Peak neoclassical toroidal viscosity at low toroidal rotation in the DIII-D tokamak

2011 ◽  
Vol 18 (5) ◽  
pp. 055711 ◽  
Author(s):  
A. J. Cole ◽  
J. D. Callen ◽  
W. M. Solomon ◽  
A. M. Garofalo ◽  
C. C. Hegna ◽  
...  
Keyword(s):  
Toroidal Rotation ◽  
Neoclassical Toroidal Viscosity

Impurity toroidal rotation profile measurement using upgraded high-resolution visible spectroscopic diagnostic on ADITYA-U tokamak

2021 ◽  
Vol 92 (6) ◽  
pp. 063517
Author(s):  
G. Shukla ◽  
M. B. Chowdhuri ◽  
K. Shah ◽  
R. Manchanda ◽  
N. Ramaiya ◽  
...  
Keyword(s):  
High Resolution ◽  
Profile Measurement ◽  
Toroidal Rotation

Influence of toroidal rotation on the tearing mode in tokamak plasmas

2020 ◽  
Vol 22 (6) ◽  
pp. 065102
Author(s):  
Zhenghao REN ◽  
Jinyuan LIU ◽  
Feng WANG ◽  
Huishan CAI ◽  
Zhengxiong WANG ◽  
...  
Keyword(s):  
Tokamak Plasmas ◽  
Tearing Mode ◽  
Toroidal Rotation

Neoclassical toroidal viscosity torque prediction via deep learning

2021 ◽  
Author(s):  
Mitchell D Clement ◽  
Nikolas Logan ◽  
Mark D Boyer
Keyword(s):  
High Performance ◽  
Plasma Stability ◽  
Energy Distributions ◽  
Coil Current ◽  
Neutral Beams ◽  
Edge Localized Modes ◽  
3D Fields ◽  
Neoclassical Toroidal Viscosity ◽  
Data Representative ◽  
Plasma Profile

Abstract GPECnet is a densely connected neural network that has been trained on GPEC data, to predict the plasma stability, neoclassical toroidal viscosity (NTV) torque, and optimized 3D coil current distributions for desired NTV torque profiles. Using NTV torque, driven by non-axisymmetric field perturbations in a tokamak, can be vital in optimizing pedestal performance by controlling the rotation profile in both the core, to ensure tearing stability, and the edge, to avoid edge localized modes (ELMs). The Generalized Perturbed Equilibrium Code (GPEC) software package can be used to calculate the plasma stability to 3D perturbations and the NTV torque profile generated by applied 3D magnetic fields. These calculations, however, involve complex integrations over space and energy distributions, which takes time to compute. Initially, GPECnet has been trained solely on data representative of the quiescent H-mode (QH) scenario, in which neutral beams are often balanced and toroidal rotation is low across the plasma profile. This work provides the foundation for active control of the rotation shear using a combination of beams and 3D fields for robust and high performance QH mode operation.

Understanding core heavy impurity transport in a hybrid discharge on EAST

2021 ◽  
Author(s):  
Shengyu Shi ◽  
Jiale Chen ◽  
Clarisse Bourdelle ◽  
Xiang Jian ◽  
Tomas Odstrcil ◽  
...  
Keyword(s):  
Density Profile ◽  
Central Region ◽  
Turbulent Transport ◽  
Accumulation Process ◽  
Plasma Parameters ◽  
Toroidal Rotation ◽  
The Core ◽  
Impurity Transport ◽  
Accumulation Phase ◽  
Bulk Plasma

Abstract The behavior of heavy/high-Z impurity tungsten (W) in the core of hybrid (high normalized beta β_N plasmas) scenario on EAST with ITER-like divertor (ILD) is analyzed. W accumulation is often observed and seriously degrades the plasma performance (Xiang Gao et al 2017 Nucl. Fusion 57 056021). The dynamics of the W accumulation process of a hybrid discharge are examined considering the concurrent evolution of the background plasma parameters. It turns out that the toroidal rotation and density peaking of the bulk plasma are usually large in the central region, which is particularly prone to the W accumulation. A time slice during the W accumulation phase is modeled, accounting for both neoclassical and turbulent transport components of W, through NEO with poloidal asymmetry effects induced by toroidal rotation, and TGLF, respectively. This modeling reproduces the experimental observations of W accumulation and identifies the neoclassical inward convection/pinch velocity of W due to the large density peaking of the bulk plasma and toroidal rotation in the central region as one of the main reasons for the W accumulation. In addition, the NEO+TGLF+STRAHL modeling can not only predict the core W density profile but also closely reconstruct the radiated information mainly produced by W in the experiment.

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