OPTICAL DIAGNOSTICS OF CORONAL LOOP INTERACTIONS

Coronal loop interactions (CLIs) are commonly observed in images of postflare loop systems recorded in the 5303 Angstrom (Fe XIV) and 6374.5 Angstrom (Fe x) lines. The CLIs appear as occasional transient brightenings at the projected intersections of adjacent loops. Observational parameters of a CLI of 1981 December 7 are used to determine values of key plasma quantities that characterize these events, leading to optical diagnostics. On the basis of this analysis, the likelihood of detecting CLIs at other coronal-line wavelengths is estimated. Finally, the possible contribution of CLIs to coronal heating is investigated in terms of the estimated frequency of binary loop-loop collisions in the solar corona and their dependence on available photospheric magnetic flux, within and outside active regions. Possible implications for heating of coronae of dMe stars are discussed.