Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Feedback Stabilization of Multiple Resistive Wall Modes
KTH, Superseded Departments, Alfvén Laboratory.ORCID iD: 0000-0002-5259-0458
KTH, Superseded Departments, Alfvén Laboratory.
Show others and affiliations
2004 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 93, no 22, 225001- p.Article in journal (Refereed) Published
Abstract [en]

Active feedback stabilization of multiple independent resistive wall modes is experimentally demonstrated in a reversed-field pinch plasma. A reproducible simultaneous suppression of several nonresonant resistive wall modes is achieved. Coupling of different modes due to the limited number of the feedback coils is observed in agreement with theory. The feedback stabilization of nonresonant RWMs also has an effect on tearing modes that are resonant in the central plasma, leading to a significant prolongation of the discharge pulse.

Place, publisher, year, edition, pages
2004. Vol. 93, no 22, 225001- p.
Keyword [en]
Feedback coils, Feedback stabilization, Multiple resistive wall modes, Reversed-field pinch (RFP)
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
URN: urn:nbn:se:kth:diva-5425DOI: 10.1103/PhysRevLett.93.225001ISI: 000225326300028Scopus ID: 2-s2.0-42749106489OAI: oai:DiVA.org:kth-5425DiVA: diva2:9787
Note
QC 20100915Available from: 2006-03-08 Created: 2006-03-08 Last updated: 2017-11-21Bibliographically approved
In thesis
1. Resistive Wall Mode Stability and Control in the Reversed Field Pinch
Open this publication in new window or tab >>Resistive Wall Mode Stability and Control in the Reversed Field Pinch
2006 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

Control of MHD instabilities using a conducting wall together with external magnetic fields is an important route to improved performance and reliability in fusion devices. Active control of MHD modes is of interest for both the Advanced Tokamak and the Reversed Field Pinch (RFP) configurations. A wide range of unstable, current driven MHD modes is present in the RFP. An ideally conducting wall facing the plasma can in principle provide stabilization to these modes. However, a real, resistive wall characterized by a wall field diffusion time, cannot stabilize the ideal MHD modes unless they rotate with Alfvénic velocity, which is usually not the case. With a resistive wall, the ideal modes are converted into resistive wall modes (RWM) with growth rates comparable to the inverse wall time. Resistive wall modes have been studied in the EXTRAP T2R thin shell RFP device. Growth rates have been measured and found in agreement with linear MHD stability calculations. An advanced system for active control has been developed and installed on the EXTRAP T2R device. The system includes an array of 128 active saddle coils, fully covering the torus surface. Experiments on EXTRAP T2R have for the first time demonstrated simultaneous active suppression of multiple independent RWMs. In experiments with a partial array, coupling of different modes due to the limited number of feedback coils has been observed, in agreement with theory. Different feedback strategies, such as the intelligent shell, the rotating shell, and mode control have been studied. Further, feedback operation with different types of magnetic field sensors, measuring either the radial or the toroidal field components have been compared

Place, publisher, year, edition, pages
Stockholm: KTH, 2006. viii, 46 p.
Series
Trita-EE, ISSN 1653-5146 ; 2006:005
Keyword
Resistive wall modes, RWM, active control, feedback, MHD modes, Reversed-Field pinch, RFP, intelligent shell, mode control
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-3867 (URN)91-7178-285-0 (ISBN)
Public defence
2006-03-17, H1, Teknikringen 33, Stockholm, 10:30
Opponent
Supervisors
Note
QC 20100929Available from: 2006-03-08 Created: 2006-03-08 Last updated: 2010-09-29Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Authority records BETA

Brunsell, Per

Search in DiVA

By author/editor
Brunsell, PerYadikin, DimitryCecconello, MarcoDrake, James Robert
By organisation
Alfvén Laboratory
In the same journal
Physical Review Letters
Other Electrical Engineering, Electronic Engineering, Information Engineering

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 82 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf