnetogram | Note |
 |
 |
NOAA 14064 |
 |
 |
NOAA 13831 |
 |
 |
NOAA 13297 |
- 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 |
 |
 |
NOAA 13581 |
 |
 |
NOAA 09601(1) |
 |
 |
NOAA 08485(1) |
1 Image obtained from MDI on SOHO
- β-γ -- Beta-Gamma : A bipolar sunspot group
that has enough complexity where a clear division cannot be drawn.
White Light image | Magnetogram | Note |
 |
 |
NOAA 14079 |
 |
 |
NOAA 13780 |
 |
 |
NOAA 13190 |
- δ -- Delta : Sunspot umbrae of opposite polarity shares
the same penumbra. Delta spots have not been designated by itself.
Usually designated in the form like beta-delta spots or beta-gamma-delta spots.
Delta designated spots are correlated with higher flaring activity. (2,3)
- β-δ -- Beta-Delta :
General beta configuration with a sunspot or two with delta configuration.
White Light image | Magnetogram | Note |
 |
 |
NOAA 14099 |
 |
 |
NOAA 13664 |
 |
 |
NOAA 13529 |
- 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 |
 |
 |
NOAA 13998 |
 |
 |
NOAA 13576 |
 |
 |
NOAA 13354 |
- 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 |
 |
 |
NOAA 13883 |
 |
 |
NOAA 09087(1) |
1 Image obtained from MDI on SOHO
References Used for This Guide
- Chaudhari, A., Singh, A., Sharma, G., & et al. (2024). Association of solar flares with magnetic complexity of the sunspot groups in solar active regions during solar cycles 23–25. Indian Journal of Physics, 98, 3075–3082. https://doi.org/10.1007/s12648-024-03101-x
- Künzel, H. (1965). Zur Klassifikation von Sonnenfleckengruppen. Astronomische Nachrichten, 288, 177.
- Jaeggli, S. A., & Norton, A. A. (2016). The magnetic classification of solar active regions 1992–2015. The Astrophysical Journal Letters, 820(1), L11.
(29-Jan-2025, initial version by Rhiannon Fleming)
(06-Mar-2025, modified to this hand written version by Aki Takeda)
(29-May-2025, modified to this HTML version by Rhiannon Fleming)
(May and June-2025, periodically modified by Rhiannon Fleming)