Transient and quasisteady behavior with rotating magnetic field current drive

Authors
Citation
Lc. Steinhauer, Transient and quasisteady behavior with rotating magnetic field current drive, PHYS PLASMA, 8(7), 2001, pp. 3367-3376
Citations number
22
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
PHYSICS OF PLASMAS
ISSN journal
1070-664X → ACNP
Volume
8
Issue
7
Year of publication
2001
Pages
3367 - 3376
Database
ISI
SICI code
1070-664X(200107)8:7<3367:TAQBWR>2.0.ZU;2-F
Abstract
The time-dependent behavior of rotating magnetic field (RMF) current drive is investigated using a two-fluid model. The important new factor is the ad dition of transverse ion mobility in contrast to rigid-ion models of the pa st. The equations simplify conveniently, allowing the behavior on each surf ace (r=const) to be isolated, which permits a quadrature solution for the i on fluid rotation. A rapid transient phase leads to quasisteady behavior th at evolves on the relatively slow diffusion timescale. The fast transient t imescale is set by the ion inertia. Unless there is an ion momentum source to balance the electron drag on the ion fluid, there is no quasisteady curr ent drive effect. Collisions with neutrals offer such a momentum source in some experiments, notably rotamaks and the Star Thrust Experiment. Other so urces of ion momentum are essential for RMF current drive in hotter, fusion -relevant plasmas. The properties of the quasisteady state are found, inclu ding the self-consistent ion fluid rotation rate and radial electric field, and RMF corrections on the pressure balance. (C) 2001 American Institute o f Physics.