Observation and theory of nonlinear mode couplings between shear Alfvén wave and magnetic island in tokamak plasmas

Chen, W.; Qiu, Zhiyong; Ding, X.T.; Xie, Huasheng; Yu, Liming; Ji, X.Q.; Li, J. X.; Li, Y. G.; Dong, J. Q.; Shi, Z.B.; Zhang, Y. P.; Cao, Jianyong; Song, X.M.; Song, Seok Goo; Xu, M.; Qi, Yang; Liu, Yi; Yan, L.W.; Duan, X.R.

doi:10.1209/0295-5075/107/25001

Cited by 28 publications

(33 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In particular, TAE modes driven by EP beam with a one-third Alfven speed are extensively observed in experiment. In many auxiliary heating experiments, for example, NBI, ECRH/ICRH (electron/ion cyclotron resonant heating), LH (lower hybrid wave heating) and so on, TAE modes are extensively observed [11][12][13]. The TAE instabilities often induce large fast particles loss and eject a great amount of EPs which can damage first wall of vacuum cell of tokamak.…”

Section: Nuclear Fusionmentioning

confidence: 99%

See 1 more Smart Citation

Simulation of toroidicity-induced Alfven eigenmode excited by energetic ions in HL-2A tokamak plasmas

Cheng

Dong

et al. 2018

Nucl. Fusion

Self Cite

View full text Add to dashboard Cite

The toroidicity-induced Alfven eigenmode (TAE) excited by energetic (fast) ions was first simulated using the GTC code for HL-2A experiments. The simulation results indicate that the fraction of energetic ions is about 3% in the experiments. The critical density of energetic ions to excite the TAE mode is around 0.023, which is in good agreement with the theoretical expectation of 0.026. The real frequency of TAE with toroidal mode number n = 3 is around 211 kHz and is inversely proportional to the square root of electron density, which is quantitatively in agreement with the experimental observation (Ding et al 2013 Nucl. Fusion 53 043015). The frequency is in resonance with the summations of toroidal precession frequency and transit frequency of passing energetic ions, indicating that resonance with passing energetic ions is dominant for the excitation of the modes in the experiment. It is also checked by the phase space structures of |δf h | 2 (strength of energetic particle distribution function) that the TAE modes are mainly induced by passing energetic ions in HL-2A. The growth rates of TAE modes increase with fast ion density and its gradient. In addition, lower n TAE modes, such as n = 1 can also be driven by energetic ions when off-axis heating with higher beam energy is employed in the experiment. The width of radial mode structures for lower n modes is usually wider than those for higher n modes. The perpendicular wave vector of the modes and Larmor radius of ions satisfy the relation |k ⊥ ρ Li | 2 1. Finally, the polarization of the mode shows that the perturbed parallel electric field is much smaller than the electrostatic parallel electric field.

show abstract

Section: Nuclear Fusionmentioning

confidence: 99%

“…. (13) Here, K and E are the first and second kinds of elliptic functions with the argument k 2 = (1/α − 1 + ε)/2ε and k p = 1/k. ε is the local inverse aspect ratio, α is the pitch angle of energetic ions, E and m h are the energy and mass of fast ions, and s is the magnetic shear.…”

Section: Simulation Of Taes Observed In Hl-2a Experimentsmentioning

confidence: 99%

Simulation of toroidicity-induced Alfven eigenmode excited by energetic ions in HL-2A tokamak plasmas

Cheng

Dong

et al. 2018

Nucl. Fusion

Self Cite

View full text Add to dashboard Cite

show abstract

“…In addition, the AMC code has also been successfully applied to the HL-2A experiment for the Alfv en modes. 31 …”

Section: Appendix C: Benchmark Of the Amc Codementioning

confidence: 99%

Parallel equilibrium current effect on existence of reversed shear Alfvén eigenmodes

Xie

Xiao

2015

Physics of Plasmas

View full text Add to dashboard Cite

A new fast global eigenvalue code, where the terms are segregated according to their physics contents, is developed to study Alfv en modes in tokamak plasmas, particularly, the reversed shear Alfv en eigenmode (RSAE). Numerical calculations show that the parallel equilibrium current corresponding to the kink term is strongly unfavorable for the existence of the RSAE. An improved criterion for the RSAE existence is given for with and without the parallel equilibrium current. In the limits of ideal magnetohydrodynamics (MHD) and zero-pressure, the toroidicity effect is the main possible favorable factor for the existence of the RSAE, which is however usually small. This suggests that it is necessary to include additional physics such as kinetic term in the MHD model to overcome the strong unfavorable effect of the parallel current in order to enable the existence of RSAE. V C 2015 AIP Publishing LLC. [http://dx.

show abstract

“…8 Toroidal Alfvén eigenmodes (TAEs) and other high frequency MHD instabilities have been observed in the experiments. 9 The frequency of those modes is higher than 200 kHz, which exceeds the resonant peak of the standard probes (130 kHz) on HL-2A. Therefore, it is essential to develop a new magnetic probe system with a linear frequency response at least 300 kHz or higher.…”

Section: Introductionmentioning

confidence: 99%

Design and construction of high-frequency magnetic probe system on the HL-2A tokamak

Liang

Sun

et al. 2017

AIP Advances

Self Cite

View full text Add to dashboard Cite

A high-frequency magnetic probe system is designed, calibrated and constructed on the HL-2A tokamak. To investigate the factors which affect the probe frequency response, the inductance and capacitance in the probe system are analyzed using an equivalent circuit. Suitable sizes and turn number of the coil, and the length of transmission cable are optimized based on the theory and detailed test in the calibration. To deal with the frequency response limitation and bake-out, the ceramic grooved technique is used and the probe is wound with a bare copper wire. A cascade filter is manufactured with a suitable bandwidth as well as a good phase consistency between channels. The system has been used in the experiment to measure high frequency (≤300 kHz) magnetohydrodynamic fluctuations, which can meet the requirement of physical analysis on HL-2A.

show abstract

Observation and theory of nonlinear mode couplings between shear Alfvén wave and magnetic island in tokamak plasmas

Cited by 28 publications

References 31 publications

Simulation of toroidicity-induced Alfven eigenmode excited by energetic ions in HL-2A tokamak plasmas

Simulation of toroidicity-induced Alfven eigenmode excited by energetic ions in HL-2A tokamak plasmas

Parallel equilibrium current effect on existence of reversed shear Alfvén eigenmodes

Design and construction of high-frequency magnetic probe system on the HL-2A tokamak

Contact Info

Product

Resources

About