Ändra sökning
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Fast Wave Current Drive and Direct Electron Heating in JET ITB Plasmas
KTH, Skolan för elektro- och systemteknik (EES), Fusionsplasmafysik.
KTH, Skolan för elektro- och systemteknik (EES), Fusionsplasmafysik.
KTH, Skolan för elektro- och systemteknik (EES), Fusionsplasmafysik.
KTH, Skolan för elektro- och systemteknik (EES), Fusionsplasmafysik.ORCID-id: 0000-0002-7142-7103
Visa övriga samt affilieringar
Antal upphovsmän: 332006 (Engelska)Ingår i: Proc 21st IAEA Fusion Energy Conference, 2006Konferensbidrag, Publicerat paper (Refereegranskat)
Abstract [en]

Experiments with Fast Wave Current Drive, FWCD, and heating have been carried out in JET Internal Transport Barrier (ITB) discharges with strongly reversed magnetic shear. In order to maximize the current drive efficiency and increase the electron damping, and at the same time modifying the current profile in the transport barrier, hot low density ITB plasmas with strongly reversed magnetic shear, close to current hole, were created with Lower Hybrid Current Drive. It was difficult to strongly modify the central plasma current, even though the calculated current drive efficiency in terms of ampere per watts absorbed by the electrons was fairly high, 0.07A/W, because of: the strongly inductive nature of the plasma current due to the high electric conductivity; the interplay between the fast wave driven current and the bootstrap current, which, due to the dependence of the bootstrap current on the poloidal magnetic field, decreases the bootstrap current as the driven current increases; and parasitic absorption of the waves that decreased the power absorbed by the electrons. The power absorbed by the electrons was measured with a power modulation technique and the associated fast wave current drive calculated. Current diffusion simulations using the JETTO transport code, assuming neoclassical resistivity, were then carried out to calculate what changes to the plasma current profile could be expected from the current drive. The simulations showed a much slower response to the current drive compared to the measured central current densities suggesting a faster current penetration in the experiments than expected from neoclassical theory. Whereas the direct electron heating by fast magnetosonic waves using dipole spectra has proven to be an effective method to heat electrons in high-temperature ITB plasmas, even for a single pass damping of only a few percent, the heating in FWCD experiments with + 90o and - 90o antenna phasings were, for similar single pass damping as for the dipole, strongly degraded by parasitic losses, and with a heating efficiency of about half that of the dipole. Observations supporting that the losses are primarily caused by the presence of rectified RF-sheath potentials come from the large differences in performance and in Beryllium-II and Carbon-IV line radiation intensities between the dipole and ±90o phasings.

Ort, förlag, år, upplaga, sidor
2006.
Nationell ämneskategori
Naturvetenskap
Identifikatorer
URN: urn:nbn:se:kth:diva-85995OAI: oai:DiVA.org:kth-85995DiVA, id: diva2:500328
Konferens
21st IAEA Fusion Energy Conference, Chengdu, China, 16-21 October 2006
Anmärkning
Author count: 33. QC 20120530Tillgänglig från: 2012-02-13 Skapad: 2012-02-13 Senast uppdaterad: 2012-05-30Bibliografiskt granskad

Open Access i DiVA

Fulltext saknas i DiVA

Personposter BETA

Johnson, Thomas

Sök vidare i DiVA

Av författaren/redaktören
Hellsten, TorbjörnLaxåback, MartinBergkvist, TommyJohnson, Thomas
Av organisationen
Fusionsplasmafysik
Naturvetenskap

Sök vidare utanför DiVA

GoogleGoogle Scholar

urn-nbn

Altmetricpoäng

urn-nbn
Totalt: 85 träffar
RefereraExporteraLänk till posten
Permanent länk

Direktlänk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf