Optical Spectroscopy for the Investigation of Transient Plasmas

This chapter is dedicated to the presentation of basic concepts of plasma diagnostics via spectroscopy techniques, including optical emission spectroscopy and absorption spectroscopy. The measurements of temperature and electron density are illustrated via several examples of transient atmospheric plasmas generated by electrical and optical discharges, for which the validity conditions and the measurements limitations are discussed. Finally, the influence of self-absorption on plasma emission is discussed, and the appropriate modeling using the radiation transfer equation is introduced. This chapter is addressed to beginners in optical spectroscopy to help them discovering this very powerful technique. Readers wishing to use this technique to diagnose their plasmas are advised to consult more specialized books.