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== MHD and Alfvén modes == | == MHD and Alfvén modes == | ||
The appearance of low-frequency Magneto-HydroDynamic (MHD) modes (some tens of kilohertz) in electron cyclotron heated plasmas depends on the rotational transform profile and the plasma density. In neutral beam injection plasmas, high-frequency modes (150- to 300-kHz) have been found in plasmas with line densities in the range 0.6 × 10<sup>19</sup> m<sup>-3</sup> to 3 × 10<sup>19</sup> m<sup>-3</sup> and heated with on/off-axis electron cyclotron heating. They are good candidates for global Alfvén eigenmodes related to the low-order resonance n/m = 3/2. | The appearance of low-frequency Magneto-HydroDynamic (MHD) modes (some tens of kilohertz) in electron cyclotron heated plasmas depends on the rotational transform profile and the plasma density. In neutral beam injection plasmas, high-frequency modes (150- to 300-kHz) have been found in plasmas with line densities in the range 0.6 × 10<sup>19</sup> m<sup>-3</sup> to 3 × 10<sup>19</sup> m<sup>-3</sup> and heated with on/off-axis electron cyclotron heating. They are good candidates for global [[Alfvén eigenmodes]] related to the low-order resonance n/m = 3/2. | ||
<ref>[http://www.new.ans.org/pubs/journals/fst/a_1283 R. Jiménez-Gómez et al., ''Analysis of Magnetohydrodynamic Instabilities in TJ-II Plasmas'', Fusion Science and Technology '''51''', 20 (2007)]</ref> | <ref>[http://www.new.ans.org/pubs/journals/fst/a_1283 R. Jiménez-Gómez et al., ''Analysis of Magnetohydrodynamic Instabilities in TJ-II Plasmas'', Fusion Science and Technology '''51''', 20 (2007)]</ref> | ||