Magnetic Class :
  The magnetic class of sunspots is important in determining how potentially volatile particular active regions may be. Sunspots are regularly observed using instruments capable of determining the magnetic polarity of sunspots and active regions. By also applying laws which have been formulated over the years, visual observations can also be used to establish the magnetic polarity and complexity of spot groups. There are basically 7 magnetic types of sunspots that are classified. They are described as follows:

Type 

A - Alpha (single polarity spot).
B - Beta (bipolar spot configuration).
G - Gamma (atypical mixture of polarities).
BG - Beta-Gamma (mixture of polarities in a dominantly bipolar configuration).
D - Delta (opposite polarity umbrae within single penumbra).
BD - Beta with a Delta configuration.
BGD - Beta-Gamma with a Delta configuration.

Example: A region labelled as having a magnetic classification
 of BG indicates that 
the sunspot
 region contains a mixture of magnetic polarities, but
 the dominant polarity of the group is bipolar. Potentially 
very powerful and potent regions are those which 
have classifications of BG, BD and BGD. As magnetic 
complexity increases, the ability of an active region 
to spawn major energetic events likewise increases.