Twisted, magnetized tubes of gas rise high above the surface of the star. There they unwind, releasing stored energy. The release of magnetic energy can occur steadily and provide for the heating of the tubes of hot gas which make up the stellar corona. Or it can occur violently and produce flares. Flares can occur on the Sun at any time, but their frequency tends to rise from a peak of five to ten a day and fall to less than one per day in a cycle of about eleven years.
Every solar flare showers the Earth in high energy particles.
A strong one can disrupt radio communications and produce spectacular displays known as the Northern and Southern Lights. Flares may even have a subtle but important effect on our weather. The flare gives the distinct impression of a twisted sheet of gas in the process of unwinding itself.