Current drive by Alfvén waves in elongated cross-section tokamak

1997 ◽  
Vol 4 (10) ◽  
pp. 3635-3643 ◽  
Author(s):  
V. S. Tsypin ◽  
A. G. Elfimov ◽  
F. M. Nekrasov ◽  
C. A. de Azevedo ◽  
A. S. de Assis
Keyword(s):  
Cross Section ◽  
Alfven Waves ◽  
Current Drive ◽  
Alfvén Waves

Current Drive by Alfvén Waves in Elongated Cross Section Tokamak

1998 ◽  
pp. 421-424
Author(s):  
V. Tsypin ◽  
A. Elfimov ◽  
M. Tendler ◽  
F. Nekrasov ◽  
C. De Azevedo ◽  
...  
Keyword(s):  
Cross Section ◽  
Alfven Waves ◽  
Current Drive ◽  
Alfvén Waves

Role of trapped and circulating particles in inducing current drive and radial electric field by Alfvén waves in tokamaks

2002 ◽  
Vol 67 (5) ◽  
pp. 301-308 ◽  
Author(s):  
V. S. TSYPIN ◽  
R. M. O. GALVÃO ◽  
I. C. NASCIMENTO ◽  
M. TENDLER ◽  
J. H. F. SEVERO ◽  
...  
Keyword(s):  
Electric Field ◽  
Radial Electric Field ◽  
Alfven Waves ◽  
Current Drive ◽  
Alfvén Waves ◽  
Trapped Particles ◽  
Transport Barriers

Absorption by trapped particles is supposed to seriously hinder current drive by Alfvén waves. However, it is shown in this paper that the same effect is rather beneficial for the emergence of the radial electric field induced by these waves, which is important for creating and maintaining transport barriers in tokamaks.

scholarly journals RESONANT ABSORPTION OF ALFVÉN WAVES IN FAT TORI WITH CIRCULAR CROSS-SECTION

1981 ◽  
pp. 643-654 ◽  
Author(s):  
K. Appert ◽  
B. Balet ◽  
R. Gruber ◽  
F. Troyon ◽  
T. Tsunematsu ◽  
...  
Keyword(s):  
Cross Section ◽  
Circular Cross Section ◽  
Resonant Absorption ◽  
Alfven Waves ◽  
Alfvén Waves

Non-inductive current drive via helicity injection by Alfvén waves in low-aspect-ratio tokamaks

1996 ◽  
Vol 56 (1) ◽  
pp. 149-174 ◽  
Author(s):  
S. Cuperman ◽  
C. Bruma ◽  
K. Komoshvili
Keyword(s):  
Magnetic Field ◽  
Aspect Ratio ◽  
Alfven Waves ◽  
Current Drive ◽  
Alfven Wave ◽  
Alfvén Waves ◽  
Drive Power ◽  
Helicity Injection ◽  
Low Aspect Ratio ◽  
Optimal Current

A theoretical investigation of radio-frequency (RF) current drive via helicity injection in low aspect ratio tokamaks is carried out. A current-carrying cylindrical plasma surrounded by a helical sheet-current antenna and situated inside a perfectly conducting shell is considered. Toroidal features of low-aspect-ratio tokamaks are simulated by incorporating the following effects: (i) arbitrarily small aspect ratio, Ro/a ≡1/∈; (ii) strongly sheared equilibrium magnetic field; and (iii) relatively large poloidal component of the equilibrium magnetic field. This study concentrates on the Alfvén continuum, i.e. the case in which the wave frequency satisfies the condition , where is an eigenfrequency of the shear Alfven wave (SAW). Thus, using low-β magneto- hydrodynamics, the wave equation with correct boundary (matching) conditions is solved, the RF field components are found, and subsequently current drive, power deposition and efficiency are computed. The results of our investigation clearly demonstrate the possibility of generation of RF-driven currents via helicity injection by Alfvén waves in low-aspect-ratio tokamaks, in the SAW mode. A special algorithm is developed that enables one to select the antenna parameters providing optimal current drive efficiency.

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