Hydrocarbon transport in a laboratory plasma (MAP)

Hydrocarbons are admitted into a laboratory plasma in order to investigate the transport processes of carbon-containing molecules in relation to redeposition processes in a fusion boundary plasma. When CH4 was introduced into the plasma, CH radical band spectra were optically identified, while in the case of C2H2 introduction, C2 radicals were also identified in addition to CH radicals. With respect to the axial transport in the plasma the characteristic decay length of the spectral intensity of the CH-radical band was smaller than that of the C2 radical band. The excitation temperature determined from the CH and C2 band spectra was observed to increase on approaching the target.