Control of Asymmetric Magnetic Perturbations in Tokamaks

[摘要] The sensitivity of tokamak plasmas to very small deviations from the axisymmetry of the magnetic field |δ→(over)Β/→(over)Β|≈ 10–4 is well known. What was not understood until very recently is the importance of the perturbation to the plasma equilibrium in assessing the effects of externally produced asymmetries in the magnetic field, even far from a stability limit. DIII-D and NSTX experiments find that when the deleterious effects of asymmetries are mitigated, the external asymmetric field was often made stronger and with an increased interaction with the magnetic field of the unperturbed equilibrium fields. This paper explains these counter intuitive results. The explanation using ideal perturbed equilibria has important implications for the control of field errors in all toroidal plasmas.

[发布日期] 2007-10-03

[学科分类] 原子、分子光学和等离子物理

[关键词] DOUBLET-3 DEVICE;MAGNETIC FIELDS;PLASMA;SENSITIVITY;STABILITY MHD;Tokamaks