Theoretical model for study of the voltage–current curve of a Langmuir-probe used in the hot region of the ECR plasma

In the last years the ATOMKI-ECRIS group started a local plasma diagnostics research project, to adapt the probe to the ECR plasma conditions. Until now we made progress in the study of the cold plasma region. The results has been reported in e.g. [L. Kenéz, S. Biri, J. Karácsony, A. Valek, Nucl. Instrum. Methods Phys. Res. B 187 (2) (2002) 249; L. Kenéz, S. Biri, J. Karácsony, A. Valek, T. Nakagawa, K.E. Stiebing, V. Mironov, Rev. Sci. Instrum. 73 (2) (2002) 617]. In this Letter we make a step further report the first experiments carried out in the hot ECR plasma. We used a simple probe inserted in the hot resonant plasma. We point out that this probe works as emitting probe. We developed a theoretical model to explain the unusual shaped voltage–current characteristics and tested its validity using computational study of the presented theory.