EXPERIMENTAL-STUDY OF THE INFLUENCE OF ION-DYNAMICS TO THE SHAPE OF HE-II P-ALPHA AND P-BETA LINES

Using a pulsed low pressure discharge in helium-hydrogen mixture, Star k broadened profiles of the first two Pashen lines of He II have been investigated. The electron density in the range (2.3-2.8) x 10(16)cm(- 3) was measured with a He-Ne laser interferometer at 3.39 mu m. The in tensity ratio of the He II 320.31nm and He I 318.77nm was employed to determine the electron temperature ranging from 34 000-38 000 K. At th ese experimental conditions profiles of investigated He II lines were recorded and compared with corresponding theoretical line shapes. Our experimental half widths for both lines are in agreement with several other experiments and some theoretical calculations. The inclusion of ion dynamics in the evaluation of the central part of P(b)eta line con siderably improves the agreement between the experiment and the theory .