DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
Login | Review | Submit | Logout | Help
Questions about this website? Contact Andrew LeBlanc Questions about ROF? Contact Chuck Greenfield
| Title | 189: Model Validation of Electron Transport Using Modulated ECH | ||
| Name: | Kenneth Gentle ( |
Affiliation: | University of Texas |
| Research Area: | Transport Model Validation | Presentation time: | Not requested | Co-Author(s): | -- |
| Description: | Many workers, for example Ross, Mikkelson, and Bravenec, have each noted that validation comparisons often prove inconclusive because uncertainties in the input parameters (density profiles, impurity profiles, etc.) can accommodate a rather broad range in predictions. One simple type of modulated ECH experiment might offer a better opportunity for testing predictions of electron thermal transport. The most rigorous test, comparing Te(r,t) over the profile and modulation period, is not yet practical. Instead, we can take advantage of the experimental observation that for square-wave modulation at typical periods, the discharge follows a nearly exponential relaxation to alternate baseline and heated states. A code like GYRO could be run for either an annulus or full plasma for the baseline (adjusted to fit within uncertainties) and heated states. The test is whether the difference in the model predictions for the two conditions matches the experimental difference. The advantage is that the poorly known inputs would be known not to change over the comparatively short modulation cycle. Experimentally, averaging over many modulation periods gives a precise determination of the differences, and the higher ECH power to be available on DII-D will greatly improve signal-to-noise in both data and model. The test can be done in whatever radial range is most appropriate for the model and for any conditions accessible from early beam heating to delay sawteeth. | ||
| Experimental Approach/Plan: | -- | ||
| Background: | -- | ||
| Resource Requirements: | -- | ||
| Diagnostic Requirements: | Full set of standard diagnostics for transport analysis plus fluctuation diagnostics appropriate to model prediction. | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
Print this page