The Physical Properties of Coronal Streamers. II.

Abstract

In this paper the plasma properties of three streamers observed in 2003by the Ultraviolet Coronagraph Spectrometer (UVCS) are presented forfive heights from 1.75 to 5.0 Rsolar. The kinetictemperatures for protons (Tk,p) and the O5+ ions(Tk,O) are derived as a function of height with preferentialheating of O5+ over protons recorded. By examining howTk,p varies with latitude at each height, an idea of themagnetic field morphology is found. At 1.75 Rsolar theelemental abundances (O, S, Ar, and Fe), electron temperature, andelectron density are derived from the UV spectral data. All threestreamers were quiescent with typical abundance values; however, nodepleted cores were found. The first ionization potential (FIP) effectwas detected for all three streamers with a bias of ~4. This isconsistent with slow solar wind in situ measurements, thereby supportingthe hypothetical connection between the two. All three streamers had ahigher than expected electron temperature. The electron densities above1.75 Rsolar are derived from the Large Angle SpectroscopicCoronagraph (LASCO) C2 polarized brightness data. Estimates for theO5+ outflow velocities are obtained using the O VIλ1032 over λ1037 intensity ratios and the estimatedelectron densities. All three streamers showed evidence of significantoutflows at 4.0 and 5.0 Rsolar.