DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
Login | Review | Submit | Logout | Help
Questions about this website? Contact Andrew LeBlanc Questions about ROF? Contact Chuck Greenfield
| Title | 246: Improve empirical error correction for right-handed plasmas | ||
| Name: | Michael J. Schaffer ( |
Affiliation: | General Atomics |
| Research Area: | Error Fields | Presentation time: | Not requested | Co-Author(s): | LaHaye, Strait, Scoville (expected) |
| Description: | Develop improved empirical error correction for right-handed plasmas. Preferably, I-coil and C-coil -based corrections would both be developed, to give experimenters more flexibility. The new correction(s) are expected to be better than the presently used (but poorly performing) right-handed corrections. | ||
| Experimental Approach/Plan: | Use the previously developed Ohmic, low-density, locked-mode error field test plasma and technique. Choice of the I-coil configuration is still open; present correction uses quartets with 180 deg phasing, but J-K Park's new theory suggests 120 deg phasing will be best. | ||
| Background: | Empirical error field corrections improve operational space for many affected experiments. Right handed plasmas (either Bt or Iplas reversed from normal) are less commonly run than the "normal" or "standard" left handed plasmas. Error correction for right handed plasmas is not as well developed as for left handed. The qualitative consensus of "right handed plasma users" is that the present error correction is inadequate and limits experiments.
New theory by J-K Park et al, PRL (accepted 2007) explains previous DIII-D empirical error correction semiquantitatively, via the coupling between the external error and correction fields with the least stable ideal MHD plasma mode, whose non axisymmetric currents strongly dominate inside the plasma. The theory will help to choose the I-coil configuration (phasing) to begin with. | ||
| Resource Requirements: | I-coil and C-coil systems essential.
Ohmic plasmas --- no NBI. | ||
| Diagnostic Requirements: | -- | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
Print this page