HR: 10:40h
AN: SH22B-02 INVITED    [Abstracts]
TI: UVCS Empirical Constraints on Theoretical Models of Solar Wind Source Regions
AU: * Kohl, J L
EM: jkohl@cfa.harvard.edu
AF: Harvard Smithsonian Center for Astrophysics, MS 50, 60 Garden Street, Cambridge, MA 02138, United States
AU: Cranmer, S R
EM: scranmer@cfa.harvard.edu
AF: Harvard Smithsonian Center for Astrophysics, MS 50, 60 Garden Street, Cambridge, MA 02138, United States
AU: Miralles, M P
EM: mmiralles@cfa.harvard.edu
AF: Harvard Smithsonian Center for Astrophysics, MS 50, 60 Garden Street, Cambridge, MA 02138, United States
AU: Panasyuk, A
EM: apanasyuk@cfa.harvard.edu
AF: Harvard Smithsonian Center for Astrophysics, MS 50, 60 Garden Street, Cambridge, MA 02138, United States
AU: Strachan, L
EM: lstrachan@cfa.harvard.edu
AF: Harvard Smithsonian Center for Astrophysics, MS 50, 60 Garden Street, Cambridge, MA 02138, United States
AB: Spectroscopic observations from the Ultraviolet Coronagraph Spectrometer (UVCS) on the Solar and Heliospheric Observatory (SOHO) have resulted in empirical models of polar coronal holes, polar plumes, coronal jets and streamers. These findings have been used to make significant progress toward identifying and characterizing the physical processes that produce extended heating in the corona and accelerate fast and slow solar wind streams. The UVCS scientific observations, which began in April 1996 and continue at this writing, have provided determinations of proton and minor ion temperatures (including evidence for anisotropic microscopic velocity distributions in coronal holes and quiescent equatorial streamers), outflow velocities, and elemental abundances. The variations in these quantities over the solar cycle also have been determined. For example, observations of large polar coronal holes at different phases of the solar cycle indicate that line width is positively correlated with outflow speed and anti-correlated with electron density. This paper will review these results, and present new results from measurements taken as the current solar activity cycle approaches solar minimum. The results regarding preferential ion heating and acceleration of heavy ions (i.e., O5+) in polar coronal holes have contributed in a major way to the advances in understanding solar wind acceleration that have occurred during the past decade. It is important to verify and confirm the key features of these findings. Hence, the results from a new analysis of an expanded set of UVCS data from polar coronal holes at solar minimum by S. R. Cranmer, A. Panasyuk and J. L. Kohl will be presented. This work has been supported by the National Aeronautics and Space Administration (NASA) under Grants NNG06G188G and NNX07AL72G and NNX06AG95G to the Smithsonian Astrophysical Observatory.
DE: 7509 Corona
DE: 7549 Ultraviolet emissions
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting