Turbulence characteristics of the I-mode confinement regime in ASDEX Upgrade - Laboratoire de Physique des Plasmas (LPP) Access content directly
Journal Articles Nuclear Fusion Year : 2017

Turbulence characteristics of the I-mode confinement regime in ASDEX Upgrade

Cyrille Honoré

Abstract

Besides strong geodesic acoustic mode (GAM) activity, turbulence in the I-mode confinement regime of ASDEX Upgrade exhibits two prominent features, the weakly coherent mode (WCM) and strongly intermittent solitary density perturbations. The nonlinear interaction between these structures is studied in detail by means of a conditional averaged wavelet-bicoherence analysis. The wavelet analysis reveals that these density perturbations are at the WCM frequency. The GAM is coupled to all frequency scales of the velocity fluctuations via a modulational instability. The WCM shows coupling to higher frequencies prior to the bursts, indicating a process resembling wave-steepening. A possible mechanism for the generation of such solitary density perturbations by a Korteweg?de Vries-like nonlinearity is discussed.
Fichier principal
Vignette du fichier
Manz_Turbulence.pdf (4.54 Mo) Télécharger le fichier
Origin : Files produced by the author(s)

Dates and versions

hal-01894829 , version 1 (18-03-2024)

Identifiers

Cite

P. Manz, T. Happel, F. Ryter, M. Bernert, G. Birkenmeier, et al.. Turbulence characteristics of the I-mode confinement regime in ASDEX Upgrade. Nuclear Fusion, 2017, 57 (8), pp.086022. ⟨10.1088/1741-4326/aa7476⟩. ⟨hal-01894829⟩
73 View
1 Download

Altmetric

Share

Gmail Facebook X LinkedIn More