Gyrokinetic entropy balances and dynamics in toroidal flux-driven ITG turbulence
| Autor: | Mikiya Muto, Kenji Imadera, Yasuaki Kishimoto |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Physics of Plasmas. 28:082304 |
| ISSN: | 1089-7674 1070-664X |
| Popis: | Overall entropy balances and radial dynamics for thermodynamic entropy and conventional fluctuation entropy are investigated by means of newly derived coupled equations and the full-f gyrokinetic simulations for toroidal flux-driven ion-temperature-gradient turbulence. When the equations are integrated over the radial direction, in the quasi-steady state, fluctuation entropy production due to collisional dissipation in velocity space and thermodynamic entropy reduction due to energy input/output in real space are found to be balanced through the generation of a heat flux and associated phase mixing. The cross-correlation analysis indicates that collisional dissipation occurs after the formation of fine-scale structures by phase mixing, while there exists an in-phase relationship between thermodynamic entropy production due to profile relaxation and heat flux. However, when the radial dynamics are retained in the equations, this relationship is found to be violated in regions exhibiting heat avalanches. This is because the thermodynamic entropy is dominated by advection, leading to a time lag between heat flux and temperature variation. |
| Databáze: | OpenAIRE |
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