Limit cycle behavior in solar and stellar coronal loops

Abstract

An attempt is made to reconcile the empirical limit cycle model of Kuin and Martens with the details stability analysis of coronal loops given by McClymont and Craig. We show that a reconciliation is possible, despite uncertainties in the model, provided an empirical ''conductive-coupling parameter'' introduced by Kuin and Martens is correctly incorporated in the analysis. When this is done, however, their model no longer accords with global limit cycle behavior; rather it implies that coronal loops are locally and globally stable, at least provided certain restrictions on the coronal heating mechanism are satisfied. The conditions required for loop stability agree with those deduced by McClymont and Craig on the basis of a comprehensive normal mode analysis. We conclude that the limit cycle model cannot be expected to provide a plausible description of coronal loop behavior.