Modification of Edge Plasma Turbulence by External Magnetic Pertubations

PDF Version Also Available for Download.

Description

Magnetostatic perturbations applied to the DIII-D plasma using a n=3 coil set have significant impact on the plasma edge, such as edge localized mode (ELM) suppression [1], but also affect the background turbulence levels. Discharges with parameters R=1.75 m, a=0.56 m, B{sub T} {approx} 1.6 T, I{sub p} {approx} 1 MA and n{sub e} {approx} 3 x 10{sup 13} cm{sup -3}-n{sub e} {approx} 7 x 10{sup 13} cm{sup -3} (low, v*{sub e} {approx} 0.1 and moderate, v*{sub e} {approx} 1 electron pedestal collisionality) were used as a target for the perturbation, [applied at 3 s Fig. 1(a) and 2 s ... continued below

Physical Description

PDF-file: 6 pages; size: 0.6 Mbytes

Creation Information

Boedo, J; McKee, G; Rudakov, D; Reiser, D; Evans, T; Moyer, R et al. June 19, 2006.

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.

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

Magnetostatic perturbations applied to the DIII-D plasma using a n=3 coil set have significant impact on the plasma edge, such as edge localized mode (ELM) suppression [1], but also affect the background turbulence levels. Discharges with parameters R=1.75 m, a=0.56 m, B{sub T} {approx} 1.6 T, I{sub p} {approx} 1 MA and n{sub e} {approx} 3 x 10{sup 13} cm{sup -3}-n{sub e} {approx} 7 x 10{sup 13} cm{sup -3} (low, v*{sub e} {approx} 0.1 and moderate, v*{sub e} {approx} 1 electron pedestal collisionality) were used as a target for the perturbation, [applied at 3 s Fig. 1(a) and 2 s Fig. 1(b)]. The global density and energy content, among many other parameters, are unaffected, raising the issue of what mechanism replaces the particle and heat exhaust otherwise mediated by ELMs. Mixed ELMs (high frequency, low amplitude Type II ELMs interspersed with Type I) in the moderate collisionality regime and Type I ELMs in the low collisionality regime, are replaced by intermittency and broadband turbulence or semiperiodic events. It is important to notice that the coils can be energized in high poloidal mode spectra (upper and lower coils produce fields in the same direction) or odd configuration (upper and lower coils produce fields in the opposite direction) and also rotated 60 deg toroidally. Although we will focus on scanning probe [2] data obtained in the scrape-off layer (SOL), other diagnostics, beam emission spectroscopy (BES), reflectometry [3], were used to study the changes in the plasma turbulence when the ELMs are suppressed and the underlying turbulence and transport change. Thomson scattering n{sub e} and T{sub e} profiles (Fig. 2) accumulated over 200 ms before (red) and during (blue) I-coil perturbation are fitted with y = a + b* tanh[(r-c)/d] resulting in a,b staying constant while d varies from -0.009 to -0.011 and c from -0.013 to -0.009, i.e. the profiles mostly broaden and shift outward, changes which may be connected to an increase in radial turbulent transport assuming no deformation of the separatrix. This broadening is seen in both low and high collisionality regimes and in the high spatial resolution probe data.

Physical Description

PDF-file: 6 pages; size: 0.6 Mbytes

Source

  • Journal Name: Poceedings of the 33rd EPS Conference on Plasma Physics, vol. 30I, n/a, December 31, 2006, P5.144

Language

Item Type

Identifier

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

  • Report No.: UCRL-JRNL-222268
  • Grant Number: W-7405-ENG-48
  • Office of Scientific & Technical Information Report Number: 899444
  • Archival Resource Key: ark:/67531/metadc884816

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

  • June 19, 2006

Added to The UNT Digital Library

  • Sept. 22, 2016, 2:13 a.m.

Description Last Updated

  • Dec. 8, 2016, 8:40 p.m.

Usage Statistics

When was this article last used?

Yesterday: 0
Past 30 days: 0
Total Uses: 8

Interact With This Article

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

International Image Interoperability Framework

IIF Logo

We support the IIIF Presentation API

Boedo, J; McKee, G; Rudakov, D; Reiser, D; Evans, T; Moyer, R et al. Modification of Edge Plasma Turbulence by External Magnetic Pertubations, article, June 19, 2006; Livermore, California. (digital.library.unt.edu/ark:/67531/metadc884816/: accessed September 18, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.