Demonstration of transient CHI startup using a floating biased electrode configuration
Abstract Results from the successful solenoid-free plasma startup using the method of transient coaxial helicity injection (transient CHI) in the QUEST spherical tokamak (ST) are reported. Unlike previous applications of CHI on HIT-II and on NSTX which required two toroidal insulating breaks to the vacuum vessel, QUEST uses a first of its kind, floating single biased electrode configuration, which does not use such a vacuum break. Instead, the CHI electrode is simply insulated from the outer lower divertor plate support structure. This configuration is much more suitable for implementation in a fusion reactor than the previous configurations. Transient CHI generated toroidal currents of 135 kA were obtained. The toroidal current during the formation of a closed flux configuration was over 50 kA. These results bode well for the application of transient CHI in a new generation of compact high-field STs and tokamaks in which the space for the central solenoid is very restricted.
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC02-09CH11466
- OSTI ID:
- 2228372
- Alternate ID(s):
- OSTI ID: 2216972; OSTI ID: 2248055
- Journal Information:
- Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 1 Vol. 64; ISSN 0029-5515
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- IAEA
- Language:
- English
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