Simulation of light emission from hydrocarbon injection in TEXTOR using the ERO code

Abstract

Reaction rate coefficients for higher hydrocarbon molecules (ethane family) have been implemented into the 3D Monte Carlo code ERO, which is used for modelling of hydrocarbon transport and light emission of spectroscopically observable radicals in the edge plasma of fusion experiments. For benchmarking of the ERO modelling, dedicated experiments were carried out at TEXTOR in which different hydrocarbon molecules (CD4, C2D4 and C2D6) were injected into the plasma near the last closed flux surface. The light emission of the hydrocarbon break-up products CD, C2 and C+ was observed. The modelled penetration depths of the light emission from the CD Gerö-band, C2 Swan band and C II are in good agreement with the experiments. The effective inverse photon efficiencies (D/XB values) for CD and C2, which include the dissociation chains of the initial molecules, are more dependent on local electron temperature than on electron density. The calculated D/XB values are in fair agreement with the experimental ones.