Composition of quasi-stationary solar wind flows from ulysses/solar wind ion composition spectrometer

Using improved, self-consistent analysis techniques, we determine the avera ge solar wind charge state and elemental composition of nearly 40 ion speci es of He, C, N, O, Ne, Mg, Si, S, and Fe observed with the Solar Wind Ion C omposition Spectrometer on Ulysses. We compare results obtained during sele cted time periods, including both slow solar wind and fast streams, concent rating on the quasi-stationary flows away from recurrent or intermittent di sturbances such as corotating interaction regions or coronal mass ejections . In the fast streams the charge state distributions are consistent with a single freezing-in temperature for each element, whereas in the slow wind t hese distributions appear to be composed of contributions from a range of t emperatures. The elemental composition shows the well-known first ionizatio n potential (FIP) bias of the solar wind composition with respect to the ph otosphere. However, it appears that our average enrichment factor of low-FI P elements in the slow wind, not quite a factor of 3, is smaller than that in previous compilations. In fast streams the FIP bias is found to be yet s maller but still significantly above 1, clearly indicating that the FIP fra ctionation effect is also active beneath coronal holes from where the fast wind originates. This imposes basic requirements upon FIP fractionation mod els, which should reproduce the stronger and more variable low-FIP bias in the slow wind and a weaker (and perhaps conceptually different) low-FIP bia s in fast streams. Taken together, these results firmly establish the funda mental difference between the two quasi-stationary solar wind types.