Location of the activity responsible for the appearance of coronal mass ejections and the sites of their ejection from the solar surface

Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, 142092 Troitsk, Russia e-mail: nshilova@izmiran.troitsk.ru

Received: 31 May 1999
Accepted: 4 February 2000

Abstract

The white-light films of coronal mass ejections for April - May, 1998 (SOHO LASCO C2, C3), retrieved from Internet, are considered. The positions of active regions on visible and back sides of the Sun for each day are studied. It is shown that a region of large flare can be localized at a distance not less than the solar radius from the place where the transient leaves the solar surface. A perturbation is transferred from the flare to this place within a time not exceeding one minute. The ejection of the CME in the field of view of C2, C3 is determined by its distance from the limb and from the projection of the neutral line of the source surface onto the Sun, rather than by the magnitude of the flare. The source surface is, by definition, a sphere where all field lines are radial. It is believed to exist at a distance 2.5 solar radius from the center of the Sun.