Open AccessObservation of Persistent Edge Current Driven by Coaxial Helicity Injection (CHI)
Author(s) -
D Mueller,
B A Nelson,
W T Hamp,
A J Redd,
T R Jarboe,
R G O'Neill,
R J Smith
Publication year - 2005
Language(s) - English
Resource type - Reports
DOI - 10.2172/839171
Subject(s) - current (fluid) , plasma , helicity , physics , toroid , coaxial , ohmic contact , torus , atomic physics , enhanced data rates for gsm evolution , nuclear physics , electrical engineering , geometry , quantum mechanics , mathematics , engineering , electrode , telecommunications , thermodynamics
Coaxial Helicity Injection, CHI, has been used on the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40 (2000) 557], the Helicity Injected Torus (HIT) [B.A. Nelson et al., Phys. Rev. Lett. 72 (1994) 3666] and HIT-II [T.R. Jarboe et al., Phys. Plasmas 5 (1998) 1807] to initiate plasma and to drive up to 400 kA of toroidal current. On HIT-II, CHI initiated discharges have been successfully coupled to ohmic sustainment [R. Raman et al., Phys. Plasmas 11 (2004) 2565]. This paper presents the first results on the use of CHI to demonstrate the persistence of edge current drive in a preestablished single-null diverted inductive discharge. Edge current drive has the potential to improve plasma stability limits [J.E. Menard et al., Nucl. Fusion 37 (1997) 595]. While most current drive methods drive current in the interior of the plasma, CHI is well suited for driving current in the edge plasma