|
The present study is the spotless flare of March 16, 1981. The morphological features of development of flare, change of the flare areas of ribbons in course of time, removed flare mottles and their correlation with the basic ribbons of flare are considered.
Three days before a powerful flare, an extensive large-scale routing is developed in appropriate active region. Activations of chromospheric fine structure along and nearby the routing precede the flare. Mainly the chromospheric structure activations occur during about 1 hour before a flare. During this time interval one can observe: 3-4 minute pulsations of dark node intensities in flare ribbon formation regions, preflare appearance of dark vortical structures around flare ribbon formation regions, appearance of dark ribbon channels over large areas in flare regions just before flare beginning, and others phenomena.
The flare process carries large-scale character. It is possible to speak about a certain regularity in development of flare ribbons: occurrence on some distance from a ribbon flare mottle and in a trace behind it of distribution of the basic body of flare ribbon in the direction of it before merge.
In summarizing the results reported here, it can be said that the flare outside sunspots may be treated as a local event in a successive chain of phenomena encompassing the large-scale network of magnetic fields. There is reason to think that the emergence of new magnetic fields is one of the factors responsible for the occurrence of flares outside sunspots. |
