Extended MHD Studies of Flow-Driven and Reconnecting Instabilities in Toroidal Plasmas

Technical Report · Wed Apr 30 04:00:00 EDT 2014

OSTI ID:1246368

Ebrahimi, Fatima ^[1]

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1. Univ. of New Hampshire, Durham, NH (United States); Office of Fusion Energy Sciences

For steady-state reactor scenarios, inductive ohmic current drive alone is not sufficient. If helicity (a topological property which quantifies the knottedness of the magnetic field lines) is created and injected into a plasma configuration, the additional linkage of the magnetic fluxes can sustain the configuration indefinitely against resistive decay. Injection of magnetic helicity into the plasma is closely related to current drive. Various techniques such as DC and AC helicity injection can be used for steady-state current drive, which both rely on relaxation process for core current penetration. However, helicity injection has also been used for edge current drive and non-inductive startup current drive. A solenoid-free plasma startup method called coaxial helicity injection (CHI) has been investigated in the NSTX, and has shown to generate a closedflux equilibrium and produce a CHI-driven current well-coupled to the induction. We propose to perform nonlinear CHI simulations in NSTX, which will provide further insight into the viability of CHI as a startup current drive technique and its role in ultimate steady-state operation of fusion reactors. The goals of our proposed simulations are to understand the physics of current relaxation by CHI in relation to transport and mode dynamics, and to perform long term simulations when CHI is coupled to the induction.

• Research Organization: University of New Hampshire, Durham, NH (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
• DOE Contract Number: SC0007868
• OSTI ID: 1246368
• Report Number(s): DE--SC0007868
• Country of Publication: United States
• Language: English

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