DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 271: ECH Modification and Control of Pedestal Profiles | ||
| Name: | Phil Snyder ( |
Affiliation: | General Atomics |
| Research Area: | ELM Control & Pedestal Physics | Presentation time: | Not requested | Co-Author(s): | -- |
| Description: | Because turbulent transport is very sensitive both to details of the temperature profiles, as well as Ti/Te, eta_i and eta_e, it is possible in certain regimes to strongly modify profiles, including the density profile by using local ECH heating. In ELMing H-mode discharges, confinement in the edge barrier region is generally so good that profiles continuously rise until an ELM is triggered. At low density, it appears that the Te profile can approximately saturate, but density remains uncontrolled and rises until ELMs are triggered. Most ELM control techniques (eg RMP and QH) appear to work by providing additional particle transport in order to control the density profile and avoid ELMs. Here we would attempt to achieve a similar effect by modifying the turbulent transport in the edge region with ECH. Preliminary studies of both ECH heating efficiency in various edge regimes, as well as TGLF studies of various mode growth rates and expected fluxes are needed to do a detailed experimental plan. | ||
| Experimental Approach/Plan: | Locate a regime in which turbulent transport, particularly particle transport, in the pedestal region is expected to be strongly sensitive to the Te profile and/or Ti/Te, and in which ECH can be efficiently coupled to the edge. Use ECH at varying power and radius to impact local transport. Goal is to control the density profile. Use discharges with a long initial ELM free period and a long ELM period and study detailed profile evolution and turbulent fluctuations. | ||
| Background: | -- | ||
| Resource Requirements: | -- | ||
| Diagnostic Requirements: | -- | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
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