2018/11/20 by Vasil Bratanov, S. M. Mahajan, Swadesh Mahajan +2
Physics and Astronomy · #Atomic physics #Classical mechanics #Excited state #Instability #Ionosphere and magnetosphere dynamics #K-epsilon turbulence model #Kinetic energy #Magnetic confinement fusion research #Mechanics #Physics #Plasma #Quantum mechanics #Scaling #Solar and Space Plasma Dynamics #Thermodynamics #Turbulence #Turbulence kinetic energy #physics.flu-dyn #physics.plasm-ph
paper · pdf · open access · doi:10.1088/1367-2630/ab1148
published in New Journal of Physics 21(4), 043046 (IOP Publishing)
arxiv created 2018/11/20 · openalex publication_date 2019/03/20 · arxiv updated 2019/05/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract The scaling of turbulent heat flux with respect to electrostatic potential is examined in the framework of a reduced (4D) kinetic system describing electrostatic turbulence in magnetized plasmas excited by the ion temperature gradient instability. Numerical simulations were instigated by, and tested the predictions of generic renormalized turbulence models like the 2D fluid model for electrostatic turbulence (Zhang and Mahajan 1993 Phys. Fluids B 5 2000). A fundamental, perhaps, universal result of this theory-simulation combination is the demonstration that there exist two distinct asymptotic states (that can be classified as weak turbulence (WT) and strong turbulence (ST) states) where the turbulent diffusivity Q scales quite differently with the strength of turbulence measured by the electrostatic energy <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo stretchy="false">∥</mml:mo> <mml:mi>ϕ</mml:mi> <mml:msup> <mml:mrow> <mml:mo stretchy="false">∥</mml:mo> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:math> . In the case of WT <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>Q</mml:mi> <mml:mo>∝</mml:mo> <mml:mo stretchy="false">∥</mml:mo> <mml:mi>ϕ</mml:mi> <mml:msup> <mml:mrow> <mml:mo stretchy="false">∥</mml:mo> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:math> , while in ST Q has a weaker dependence on the electrostatic energy and scales as <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo stretchy="false">∥</mml:mo> <mml:mi>ϕ</mml:mi> <mml:mo stretchy="false">∥</mml:mo> </mml:math> .