Self-absorption of Hβ line in pellet ablation clouds in devices with magnetic confinement of high-temperature plasma

We have determined the optical absorption depth for Hβ line in clouds of secondary plasma near pellets ablating in high-temperature plasma of devices with magnetic confinement. It is established that, for all values of the electron concentration (1016–3 × 1017 cm−3) and electron temperature (2–5 eV) measured in typical impurity pellet clouds, the absorption is negligibly small. At the same time, it can be significant in clouds of higher density (1017–5 × 1017 cm−3) with a temperature of 1–2 eV, which are typical of cryogenic fuel pellets.