34th Solar Physics Division Meeting, June 2003
Session 4 Corona II
Poster, Monday, June 16, 2003, 3:30-5:00pm, Mezzanine

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[4.09] The 2001 June 21 Eclipse Polarimetric Observations of the Fe XIII 1074.7 nm Emission Line

S. R. Habbal (UWA and CfA), M. B. Arndt (Bridgewater State College), M. H. Nayfeh (University of Illinois Urbana-Champaign), J. Arnaud (Observatoire Midi Pyrenees), J. Johnson (Electricon), S. Hegwer (National Solar Observatory), A. Ene (Stanford University)

Polarimetric measurements of the coronal forbidden lines have been recognized for quite some time as a diagnostic tool for inferring the direction of the coronal magnetic field. Following the first successful measurements by Eddy et al. (1973) during the total solar eclipse of 1966, an observing campaign using the coronagraph at Sacramento Peak Observatory was pursued between 1977-1980 (Arnaud and Newkirk, 1987). All these measurements yielded the surprising result that the direction of polarization implied a predominantly radial coronal magnetic field. We report on the polarization measurements of the Fe XIII 1074.7nm line, the strongest of the coronal forbidden lines, which were obtained during the total solar eclipse of 2001 June 21 from Zambia. In addition to confirming the earlier results of a predominantly radial field, the signature of nano-size interplanetary dust in the inner corona, most likely in the form of silicon nanoparticles, appeared for the first time in these measurements. The signature of these particles also coincides with the radial expansion of coronal holes outwards from the Sun, a signature that has never appeared in any measurement before.

Support for this work was provided by NSF grant ATM-0003661 and NASA grant NAG5-10873

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