Verification of the algorithm for emission tomography of plasma inhomogeneities in a plasma-chemical reactor using the Langmuir multiprobe

The few-view emission tomography (ET) of plasma, which introduces physical properties of objects into a reconstruction algorithm, requires a reliable experimental verification using independent methods for validating an adopted model of plasma inhomogeneities. The chosen test object—low-temperature argon plasma in a reactor with a remote plasma source—allows one to study the two-dimensional spatial distribution of a concentration of Ar+ ions, which is calculated using the two-view ET, and to verify results using direct measurements by a Langmuir multiprobe located in the plane of tomographic scanning. Studies are carried out for the chamber pressure 2–12 mTorr; the sensitivity of the ion-field homogeneity to the external magnetic field is estimated. A close agreement between concentration fields of Ar+, which are measured and reconstructed by tomography, is obtained. The divergence between the probe method and the ET data reconstruction with respect to two views is not above 10%.