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Updated: Aug 6, 2025

Building Langmuir Probes and Emissive Probes for Plasma Potential Measurements in Low Pressure, Low Temperature Plasmas
Published on: May 25, 2021
A simplified model to estimate nonlinear turbulent transport by linear dynamics in plasma turbulence
Tomonari Nakayama1, Motoki Nakata2,3,4, Mitsuru Honda5
1The Graduate University for Advanced Studies, SOKENDAI, Toki, Gifu, 509-5292, Japan. nakayama.tomonari@nifs.ac.jp.
Abstract:
A simplified model to estimate nonlinear turbulent transport only by linear calculations is proposed, where the turbulent heat diffusivity in tokamak ion temperature gradient(ITG) driven turbulence is reproduced for a wide parameter range including near- and far-marginal ITG stability. The optimal nonlinear functional relation(NFR) between the turbulent diffusivity, the turbulence intensity [Formula: see text], and the zonal-flow intensity [Formula: see text] is determined by means of mathematical optimization methods. Then, an extended modeling for [Formula: see text] and [Formula: see text] to incorporate the turbulence suppression effects and the temperature gradient dependence is carried out. The simplified transport model is expressed as a modified nonlinear function composed of the linear growth rate and the linear zonal-flow decay time. Good accuracy and wide applicability of the model are demonstrated, where the regression error of [Formula: see text] indicates improvement by a factor of about 1/4 in comparison to that in the previous works.
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