The rapid realignment of the magnetic fields induces intense electric currents which heat the plasma and produce extreme H-alpha brightening, which for flare brightness is defined as at least twice the normal chromospheric emission level. As the flare dies down, the sheared field line produced by the original motion and marked by the filament is replaced by loop prominences or field transition arches which arc more directly between two opposite polarity areas, tracing out the new field lines nearly perpendicular to the original neutral line boundary. At that point, the magnetic fields are connected in the lowest possible energy state and, unless further flux emerges, the flares should be over. The frequency of solar flares is directly related to sunspot activity, with few occurring near sunspot minimum. Near sunspot maximum, small ones occur almost daily, and major flares can happen several times per week.
Compact flares are usually smaller and somewhat more frequent than major flares.
They often occur in a pre-existing loop or arch filament system, and little structural change in the area is observed. Compact flares can be seen in or near Emerging Flux Regions, and produce mainly small surges or none at all. Subflares are the smallest of the compact class, and are short-lived, being only slightly brighter than active plage. Major flares are considerably more violent and longer lived, frequently producing large surges or sprays of bright gas. Major flares often cover large areas of the sun and cause plage brightening expanding outward across the solar disk.