Recorded presentation4.3
Using Solar and In-Situ Observations to Improve and Constrain Corona & Solar Wind Models
C. Nick Arge, Air Force Research Lab, Kirtland AFB, NM; and M. J. Owens
Photospheric magnetic field synoptic maps serve as a key driver to all coronal and solar wind models. It is important therefore that these fields are determined as accurately as possible. Measurements of the line-of-sight (LOS) photospheric field near the Sun's poles are often highly unreliable because of their close proximity to the limb (i.e., only a small component of the field vector is directed toward the observer) and because the Sun's rotation axis is inclined 7.25° to the ecliptic plane. The least reliable measurements in photospheric field synoptic maps thus tend to be those located near the poles (i.e., in constructing such maps, individual field measurements far from central meridian have the lowest weighting, while those near central meridian have the highest). Coronal and solar wind models (both simple and advanced) are very sensitive to the Sun's polar fields thus making it especially important that they are known as well as possible. In this study, we apply a polar field correction technique that we have developed [Arge and Pizzo, 2000] to LOS photospheric magnetic field Carrington maps from Mount Wilson and National (at Kitt Peak) Solar Observatories. We then use both the polar corrected as well as the uncorrected maps in the Wang-Sheeley-Arge (WSA) model to determine the improvement in the model's predictions of coronal and solar wind parameters. This is done by comparing the WSA solar wind predictions (i.e., solar wind speed, IMF polarity, and the inclination of the current sheet at sector crossings) at L1 with the observations from the WIND and ACE spacecraft and by comparing observed and predicted coronal holes for a selected set of Carrington maps over the solar cycle. Recorded presentation
Session 4, New Data Sources And Products
Monday, 21 January 2008, 4:00 PM-5:30 PM, 221
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