SLOW ERUPTION: The magnetic canopy of a sunspot group just over the sun’s southwestern limb slowly erupted on Oct. 28th. When the hours-long eruption was over, this bright arcade formed over the blast site, marking the location where the explosion occured:

Arcade loops appear after many solar flares. It is how the magnetic fields of sunspots settle down after a significant eruption. This particular eruption hurled a massive CME into space, but Earth was not in the line of fire.

fr/spaceweather.com