DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 73: Mach Number Scan With Similar Parameters as JT-60U | ||
| Name: | C. Craig Petty ( |
Affiliation: | General Atomics |
| Research Area: | Transport | Presentation time: | Not requested | Co-Author(s): | E. J. Doyle, Yoshihiko Koide, Yoshiteru Sakamoto, Hajime Urano |
| Description: | The goal of this joint experiment is to determine the effect of Mach number on H-mode transport over a large range of rho* and a small range of aspect ratio. New machine capabilities allow us to perform a similarity experiment between JT-60U and DIII-D where the Mach No. (rotation) is varied from positive to negative values using co-/counter-/balanced-NBI. | ||
| Experimental Approach/Plan: | Perform three step comparison, as follows: (1) Both tokamak should scan the Mach number from positive to negative values using co-/counter-NBI at constant density, temperature, current, and magnetic field in H-mode plasmas. Keeping the plasma parameters fixed rather than the NBI power fixed will simplify the interpretation of the data because we will not have to worry about the effects of beta, collisionality, or relative gyroradius scaling on transport. (2) To help project the effect of rotation scaling of transport to ITER, each tokamak should make a second Mach number scan at a different rho* value. The plasma beta, collisionality, safety factor, and range of Mach numbers studied should be the same for the two different rho* values. This will allow us to determine whether the effect of Mach number on transport becomes stronger or weaker for larger devices like ITER. (3) The experiments on JT-60U and DIII-D should be joined together by matching the important dimensionless parameters. Since JT-60U has a higher aspect ratio than DIII-D, it is better to match the poloidal parameters rather than the toroidal parameters. Thus the two machines can match beta_poloidal in addition to collisionality and safety factor. The difference in the rho*_poloidal values should be made as small as possible by comparing a high field case on DIII-D to a low field case on JT-60U. The poloidal cross-section of the two devices should also be matched as well as possible. | ||
| Background: | Similarity experiments provide a powerful tool with which to investigate transport physics. Here, we propose to utilize this tool to investigate the effect of plasma rotation (Mach no.) on transport. This is ITPA Joint Proposal TP-6.2. | ||
| Resource Requirements: | NBI: At least 5 sources. | ||
| Diagnostic Requirements: | -- | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
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