DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 107: neutral beam injection for MSE calibration and comparison of NBCD with code calculations | ||
| Name: | Jay Jayakumar ( |
Affiliation: | Lawrence Livermore National Laboratory |
| Research Area: | Heating & Current Drive | Presentation time: | Not requested | Co-Author(s): | Mike Makowsi, Chris Holcomb |
| Description: | MSE Calibration- Both in-vessel and beam-in-gas calibration techniques have less than the required correlation with MSE calibration under plasma conditions. In the past discharges with Ip ramp and pulsed beams have been used in conjunction with kinetic fits to calculate current profile and calibrate MSE offsets, in turn. However, since the beam power and energy are high compared to the background plasma, beam injection causes non-steady state conditions, where thermal and current profiles are evolving during and between pulses. It is likely that the plasma is also moving during these pulses. Therefore, Ip ramp discharges with beam pulses will be obtained and time dependent TRANSP will be carried out with the results coupled to free boundary equilibrium evolution in CORSICA. In addition, discharges with one steady beam and one pulsed beam will be obtained so that the pulsed beam is not a major perturbation compared to the background energy and power. Since changes in current profile are more accurately obtained by MSE compared to absolute current density profile, change in MSE angles would give NBCD profiles accurately as in ECCD experiments. Careful free boundary effects need to be included through TRANSP and CORSICA analysis would be required. High quality temperature, density and radial electric field measurements with fast-ion diagnostics would be needed to carry out this experiment.
These experiments would be repeated for Hybrid plasmas where controlled beam pulses would be applied to compare calculated plasma response and observed change in electric field, current profile and neutron flux. These experiments would be repeated for high beta shot start up conditions with high q conditions. During the above, beam attenuation will also be monitored using MSE and BES intensities. Additional experiments with a well defined ECCD would also be useful in consistency checks. | ||
| Experimental Approach/Plan: | Low impurity plasma is required to minimize systematic errors in MSE system.
Accurate diagnostic capabilities including BES and if possible, reflectometry would be used. * Shots with Ip ramp with 30 left pulses over either no beam or selected steady beams. * Shots with beam pulses during flat top conditions, low beta discharges. * low rotation discharges. All shots preferably with L-mode. | ||
| Background: | -- | ||
| Resource Requirements: | Up to 5 beams one of which has to be 30 left and the other 330 left, one of them a counter beam and another 210 beam. | ||
| Diagnostic Requirements: | MSE, Thomson with CO2, ECE, CER with required beams (pulsed), BES | ||
| Analysis Requirements: | Extensive TRANSP and CORSICA analysis | ||
| Other Requirements: | -- | ||
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