Short-duration changes in green-corona structures

Using films of the green corona the characteristic properties were derived of short-duration changes in coronal structures in particular loop expansion, formation, brightening and disappearance, stepwise growth, fast expansion and dark space changes. The loop expansion is a completely different process from stepwise growth. The mass and energy increase of a typical loope expansion are of the order of 1010 kg and 1023 J, respectively. The energy increase is comparable to the energy of a coronal event or a spray prominence. A comparison of the plasma energy increase and of the magnetic field showed that the magnetic field of the loop is the main factor in loop expansion. Kinetic energy density for active features in all three layers of the solar atmosphere are compared. In general it decreases with the increasing height of the feature. (author)