Validation of gyrokinetic simulations with measurements of electron temperature fluctuations and density-temperature phase angles on ASDEX Upgrade
[1];
[2];
[3];
[4];
[5];
- Max Plank Inst. for Plasma Physics, Garching (Germany); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center
- Max Plank Inst. for Plasma Physics, Garching (Germany)
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center
- Max Plank Inst. for Plasma Physics, Garching (Germany); Technische Univ. München, Garching (Germany). Physik-Dept.
- Technische Univ. München, München (Germany). Lehrstuhl für Hochfrequenztechnik
- Ecole Polytechnique, Palaiseau (France). Lab. de Physique des Plasmas
Measurements of turbulent electron temperature fluctuation amplitudes, $$δT_e⊥/T_e$$, frequency spectra, and radial correlation lengths, $$L_r(T_{e⊥}$$), have been performed at ASDEX Upgrade using a newly upgraded Correlation ECE diagnostic in the range of scales $$k_⊥<1.4 cm^{-1}, k_r < 3.5 cm^{-1} (k_⊥ρ_s < 0.28$$ and $$k_rρ_s < 0.7$$). The phase angle between turbulent temperature and density fluctuations, αnT, has also been measured by using an ECE radiometer coupled to a reflectometer along the same line of sight. These quantities are used simultaneously to constrain a set of ion-scale non-linear gyrokinetic turbulence simulations of the outer core (ρtor = 0.75) of a low density, electron heated L-mode plasma, performed using the gyrokinetic simulation code, GENE. The ion and electron temperature gradients were scanned within uncertainties. It is found that gyrokinetic simulations are able to match simultaneously the electron and ion heat flux at this radius within the experimental uncertainties. The simulations were performed based on a reference discharge for which $$δT_{e⊥}/T_e$$ measurements were available, and $$L_r(T_{e⊥}$$) and αnT were then predicted using synthetic diagnostics prior to measurements in a repeat discharge. While temperature fluctuation amplitudes are overestimated by >50% for all simulations within the sensitivity scans performed, good quantitative agreement is found for $$L_r(T_{e⊥}$$) and αnT. Finally, a validation metric is used to quantify the level of agreement of individual simulations with experimental measurements, and the best agreement is found close to the experimental gradient values.
- Research Organization:
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- Contributing Organization:
- ASDEX Upgrade Team
- Grant/Contract Number:
- SC0006419; SC0017381
- OSTI ID:
- 1540164
- Alternate ID(s):
- OSTI ID: 1426527
- Journal Information:
- Physics of Plasmas, Vol. 25, Issue 5; ISSN 1070-664X
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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