DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 114: Test of TGLF transport model in pedestal | ||
| Name: | Richard Groebner ( |
Affiliation: | General Atomics |
| Research Area: | ELM Control & Pedestal Physics | Presentation time: | Not requested | Co-Author(s): | P. Snyder |
| Description: | Produce H-mode discharges with long ELM-free period and with long inter-ELM periods. Characterize pedestal in great detail, both during the ELM-free phase and during the inter-ELM phase, for use in benchmarking the TGLF transport model in the pedestal. (These data will also be useful for testing other models.) | ||
| Experimental Approach/Plan: | Produce long ELM-free discharge (118897 would be good target). Use breathing and high time resolution CER to obtain profiles with high spatial resolution as a function of time in the ELM-free phase and early in the ELMing phase. Use edge MSE to obtain data for q profile. Obtain pedestal profiles of density fluctuation level and radial correlation length. Obtain this data set at different values of q95, achieved by changing Bt. | ||
| Background: | On June 16, 2004, an experiment was performed to characterize the pedestal for purposes of providing a dataset to be used in benchmarking the TGLF code. This dataset has been very useful for a number of edge modeling projects, including some initial testing of the TGLF code. However, this dataset is showing its age. We now know how to obtain improved data with the diagnostics used in 2004 but more importantly, we have new diagnostics which can be used to measure important quantities not available in 2004. These include the edge MSE to provide q (and magnetic shear) profiles, the quadrature reflectometer to obtain profiles of density fluctuations in the pedestal and the edge profile reflectometer to obtain highly resolved edge density profiles. In addition, the new Te fluctuations diagnostic could be used to obtain useful data at the inner edge of the pedestal. Thus, we can now obtain a much improved dataset for benchmarking TGLF (and other edge codes) and we propose to do so. | ||
| Resource Requirements: | All beams needed except 210 sources.
Lower cryopump. | ||
| Diagnostic Requirements: | TS, CER, CO2, edge MSE, BES, quadrature reflectometer, profile reflectometer, Te fluctuations diagnostic | ||
| Analysis Requirements: | Analyze diagnostic data to obtain best profiles at several different times during evolution of ELM-free pedestal. Use CER (and edge MSE, if possible) to obtain profiles of edge Er shearing rate. Compare these to maximum linear growth rates from TGLF to see if pedestal occurs where ExB shearing rate exceeds turbulence growth rate. When non-linear version of TGLF is available in a transport code, use the model to see if it can predict the observed build-up of the pedestal and evolution of density fluctuation level. | ||
| Other Requirements: | -- | ||
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