Ultraviolet coronagraph spectrometer observations of a high-latitude coronal hole with high oxygen temperatures and the next solar cycle polarity

We announce the resurgence of extreme ion properties in a large, high-latit ude coronal hole observed above the north heliographic pole in 2001 Februar y at solar maximum. The observations were taken with the Ultraviolet Corona graph Spectrometer on the Solar and Heliospheric Observatory. These observa tions are part of an ongoing campaign to determine the plasma properties of coronal holes during the current solar cycle. In this Letter, we compare t he observations and analysis of O VI lambda lambda 1032, 1037 spectral line s of a high-latitude coronal hole in 2001 with observations of an equatoria l solar maximum hole in 1999 and polar coronal holes observed near solar mi nimum (1996-1997). These lines provide spectroscopic diagnostics of O+5 vel ocity distributions and outflow velocities. The O vi line profiles show a n arrow core and broad wings. The narrow core is attributed to foreground and background streamers and, possibly, dense polar plumes at the lowest obser ved heights. The broad wings are attributed to the coronal hole. The compar ison of the coronal hole line widths shows that the O+5 perpendicular kinet ic temperatures in the 2001 high-latitude hole are similar to those observe d in polar coronal holes at solar minimum. These observations of extremely high ion kinetic temperatures (exceeding 10(8) K) at the north pole in 2001 occurred nearly simultaneously with the polarity change of the Sun's magne tic field, as seen in recent magnetogram data. This coronal hole in 2001 ma y represent the first manifestation of the negative polarity polar coronal holes that will dominate the Sun's open magnetic flux tubes at the next sol ar minimum. The reappearance of broad O vi profiles at a time when not all of the "new polarity" magnetic flux has migrated to the poles was an intere sting development. The variations in coronal hole parameters with the solar cycle provide constraints on models of extended coronal heating.