EUV SPECTROSCOPY OF THE SUNSPOT REGION NOAA-7981 USING SOHO-II - VELOCITIES AND LINE-PROFILES

We have studied the dynamics in the sunspot transition region between the chromosphere and the corona and investigated the extension of the Bow field into the corona. Based on EUV spectra of a medium size sunsp ot and its surroundings, NOAA 7981, observed with CDS and SUMER on SOH O, we derive line-of-sight velocities and study the line profiles for a series of emission lines. The flow field in the low corona is found to differ markedly from that in the transition region. In the transiti on region the relative line-of-sight velocity shows ar. upflow in the umbra and relatively large areas with downflow that cover part of the penumbra. The spatial extent of these arf:as with upflow and downflow increases with increasing temperature in the transition region, but th e whole Bow field changes character as the temperature increases from the upper transition region to the low corona. Based on a calibration of the SUMER wavelength scale we find that the entire sunspot transiti on zone appears to be moving downwards towards the chromosphere. The r elation between this finding and the general tendency for transition-r egion lines to show a net red shift is discussed, Several of the trans ition-region spectral line profiles are observed to show two line comp onents with Gaussian shape and line-of-sight velocities that differ ma rkedly. Several of the line profiles that are composed of two spectral line components occur close to the dividing line between up-and downf low. A discussion of this observation is presented. In small regions w ith spatial extent of a few are sec we detect enhanced continuum emiss ion underlying explosive events. The similarities between explosive ev ents with continuum emission and the moustaches observed in H alpha cl ose to sunspots are so striking that we are tempted to introduce the n otation 'transition-region moustaches'.