A Steady-state Supersonic Downflow in the Transition Region above a Sunspot Umbra

Thomas Straus, Bernhard Fleck, Vincenzo Andretta

We investigate a small-scale ($\approx$ 1.5 Mm along the slit), supersonic downflow of about 90 km s${}^{-1}$ in the transition region above the light-bridged sunspot umbra in AR 118…