ocr: LASCO C2 running difference" image of the large halo' CME of 7 April 1997. The event is called a halo' event because the circular areas of the edges of the blast seem to form kind of a halo around the Sun. This event caused a signiticant amount of geomagnetic activily in northern regions all over the world on 10-11 April 1997, with beautiful displays caused by aurora borealis.
