Relativistic toroidal light solitons in plasma

Zhong-ming, Cheng; Wu, Hui‐Chun; Yu, M. Y.; Dachao, Deng

doi:10.1088/2058-6272/aca232

Cited by 5 publications

(3 citation statements)

References 34 publications

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“…In comparison with the n = 1 components, figure 13(a) shows that the nonlinear evolution of high-order harmonics for Λ 0 = 0.6, and we find n = 2 components have a larger saturation amplitude. These results indicate that the dominant modes driven by passing EPs are always the n > 1 non-resonant EPMs whether it is linear or nonlinear evolution, which are consistent with our previous works [50]. Nevertheless, when Λ 0 = 1.0, figure 13(b) shows that the saturation amplitude of the n = 1 components is the largest in the nonlinear stage, which are consistent with the numerical investigation of Ren et al in trend [35].…”

Section: Different Mode Saturation Level Analysissupporting

confidence: 91%

Simulation of non-resonant high-order harmonics energetic particle modes in tokamak plasmas

Liu,

Ren,

Yang

et al. 2024

Phys. Scr.

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Based on the parameters of the HL-2A experiment, the effect of energetic particles (EPs) on non-resonant high-order harmonics energetic particle modes (EPMs) with qmin>1 is investigated in the present work. Hybrid kinetic-magnetohydrodynamic nonlinear code M3D-K is performed to simulate the linear properties and the nonlinear evolution of the non-resonant EPM during neutral beam injection (NBI). To deeply understand the physical mechanism of interaction resonant between energetic-ions and non-resonant EPM, this work compares the effects of passing energetic particles and trapped energetic particles on the non-resonant EPM instabilities. It is numerically identified that EPs’ effects on high n harmonics (m/n = 2/2, 3/3, 4/4) instability are more obvious than the m/n = 1/1 mode. Furthermore, the effects of energetic particles injection energy, the minimum safety factor qmin , toroidal rotation and beam ion distribution on the features of high n harmonics are also investigated specifically. Toroidal rotation is found to suppress high n harmonics, which is more obvious for the modes driven by trapped particles. Nonlinear simulation results show that these non-resonant high n harmonics can induce larger energetic ion transport, which may affect the plasma confinement performance.

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Section: Different Mode Saturation Level Analysissupporting

confidence: 91%

Simulation of non-resonant high-order harmonics energetic particle modes in tokamak plasmas

Liu,

Ren,

Yang

et al. 2024

Phys. Scr.

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“…A novel electromagnetic probe array (EMPA), with a high sampling rate (2 MHz) and self-resonant frequency, has recently been developed on EAST. The EMPA can provide higher frequency magnetic fluctuation measurements [30].…”

Section: Experimental Setup and Observationsmentioning

confidence: 99%

Bursting core-localized ellipticity-induced Alfvén eigenmodes driven by energetic electrons during EAST ohmic discharges

Su,

Lan,

Zhou

et al. 2024

Nucl. Fusion

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A series of high-frequency (400~1000 kHz) bursting core-localized Alfvén instabilities have been observed during ohmic discharges in EAST tokamak. The instability trigger favours the discharge conditions of low toroidal magnetic field and low electron density. The toroidal mode numbers are mainly n=2~3 and they propagate in the ion diamagnetic drift (co-current) direction. These modes are radially localized in the range of ρ_tor=0.2~0.35 based on Doppler BackScatter (DBS) measurement. They are identified as ellipticity-induced Alfvén eigenmodes (EAEs) occurring at q=1 rational surfaces by magnetohydrodynamics (MHD) simulations using the realistic geometry and plasma profiles. The EAEs show regular bursts with ~10 milliseconds duration along with the mode frequency chirping downwards and upwards rapidly. It is also found that sawtooth events can interrupt the growth and evolution of the EAEs, causing the modes to disappear immediately. Passing energetic electrons (EEs) that move much faster than Alfvén velocity are responsible for the destabilization of these EAEs, which attribute to the fact that the large poloidal and toroidal frequencies mostly cancel each other and satisfy the EAE resonance condition with primary energy exchange. These novel experimental results of the wave-particle interaction between EAEs and EEs are helpful for extrapolating alpha particle physics that are characterized by small orbit width with respect to machine size in future fusion reactors.

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“…We have conducted experiments to measure both terms for discharge parameters very similar to those used here. We used another Langmuir probe array [56], which was able to measure the Reynolds power. Figure 16 shows the measurement results in the SOL.…”

Section: Appendix Cmentioning

confidence: 99%

How turbulent transport broadens the heat flux width: local SOL production or edge turbulence spreading?

Wu,

Diamond,

Nie

et al. 2023

Nucl. Fusion

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This paper uses data from limited HL-2A Ohmic-plasma to answer the question of how turbulent transport broadens the heat flux width. A key issue in this study is the determination of the origin of SOL turbulence. We develop the concept of the energy production ratio R_a, which compares the flux of turbulence energy across the LCFS to the net, integrated energy production in the SOL. The flux of turbulence energy (i.e., spreading) is measured directly, using Langmuir probes. Experimental data is used to evaluate R_a. Results show that usually R_a>1, indicating that SOL turbulence is energized primarily by edge turbulence spreading. The exceptions – cases where R_a<1 – are those with relatively stronger E×B shear near the LCFS. The latter inhibits both turbulence spreading and local SOL production, but has greater effects on spreading. High blob fraction in the turbulence correlates with large values of R_a. The implications for heat flux width physics are discussed.

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Relativistic toroidal light solitons in plasma

Cited by 5 publications

References 34 publications

Simulation of non-resonant high-order harmonics energetic particle modes in tokamak plasmas

Simulation of non-resonant high-order harmonics energetic particle modes in tokamak plasmas

Bursting core-localized ellipticity-induced Alfvén eigenmodes driven by energetic electrons during EAST ohmic discharges

How turbulent transport broadens the heat flux width: local SOL production or edge turbulence spreading?

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