Britannica
Sources used in this answer
Why do large solar flares often occur near delta sunspots?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
Sun
Joshua trees at sunset, Joshua Tree National Park, southern California, U.S.
Large solar flares often occur near delta () sunspots because of their complex magnetic structure. While most sunspots possess a single magnetic polarity, a spot contains two or more umbras of opposite polarity within the same penumbra.1
When these spots of opposite polarity are squeezed together, they create a steep magnetic gradient. This configuration stores significant amounts of energy in the form of electrical currents that sustain the magnetic fields. When these fields are twisted or sheared by material motion, that stored energy is cataclysmically released in the form of a solar flare.1