Published online by Cambridge University Press: 04 July 2016
At the very high flight speeds of ballistic missiles, re-entering satellites and meteorites, the air in contact with the body may attain very high temperatures and may even become ionised. For example, the air in the stagnation region of a low-drag ballistic missile re-entering the Earth's atmosphere can reach a temperature of 8000°K and the electron density may be as high as 1016 per c.c. In any experimental work on high enthalpy flow it therefore becomes necessary to have techniques for measuring these high temperatures and high electron densities. The aim of the present paper is to describe techniques for measuring these quantities.