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Neoclassical tearing physics in the spherical tokamak MAST
R J Buttery1, O Sauter, R Akers
1EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxfordshire, OX14 3DB, United Kingdom.
Physical Review Letters
|March 23, 2002
Summary
Neoclassical tearing modes, a key performance limit in tokamaks, behave as predicted in spherical tokamaks (STs). Stabilizing field-curvature effects offer hope for avoiding these modes in STs with profile control.
Area of Science:
- Plasma physics
- Fusion energy research
Background:
- Neoclassical tearing modes (NTMs) represent a primary performance limitation in conventional tokamak devices.
- Understanding NTM behavior is crucial for advancing magnetic confinement fusion.
Purpose of the Study:
- To present the first experimental validation of neoclassical tearing mode physics within a spherical tokamak (ST) configuration.
- To assess the applicability of existing theoretical models to NTMs in STs.
Main Methods:
- Experimental analysis of plasma behavior in the MAST spherical tokamak.
- Comparison of experimental results with established theoretical models for NTMs.
- Computational modeling to investigate stabilizing effects.
Main Results:
- NTM behavior in the ST aligns well with current theoretical predictions.
- Sawtooth events were observed to more readily initiate NTMs in the ST scenarios.
- Modeling highlighted the significant role of stabilizing field-curvature effects.
Conclusions:
- Existing theoretical frameworks adequately describe NTM physics in spherical tokamaks.
- Field-curvature effects are important for stabilizing NTMs.
- Optimistic outlook for mitigating NTMs in STs through judicious profile control.
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