. A two-dimensional, vertical cross section of the magnetic-network model of the solar transition region. The motion of supergranular convective cells (bottom) concentrates magnetic fields at their boundaries in the photosphere. The magnetic fields (arrowed lines) are pushed together and amplified up to 0.1 Tesla at the cell edges. Heating in the chromosphere above this magnetic network produces bright calcium emission (Fig. 5.12). The concentrated magnetic fields expand and flare out with height in the overlying corona. Temperature contours between log T = 6..1 (corona) and log T = 5.4 (upper transition region) are marked.
Copyright 2010, Professor Kenneth R. Lang, Tufts University