Density diagnostics and inhomogeneous plasmas. I - Isothermal plasmas
Abstract
The problem of interpreting density-sensitive line strengths from an isothermal plasma of inhomogeneous density is addressed. In the case of two observed lines, the results may be expressed in terms of a spectroscopic mean density which is the density of a homogeneous plasma with the same line ratio. The spectroscopic mean density value will vary for different line pairs, and differ from the volumetric mean and emissivity mean unless the plasma is actually homogeneous. Illustrative diagnosis of an exponential atmosphere model demonstrates how large a variation in density ratio can occur and how this variation serves to measure the plasma inhomogeneity. This effect explains the different densities commonly inferred for the same source by application of different diagnostic line pairs. As the number of lines observed is increased, in principle a complete solution for the plasma structure and correct total volume is approached.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- October 1989
- Bibcode:
- 1989A&A...224..328A
- Keywords:
-
- Nonuniform Plasmas;
- Plasma Diagnostics;
- Solar Atmosphere;
- X Ray Spectroscopy;
- Density Distribution;
- Isothermal Processes;
- Line Spectra;
- Plasma Density;
- Plasma Temperature;
- Plasma Physics