DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 163: How to maximize ELM control resources? | ||
| Name: | Yongkyoon In ( |
Affiliation: | FARTECH, Inc. |
| Research Area: | ELM Control & Pedestal Physics | Presentation time: | Not requested | Co-Author(s): | M. Fenstermacher |
| Description: | The proposal is to investigate how to maximize the ELM control resources. First, we will investigate if ELM suppression is feasible with modulated n=3 field. If the ELM suppression is feasible without operating DC field, we will search for the optimized duty cycles of the pulses, and pulse shapes. However, if n=3 DC field is found to be absolutely needed for ELM control, we can find an operationally feasible way [e.g. only every other I-coils on, with the other I-coils idle]. As a result, the operational strategy to make the most of ELM control resources in ITER can be established. | ||
| Experimental Approach/Plan: | Establish the operational window of ELM suppression in ITER-like plasmas. Once an optimized condition for ELM control is found, modulate the I-coils with square pulses which would allow the I-coils to be running in various frequencies (e.g. tens of Hz, hundreds of Hz, up to thousand of Hz). If ELM suppression is feasible in modulated I-coils, test various types of pulse shapes (e.g. squares, triangle, sinusoidal) with an optimized frequency. If no ELM suppression is achieved using the pulse modulation, the I-coils would be running in DC manner with only every other coils on.
In this operational testing, both odd and even parities can be evaluated. | ||
| Background: | While ITER design review has not been finalized, the midplane ITER coils are expected to have multiple purposes; error field correction, RMP and RWM. Considering that the control resources of power supply and coils are limited, it is important to know the lower and upper limits necessary for each topical purpose. While the error field correction needs to be operated in DC-like manner and RWM would need to be running faster in the order of resistive wall time, it is not clear that the RMP would need n=3 DC field constantly. Once the necessity of DC field for ELM control can be relaxed, the limited resources of power supply and coils can be utilized in more effective way. If the RMP physics demands the steady demands of DC field, the operational strategy to maximize the limited resources needs to be established. | ||
| Resource Requirements: | 5 co-beams | ||
| Diagnostic Requirements: | -- | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | fully independent I-coil control is desirable | ||
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