Kiel 2004 – wissenschaftliches Programm

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P: Plasmaphysik

P 9: Diagnostische Methoden II

P 9.2: Fachvortrag

Dienstag, 9. März 2004, 15:45–16:05, H\"orsaal H

Radially Resolved Rotational Temperature Profiles of Hydrogen in an Inductively Coupled Plasma — •Mohammed Abdel-Rahman, Volker Schulz-von der Gathen, and Hans-Frieder Döbele — Universität Duisburg-Essen, Campus Essen, 45117 Essen

Rotational temperatures of hydrogen in an inductively coupled RF- discharge are measured by optical emission spectroscopy using the rotational Q-Branch of the Fulcher-α (v=2) system. Radially resolved temperatures are obtained by Abel inversion (Fourier method) of the first 5 Fulcher line intensities measured with a stepper-motor controlled mirror. The rotational temperatures are subsequently calculated from the emissivities. The discharge with an optically accessible distance of 30 mm between coil window and grounded electrode (φ=100 mm) is operated at a pressure of 15 Pa and transceiver powers between 150 and 350 W. The variation of T_rot(r) is examined as a function of power. The behaviour is compared with the emission intensity profile. Results show that there is no time dependence of T_rot obtained neither in H- nor in E-mode in contrast to capacitively coupled discharges. The rotational temperature increases with power. On the central axis the temperature decreases from a maximum near the coil towards the lower grounded electrode. Radially a nearly constant temperature plateau is obtained in the area below the coil which is in the range of 400 K in the E-mode at 150 W and more than 550 K in the H-mode. The rotational temperature falls off rapidly at distances of more than about 40 mm from the discharge axis.