A newly designed actively water-cooled Langmuir probe for tokamak devices.

Conventional Langmuir probes used in tokamak devices get damaged easily and even melt when exposed to divertor plasma with high thermal and particle loads. Recently, the Institute of Plasma Physics, Chinese Academy of Science, aimed to overcome this issue by designing and manufacturing an uncompensated tungsten/oxygen-free copper (OFC)/CuCrZr-alloy structure-based actively water-cooled Langmuir probe, which showed excellent heat removal capability in finite element analyses (FEA). The heat resistance and antiheat fatigue property of the proposed probe were verified by conducting electron beam high heat flux (HHF) tests. Results show that the maximum temperatures of the probe's tungsten surface were approximately 445 °C and 875 °C under heat loads of 10 and 20 MW/m2, respectively. The probe successfully passed 600 cycles of 10 and 20 MW/m2 thermal fatigue HHF tests. Moreover, no obvious damages were found on the tungsten surface and W/OFC/CuCrZr joints. FEA and HHF test results proved the reliability of the newly designed uncompensated probe. In view of this progress, it is promising to apply this actively water-cooled probe in tokamak devices for plasma diagnostics. [ABSTRACT FROM AUTHOR]