Linear microstability analysis of a low-Z impurity doped tokamak plasma
Romanelli, M. (Michele), Szepesi, Gabor, Peeters, A. G., Apicella, M. L., Marinucci, M., Mazzotta, C., Mazzitelli, G. and Frigione, D.. (2011) Linear microstability analysis of a low-Z impurity doped tokamak plasma. Nuclear Fusion, Vol.51 (No.10). Article: 103008. ISSN 0029-5515Full text not available from this repository.
Official URL: http://dx.doi.org/10.1088/0029-5515/51/10/103008
Improved electron and deuterium energy and particle confinement in the presence of low-Z impurities have been observed in many tokamaks under various experimental conditions. Peaked electron density profiles have been obtained in the Frascati Tokamak Upgrade (FTU) ohmic plasmas where a high concentration of lithium has been detected following the installation of a Liquid Lithium Limiter (LLL). This paper presents the results of a gyrokinetic study on the effects of lithium and other low-Z impurities on the linear stability of deuterium and electron temperature driven modes and their associated fluxes for plasma parameters such as those found in the core of LLL-FTU plasmas.
Simulations show that a lithium concentration in excess of n(Li)/n(e) = 15%, as estimated in the initial phase of a reference FTU discharge, is found to have a strong stabilizing effect on the TEM and high-frequency ETG modes. A significant stabilization of the electron driven modes can still be observed when the lithium concentration is reduced to 3%.
In the presence of a significant impurity concentration (n(Li)/n(e) = 3-15%) the long wavelength ITG modes drive an inward electron and deuterium flux and outward lithium flux. This process may lead eventually to an increased electron and deuterium density peaking and a reduced Z(eff) (lithium density below nLi/ne = 1%).
|Item Type:||Journal Article|
|Subjects:||Q Science > QC Physics|
|Divisions:||Faculty of Science > Physics|
|Library of Congress Subject Headings (LCSH):||Tokamaks, Plasma confinement, Plasma turbulence, Lithium|
|Journal or Publication Title:||Nuclear Fusion|
|Publisher:||Institute of Physics Publishing Ltd.|
|Official Date:||October 2011|
|Page Range:||Article: 103008|
|Access rights to Published version:||Restricted or Subscription Access|
|Funder:||Research Councils UK (RCUK), European Commission (EC), Engineering and Physical Sciences Research Council (EPSRC), Culham Centre for Fusion Energy (CCFE)|
|Grant number:||EP/1501045 (RCUK), EP/H002081/1 (EPSRC)|
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