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NTM research opportunities. Presented by D. A. Gates At the MHD SFG meeting August 25, 2005. Motivation. Neoclassical tearing modes are recognized as potentially performance limiting for ITER ITER Physics Basis, Chapter 3.2 Nucl. Fusion 39 (1999) 2251-2389
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NTM research opportunities Presented by D. A. Gates At the MHD SFG meeting August 25, 2005
Motivation • Neoclassical tearing modes are recognized as potentially performance limiting for ITER • ITER Physics Basis, Chapter 3.2 Nucl. Fusion 39 (1999) 2251-2389 • 2/1 NTMs have can lock and cause disruptions • 3/2 NTMs degrade confinement. • There is not a demonstrated ability to predict mode onset from first a first principles theory • Most existing analysis is based on high aspect ratio circular cross-section theory (even for STs!)
NTM modeling developments • Real geometry • Rosenberg, AL, Gates, DA, Pletzer, A, et al. Modeling of neoclassical tearing mode stability for generalized toroidal geometry PHYS PLASMAS 9 (11): 4567-4572 NOV 2002 • Also see work by D. Brennan • Onset criteria • Calculate D’ • Evaluate threshold models (e.g. ion polarization current model and c/ c|| model)
New research opportunities • Include effects of rotation (and shear) on stability • Non-linear effects • FIR (Frequently interrupted regime) (S. Gunther, et al.) • effect of NTMs on confinement • Effect of island size on rotation • Mode coupling • Kinetic models for mode onset
JET-ITER collaboration • The arbitrary geometry code developed by Adam Rosenberg would be a useful contribution to JET-ITER • This would require ~1 man-year of effort to develop the code as a more robust tool