Temporal Evolution of a Streamer Complex: Coronal and in Situ Plasma Parameters

Abstract

In this paper we report on observations acquired by the Ultra Violet Coronagraph Spectrometer (UVCS) aboard the Solar and Heliospheric Observatory (SOHO), from 10 to 17 June 2000, at the time of a SOHO-Sun-Ulysses quadrature. UVCS took data at 1.6 and 1.9 solar radii, with a slit normal to the solar radius and centered along the radial to Ulysses. A streamer complex was sampled by UVCS, throughout the quadrature campaign, giving us the opportunity to derive plasma parameters in different streamers, and to compare them with plasma properties measured in situ. Large Angle Spectroscopic Coronagraph (LASCO) images above 2 solar radii helped us understand the temporal evolution of the streamer complex. We derive densities, temperatures and elemental abundances in two streamers, which have different temperatures and element abundances. In spite of these differences, both structures have the same FIP bias. The Fe/O ratio, which may be considered a proxy for the FIP effect, was measured (\it in situ} by the Solar Wind Ion Composition Spectrometer (SWICS) aboard the Ulysses spacecraft. Values of Fe/O measured in the corona, at the sites where in situ plasma originated, agree with in situ Fe/O values.