- Conference date: 5-9 Oct 1998
- Location: Nantucket, Massachusetts (USA)
Accurate knowledge of the structured ambient global solar wind flow is a prerequisite for modeling the propagation of solar disturbances, such as coronal mass ejections (CMEs), to Earth. The Wang-Sheeley model (an empirical model which predicts the background solar wind speed and interplanetary magnetic field polarity) can potentially provide such information. We have made a number of modifications to the basic technique that greatly improve the reliability of the model. First, the relationship between the magnetic field expansion factor and solar wind velocity at the source surface has been adjusted to produce a much better statistical fit between the model’s speed predictions and the WIND satellite observations. Second, a method for identifying and removing problematic magnetograms from Wilcox Solar Observatory (WSO) has been developed and applied. Third, we have corrected WSO line-of-sight magnetograms for polar field strength modulation effects that result from the annual variation in the solar b angle. Fourth, we have explored a number of techniques to optimize construction of daily updated synoptic maps from the daily WSO magnetograms. We report on a comprehensive statistical analysis comparing Wang-Sheeley model predictions with the WIND satellite data set. We find that the above modifications to the basic technique measurably improve the model’s predictive performance.
- Solar wind
- Interplanetary magnetic fields
- Solar coronal mass ejection
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