Progress in coronal physics

Abstract

This paper reviews research highlights of the past five years. Considerable progress has been made in observing and interpreting coronal mass ejections. The stability of coronal loops is much better understood and new observations of the onset of wind streams in coronal holes have been made. Observations from the Solar Maximum Mission should helpt to clarify the physics of the active corona.The mechanisms that heat the corona and accelerate the high-speed wind streams remain to be identified, however. Solar Physics 100 (1985) 281-287. 0038-0938/85.15. 9 1985 by D. Reidel Publishing Company

On the Association between Coronal Mass Ejections and Coronal Holes

“…From details like those given in Fig 1 we infer that mostly sharp (small span 20°) CMEs are not associated with coronal holes. Further, the sharp (small span) CMEs may be produced by various models, proposed by various investigators, described in a recent review by Zirker (1985). On the other hand we suggest that the CMEs associated with coronal holes may be produced by some mechanism by which the mass ejected by some flares or active prominences, gets connected with open magnetic field lines or coronal holes and moves along these open magnetic lines of coronal holes to produce large span CMEs.…”

“…The coronagraphs aboard the SMM and SOLWIND satellites, as well as Mark III polarimeter at Mauna Loa and the Culgoora radio heliograph, have revealed about a complex phenomenon, namely CMEs. The three categories of CMEs are characterized by different maximum speeds (Zirker, 1985). The flare associated CMEs^show speed upto 1200 km s those associated with prominerces upto 600^km s and the spontaneous CMEs show speeds only upto about 500 km s .…”

“…To within a factor of two, the pre existing mass seems sufficient to account for the mass in the CME (Zirke^, 1985). Theoretical models that have attempted to interpret these events are gradually improving but the complete understanding of the dynamics much less the origin of CMEs remains a distant goal (Zirker, 1985). Low (1984) classifies current models of CMEs into two groups one of them represents the CME as a wave like nonlinear MHD response to impulsive energy inputat the base of the corona (eg.…”