scholarly journals Role of density gradient driven trapped electron mode turbulence in the H-mode inner core with electron heating

2016 ◽  
Vol 23 (5) ◽  
pp. 056112 ◽  
Author(s):  
D. R. Ernst ◽  
K. H. Burrell ◽  
W. Guttenfelder ◽  
T. L. Rhodes ◽  
A. M. Dimits ◽  
...  
Keyword(s):  
Density Gradient ◽  
Inner Core ◽  
Electron Heating ◽  
Electron Mode ◽  
Trapped Electron

scholarly journals Collisionless microinstabilities in stellarators. Part 4. The ion-driven trapped-electron mode

2017 ◽  
Vol 83 (4) ◽  
Author(s):  
G. G. Plunk ◽  
J. W. Connor ◽  
P. Helander
Keyword(s):  
Free Energy ◽  
Density Gradient ◽  
Magnetic Confinement ◽  
Particle Trapping ◽  
Trapped Electrons ◽  
Particle Orbits ◽  
Electron Mode ◽  
Gyrokinetic Simulations ◽  
Trapped Electron

Optimised stellarators and other magnetic-confinement devices having the property that the average magnetic curvature is favourable for all particle orbits are called maximum-$J$ devices. They have recently been shown to be immune to trapped-particle instabilities driven by the density gradient. Gyrokinetic simulations reveal, however, that another instability can arise, which is also associated with particle trapping but causes less transport than typical trapped-electron modes. The nature of this instability is clarified here. It is shown to be similar to the ‘ubiquitous mode’ in tokamaks and is driven by ion free energy, but requires trapped electrons to exist.

scholarly journals Role of zonal flows in trapped electron mode turbulence through nonlinear gyrokinetic particle and continuum simulation

2009 ◽  
Vol 16 (5) ◽  
pp. 055906 ◽  
Author(s):  
D. R. Ernst ◽  
J. Lang ◽  
W. M. Nevins ◽  
M. Hoffman ◽  
Y. Chen ◽  
...  
Keyword(s):  
Zonal Flows ◽  
Electron Mode ◽  
Trapped Electron

scholarly journals The role of collisionless trapped electron mode turbulence on removal of helium ash and transport of deuterium-tritium ions

2020 ◽  
Vol 61 (1) ◽  
pp. 016020
Author(s):  
Weixin Guo ◽  
Mingzhu Zhang ◽  
Lu Wang ◽  
Ge Zhuang
Keyword(s):  
Electron Mode ◽  
Trapped Electron

scholarly journals Role of trapped electron mode turbulence in internal transport barrier control in the Alcator C-Mod Tokamak

2004 ◽  
Vol 11 (5) ◽  
pp. 2637-2648 ◽  
Author(s):  
D. R. Ernst ◽  
P. T. Bonoli ◽  
P. J. Catto ◽  
W. Dorland ◽  
C. L. Fiore ◽  
...  
Keyword(s):  
Transport Barrier ◽  
Electron Mode ◽  
Internal Transport Barrier ◽  
Trapped Electron ◽  
Internal Transport

Gyrokinetic simulation of collisionless trapped-electron mode turbulence

2005 ◽  
Vol 12 (7) ◽  
pp. 072309 ◽  
Author(s):  
Tilman Dannert ◽  
Frank Jenko
Keyword(s):  
Electron Mode ◽  
Trapped Electron

Study of turbulence in the high betap discharge using only RF heating on EAST

2022 ◽  
Author(s):  
shuyu Zheng ◽  
Debing Zhang ◽  
Erbing Xue ◽  
Limin Yu ◽  
Xianmei Zhang ◽  
...  
Keyword(s):  
Electron Collision ◽  
Rf Heating ◽  
Plasma Parameters ◽  
Equilibrium Data ◽  
Electron Mode ◽  
Radio Frequency Waves ◽  
Thermal Diffusivities ◽  
Gyrokinetic Simulations ◽  
Trapped Electron ◽  
Scale Length

Abstract High poloidal beta scenarios with favorable energy confinement (β_p~1.9, H_98y2~1.4) have been achieved on Experimental Advanced Superconducting Tokamak (EAST) using only radio frequency waves heating. Gyrokinetic simulations are carried out with experimental plasma parameters and tokamak equilibrium data of a typical high β_p discharge by the GTC code. Linear simulations show that electron temperature scale length and electron density scale length destabilize the turbulence, collision effects stabilize the turbulence, and the instability propagates in the electron diamagnetic direction. These indicate that the dominant instability in the core of high β_p plasma is collisionless trapped electron mode. Ion thermal diffusivities calculated by nonlinear gyrokinetic simulations are consistent with the experimental value, in which the electron collision effects play an important role. Further analyses show that instabilities with k_θ ρ_s>0.38 are suppressed by collision effects and collision effects reduce the radial correlation length of turbulence, resulting in the suppression of the turbulence.

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