Excitation of internal kink mode by barely trapped suprathermal electrons

Sun, Yuan; Wan, Baonian; Wang, Shaojie; Zhou, Deng; Hu, Liqun; Shen, Biao

doi:10.1063/1.2044467

Cited by 19 publications

(20 citation statements)

References 12 publications

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“…(32) can be obtained from Eqs. (6), (8) and (31), noting that, for resonant particles involved in the δH N L,z dynamics…”

Section: Nonlinear Amplitude Equationmentioning

confidence: 99%

“…Equations ( 4) and ( 12) generalize the electron fishbone dispersion relations, analysed recently [12,13,31], to both trapped and barely circulating fast particles, including (s, α) model equilibrium effects on ωd . A detailed discussion of the circulating electron effect on δ Ŵk was recently given in [32].…”

Section: Resonant Excitation By Trapped and Barely Circulating Supra-...mentioning

confidence: 99%

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Electron fishbones: theory and experimental evidence

et al. 2007

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We discuss the processes underlying the excitation of fishbone-like internal kink instabilities driven by supra-thermal electrons generated experimentally by different means: Electron Cyclotron Resonance Heating (ECRH) and by Lower Hybrid (LH) power injection. The peculiarity and interest of exciting these electron fishbones by ECRH only or by LH only is also analyzed. Not only the mode stability is explained, but also the transition between steady state nonlinear oscillations to bursting (almost regular) pulsations, as observed in FTU, is interpreted in terms of the LH power input. These results are directly relevant to the investigation of trapped alpha particle interactions with low-frequency MHD modes in burning plasmas: in fact, alpha particles in reactor relevant conditions are characterized by small dimensionless orbits, similarly to electrons; the trapped particle bounce averaged dynamics, meanwhile, depends on energy and not mass.

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“…(32) can be obtained from Eqs. (6), (8) and (31), noting that, for resonant particles involved in the δH N L,z dynamics…”

Section: Nonlinear Amplitude Equationmentioning

confidence: 99%

Section: Resonant Excitation By Trapped and Barely Circulating Supra-...mentioning

confidence: 99%

Electron fishbones: theory and experimental evidence

et al. 2007

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“…11 and 12) with LHW injection. Some authors have proposed several theoretical models: the dominant notion proposed by Wong et al, 9 Zonca et al, 8 and Wang et al [13][14][15][16][17] is that the ideal kink mode resonates with barely trapped energetic electrons for they spend longer time on the high field side, resulting in their precessional direction reversing to the same as that of energetic ions.…”

Section: Introductionmentioning

confidence: 97%

Nonideal fishbone instability excited by trapped energetic electrons

2013

Physics of Plasmas

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It is shown that trapped energetic electrons can resonate with the collisionless m ¼ 1 nonideal kink mode, therefore exciting the nonideal e-fishbone, which would often lead to a drop in soft x-ray emissivity and frequency chirping. The theory predictions agree well with the experimental observations of e-fishbone on HL-2A. It is also found that the effects of MHD energy of background plasma might be the reason for the observed phenomena: frequency chirping up and down, and V-font-style sweeping. V C 2013 American Institute of Physics.

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“…fishbone instability [13][14][15]), while they can also change the stability of the TM [16][17][18][19]. Energetic electrons come into play in a similar way although the electron dynamics is different from ions in electromagnetic fields [20,21]. It had been proved that energetic electrons can resonantly destabilize the internal kink either by the drift-reversal effect or due to a negative magnetic shear [22,23].…”

Section: Introductionmentioning

confidence: 99%

On the interaction of energetic electrons with a tearing mode in density-sweeping tokamak plasmas

Lin

Shen

et al. 2015

Nucl. Fusion

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We present a detailed study on the interaction between energetic electrons and the m/n = 2/1 tearing mode (m, n are respectively the poloidal and toroidal mode number) which was investigated in a deliberate experiment via actively controlling the bulk electron density (Li et al 2014 Nucl. Fusion 54 042001). Energetic electrons were generated by the residual loop voltage in the ohmically heated plasma where periodic bursts of magnetic perturbations were frequently observed. The frequency evolution of the mode is similar to the well-known fishbone (m/n = 1/1) or the 'off-axis' fishbone in high-beta plasma (Heidbrink et al 2011 Plasma Phys. Control. Fusion 53 085028), but demonstrates the characteristic of a tearing mode. In particular, it can increase the average intensity of H-alpha radiation as the mode grows, which is distinctive from the following oscillatory phase. The dynamics of the mode are strongly influenced by the increasing background electron density, suggesting a collisionality dependence. This qualitatively agrees with the prediction of a drift kinetic theory.

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Excitation of internal kink mode by barely trapped suprathermal electrons

Cited by 19 publications

References 12 publications

Electron fishbones: theory and experimental evidence

Electron fishbones: theory and experimental evidence

Nonideal fishbone instability excited by trapped energetic electrons

On the interaction of energetic electrons with a tearing mode in density-sweeping tokamak plasmas

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