Coronal Heating by Collision and Cancellation of Magnetic Elements

Abstract

A model is proposed for the coronal response to the interaction between randomly moving photospheric magnetic flux elements. In this model the collision between two elements of opposing signs results in reconnection and the appearance of an X-ray bright point. A section of quiet Sun on which elements are distributed and moving randomly will contain a number of X-ray bright points. The model combines a distribution of element sizes, random velocities of the elements, and a model for pair-wise collisions. This results in quantitative predictions for surface density of X-ray bright points, the distribution of their luminosities, and their contribution to the total heat flux in the quiet Sun. The predictions depend principally on the densities of flux elements of each sign B_+ and B_-, the average element size Φ, and the random velocity v_0. The predicted heat flux, F_XBP=0.1B_+B_-v_0, is in rough agreement with published observational studies of X-ray bright points but well below the flux required to supply heat to the quiet Sun corona. Other predictions of the model are similarly consistent with published studies.