TY - JOUR
T1 - Cross-code gyrokinetic verification and benchmark on the linear collisionless dynamics of the geodesic acoustic mode
AU - Biancalani, A
AU - Bottino, A
AU - Ehrlacher, C.
AU - Grandgirard, Virginie
AU - Merlo, G.
AU - Novikau, I.
AU - Qiu, Z.
AU - Sonnendrücker, E.
AU - Garbet, X.
AU - Görler, T.
AU - Leerink, S.
AU - Palermo, F.
AU - Zarzoso, D.
PY - 2017/6/1
Y1 - 2017/6/1
N2 - The linear properties of the geodesic acoustic modes (GAMs) in tokamaks are investigated by means of the comparison of analytical theory and gyrokinetic numerical simulations. The dependence on the value of the safety factor, finite-orbit-width of the ions in relation to the radial mode width, magnetic-flux-surface shaping, and electron/ion mass ratio are considered. Nonuniformities in the plasma profiles (such as density, temperature, and safety factor), electro-magnetic effects, collisions, and the presence of minority species are neglected. Also, only linear simulations are considered, focusing on the local dynamics. We use three different gyrokinetic codes: the Lagrangian (particle-in-cell) code ORB5, the Eulerian code GENE, and semi-Lagrangian code GYSELA. One of the main aims of this paper is to provide a detailed comparison of the numerical results and analytical theory, in the regimes where this is possible. This helps understanding better the behavior of the linear GAM dynamics in these different regimes, the behavior of the codes, which is crucial in the view of a future work where more physics is present, and the regimes of validity of each specific analytical dispersion relation.
AB - The linear properties of the geodesic acoustic modes (GAMs) in tokamaks are investigated by means of the comparison of analytical theory and gyrokinetic numerical simulations. The dependence on the value of the safety factor, finite-orbit-width of the ions in relation to the radial mode width, magnetic-flux-surface shaping, and electron/ion mass ratio are considered. Nonuniformities in the plasma profiles (such as density, temperature, and safety factor), electro-magnetic effects, collisions, and the presence of minority species are neglected. Also, only linear simulations are considered, focusing on the local dynamics. We use three different gyrokinetic codes: the Lagrangian (particle-in-cell) code ORB5, the Eulerian code GENE, and semi-Lagrangian code GYSELA. One of the main aims of this paper is to provide a detailed comparison of the numerical results and analytical theory, in the regimes where this is possible. This helps understanding better the behavior of the linear GAM dynamics in these different regimes, the behavior of the codes, which is crucial in the view of a future work where more physics is present, and the regimes of validity of each specific analytical dispersion relation.
UR - http://www.scopus.com/inward/record.url?scp=85021269905&partnerID=8YFLogxK
U2 - 10.1063/1.4985571
DO - 10.1063/1.4985571
M3 - Article
AN - SCOPUS:85021269905
SN - 1070-664X
VL - 24
SP - 1
EP - 17
JO - Physics of Plasmas
JF - Physics of Plasmas
IS - 6
M1 - 062512
ER -