Observation and characterization of the effect of electron cyclotron waves on toroidal rotation in EAST L-mode discharges

Chen, Jun; Hu, R. J.; Lyu, Bo; Wang, Fudi; WANG, Xiaojie; Xu, Handong; Li, Yingying; Fu, Jia; Yin, Xianghui; Wu, Dajun; LIU, Fukun; Zang, Qing; Liu, Haiqing; Shi, Yuejiang; Mao, Shifeng; Yu, Yi; Wan, Baonian; YE, Minyou; Shen, Yuquan

doi:10.1088/2058-6272/aa7cec

Cited by 4 publications

(1 citation statement)

References 19 publications

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“…While NBIs have been a popular tool to modify plasma rotations, applications of RF (Radio Frequency) wave heating systems such as ICRF (Ion Cyclotron Range of Frequency), LHCD (Lower Hybrid Current Drive), and ECRH (Electron Cyclotron Resonance Heating), have also proven to modify plasma rotations, thus can affect RS profiles and their magnitudes. Some recent publications from EAST experiments on intrinsic rotations with various RF heating tools can be found in [25][26][27][28][29]. Knowing such diverse rotation responses to RF waves, it is reasonable to assume that seeminglybalanced rotations can be attained by combined application of NBIs and RF waves as done during the 2019 EAST campaign.…”

Section: Introductionmentioning

confidence: 99%

A neoclassical validation of balanced and unbalanced rotations on EAST H-mode discharges

Bae,

Jin,

Lyu

et al. 2024

Plasma Phys. Control. Fusion

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Predicting Residual Stress (RS) contribution to intrinsic rotation is one of the major challenges in the study of momentum transport in tokamaks. One efficient experimental means of quantifying RS torque magnitude is to generate radially-flat and near-zero rotation profiles, termed “balanced rotations” in this work, using counter-Ip Neutral Beam Injections (NBIs) to effectively cancel the torques from co-Ip NBIs. One remaining question, however, is on whether or not the attained velocity profile is well zeroed and flat enough so that the predicted RS torques based on perfect balance assumption can be used for further studies such as fitting of diffusive and convective coefficients to match with experiments. This article presents a neoclassical means of validating the attained balanced and unbalanced rotations at EAST to consequently validate the predicted RS torque profiles, using TRANSP/NUBEAM and a recently-developed neoclassical rotation/transport code TransROTA [Comp. Phys. Comm. 296(2024) 108992]. Both balanced and unbalanced EAST H-mode discharges are analyzed to find that the suggested neoclassical validation methodology successfully validates attained balanced rotations. It also finds that neoclassical gyroviscous (NGV) torque serves as the balance-breaking mechanism for axisymmetric plasmas and the balance-breakings start from the core and propagate towards the edge. This work also suggests the possibility of using the neoclassical methodology to find locally-balanced rotations at an elevated velocity range near ~20 km/s, which implies possible scaling of RS torques up to a certain elevated velocity range.

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Section: Introductionmentioning

confidence: 99%

A neoclassical validation of balanced and unbalanced rotations on EAST H-mode discharges

Bae,

Jin,

Lyu

et al. 2024

Plasma Phys. Control. Fusion

Self Cite

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Study of core plasma rotation characteristics of RF-heated H-mode discharges on experimental advanced superconducting tokamak

et al. 2020

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RF-heated H-mode plasmas are readily achieved with lower hybrid current drive and ICRF heating on experimental advanced superconducting tokamak (EAST). Characteristics of H-mode plasma rotation are studied, including the behaviors for non-stationary and stationary H-mode discharges. Experimental results indicate that substantial co-current core rotation increment is observed at L-H transition. For non-stationary discharges with multiple L-H transitions, central plasma rotation varies as the plasma enters and exits the H-mode phase. Rotation increase over L-H transition is linearly correlated with plasma stored energy for both edge localized mode (ELM)-free phases and phases with type-III ELMs. For stationary H-mode discharges with type-III ELMs, core plasma rotation profile is elevated and remains stable during the H-mode phase, although the occurrence of ELMs tends to slow down the core rotation, especially for type-I ELMs where the entire core profiles are affected. Evolution of plasma rotation is fitted with a source-free transport equation and it is found that the momentum transport is dominated by diffusion and explains the flat profile in the core. Based on the Rice scaling and for the same stored energy increase, smaller increase in the core rotation is observed for H-mode discharges with type-III ELMs than for ELM-free discharges. A linear fit indicates that the slope is 75% larger for the ELM-free discharges data.

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Influence of toroidal rotation from electron cyclotron resonance heating in KSTAR

Lee

2020

Physics of Plasmas

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Toroidal rotation behaviors from electron cyclotron resonance heating (ECH) injected Ohmic and high confinement mode (H-mode) plasmas are investigated in KSTAR. The on-axis ECH injection induces core toroidal rotation reversal by neoclassical toroidal viscosity (NTV) damping torque coincided with trapped electron mode (TEM)-driven co-current rotation torque in the countercurrent rotating Ohmic plasmas. In the ECH triggered H-mode plasmas with enhanced heating power, the toroidal rotation in the central region turns to the countercurrent direction and co-current direction in the outer region of the plasma.

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Observation and characterization of the effect of electron cyclotron waves on toroidal rotation in EAST L-mode discharges

Cited by 4 publications

References 19 publications

A neoclassical validation of balanced and unbalanced rotations on EAST H-mode discharges

A neoclassical validation of balanced and unbalanced rotations on EAST H-mode discharges

Study of core plasma rotation characteristics of RF-heated H-mode discharges on experimental advanced superconducting tokamak

Influence of toroidal rotation from electron cyclotron resonance heating in KSTAR

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