Ultra-high beta in numerical simulations of a tearing-mode reduced reversed-field pinch
2007 (English)In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 47, no 9, 1184-1188 p.Article in journal (Refereed) Published
In the advanced reversed-field pinch (RFP), current profile control (CPC) enables energy confinement time and poloidal beta to increase substantially as compared with the conventional RFP due to reduced magnetic field stochasticity. Numerical simulations using the three-dimensional non-linear resistive MHD-code DEBSP are performed showing that the poloidal beta is not limited to the m ≤ 0 stability criterion βθ < 1/2. Instead, as tearing modes are diminished, it may approach unity. The beta criterion is theoretically analysed and a new, more general, criterion is derived. Analytic estimates of the resistive tearing and g-mode growth rates are derived for m ≤ 0, and it is shown that both tearing and g-mode growth rates decrease significantly as CPC is employed. Furthermore, quasi-steady state operation with increased confinement due to active control of the current profile is numerically demonstrated for the advanced RFP for a scenario with βθ < 1/2.
Place, publisher, year, edition, pages
2007. Vol. 47, no 9, 1184-1188 p.
Betatrons, Computer simulation, Magnetic fields, Magnetohydrodynamics
IdentifiersURN: urn:nbn:se:kth:diva-6335DOI: 10.1088/0029-5515/47/9/015ISI: 000249968800018ScopusID: 2-s2.0-34548236281OAI: oai:DiVA.org:kth-6335DiVA: diva2:11020
QC 20101005. Uppdaterad från Submitted till Published (20101005).2006-11-132006-11-132010-10-05Bibliographically approved