scholarly journals Surface currents associated with external kink modes in tokamak plasmas during a major disruption

2017 ◽  
Vol 24 (10) ◽  
pp. 102520 ◽  
Author(s):  
C. S. Ng ◽  
A. Bhattacharjee
Keyword(s):  
Surface Currents ◽  
Tokamak Plasmas ◽  
Major Disruption ◽  
External Kink

Prevention of ECCD triggering explosive bursts in reversed magnetic shear tokamak plasmas for disruption avoidance

2022 ◽  
Author(s):  
Tong Liu ◽  
Zheng-Xiong Wang ◽  
Lai Wei ◽  
Jialei Wang
Keyword(s):  
Control Strategies ◽  
Control Process ◽  
Rational Surface ◽  
Current Drive ◽  
Tokamak Plasmas ◽  
Tearing Mode ◽  
Magnetic Shear ◽  
Rational Surfaces ◽  
Major Disruption ◽  
Neoclassical Tearing Mode

Abstract The explosive burst excited by neoclassical tearing mode (NTM) is one of the possible candidates of disruptive terminations in reversed magnetic shear (RMS) tokamak plasmas. For the purpose of disruption avoidance, numerical investigations have been implemented on the prevention of explosive burst triggered by the ill-advised application of electron cyclotron current drive (ECCD) in RMS configuration. Under the situation of controlling NTMs by ECCD in RMS tokamak plasmas, a threshold in EC driven current has been found. Below the threshold, not only are the NTM islands not effectively suppressed, but also a deleterious explosive burst could be triggered, which might contribute to the major disruption of tokamak plasmas. In order to prevent this ECCD triggering explosive burst, three control strategies have been attempted in this work and two of them have been recognized to be effective. One is to apply differential poloidal plasma rotation in the proximity of outer rational surface during the ECCD control process; The other is to apply two ECCDs to control NTM islands on both rational surfaces at the same time. In the former strategy, the threshold is diminished due to the modification of classical TM index. In the latter strategy, the prevention is accomplished as a consequence of the reduction of the coupling strength between the two rational surfaces via the stabilization of inner islands. Moreover, the physical mechanism behind the excitation of the explosive burst and the control processes by different control strategies have all been discussed in detail.

Recombination kinetics of impurities during a major disruption in tokamak plasmas

2005 ◽  
Vol 31 (6) ◽  
pp. 439-451 ◽  
Author(s):  
V. A. Shurygin ◽  
N. N. Brevnov ◽  
Yu. V. Gott
Keyword(s):  
Tokamak Plasmas ◽  
Major Disruption ◽  
Kinetics Of ◽  
Recombination Kinetics

Ion Heating Characteristics of Merging Spherical Tokamak Plasmas using the Improved Doppler Tomography Spectroscopy System

2014 ◽  
Vol 134 (9) ◽  
pp. 523-524
Author(s):  
Hideya Koike ◽  
Masanobu Annoura ◽  
Kento Nishida ◽  
Hiroshi Tanabe ◽  
Michiaki Inomoto ◽  
...  
Keyword(s):  
Spherical Tokamak ◽  
Tokamak Plasmas ◽  
Ion Heating ◽  
Doppler Tomography ◽  
Spectroscopy System

scholarly journals Effects of plasma turbulence on the nonlinear evolution of magnetic island in tokamak

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Minjun J. Choi ◽  
Lāszlo Bardōczi ◽  
Jae-Min Kwon ◽  
T. S. Hahm ◽  
Hyeon K. Park ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Nonlinear Evolution ◽  
Plasma Turbulence ◽  
Magnetized Plasmas ◽  
Tokamak Plasmas ◽  
Magnetic Islands ◽  
Magnetic Island ◽  
Reconnection Site ◽  
Ambient Turbulence

AbstractMagnetic islands (MIs), resulting from a magnetic field reconnection, are ubiquitous structures in magnetized plasmas. In tokamak plasmas, recent researches suggested that the interaction between an MI and ambient turbulence can be important for the nonlinear MI evolution, but a lack of detailed experimental observations and analyses has prevented further understanding. Here, we provide comprehensive observations such as turbulence spreading into an MI and turbulence enhancement at the reconnection site, elucidating intricate effects of plasma turbulence on the nonlinear MI evolution.

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