34th Solar Physics Division Meeting, June 2003
Session 11 Photosphere and Chormosphere II
Oral, Tuesday, June 17, 2003, 1:30-3:30pm, Auditorium

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[11.06] Weak IR Lines Reveal Rapid Outflow in Cool Magnetic Penumbra

M.J. Penn (NSO), W.D. Cao (Yunnan Observatory and NJIT), S.R. Walton, G.A. Chapman (Cal State Northridge), W. Livingston (NSO)

New imaging spectropolarimetric observations of the Evershed flow in sunspot penumbrae using weak infrared molecular absorption lines are presented. A plane-polar coordinate system in the sunspot frame is defined, allowing averaging of many raw spectra. Molecular lines show Doppler shifts implying typical horizontal outflow speeds of 6 to 9 km/sec. The Ti I polarimetric spectra show the same rapid outflow and suggest an average penumbral magnetic field strength of 1400 Gauss. While these observations show Doppler shifts of the entire line profile the velocities are in better agreement with previous measurements from spectral line asymmetries.

The author(s) of this abstract have provided an email address for comments about the abstract: mpenn@noao.edu

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Bulletin of the American Astronomical Society, 35 #3
© 2003. The American Astronomical Soceity.