uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Anomalous and classical neutral beam fast ion diffusion on JET
Show others and affiliations
2009 (English)In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 51, no 4, 044004- p.Article in journal (Refereed) Published
Abstract [en]

Trace tritium experiments (TTE) on JET were analysed using Monte Carlo modelling of the neutron emission resulting from the neutral beam injection (NBI) of short (similar to 300 ms) tritium ( T) beam blips into reversed shear, hybrid ELMy H-mode and L-mode deuterium plasmas for a wide range of plasma parameters. The calculated neutron fluxes from deuterium-tritium ( DT) reactions could only be made consistent with all plasmas by applying an artificial reduction of the T beam power in the modelling of between 20% and 40%. A similar discrepancy has previously been observed in both JET (Gorini et al 2004 Proc. 31st EPS Conf. on Plasma Physics ( London, UK) vol 28G (ECA)) and TFTR (Ruskov et al 1999 Phys. Rev. Lett. 82 924), although no mechanism has yet been found that could explain such a difference in the measured T beam power. Applying this correction in the T beam power, good agreement between calculated and measured DT neutron emission profiles was obtained in low to moderate line averaged density ((n(e)) over bar < 4 x 10(19) m(-3)) ELMy H-Mode plasmas assuming that the fast beam ions experience no, or relatively small, anomalous diffusion (D-an << 0.5 m(2) s(-1)). However, the modelled neutron profiles do not agree with measurements in higher density plasmas using the same assumption and the disagreement between the measured and calculated shape of the neutron profile increases with plasma density. In this paper it is demonstrated that large anomalous losses of fast ions have to be assumed in the simulations to improve agreement between experimental and simulated neutron profiles, characterized by the goodness of fit. Various types of fast ion losses are modelled to explain aspects of the data, though further investigation will be required in order to gain a more detailed understanding of the nature of those anomalous losses.

Place, publisher, year, edition, pages
2009. Vol. 51, no 4, 044004- p.
National Category
Physical Sciences
URN: urn:nbn:se:uu:diva-129146DOI: 10.1088/0741-3335/51/4/044004ISI: 000264708500005OAI: oai:DiVA.org:uu-129146DiVA: diva2:337757
Available from: 2010-08-09 Created: 2010-08-05 Last updated: 2010-08-09Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text
By organisation
Department of Neutron Research
In the same journal
Plasma Physics and Controlled Fusion
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 145 hits
ReferencesLink to record
Permanent link

Direct link