Local measurements of tearing mode flows and the magnetohydrodynamic dynamo in the Madison Symmetric Torus reversed-field pinch

D. A. Ennis, D. Craig, S. Gangadhara, J. K. Anderson, D. J. Den Hartog, F. Ebrahimi, G. Fiksel, S. C. Prager

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

The first localized measurements of tearing mode flows in the core of a hot plasma are presented using nonperturbing measurements of the impurity ion flow. Emission from charge exchange recombination is collected by a novel high optical throughput duo spectrometer providing localized (±1 cm) measurements of C+6 impurity ion velocities resolved to <500 m/s with high bandwidth (100 kHz). Poloidal tearing mode flows in the Madison Symmetric Torus reversed-field pinch are observed to be localized to the mode resonant surface with a radial extent much broader than predicted by linear magnetohydrodynamic (MHD) theory but comparable to the magnetic island width. The relative poloidal flow amplitudes among the dominant core modes do not reflect the proportions of the magnetic amplitudes. The largest correlated flows are associated with modes having smaller magnetic amplitudes resonant near the midradius. The MHD dynamo due to these flows on the magnetic axis is measured to be adequate to balance the mean Ohm's law during reduced tearing activity and is significant but does not exclude other dynamo mechanisms from contributing during a surge in reconnection activity.

Original languageEnglish (US)
Article number082102
JournalPhysics of Plasmas
Volume17
Issue number8
DOIs
StatePublished - Aug 1 2010
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

Fingerprint Dive into the research topics of 'Local measurements of tearing mode flows and the magnetohydrodynamic dynamo in the Madison Symmetric Torus reversed-field pinch'. Together they form a unique fingerprint.

  • Cite this

    Ennis, D. A., Craig, D., Gangadhara, S., Anderson, J. K., Den Hartog, D. J., Ebrahimi, F., Fiksel, G., & Prager, S. C. (2010). Local measurements of tearing mode flows and the magnetohydrodynamic dynamo in the Madison Symmetric Torus reversed-field pinch. Physics of Plasmas, 17(8), [082102]. https://doi.org/10.1063/1.3458667