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

• Published in: Physics of plasmas 2014-01, Vol.21 (1), p.12503
• Main Authors: Hao, G. Z., Liu, Y. Q., Wang, A. K., Xu, M., Qu, H. P., Peng, X. D., Wang, Z. H., Xu, J. Q., Qiu, X. M.
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Computational fluid dynamics; Curvature; EIGENVALUES; M CODES; Plasma physics; PLASMA PRESSURE; Pressure effects; Rotating plasmas; SOUND WAVES; Tearing; TEARING INSTABILITY; TORQUE
• ISSN: 1070-664X; 1089-7674
• DOI: 10.1063/1.4861376

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.