Abstract
The distribution of excited states of He atoms in the presence of plasma electrons is studied theoretically and experimentally. It is shown that (a) excitation transfer is important when the electron density exceeds a few times 1016 m-3 and that (b) with increasing electron density, the relative population of levels with the same main and spin quantum numbers approaches a thermal equilibrium between such levels, even when the system is very far from equilibrium in other respects.