ISSN:
1573-093X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract The problem of physical relationships between different active regions has been dealt with only rarely and mainly in connection with flares. How sympathetic activity can be triggered between distant regions is therefore, so far, largely unknown. Soft X-ray images of large-scale coronal structures connecting different active regions were obtained by Skylab nearly 20 years ago, while SMM, more recently, did not provide any clear evidence for this kind of loop. As a consequence, we do not know how common these features are nor how they form nor whether they represent the only means by which distant active regions may be linked. In the latter case, however, interconnecting loops should be detected by analyzing the interaction between different active regions. We examine here a set of images of an active region complex, acquired on June 24-25, 1980, by the Hard X-ray Imaging Spectrometer on SMM, with the purpose of establishing whether there was any interplay between the frequent activity observed at different sites in the activity center and, in such a case, how the interaction was established. By analyzing both quiet and active orbits we show that, as a rule, activity originating in one region triggers the other region's activity. However, we find little unambiguous evidence for the presence of large-scale interconnecting loops. A comparison of X-ray images with magnetic field observations suggested that we interpret the active region behavior in terms of the interaction between different loop systems, in a scenario quite analogous to the interacting bipole representation of individual flares. We conclude that active region interplay provides an easily observable case to study the time-dependent topology and the mechanisms for the spreading of activity in transient events over all energy scales.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00667987
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