Emissive probe measurement of electron temperature in recombining plasma produced in the linear divertor simulator TPD-II

Emissive probe (EP) measurement of the electron temperature Te, which was proposed by Shindo et al. [Rev. Sci. Instrum. 59 (1988) 2002] is applied to the measurement of Te in the detached recombining plasma produced in the linear divertor simulator. In the determination of Te by the EP method, we consider application limits based on the space-charge-limit effect studied by Ye and Takamura [Phys. Plasmas 7 (2000) 3457]. We have observed that as neutral pressure is increased for developing the plasma detachment, Te obtained with the EP decreases from a few eV to 0.4 eV, on the other hand, the Langmuir probe (LP) method gives anomalously high Te of 3–9 eV. The EP method yields more reliable value of Te than the LP method does. The electron temperature obtained through the spectroscopic method is also shown.