Thermography of the divertor floor tiles during neon injection in TCV
An infrared (IR) thermography system viewing the tokamak à configuration variable (TCV) lower divertor target tiles has recently been installed to monitor tile temperature and hence deposited power flux at the outer strike zone of ohmic single null lower diverted discharges in the TCV standard shot configuration. Operating the IR-camera in both fast line scan mode and two-dimensional image mode, first results are presented during detached divertor experiments with Neon injection. During L-mode without Neon injection approximately 50% to 60% of P(SOL) reaches the outer strike zone on the divertor tiles. In contrast, during Neon injection, power flux reductions of a factor of typically between 1.5 and 2 are obtained, consistent with the partial detachment observed by tile mounted Langmuir probes. The power flux reduction is accompanied by a broadening of the power deposition profile. In many discharges, particularly at higher current, H-mode transitions occurred followed both by ELMy and edge localized mode (ELM)-free periods. The ELMs are seen as bursts of power deposition and a 3 to 4 times broader profile compared with the ELM-free phase. The energy expelled by an individual large ELM is between 8% and 12% of the total stored energy.
Bibliographic Reference: Article: Bulletin of the American Physical Society, Vol. 42 (1997) No. 10, p.1858
Record Number: 199810137 / Last updated on: 1998-02-12
Original language: en
Available languages: en