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Startup of spherical tokamak component test facility by co-axial helicity injection

Author: Xianzhu Tang
Requested Type: Consider for Invited
Submitted: 2006-12-18 11:51:05


Contact Info:
Los Alamos National Laboratory
T-15, MS K717
Los Alamos, NM   87545

Abstract Text:
A major challenge in spherical tokamak (ST) path to controlled fusion energy is the need for solenoid-free startup. This unique requirement by ST is also important to the Component Test Facility (CTF) of which an ST is the leading candidate design. Co-axial helicity injection (CHI) has been investigated as the primary option on the National Spherical Torus Experiment (NSTX), following the earlier success on HIT-II. Related laboratory applications include the formation of a spheromak and a spherical tokamak with a plasma center column (ST-PCC). The scale-up of the CHI scheme for ST reactors and the Component Test Facility requires a clear understanding of the physics underlying current multiplication and flux amplification, which are two critical measures in assessing the usefulness of magnetic helicity injection for forming the plasma confining magnetic fields. This talk will present theoretical and computational studies that clarify the essential physics, along with a comparison with that of the spheromak and ST-PCC experiments. An important application of the new physics understanding leads to the so-called relaxed transient co-axial helicity injection scheme for solenoid-free ST startup, which can deliver reactor-grade high current multiplication and flux amplification.

Characterization: E3


University of Maryland

Innovative Confinement Concepts Workshop
February 12-14, 2007
College Park, Maryland

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