Thermal instability and non-equilibrium in solar coronal loops: from coronal rain to long-period intensity pulsations

A brave effort to describe what happens when "coronal rain" somewhat mysteriously appears. Recall that this began with H-alpha observations that spectroscopically revealed blobs of emission forming out of nowhere, and the streaming down along loops out of the corona and back into the chromosphere where it belonged. This is the last stage of flare loop cooling, and appears in other circumstances when hydrostatic dis-equilibrium allows this kind of dynamics. Here "CCTR" represents the "Condensation-Corona Transition Region", a possibly vanishingly thin surface separating a cooling volume from its surroundings. The paper describes the dynamics of the process, driven theoretically by Field's thermal instability.