Conduction terms as a function of position (in the range 0–30 Mm for visualisation purposes). Conduction by neutral H (dashed line) goes to zero at the edge of the thread where the plasma is fully ionised. Conduction by neutral He (dotted line) dominates inside the thread and becomes zero in the corona where there is conduction by electrons only (continuous line). The same parameters as in Fig. 10 are used.