OBSERVATIONS OF POLAR PLUMES WITH THE SUMER INSTRUMENT ON SOHO

We present new observations of O VI 1032 Angstrom line profiles in pol ar plumes, and inter-plume regions, on the disk and above the limb in the north coronal hole obtained with the SUMER (Solar Ultraviolet Meas urements of Emitted Radiation) instrument on the SOHO (Solar and Helio spheric Observatory) spacecraft. On 22 May 1996, a 5 x 5 are min spect roheliogram was scanned above the north polar coronal hole with the en trance slit extending from 1.03 to 1.33 solar radii with 1.5 arc sec s patial resolution and approximate to 0.044 Angstrom per pixel spectral resolution in the wavelength range 1020-1040 Angstrom. Detailed plume structure in O VI 1032 Angstrom can be seen extending beyond 1.3 sola r radii, with intensities in the plume regions 10-50% brighter, but li ne widths 10-15% narrower, than the inter-plume regions. Possible expl anations for this observed anti-correlation between line width and int ensity in the plume and inter-plume regions are discussed. We conclude that the source of the high-speed solar wind may not be polar plumes, but the inter-plume lanes associated with open magnetic field regions of the chromospheric network.