Resonant and non-resonant internal kink modes excited by the energetic electrons on HL-2A tokamak

Yu, Liming; Chen, W.; Jiang, M.; Shi, Z.B.; Ji, X.Q.; Ding, X.T.; Li, Y.G.; Ma, Rui; Shi, P.W.; Song, Shaodong; Yuan, B.S.; Zhou, Yan; Song, X.M.; Dong, J. Q.; Xu, M.; Liu, Y.; Yan, L.W.; Yang, Qingwei; Xu, Yuhong; Duan, X.R.; Team, Hl A

doi:10.1088/1741-4326/aa4f5e

Cited by 43 publications

(31 citation statements)

References 32 publications

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“…We investigate the well-understood positive shear safety factor profile first, to validate our results. Then, we increase q 0 from 0.94 to 0.99 then 1.01, to investigate the non-resonant mode [26] regime of q 0 > 1 with no q = 1 rational surface existing. It is found that even if the mode is non-resonant due to the absence of q = 1 surface, it is still unstable due to energetic ions drive.…”

Section: Numerical Resultsmentioning

confidence: 99%

Energetic-ion excited internal kink modes with weak magnetic shear in ${{\boldsymbol{q}}}_{0}\gt 1$ tokamak plasmas

Chen

Wang

et al. 2017

Chinese Phys. B

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The energetic particle driven internal kink mode is investigated in this paper for q 0 > 1 tokamak plasma with weak magnetic shear. With the effect of energetic particles, the m/n = 1/1 internal mode structure in tokamak plasma does not appear as a rigid step-function when safety factor passes through q = 1 rational surface. It is found that even when the rational surface is removed, the mode may be still unstable under the low magnetic shear condition if the energetic particle drive is strong enough; with the low shear region of safety factor profile widening, the mode becomes more unstable with its growth-rate increasing. Furthermore, we find that the existence of the q = 1 rational surface does not have a significant effect on the stability of the plasma if energetic particles are present, which is very different from the scenarios of the ideal-MHD modes.

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Section: Numerical Resultsmentioning

confidence: 99%

Energetic-ion excited internal kink modes with weak magnetic shear in ${{\boldsymbol{q}}}_{0}\gt 1$ tokamak plasmas

Chen

Wang

et al. 2017

Chinese Phys. B

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“…The non-resonant e-fishbone modes are driven on HL-2A tokamak with high power ECRH and co-ECCD. [56] The co-ECCD means driving direction of ECCD is the same to plasma current. Unlike resonant e-fishbone modes with periodic strong bursting amplitude and rapid chirping-down frequency, non-resonant modes always have saturated amplitudes and keeps for a long time, as shown in Fig.…”

Section: Reviewmentioning

confidence: 99%

Energetic Particle Physics on the HL-2A Tokamak: A Review

Shi¹,

Chen²,

Duan³

2021

Chinese Phys. Lett.

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Interaction between shear Alfvén wave (SAW) and energetic particles (EPs) is one of major concerns in magnetically confined plasmas since it may lead to excitation of toroidal symmetry breaking collective instabilities, thus enhances loss of EPs and degrades plasma confinement. In the last few years, Alfvénic zoology has been constructed on HL-2A tokamak and series of EPs driven instabilities, such as toroidal Alfvén eigenmodes (TAEs), revered shear Alfvén eigenmodes (RSAEs), beta induced Alfvén eigenmodes (BAEs), Alfvénic ion temperature gradient (AITG) modes and fishbone modes, have been observed and investigated. Those Alfvénic fluctuations show frequency chirping behaviors through nonlinear wave-particle route, and contribute to generation of axisymmetric modes by nonlinear wave-wave resonance in the presence of strong tearing modes. It is proved that the plasma confinement is affected by Alfvénic activities from multiple aspects. The RSAEs resonate with thermal ions, and this results in an energy diffusive transport process while the nonlinear mode coupling between core-localized TAEs and tearing modes trigger avalanche electron heat transport events. Effective measures have been taken to control SAW fluctuations and the fishbone activities are suppressed by electron cyclotron resonance heating. Those experimental results will not only contribute to better understandings of energetic particles physics, but also provide technology bases for active control of Alfvénic modes on International Thermonuclear Experimental Reactor (ITER) and Chinese Fusion Engineering Testing Reactor (CFETR).

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“…In HL-2A, the ECEI diagnostic has been extensively used to detect the 2D structure of large scale MHD modes [10,11,15,16], such as tearing mode, fishbone, and sawtooth crash. Figure 7 shows the mode structure of the m/n=2/1 tearing mode.…”

Section: Multi-scale Interaction Between Tm and Turbulencementioning

confidence: 99%

Development of ECE/ECEI diagnostics and MHD-related studies on HL-2A tokamak

et al. 2019

Self Cite

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A novel 60-channel electron cyclotron emission (ECE) radiometer has been designed and tested for the measurement of electron temperature profiles on the HL-2A tokamak. This system is based on the intermediate frequency division technique, and has the features of wide working frequency range (60−90 GHz) and high temporal-spatial resolution (3 µs, 1 cm), which covers almost the entire plasma region. Also, an electron cyclotron emission imaging (ECEI) system has been developed for studying two dimensional electron temperature fluctuations. It is comprised of several front-end quasi-optical lenses, a 24 channel heterodyne imaging array with a tunable RF frequency range spanning 60−135 GHz, and a set of back-end ECEI electronics that together generate two 24×8 array images of the 2nd harmonic X-mode electron cyclotron emission from the HL-2A plasma. The measurement region can be flexibly shifted due to two independent local oscillator sources, and the field of view can be adjusted easily by changing the position of the zoom lenses as well. The temporal resolution is about 2.5 µs and the achievable spatial resolution is 1 cm. The ECE/ECEI diagnostics have been demonstrated to be powerful tools to study MHD-related physics including the multi-scale interaction between macro-scale MHD and micro-scale turbulence on the HL-2A tokamak.

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Resonant and non-resonant internal kink modes excited by the energetic electrons on HL-2A tokamak

Cited by 43 publications

References 32 publications

Energetic-ion excited internal kink modes with weak magnetic shear in ${{\boldsymbol{q}}}_{0}\gt 1$ tokamak plasmas

Energetic-ion excited internal kink modes with weak magnetic shear in ${{\boldsymbol{q}}}_{0}\gt 1$ tokamak plasmas

Energetic Particle Physics on the HL-2A Tokamak: A Review

Development of ECE/ECEI diagnostics and MHD-related studies on HL-2A tokamak

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