Book contents
- Frontmatter
- Contents
- Preface to the first edition
- Preface to the second edition
- 1 Plasma diagnostics
- 2 Magnetic diagnostics
- 3 Plasma particle flux
- 4 Refractive-index measurements
- 5 Electromagnetic emission by free electrons
- 6 Electromagnetic radiation from bound electrons
- 7 Scattering of electromagnetic radiation
- 8 Neutral atom diagnostics
- 9 Fast ions and fusion products
- Appendix 1 Fourier analysis
- Appendix 2 Errors, fluctuations, and statistics
- Appendix 3 Survey of radiation technology
- Appendix 4 Definitions and identities of fundamental parameters
- Appendix 5 Atomic rates for beam diagnostics
- Glossary
- References
- Index
6 - Electromagnetic radiation from bound electrons
Published online by Cambridge University Press: 23 November 2009
- Frontmatter
- Contents
- Preface to the first edition
- Preface to the second edition
- 1 Plasma diagnostics
- 2 Magnetic diagnostics
- 3 Plasma particle flux
- 4 Refractive-index measurements
- 5 Electromagnetic emission by free electrons
- 6 Electromagnetic radiation from bound electrons
- 7 Scattering of electromagnetic radiation
- 8 Neutral atom diagnostics
- 9 Fast ions and fusion products
- Appendix 1 Fourier analysis
- Appendix 2 Errors, fluctuations, and statistics
- Appendix 3 Survey of radiation technology
- Appendix 4 Definitions and identities of fundamental parameters
- Appendix 5 Atomic rates for beam diagnostics
- Glossary
- References
- Index
Summary
Atoms and ions of the working gas and trace impurities emit radiation when transitions of electrons occur between the various energy levels of the atomic system. The radiation is in the form of narrow spectral lines, unlike the continuum of free-electron radiation such as bremsstrahlung. It was, of course, the study of these spectral lines that originally led to the formation of the quantum theory of atoms.
Because of the enormous complexity of the spectra of multielectron atoms it would be inappropriate here to undertake an introduction to atomic structure and spectra. Many excellent textbooks exist [e.g., Thorne (1974) or, for a more complete treatment, Slater (1968)] that can provide this introduction at various levels of sophistication. Instead we shall assume that the energy level structure of any species of interest is known, because of experimental or theoretical spectroscopic research. Then we shall discuss those aspects of spectroscopy that more directly relate to our main theme, plasma diagnostics. It is fairly well justified for neutral atoms and for simpler atomic systems with only a few electrons, to assume that spectral structure is known (speaking of the scientific enterprise as a whole, not necessarily for the individual student!). It is not so well justified for highly ionized heavy ions that occur in hot plasmas. The spectra of such species are still a matter of active research; therefore, it should not automatically be assumed that all aspects of these spectra are fully understood. However, for those diagnostic purposes that we shall discuss, the gaps in our knowledge are not particularly important.
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- Information
- Principles of Plasma Diagnostics , pp. 217 - 272Publisher: Cambridge University PressPrint publication year: 2002