Reduced models for ETG transport in the tokamak pedestal
Open Access
- 1 June 2022
- journal article
- research article
- Published by AIP Publishing in Physics of Plasmas
- Vol. 29 (6)
- https://doi.org/10.1063/5.0087403
Abstract
This paper reports on the development of reduced models for electron temperature gradient (ETG) driven transport in the pedestal. Model development is enabled by a set of 61 nonlinear gyrokinetic simulations with input parameters taken from pedestals in a broad range of experimental scenarios. The simulation data have been consolidated in a new database for gyrokinetic simulation data, the multiscale gyrokinetic database (MGKDB), facilitating the analysis. The modeling approach may be considered a generalization of the standard quasilinear mixing length procedure. The parameter η, the ratio of the density to temperature gradient scale length, emerges as the key parameter for formulating an effective saturation rule. With a single order-unity fitting coefficient, the model achieves an error of 15%. A similar model for ETG particle flux is also described. We also present simple algebraic expressions for the transport informed by an algorithm for symbolic regression.Funding Information
- Fusion Energy Sciences (DE-SC0018429)
- Fusion Energy Sciences (DE-FG02-04ER54742)
- EUROfusion (101052200)
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