Jena 2013 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 10: Poster: Plasmadiagnostik
P 10.6: Poster
Mittwoch, 27. Februar 2013, 16:30–18:30, Poster EG
Comparative electron density measurements of microwave interferometry and Langmuir probe diagnostics. — •Christian Küllig, Thomas Wegner, and Jürgen Meichsner — Institute of Physics, University of Greifswald, 17489 Greifswald
Microwave interferometry (MWI) and Langmuir probe diagnostics (LPD) are comparatively applied at a capacitively coupled radio frequency (CCRF) discharge, which is rarely presented in literature. Thereby, the non-invasive MWI directly provides line integrated electron densities ñe,mwi. Whereby, the probe diagnostics provides local electron density ne,p values, but is disturbing the discharge.
This contribution presents results of the LPD regarding the spatial distribution (radial, axial) of the ion saturation current. The current maximum at the position s of the axial profile shows a pressure dependence ∝ p−1/3, like a collision dominated sheath, for CCRF argon and oxygen plasma. Whereby, s corresponds approximately to the mean RF sheath thickness.
Moreover, this contribution shows radial resolved electron density profiles ne(r), which are determined by means of LPD using the Druyvesteyn evaluation.
This radial absolute electron density profiles are numerically integrated (ñe,p=∫ne,p dz) and provide line integrated electron density values.
These can be compared with the line integrated electron density values measured by means of MWI, ñe,mwi.
The line integrated electron density from LPD differs in a factor of 0.37 compared with MWI, which is in good accordance with literature.
// Funded by the DFG CRC/Transregio 24, project B5.