scholarly journals Suppressing electron turbulence and triggering internal transport barriers with reversed magnetic shear in the National Spherical Torus Experiment

2012 ◽  
Vol 19 (5) ◽  
pp. 056120 ◽  
Author(s):  
J. L. Peterson ◽  
R. Bell ◽  
J. Candy ◽  
W. Guttenfelder ◽  
G. W. Hammett ◽  
...  
Keyword(s):  
Spherical Torus ◽  
Magnetic Shear ◽  
Transport Barriers ◽  
Internal Transport Barriers ◽  
Internal Transport

scholarly journals Internal transport barriers in the National Spherical Torus Experiment

2009 ◽  
Vol 16 (5) ◽  
pp. 056120 ◽  
Author(s):  
H. Y. Yuh ◽  
F. M. Levinton ◽  
R. E. Bell ◽  
J. C. Hosea ◽  
S. M. Kaye ◽  
...  
Keyword(s):  
Spherical Torus ◽  
Transport Barriers ◽  
Internal Transport Barriers ◽  
Internal Transport

Toroidal equilibrium states with reversed magnetic shear and parallel flow in connection with the formation of Internal Transport Barriers

2015 ◽  
Vol 81 (4) ◽  
Author(s):  
Ap. Kuiroukidis ◽  
G. N. Throumoulopoulos
Keyword(s):  
Magnetic Field ◽  
Linear Stability ◽  
Current Density ◽  
Sufficient Condition ◽  
Magnetic Shear ◽  
Transport Barriers ◽  
Internal Transport Barriers ◽  
The Stability ◽  
The Magnetic Field ◽  
Internal Transport

We construct nonlinear toroidal equilibria of fixed diverted boundary shaping with reversed magnetic shear and flows parallel to the magnetic field. The equilibria have hole-like current density and the reversed magnetic shear increases as the equilibrium nonlinearity becomes stronger. Also, application of a sufficient condition for linear stability implies that the stability is improved as the equilibrium nonlinearity correlated to the reversed magnetic shear gets stronger with a weaker stabilizing contribution from the flow. These results indicate synergetic stabilizing effects of reversed magnetic shear, equilibrium nonlinearity and flow in the establishment of Internal Transport Barriers (ITBs).

Physics of strong internal transport barriers in JT-60U reversed-magnetic-shear plasmas

2006 ◽  
Vol 48 (5A) ◽  
pp. A55-A61 ◽  
Author(s):  
N Hayashi ◽  
T Takizuka ◽  
Y Sakamoto ◽  
T Fujita ◽  
Y Kamada ◽  
...  
Keyword(s):  
Magnetic Shear ◽  
Transport Barriers ◽  
Internal Transport Barriers ◽  
Internal Transport

Effects of a non-monotonic safety factor on the particle transport and diffusion in the case of a reversed magnetic shear

2009 ◽  
Vol 76 (1) ◽  
pp. 29-37
Author(s):  
M. GHABBOURI ◽  
D. SAIFAOUI ◽  
A. BOULEZHAR ◽  
A. DEZAIRI ◽  
M. EL MOUDEN
Keyword(s):  
Safety Factor ◽  
Particle Transport ◽  
Numerical Study ◽  
Dominant Role ◽  
Magnetic Shear ◽  
Transport Barriers ◽  
Internal Transport Barriers ◽  
Transport And Diffusion ◽  
And Diffusion ◽  
Internal Transport

AbstractThis work is based on a numerical study of particle transport and diffusion using ITER parameters. In particular, the effects of introducing a non-monotonic safety factor (NMSF) in the case of a reversed magnetic shear are shown. These results are compared with those found by using a monotonic safety factor (MSF). Double internal transport barriers are detected influencing the transport and diffusion of particles. The choices of the mode (m, n) and the m/n values play a dominant role for the particle diffusion, which leads to an improvement of the magnetic confinement.

Bursty transport in tokamak turbulence: Role of zonal flows and internal transport barriers

2001 ◽  
Vol 41 (8) ◽  
pp. 995-1001 ◽  
Author(s):  
S. Benkadda ◽  
P. Beyer ◽  
N. Bian ◽  
C. Figarella ◽  
O. Garcia ◽  
...  
Keyword(s):  
Zonal Flows ◽  
Transport Barriers ◽  
Internal Transport Barriers ◽  
Internal Transport

The ITB dynamics controlled by internal kink modes on HL-2A tokamak

2021 ◽  
Author(s):  
Xiaoxue He ◽  
Longwen Yan ◽  
Deliang Yu ◽  
Wei Chen ◽  
Liming Yu ◽  
...  
Keyword(s):  
High Performance ◽  
Fusion Reactor ◽  
Rotation Velocity ◽  
Plasma Current ◽  
Ion Temperature ◽  
Lower Plasma ◽  
Transport Barriers ◽  
Internal Transport Barriers ◽  
Foot Position ◽  
Internal Transport

Abstract The active control of internal transport barriers (ITBs) is an important issue to achieve high performance plasma in a fusion reactor. A critical challenge of ITB control is to increase the ITB position. The ITBs with internal kink modes (IKMs), such as fishbone instability and long-live mode (LLM) with mode number of m/n = 1/1 are frequently observed on HL-2A tokamak in neutral beam heated discharges. The correlation of fishbone instability/LLM with ITBs is analyzed in order to extend the ITB radius. It has been revealed that fishbone instability and LLM are often excited after the ITB formation. Therefore, fishbone instability and LLM play no role in triggering ITBs on HL-2A tokamak. On the other hand, they may slow down the outward radial expansion and then shrink the foot position of ITB, and damp the gradient growth of ion temperature and rotation velocity. Since the perturbation of LLM is weaker than that of fishbone instability, the shrinking effect of ITB foot and braking effect on gradient growth are slighter than those of fishbone instability. Compared with the LLM, fishbone instability routinely appears in plasmas with lower density, higher heating power and lower plasma current. In addition, large ITBs without IKMs are also discussed on HL-2A tokamak. The large ITB is the largest one, the fishbone ITB is the strongest one and the LLM ITB is the widest one in three ITBs, where the ‘large’, ‘strong’ and ‘wide’ qualifications correspond to ITB position ρITB, the normalized temperature gradient R/LT, and its width W/a. Therefore, the large ITB position may be obtained if the IKMs are effectively controlled in a tokamak.

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