Experimental studies on E×B drift rotational transform and confinement in the bumpy torus NBT-1M

Author

Iguchi, H. ; Takasugi, K. ; Shoji, T. ; Hosokawa, M. ; Komori, A. ; Fujiwara, M. ; Ikegami, H.

Author_Institution

Nat. Inst. for Fusion Sci., Nagoya, Japan

Volume

22

Issue

4

fYear

1994

fDate

8/1/1994 12:00:00 AM

Firstpage

410

Lastpage

417

Abstract

Experimental studies on E×B drift rotational transform for toroidal plasma confinement were carried out using a bumpy torus NBT-1M. An inward radial electric field was observed, which induced E×B poloidal precession and formed closed drift surfaces in a conventional ECH configuration. However, the confinement was degraded by the plasma convective loss due to the asymmetric potential profile and core electrostatic fluctuations. By the use of a combination of two frequencies for ECH (18 GHz and 8.5 GHz), we could reduce both the potential asymmetry and the fluctuation. In this operation, the plasma confinement by E×B drift rotational transform was demonstrated more clearly than that in the conventional single frequency operation

Keywords

Tokamak devices; fluctuations; plasma diagnostics; plasma toroidal confinement; plasma transport processes; 18 GHz; 8.5 GHz; E×B drift rotational transform; E×B poloidal precession; NBT-1M; asymmetric potential profile; bumpy torus; closed drift surfaces; confinement; conventional ECH configuration; core electrostatic fluctuations; fluctuation; inward radial electric field; plasma confinement; plasma convective loss; potential asymmetry; single frequency operation; toroidal plasma confinement; Electrons; Fluctuations; Frequency; Magnetic confinement; Magnetic devices; Plasma confinement; Plasma devices; Plasma measurements; Probes; Toroidal magnetic fields;

fLanguage

English

Journal_Title

Plasma Science, IEEE Transactions on

Publisher

ieee

ISSN

0093-3813

Type

jour

DOI

10.1109/27.310648

Filename

310648