Solenoid-free Plasma Start-up in NSTX using Transient CHI

Journal Article · Mon Jan 05 00:00:00 EST 2009 · Nuclear Fusion, vol. 49, n/a, May 1, 2009, pp. 065006

DOI:https://doi.org/10.1007/s10894-008-9182-x· OSTI ID:1019054

Raman, R; Jarboe, T; Nelson, B; Mueller, D; Soukhanovskii, V A

Experiments in NSTX have now demonstrated the coupling of toroidal plasmas produced by the technique of Coaxial Helicity Injection (CHI) to inductive sustainment and ramp-up of the toroidal plasma current. In these discharges, the central Ohmic transformer was used to apply an inductive loop voltage to discharges with a toroidal current of about 100 kA created by CHI. The coupled discharges have ramped up to >700 kA and transitioned into an H-mode demonstrating compatibility of this startup method with conventional operation. The electron temperature in the coupled discharges reached over 800 eV and the resulting plasma had low inductance, which is preferred for long-pulse high performance discharges. These results from NSTX in combination with the previously obtained record 160 kA non-inductively-generated startup currents in an ST or tokamak in NSTX demonstrate that CHI is a viable solenoid-free plasma startup method for future STs and tokamaks.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 1019054
• Report Number(s): LLNL-JRNL-409684; TRN: US1103561
• Journal Information: Nuclear Fusion, vol. 49, n/a, May 1, 2009, pp. 065006, Vol. 49
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION
COMPATIBILITY
ELECTRIC CURRENTS
ELECTRON TEMPERATURE
HELICITY
INDUCTANCE
PERFORMANCE
PLASMA
START-UP
TRANSFORMERS
TRANSIENTS