TITLE

Reactor prospect of spheromak concept by electrostatic helicity injection

AUTHOR(S)
Tang, X. Z.; Boozer, A. H.
PUB. DATE
July 2008
SOURCE
Physics of Plasmas;Jul2008, Vol. 15 Issue 7, p072510
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The highest performing spheromaks in the laboratory are formed by electrostatic helicity injection. Discharges with up to 1 MA plasma current and core electron temperature as high as 500 eV have been recently obtained. For such a scheme to scale-up to a reactor, however, a much higher current multiplication factor (plasma current over injector current) must be achieved. It is shown here that spheromak current multiplication is linearly proportional to flux amplification (ratio of poloidal fluxes inside and outside the separatrix of the mean field). Hence, spheromak optimization is centered around achieving high flux amplification, which is provided by linear or nonlinear resonant coupling between helicity injector and the spheromak force-free eigenmode. The nonlinear resonant field amplification is the most promising route to high flux amplification in a realistic plasma that often significantly deviates from the Taylor state. Accessing such nonlinear resonant field amplification can be facilitated by auxiliary current drive around the magnetic axis and auxiliary heating to break the electron temperature constraint on flux amplification.
ACCESSION #
34360784

 

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