TY - JOUR
T1 - Simulation study of hysteresis in the gradient-flux relation in toroidal plasma turbulence
AU - Kasuya, N.
AU - Sugita, S.
AU - Inagaki, S.
AU - Itoh, K.
AU - Yagi, M.
AU - Itoh, S. I.
N1 - Publisher Copyright:
© 2015 IOP Publishing Ltd.
PY - 2015/4/1
Y1 - 2015/4/1
N2 - Global nonlinear simulations with heat modulation are carried out to understand the turbulent transport mechanism in toroidal plasmas. Rapid propagation of the heat modulation and a hysteresis in the gradient-flux relation are found in the turbulent simulation of drift-interchange modes. A global mode is excited nonlinearly, and the nonlinear couplings with Reynolds stress take a finite temporal duration for self-consistent redistribution of the energy. The mode also has a seesaw effect: increase of the amplitude of the global mode at one position affects the turbulence at the other radial position not by inducing the radial flux by itself, but by absorbing the energy from microscopic modes. Successive excitations of microscopic modes cause the accelerated propagation of the flux change like turbulence spreading after the onset of modulation. Owing to these non-diffusive processes, the hysteresis appears in the gradient-flux relation, which is compared with experiments.
AB - Global nonlinear simulations with heat modulation are carried out to understand the turbulent transport mechanism in toroidal plasmas. Rapid propagation of the heat modulation and a hysteresis in the gradient-flux relation are found in the turbulent simulation of drift-interchange modes. A global mode is excited nonlinearly, and the nonlinear couplings with Reynolds stress take a finite temporal duration for self-consistent redistribution of the energy. The mode also has a seesaw effect: increase of the amplitude of the global mode at one position affects the turbulence at the other radial position not by inducing the radial flux by itself, but by absorbing the energy from microscopic modes. Successive excitations of microscopic modes cause the accelerated propagation of the flux change like turbulence spreading after the onset of modulation. Owing to these non-diffusive processes, the hysteresis appears in the gradient-flux relation, which is compared with experiments.
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U2 - 10.1088/0741-3335/57/4/044010
DO - 10.1088/0741-3335/57/4/044010
M3 - Article
AN - SCOPUS:84930224748
SN - 0741-3335
VL - 57
JO - Plasma Physics and Controlled Fusion
JF - Plasma Physics and Controlled Fusion
IS - 4
M1 - 044010
ER -