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Plasma Parameters in the COMPASS Divertor During Ohmic Plasmas
Author(s) -
Dimitrova M.,
Dejarnac R.,
Popov Tsv. K.,
Ivanova P.,
Vasileva E.,
Kovačič J.,
Stöckel J.,
Havlicek J.,
Janky F.,
Panek R.
Publication year - 2014
Publication title -
contributions to plasma physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.531
H-Index - 47
eISSN - 1521-3986
pISSN - 0863-1042
DOI - 10.1002/ctpp.201410073
Subject(s) - divertor , plasma , atomic physics , tokamak , distribution function , electron , compass , range (aeronautics) , physics , electron temperature , population , materials science , nuclear physics , demography , quantum mechanics , sociology , composite material
This paper reports on probe measurements of the electron energy distribution function and plasma potential in the divertor region of the COMPASS tokamak during D‐shaped plasmas. The probe data have been processed using the novel first‐derivative technique. A comparison with the results obtained by processing the same data with the classical probe technique, which assumes Maxwellian electron energy distribution functions is presented and discussed. In the vicinity of the inner and outer strike points of the divertor the electron energy distribution function can be approximated by a bi‐Maxwellian, with a dominating low‐energy electron population (4‐7 eV) and a minority of higher energy electrons (12‐25 eV). In the private flux region between the two strike points the electron energy distribution function is found to be Maxwellian with temperatures in the range of 7‐10 eV. The comparative analysis using both techniques has allowed a better insight into the underlying physical processes at the divertor region of the COMPASS tokamak. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)