Resistive wall tearing mode generated finite net electromagnetic torque in a static plasma

Abstract

The MARS-F code [Y. Q. Liu et al., Phys. Plasmas 7, 3681 (2000)] is applied to numerically investigate the effect of the plasma pressure on the tearing mode stability as well as the tearing mode-induced electromagnetic torque, in the presence of a resistive wall. The tearing mode with a complex eigenvalue, resulted from the favorable averaged curvature effect [A. H. Glasser et al., Phys. Fluids 18, 875 (1975)], leads to a re-distribution of the electromagnetic torque with multiple peaking in the immediate vicinity of the resistive layer. The multiple peaking is often caused by the sound wave resonances. In the presence of a resistive wall surrounding the plasma, a rotating tearing mode can generate a finite net electromagnetic torque acting on the static plasma column. Meanwhile, an equal but opposite torque is generated in the resistive wall, thus conserving the total momentum of the whole plasma-wall system. The direction of the net torque on the plasma is always opposite to the real frequency of the mode, agreeing with the analytic result by Pustovitov [Nucl. Fusion 47, 1583(2007]. When the wall time is close to the oscillating time of the tearing mode, the finite net torque reaches its maximum. Without wall or with an ideal wall, no net torque on the static plasma is generated by the tearing mode. However, re-distribution of the torque density in the resistive layer still occurs. V C 2014 AIP Publishing LLC.

Toroidal modeling of energetic passing particle drift kinetic effects on tearing mode stability

“…The total momentum conservation of the plasma-wall system still holds in this case, since the same amount of net torque, but with the opposite sign, is generated in the resistive wall due to the wall eddy current. We note that similar results for the J × B torque were previously reported [29], but with different origin for the finite mode frequency. In reference [29], no EPs were included and the finite mode frequency was induced by the GGJ effect.…”

“…We note that similar results for the J × B torque were previously reported [29], but with different origin for the finite mode frequency. In reference [29], no EPs were included and the finite mode frequency was induced by the GGJ effect. The latter is absent in this work due to complete elimination by the thermal transport effect as discussed earlier.…”

Modification of favorable average curvature effect by changing parallel sound wave behavior in tokamak plasmas

“…The roles of the GGJ effect in the above two problems have been extensively studied for many years. On the other hand, the underlying physics associated with the GGJ effect remains an interesting research topic [4,[14][15][16][17]. A fundamental understanding is the role played by the parallel sound waves [1,17].…”

Effect of negative triangularity on tearing mode stability in tokamak plasmas

“…The effect is captured by the resistive Mercier index D R , which is typically negative in tokamak geometry. As interesting consequences, the GGJ-effect can introduce finite frequency to the mode even in a static plasma [11][12][13]. A rotating TM (in an initially static plasma) in turn generates net electromagnetic torque and drives plasma flow [12].…”

“…As interesting consequences, the GGJ-effect can introduce finite frequency to the mode even in a static plasma [11][12][13]. A rotating TM (in an initially static plasma) in turn generates net electromagnetic torque and drives plasma flow [12]. Furthermore, the GGJ-effect induced energy dissipation was also found responsible for a strong stabilization of the resistive-plasma resistive wall mode (RP-RWM) [12].…”