THE EFFECT OF SPATIALLY DEPENDENT HEATING ON THE THERMAL EQUILIBRIA OF CORONAL LOOPS

The thermal equilibria along a symmetric coronal loop with constant cr oss-sectional area is investigated in the absence of gravity. A corona l heating function that depends on distance along the loop is consider ed and the effects of varying the values of the parameters involved in the governing equations are studied. It is found that there is a crit ical decay length of the heating below which a hot coronal loop does n ot exist. It is suggested that thermal non-equilibrium occurs, allowin g the existence of catastrophic cooling and it is shown that prominenc e-type equilibria are possible. A study of the stability of the equili brium up to a second order approximation is presented, and it is found that the response of the structure not only depends on the amplitude of the disturbance, but also on whether the disturbance increases or d ecreases the equilibrium temperature.