Initial studies of steady inductive helicity injection on the HIT-SI experiment

• Published in: IEEE transactions on plasma science Vol. 33; no. 2; pp. 723 - 728
• Main Authors: Sieck, P.E., Hamp, W.T., Izzo, V.A., Jarboe, T.R., Nelson, B.A., O'Neill, R.G., Redd, A.J., Smith, R.J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01-04-2005; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Arrays; Compact tori; Evolution; Exact sciences and technology; Flux; Fusion; Fusion reactors; Helicity; helicity injection; Helium; Injectors; Magnetic confinement; Magnetic confinement and equilibrium; Magnetic fields; Magnetic flux; Magnetohydrodynamic power generation; magnetohydrodynamics; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; Plasma; Plasma confinement; Plasma currents; Plasma devices; Plasma measurements; Plasma waves; plasmas; reversed-field pinches; Segments; spheromaks; Stellarators, torsatrons, heliacs, bumpy tori, and other toroidal confinement devices; Toroidal magnetic fields; Voltage; Thermonuclear reactors; Magnetized plasma; Compact torus; magnetic fields; plasmas; spheromaks; magnetohydrodynamics; Spheromak devices; Reverse-field pinch; Experimental study; Compact tori; plasma measurements; Helicity; reversed-field pinches; Plasma diagnostics; Magnetic confinement; Plasma magnetohydrodynamics; Confined plasma; Current-drive heating; fusion reactors; Plasma waves; helicity injection
• ISSN: 0093-3813; 1939-9375
• DOI: 10.1109/TPS.2005.845303

The helicity-injected torus (HIT-SI) is designed to produce a "bow tie" spheromak, formed and sustained by steady inductive helicity injection (SIHI) current drive (Jarboe, 1999). SIHI is implemented via two "helicity injectors." Each injector acts as a 180/spl deg/ segment of a reversed-field pinch (RFP), with a typical peak current of 11 kA and a peak flux of 0.5 mWb. The toroidal loop voltage, toroidal injector plasma current, and toroidal flux of a single injector all oscillate sinusoidally at a frequency of 5 kHz and nearly in phase, so the single injector helicity injection rate and power input to the plasma are always positive. Operating the two injectors 90/spl deg/ out of phase in time provides nearly constant power input and helicity injection rate. To date, injector plasmas have been sustained in this manner for over 5 ms. An internal magnetic probe array has been installed in one of the injectors. Observations of the injector fields will be presented, illustrating the evolution of the field structure through the injector cycle.