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
Numerical studies of confinement scalings for the dynamo-free reversed-field pinch
KTH, School of Electrical Engineering (EES), Centres, Alfvén Laboratory Centre for Space and Fusion Plasma Physics.
KTH, School of Electrical Engineering (EES), Centres, Alfvén Laboratory Centre for Space and Fusion Plasma Physics.ORCID iD: 0000-0001-6379-1880
2007 (English)In: Nuclear Fusion, ISSN 0029-5515, E-ISSN 1741-4326, Vol. 47, no 1, 9-16 p.Article in journal (Refereed) Published
Abstract [en]

In the reversed-field pinch (RFP), tearing modes associated with the dynamo are responsible for reduced energy- and particle confinement. In this study, it is observed that by implementing current profile control (CPC) in the RFP, a dynamo-free state can be achieved. The effect of CPC in the RFP is examined by the use of numerical simulations, and scaling laws are presented for confinement parameters. The model is nonlinear MHD in 3D including finite resistivity and pressure. A linear regression analysis is performed on simulation data from a series of computer runs for a set of initial parameter values. Scaling laws are determined for radial magnetic field, energy confinement time, poloidal beta and temperature. Confinement is improved substantially as compared with the conventional RFP - the temperature reaches reactor relevant levels by ohmic heating alone. It is observed that the configuration spontaneously develops into a quasi single helicity state. The CPC scheme is designed to eliminate the fluctuating electric dynamo field Ef ≤ -〈v × B〉, using feedback of an externally imposed electric field. The focus of this study is on obtaining principal theoretical optimization of confinement in the RFP by implementing CPC and to formulate scaling laws for confinement parameters, thus investigating the reactor viability of the concept.

Place, publisher, year, edition, pages
2007. Vol. 47, no 1, 9-16 p.
Keyword [en]
Computer simulation, Electric conductivity, Joule heating, Magnetohydrodynamics, Optimization, Plasma confinement, Regression analysis, Scaling laws
National Category
Fusion, Plasma and Space Physics
Identifiers
URN: urn:nbn:se:kth:diva-6334DOI: 10.1088/0029-5515/47/1/002ISI: 000243953900005Scopus ID: 2-s2.0-33947622628OAI: oai:DiVA.org:kth-6334DiVA: diva2:11019
Note
QC 20100924. Uppdaterad från Accepted till Published (20100924).Available from: 2006-11-13 Created: 2006-11-13 Last updated: 2017-12-14Bibliographically approved
In thesis
1. Numerical studies of current profile control in the reversed-field pinch
Open this publication in new window or tab >>Numerical studies of current profile control in the reversed-field pinch
2006 (English)Doctoral thesis, comprehensive summary (Other scientific)
Abstract [en]

The Reversed-Field Pinch (RFP) is one of the major alternatives for realizing energy production from thermonuclear fusion. Compared to alternative configurations (such as the tokamak and the stellarator) it has some advantages that suggest that an RFP reactor may be more economic. However, the conventional RFP is flawed with anomalously large energy and particle transport (which leads to unacceptably low energy confinement) due to a phenomenon called the "RFP dynam".

The dynamo is driven by the gradient in the plasma current in the plasma core, and it has been shown that flattening of the plasma current profile quenches the dynamo and increases confinement. Various forms of current profile control schemes have been developed and tested in both numerical simulations and experiments.

In this thesis an automatic current profile control routine has been developed for the three-dimensional, non-linear resistive magnetohydrodynamic computer code DEBSP. The routine utilizes active feedback of the dynamo associated fluctuating electric field, and is optimized for replacing it with an externally supplied field while maintaining field reversal. By introducing a semi-automatic feedback scheme, the number of free parameters is reduced, making a parameter scan feasible. A scaling study was performed and scaling laws for the confinement of the advanced RFP (an RFP with enhanced confinement due to current profile control) have been obtained.

The conclusions from this research project are that energy confinement is enhanced substantially in the advanced RFP and that poloidal beta values are possible beyond the previous theoretical limit beta βΘ < ½. Scalings toward the reactor regime indicate strongly enhanced confinement as compared to conventional RFP scenarios, but the question of reactor viability remains open.

Place, publisher, year, edition, pages
Stockholm: KTH, 2006. 52 p.
Series
Trita-EE, ISSN 1653-5146 ; 2006:053
Keyword
Reversed-Field Pinch, RFP, Current Profile Control, CPC, DEBS, DEBSP, active control, feedback, MHD.
National Category
Fusion, Plasma and Space Physics
Identifiers
urn:nbn:se:kth:diva-4167 (URN)91-7178-500-0 (ISBN)
Public defence
2006-11-30, Kollegiesalen (F3), Lindstedtsvägen 26, Stockholm, 10:00
Opponent
Supervisors
Note
QC 20101101Available from: 2006-11-13 Created: 2006-11-13 Last updated: 2010-11-01Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Authority records BETA

Scheffel, Jan

Search in DiVA

By author/editor
Dahlin, Jon-ErikScheffel, Jan
By organisation
Alfvén Laboratory Centre for Space and Fusion Plasma Physics
In the same journal
Nuclear Fusion
Fusion, Plasma and Space Physics

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 52 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