SOHO ‐ Ulysses Spring 2000 Quadrature: Coronal Diagnostic Spectrometer and SUMER Results

Abstract

We present results from SOHO/CDS and SOHO/SUMER coordinated observations of coronal streamers made during the spring 2000 quadrature of SOHO, the Sun, and Ulysses. These observations form part of the JOP 112, which is primarily aimed at investigating the composition of the regions of the corona and the solar wind observed by both SOHO and Ulysses. SU MER and CDS observed the low corona from the limb up to about 1.3 R ⊙ from the Sun center. The physical parameters of the plasma, such as electron density, temperature, emission measure, and composition, are measured along the radial direction, toward Ulysses. The variation in these parameters over the 6 day series of observations was examined, and no significant change was seen. The dependence of these parameters on the solar latitude was also investigated. The results indicate that the observed streamers are homogeneous, of coronal composition, and nearly in hydrostatic equilibrium. The structures remained almost stable during the whole period of the observations.