Plasma Diagnostics of the Large-Scale Corona with SUMER. I. Measurements at the West Limb
Abstract
In the present work we analyze the physical properties of the quiet-Sun plasma measured in a 0.5×1.8 Rsolar region above the west solar limb (Rsolar=solar radius). We make use of large scans obtained with the SUMER spectrometer on board SOHO to construct two-dimensional spatial maps of line intensities, electron temperature, emission measure, element abundances, line widths and nonthermal velocities, and photoexcitation effects covering the entire field of view. Electron densities were measured in a more limited portion of the field of view. The aim of the paper is to identify tracers of coronal hole and quiet-Sun plasma at high altitudes that allow us to measure the position of the coronal hole/quiet-Sun boundaries, and to provide a comprehensive, empirical picture of the off-limb solar corona that can provide theoreticians with experimental constraints to their models of the large-scale coronal structure, coronal heating, and solar wind acceleration.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2006
- DOI:
- 10.1086/503247
- Bibcode:
- 2006ApJ...643.1258L
- Keywords:
-
- Atomic Data;
- Plasmas;
- Sun: Corona