Direct measurements of safety factor profiles with motional Stark effect for KSTAR tokamak discharges with internal transport barriers

2017 ◽  
Vol 88 (6) ◽  
pp. 063505 ◽  
Author(s):  
J. Ko ◽  
J. Chung
Keyword(s):  
Safety Factor ◽  
Stark Effect ◽  
Direct Measurements ◽  
Transport Barriers ◽  
Internal Transport Barriers ◽  
Motional Stark Effect ◽  
Internal Transport

scholarly journals Перенос тепла и частиц в начальной фазе омических разрядов сферического токамака Глобус-М

2019 ◽  
Vol 45 (13) ◽  
pp. 17
Author(s):  
А.Ю. Тельнова ◽  
Г.С. Курскиев ◽  
Н.Н. Бахарев ◽  
В.К. Гусев ◽  
Е.О. Киселев ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Safety Factor ◽  
Initial Conditions ◽  
Transport Processes ◽  
Density Peak ◽  
Transport Barriers ◽  
Internal Transport Barriers ◽  
Plasma Core ◽  
Internal Transport ◽  
Electron Density Peak

AbstractThe results of experiments and simulations of the transport of heat and particles in the Globus-M spherical tokamak are presented. Investigations were carried out in the ohmic mode in hydrogen and deuterium plasma. It is shown that in the phase of current growth under the same initial conditions, as long as the condition is met at which the minimum of the safety factor exceeds unity, two scenarios of discharge development are possible: with an electron temperature dive or with an electron density peak. After the safety factor reaches the value of 1, the differences are no longer observed. Modeling of transport processes using the ASTRA code showed that the dive of the electron temperature and density is a consequence of the decrease in the transport of heat and particles in the plasma core (i.e., the presence of internal transport barriers).

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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