Related Experiment Video
Updated: Jul 11, 2026
06:42
Magnetically Induced Rotating Rayleigh-Taylor Instability
Published on: March 3, 2017
Transport in two-fluid magnetohydrodynamic turbulence
1Department of Applied Mathematics, University of Sheffield, Sheffield, S3 7RH, United Kingdom.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|October 13, 2007
Summary
This study introduces a theory for turbulent transport in two-fluid reduced magnetohydrodynamics (MHD). Kinetic Alfven waves weaken magnetic field quenching, reducing turbulent magnetic diffusivity.
Area of Science:
- Plasma Physics
- Fluid Dynamics
- Magnetohydrodynamics (MHD)
Background:
- Turbulent transport of magnetic flux and momentum is crucial in plasma physics.
- Single-fluid reduced MHD models often overestimate the quenching of magnetic fields.
Purpose of the Study:
- To develop a theory for transport in two-fluid 3D reduced MHD turbulence.
- To investigate the role of kinetic Alfven waves and shear flows on turbulent transport.
Main Methods:
- Theoretical modeling of two-fluid reduced MHD turbulence.
- Consistent inclusion of shear flows and magnetic fields.
- Analysis of kinetic Alfven wave and drift wave effects.
Main Results:
- Kinetic Alfven waves weaken turbulent transport quenching of strong magnetic fields.
- Turbulent magnetic diffusivity is proportional to (eta/Omega)^(1/3)B(0)^(-2).
- Momentum transport is diffusive with enhanced eddy viscosity compared to single-fluid MHD.
Conclusions:
- Two-fluid effects, particularly kinetic Alfven waves, are essential for accurate modeling of turbulent transport.
- The findings have implications for understanding shear flow instabilities in magnetized plasmas.
Related Concept Videos
01:07Laminar and Turbulent Flow
Fluid dynamics is the study of fluids in motion. Velocity vectors are often used to illustrate fluid motion in applications like meteorology. For example, wind—the fluid motion of air in the atmosphere—can be represented by vectors indicating the speed and direction of the wind at any given point on a map. Another method for representing fluid motion is a streamline. A streamline represents the path of a small volume of fluid as it flows. When the flow pattern changes with time, the streamlines...
01:24Turbulent Flow
Turbulent flow is characterized by unpredictable fluctuations in velocity and pressure, which result in a chaotic fluid movement distinct from the orderly patterns of laminar flow. While laminar flow is governed by smooth, parallel layers with minimal mixing, turbulent flow exhibits highly irregular, three-dimensional patterns. This behavior arises due to instabilities in the fluid's velocity profile, and amplifies as the flow velocity increases. Minor disturbances, known as turbulent spots,...
01:17Steady, Laminar Flow Between Parallel Plates
Understanding steady, laminar flow between parallel plates is essential for analyzing and designing flow in narrow rectangular channels, commonly found in various water conveyance and drainage systems. The Navier-Stokes equations govern fluid motion and are generally challenging to solve due to their nonlinearity. However, simplifications are possible in certain cases, like the steady laminar flow between parallel plates. For this scenario, we assume steady, incompressible, laminar flow.
01:24Reynolds Transport Theorem
The Reynolds transport theorem provides a framework to relate the time rate of change of an extensive property within a system to that in a control volume, which is crucial for analyzing fluid dynamics. Extensive properties, such as mass, velocity, acceleration, temperature, and momentum, can be expressed in terms of the mass of a fluid portion. These properties are called extensive because they depend on the system's size, while intensive properties are their corresponding values per unit mass.
01:22Couette Flow
Couette flow represents the flow of fluid between two parallel plates, with one plate fixed and the other moving with a constant velocity. This configuration allows for a simplified analysis using the Navier-Stokes equations, which govern fluid motion under conditions of viscosity and incompressibility. For Couette flow, the assumptions include a steady, laminar, incompressible flow with a zero-pressure gradient in the flow direction. This flow type is beneficial for understanding shear-driven...
01:18Newtonian Fluid: Problem Solving
Newtonian fluids exhibit a constant viscosity, meaning their shear stress and shear strain rate are directly proportional. This property ensures a predictable and stable response to applied forces, maintaining a linear relationship between force and flow. Examples include water, air, and light oils, consistently demonstrating this proportional behavior regardless of external conditions.
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...