DIII-D RESEARCH OPPORTUNITIES FORUM FOR THE 2008 EXPERIMENTAL CAMPAIGN
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| Title | 31: Parametric dependencies of RWM damping in rotating plasmas | ||
| Name: | Holger Reimerdes ( |
Affiliation: | Columbia University |
| Research Area: | RWM Physics | Presentation time: | Not requested | Co-Author(s): | S.A. Sabbagh |
| Description: | Compare RWM damping under varying plasma conditions (e.g. ion collisionality, plasma rotation) for a test of RWM theory (joint experiment with NSTX). | ||
| Experimental Approach/Plan: | Measure RWM damping in high beta plasmas using active MHD spectroscopy under changing plasma conditions. We can vary the electron density to confirm NSTX observations of increased RWM damping (lower critical rotation) with increasing ion collisionality. Furthermore, we plan to vary the plasma rotation using simultaneous co- and counter-NBI to test predictions of decreasing RWM damping with increasing plasma rotation. | ||
| Background: | NSTX magnetic braking experiments showed a variation of the rotation threshold with ion collisionality, nu_ii. Increasing nu_ii by almost an order of magnitude resulted in a significantly lower (about 30%) critical rotation [Sontag, Sabbagh, Zhu et al. Nucl. Fusion 47 (2007) 1005]. Kinetic theory including trapped particle precession can predict less stability at intermediate rotation values. | ||
| Resource Requirements: | 5 co- and 2 counter-NBI | ||
| Diagnostic Requirements: | -- | ||
| Analysis Requirements: | -- | ||
| Other Requirements: | -- | ||
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