Dynamic current injection into magnetic loops in active regions I. Supplies of energy and mass to active-region corona in the form of dynamic loop brightenings

One of the discoveries by Yohkoh is that a large part of the soft X-ray emi ssion from the active-region corona comes from hot gas injected dynamically into magnetic loops from below. We propose that the major part of the supp ly of energy and mass to active region corona may be due to a dynamical lea kage of magnetic twists produced in the subphotospheric convection layer. T hese twists naturally propogate out along;he magnetic field to the active r egion corona as a large-amplitude torsional Alfven-wave packet (TAWP, equiv alent to a coaxially self-closed packet of MHD current), and the active-reg ion corona is a dumping ground for such currents. These TAWP's: which are p assively produced in the dominant gas motion in the convection layer, dynam ically influence the lower pressure gas as they propagate out into the chro mosphere and the corona. The Bur tube in the corona is pinched near the axi s and heated. The pinched region propagates dynamically with the Alfven vel ocity along the magnetic loop, driving the pinch-heated high-temperature ga s into a spinning jet ia sweeping pinch). This may explain the supply of en ergy and mass to active-region corona in the form of the active-region loop brightenings found by Yohkoh.