DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 245: Real time disruption detection/mitigation | ||
| Name: | Michael Walker ( |
Affiliation: | General Atomics |
| Research Area: | Disruptions | Presentation time: | Not requested | Co-Author(s): | Al Hyatt, Dave Humphreys, Eric Hollmann, Phil West |
| Description: | Begin implementation of basic disruption detectors. Then integrate with a disruption mitigation trigger (for massive gas puff or other mitigation scheme). Eventual target is to demonstrate routine detection and mitigation of all disruptions, but build this capability in a stepwise manner over several operational campaigns. Begin this year concentrating on disruptions in Ip rampdown. Develop rampdown scenarios relevant to ITER operations. | ||
| Experimental Approach/Plan: | Begin with implementation of some basic disruption detection algorithms in the PCS for real time use. First, execute in real-time code in a non-interfering manner. Next, phase in disruption mitigation, but trigger only if disruption occurs during the Ip ramp-down. If this type of operation will be accepted as a piggyback on sufficiently many experiments, no dedicated time is needed. If not, then request a half day to either demonstrate no adverse effects on experiments or develop methods to prevent adverse effects. Incorporate additional and improved detection logic as understanding of disruption precursors improves. Enable triggering of alternative mitigation methods to support experimental testing of these methods.
Experiment with control scenarios relevant to ITER that incorporate various combinations of reductions in heating, shape modification, and disruption detection and mitigation. Coordinate with work on disruption data base for development of disruption detectors and with people working on disruption mitigation physics to obtain good data for physics studies. Develop database of effects on early phase of subsequent discharge after mitigated and unmitigated disruptions. Monitor impurity line emission and radiated power during breakdown and burn-through, gas fueling to reach target density, volt-second consumption, and early MHD activity. | ||
| Background: | The problem of disruption detection and mitigation is critical for ITER, and especially relevant in rampdown since there presently appears to be no viable rampdown scenario for ITER operation. Many of the causes of disruptions are well known and, in some cases, real-time capable detection algorithms already exist. Studies of disruption mitigation have been ongoing at DIII-D for several years, so the mitigation actuators are in place and mature. It has been possible �??in principle�?� for some time to do routine disruption and mitigation for DIII-D plasmas, but the ability to do this routine process has never actually been demonstrated. In addition, the relevance of the mitigation scenarios to ITER has not yet been demonstrated. | ||
| Resource Requirements: | Machine Time: 4 hour experiment + piggybacks
Number of neutral beam sources: >=4 PCS programming support for implementation of detection and triggering logic. | ||
| Diagnostic Requirements: | -- | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
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