The 2D mode structure symmetry breaking of the ion temperature gradient mode is studied analytically and numerically based on the mixed initial-value-eigenvalue approach, the Gyrokinetic PIC code ORB5 and the gyrokinetic Eulerian code GKW. The radial propagation and amplitude variation, in terms of the real and imaginary parts of the generalized "tilting parameter" θk, are treated in the framework of the Mode Structure Decomposition approach. The radial symmetry breaking is shown to be intimately coupled to the parallel symmetry breaking. In particular, I m { θ k } can lead to the increase in the local growth rate and the absolute value of the real frequency, as well as to parallel symmetry breaking. The complex θk can be measured in global simulations and accounted for in local simulations. This provides a way to include global effects related to the mode radial propagation and the intensity gradient in local descriptions and can be important for the study of momentum transport. © 2017 EURATOM.

Symmetry breaking of ion temperature gradient mode structure: From local to global analysis

Zonca, F.
2017

Abstract

The 2D mode structure symmetry breaking of the ion temperature gradient mode is studied analytically and numerically based on the mixed initial-value-eigenvalue approach, the Gyrokinetic PIC code ORB5 and the gyrokinetic Eulerian code GKW. The radial propagation and amplitude variation, in terms of the real and imaginary parts of the generalized "tilting parameter" θk, are treated in the framework of the Mode Structure Decomposition approach. The radial symmetry breaking is shown to be intimately coupled to the parallel symmetry breaking. In particular, I m { θ k } can lead to the increase in the local growth rate and the absolute value of the real frequency, as well as to parallel symmetry breaking. The complex θk can be measured in global simulations and accounted for in local simulations. This provides a way to include global effects related to the mode radial propagation and the intensity gradient in local descriptions and can be important for the study of momentum transport. © 2017 EURATOM.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.12079/1793
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