Target Langmuir (electrostatic) probe array is a crucial diagnostics to measure target plasma parameters such as electron temperature (Te) and electron density (ne).
Profiles of ion saturation current (Isat), electron temperature (Te) and floating potential (Vf) at the divertor target are measured directly.
Studies of a cold and dense divertor and detached divertor plasmas have been accomplished. SOL/divertor plasma density and temperature are evaluated using an interpretative divertor code based on the Langmuir probe data. These SOL/divertor plasma data are also used for transport studies of neutrals and impurities such as carbon ions.
Langmuir probes are mounted on the divertor target tiles
Shape: All Dome-type, 6 mm diameter, 1.3(1.2~1.5) mm protruded.
Materials: Carbon Fiber Composite.
|Type:||(1)||Single-probe array (inboard 9 and outboard 9 poloidal locations):
Is, Te, Vf profiles are provided routinely with 1-10ms time resolution (from 2003).
|(2)||Single-probe array (inboard 6 and outboard 6 poloidal locations):
Vf profiles are provided routinely with 0.01-0.1mstime resolution (from 2005).
|(3)||Single-probe array (8 Upper-Inner first wall):
Is, Te, Vf profiles are provided with 2-20ms time resolution (from 2005), only in case that the plasma approaches the probe.
|KS4020 system (14ch):||Is, Te, Vf measurements at 10 locations near strike points, V-scan period of typ. 1-20 ms with typ. 200-20kHz sampling.
512kwords/channel, signal resolution of 12bits (+-2048).
Maximum 5 "Burst period" (faster sampling mode: up to 500kHz) is available.
|KS4008 system (32ch):||Is, Te, Vf measurements at 8 locations on upper divertor tiles, V-scan period of typ. 1-20 ms with typ. 200-20kHz sampling, 512kwords/channel, signal resolution of 16bits (+-32768).
Maximum 5 "Burst period" (faster sampling mode: up to 130kHz) is available, and Vf measurements at 12 locations with 20-100kHz sampling, and Is, Te, Vf measurements at 8 locations on upper-inner first wall.