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Collisional model of quasilinear transport driven by toroidal electrostatic ion temperature gradient modes

István Pusztai (Institutionen för radio- och rymdvetenskap, Icke-linjär elektrodynamik) ; Tünde Fülöp (Institutionen för radio- och rymdvetenskap, Icke-linjär elektrodynamik) ; Jeff Candy ; R.J. Hastie
Physics of Plasmas (1070-664X). Vol. 16 (2009), p. 072305.
[Artikel, refereegranskad vetenskaplig]

The stability of ion temperature gradient (ITG) modes and the quasilinear fluxes driven by them are analyzed in weakly collisional tokamak plasmas using a semianalytical model based on an approximate solution of the gyrokinetic equation, where collisions are modeled by a Lorentz operator. Although the frequencies and growth rates of ITG modes far from threshold are only very weakly sensitive to the collisionality, the $a/L_{Ti}$ threshold for stability is affected significantly by electron-ion collisions. The decrease in collisionality destabilizes the ITG mode driving an inward particle flux, which leads to the steepening of the density profile. Closed analytical expressions for the electron and ion density and temperature responses have been derived without expansion in the smallness of the magnetic drift frequencies. The results have been compared with gyrokinetic simulations with GYRO and illustrated by showing the scalings of the eigenvalues and quasilinear fluxes with collisionality, temperature scale lengt, and magnetic shear.

Nyckelord: turbulent transport, microinstabilities, ion temperature gradient mode, quasilinear flux, stability

DOI: 10.1063/1.3168611

Denna post skapades 2009-07-31. Senast ändrad 2015-07-28.
CPL Pubid: 95691


Institutioner (Chalmers)

Institutionen för radio- och rymdvetenskap, Icke-linjär elektrodynamik (2005-2010)



Chalmers infrastruktur

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