Prevention of m/n=2/1 tearing modes (TM) by electro-magnetic torque injection has been successful in DIII-D and RFX-mod where plasma conditions and plasma shape are completely different [1]. Understanding the internal structure in the post-unlocked phase is a pre-requisite to its application to reactor relevant plasmas such as in ITER. Ti and toroidal rotation perturbations show there exist several radially different TM layers. However, the phase shift between the applied field and the plasma response is rather small from plasma edge to the q~3 domain, indicating that a kink-like response prevails. The biggest threat for sustaining an unlocked 2/1 mode is sudden distortion of the rotational profile due to the internal mode reconnection. Possible TM layer structure will be discussed with numerical MHD codes and TRANSP.
Multi-layered mode structure of locked-tearing-modes after unlocking
Paccagnella R
2015
Abstract
Prevention of m/n=2/1 tearing modes (TM) by electro-magnetic torque injection has been successful in DIII-D and RFX-mod where plasma conditions and plasma shape are completely different [1]. Understanding the internal structure in the post-unlocked phase is a pre-requisite to its application to reactor relevant plasmas such as in ITER. Ti and toroidal rotation perturbations show there exist several radially different TM layers. However, the phase shift between the applied field and the plasma response is rather small from plasma edge to the q~3 domain, indicating that a kink-like response prevails. The biggest threat for sustaining an unlocked 2/1 mode is sudden distortion of the rotational profile due to the internal mode reconnection. Possible TM layer structure will be discussed with numerical MHD codes and TRANSP.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
