The density structure of a solar polar coronal hole

Abstract

Electron densities derived from Si III, Ne VII, Mg VIII, Si VIII, and Mg IX line ratios observed above the limb of a polar coronal hole with the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on the Solar and Heliospheric Observatory (SoHO) are presented. The electron densities are consistent with a constant pressure of 1.6×10¹⁴cm^-3K (logP_e=14.2).