Soft X-ray emission spectra from highly charged tungsten ions as a quantitative diagnostic of fusion plasmas
Abstract
Future tokamak scenarios will incorporate high-Z plasma facing components. The ASDEX Upgrade divertor tokamak is studying conventional and advanced plasma scenarios with a central column whose face exposes 6.5 m^2 of tungsten tiles to the hot plasma. Moderate resolution X-ray spectra are recorded with a Bragg crystal spectrometer; emission from N- and M-shell W ions (W^41+ to W^50+) is observed from the plasma core. A Johann-type spectrometer serves as a high resolution monitor of important X-ray diagnostic lines. ADAS compatable tables of photon emission coefficients (PECs) for the above W ions have been computed with a detailed collisional-radiative model. The PECs have been calculated with special attention to the contribution from inner-shell ionization and dielectronic recombination to the line emission. Using the tabulated PECs and a impurity transport code, the absolute signals from the highly charged W ions have been simulated. W concentrations in the range of 10-6 up to a few × 10-5 have been extracted, depending on the configuration and plasma operation mode.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- October 2001
- Bibcode:
- 2001APS..DPPQP1052F