STABILZATION OF NEOCLASSICAL TEARING MODES BY LOCALIZED ECCD IN DIII-D

PDF Version Also Available for Download.

Description

Neoclassical tearing modes (NTMs) are MHD modes which can become destabilized in a tokamak by a helical pressure perturbation. The NTM is particularly well suited to control since the mode is linearly stable although nonlinearly unstable, so if the island amplitude can be decreased below a threshold size the mode will decay and vanish. One means of shrinking the island is the replacement of the ''missing'' bootstrap current by a localized current generated by electron cyclotron current drive (ECCD). This method has been applied to the m=3/n=2 and the 2/1 tearing modes in DIII-D, in H-mode plasmas with ongoing ELMs ... continued below

Physical Description

Medium: X; Size: 11 pages

Creation Information

Prater, R.; Eliss, R. A., III; La Haye, R. J.; Lohr, J. M.; Luce, T. C.; Perkins, F. W. et al. May 1, 2002.

Context

This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by UNT Libraries Government Documents Department to Digital Library, a digital repository hosted by the UNT Libraries. More information about this article can be viewed below.

Who

People and organizations associated with either the creation of this article or its content.

Sponsor

Publisher

Provided By

UNT Libraries Government Documents Department

Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.

Contact Us

What

Descriptive information to help identify this article. Follow the links below to find similar items on the Digital Library.

Description

Neoclassical tearing modes (NTMs) are MHD modes which can become destabilized in a tokamak by a helical pressure perturbation. The NTM is particularly well suited to control since the mode is linearly stable although nonlinearly unstable, so if the island amplitude can be decreased below a threshold size the mode will decay and vanish. One means of shrinking the island is the replacement of the ''missing'' bootstrap current by a localized current generated by electron cyclotron current drive (ECCD). This method has been applied to the m=3/n=2 and the 2/1 tearing modes in DIII-D, in H-mode plasmas with ongoing ELMs and sawteeth, both of which generate seed islands periodically. In the case of the 3/2 mode, full suppression was obtained robustly by applying about 1.5 MW of ECCD very near the flux surface of maximum mode amplitude. When the mode first appears in the plasma the stored energy decreases by 30%, but when the mode is stabilized by the ECCD the beta may be raised above the initial threshold pressure by 20% by additional neutral beam heating, thereby effecting an improvement in the limiting beta of nearly a factor 2. An innovative automated search algorithm was implemented to find and retain the optimum location for the ECCD in the presence of the mode. Only partial success has been obtained in stabilizing the 2/1 mode by ECCD, but calculations indicate that ECCD power near 3 MW should be adequate for complete suppression of this mode.

Physical Description

Medium: X; Size: 11 pages

Notes

Oakland Operations Office, Oakland, CA (US); INIS

Source

  • 12th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating, Aix-En-Provence (FR), 05/13/2002--05/16/2002; Other Information: THIS IS A PREPRINT OF A PAPER PRESENTED AT THE 12TH JOINT WORKSHOP ON ELECTRON CYCLOTRON EMISSION AND ELECTRON CYCLOTRON RESONANCE HEATING, MAY 13-16,2002, IN AIX-EN-PROVENCE, FRANCE, AND TO BE PUBLISHED IN THE ''PRODEEDINGS''

Language

Item Type

Identifier

Unique identifying numbers for this article in the Digital Library or other systems.

  • Report No.: NONE
  • Grant Number: AC03-99ER54463
  • Office of Scientific & Technical Information Report Number: 804886
  • Archival Resource Key: ark:/67531/metadc740561

Collections

This article is part of the following collection of related materials.

Office of Scientific & Technical Information Technical Reports

Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.

What responsibilities do I have when using this article?

When

Dates and time periods associated with this article.

Creation Date

  • May 1, 2002

Added to The UNT Digital Library

  • Oct. 18, 2015, 6:40 p.m.

Description Last Updated

  • Jan. 4, 2017, 2:07 p.m.

Usage Statistics

When was this article last used?

Yesterday: 0
Past 30 days: 0
Total Uses: 3

Interact With This Article

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

Citations, Rights, Re-Use

Prater, R.; Eliss, R. A., III; La Haye, R. J.; Lohr, J. M.; Luce, T. C.; Perkins, F. W. et al. STABILZATION OF NEOCLASSICAL TEARING MODES BY LOCALIZED ECCD IN DIII-D, article, May 1, 2002; United States. (digital.library.unt.edu/ark:/67531/metadc740561/: accessed December 15, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.