Dynamics of solar prominence on December 7, 1978

Abstract

The 1978 December 7 eruptive prominence with a helical structure is analysed. Attention is given to the distribution of magnetic helicity, a measure of helical structure, and the morphology and evolution of this event. The prominence was an edge-on case. The southern leg of the prominence consisted of two (four) helical threads which suggested a tube. A disruption probably occurred in the upper part of this leg. The threads in the northern leg were nearly radially oriented to the solar surface, and consisted from several subfilaments, tangled in a small-scale. The central region unwound after disruption,similarly as at the top (these threads were during next evolution connected with the northern leg), showing a much the helicity, both, large-and small-scale. Moreover, there tangled kinks probably displayedin some parts of the prominence. Observed height: 2 − 7 × 10⁵ km, the projected speed of the prominence head of 180 km s^-1, estimated of magnetic field strength of 1 × 10⁻⁴ T.