- Conference date: 22–26 March 2009
- Location: Monterey (California)
Most tokamak‐based reactor concepts require the use of noble gases to form either a radiative mantle or divertor to reduce conductive heat exhaust to tolerable levels for plasma facing components. Predicting the power loss necessary from impurity radiation is done using electron temperature‐dependent “cooling‐curves” derived from ab initio atomic physics models. We present here a technique to verify such modeling using highly radiative, argon infused discharges on Alcator C‐Mod. A novel x‐ray crystal imaging spectrometer is used to measure spatially resolved profiles of line‐emissivity, constraining impurity transport simulations. Experimental data from soft x‐ray diodes, bare AXUV diodes and foil bolometers are used to determine the local emissivity in three overlapping spectral bands, which are quantitatively compared to models. Comparison of broadband measurements show agreement between experiment and modeling in the core, but not over the entire profile, with the differences likely due to errors in the assumed radial impurity transport outside of the core. Comparison of x‐ray line emission modeling to measurements suggests an additional problem with the collisional‐radiative modeling of that charge state.
- Collision theories
- Ab initio calculations
- Atomic and molecular physics
- Heat conduction
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