Book contents
- Frontmatter
- Contents
- Preface
- Part A The Fundamentals of MHD
- Introduction: The Aims of Part A
- 1 A Qualitative Overview of MHD
- 2 The Governing Equations of Electrodynamics
- 3 The Governing Equations of Fluid Mechanics
- 4 Kinematics of MHD: Advection and Diffusion of a Magnetic Field
- 5 Dynamics at Low Magnetic Reynolds Numbers
- 6 Dynamics at Moderate to High Magnetic Reynolds' Number
- 7 MHD Turbulence at Low and High Magnetic Reynolds Number
- Part B Applications in Engineering and Metallurgy
- Appendices
- Bibliography
- Subject Index
1 - A Qualitative Overview of MHD
Published online by Cambridge University Press: 26 February 2010
- Frontmatter
- Contents
- Preface
- Part A The Fundamentals of MHD
- Introduction: The Aims of Part A
- 1 A Qualitative Overview of MHD
- 2 The Governing Equations of Electrodynamics
- 3 The Governing Equations of Fluid Mechanics
- 4 Kinematics of MHD: Advection and Diffusion of a Magnetic Field
- 5 Dynamics at Low Magnetic Reynolds Numbers
- 6 Dynamics at Moderate to High Magnetic Reynolds' Number
- 7 MHD Turbulence at Low and High Magnetic Reynolds Number
- Part B Applications in Engineering and Metallurgy
- Appendices
- Bibliography
- Subject Index
Summary
The neglected borderland between two branches of knowledge is often that which best repays cultivation, or, to use a metaphor of Maxwell's, the greatest benefits may be derived from a cross-fertilisation of the sciences.
Rayleigh (1884)What is MHD?
Magnetic fields influence many natural and man-made flows. They are routinely used in industry to heat, pump, stir and levitate liquid metals. There is the terrestrial magnetic field which is maintained by fluid motion in the earth's core, the solar magnetic field which generates sunspots and solar flares, and the galactic magnetic field which is thought to influence the formation of stars from interstellar clouds. The study of these flows is called magnetohydrodynamics (MHD). Formally, MHD is concerned with the mutual interaction of fluid flow and magnetic fields. The fluids in question must be electrically conducting and non-magnetic, which limits us to liquid metals, hot ionised gases (plasmas) and strong electrolytes.
The mutual interaction of a magnetic field, B, and a velocity field, u, arises partially as a result of the laws of Faraday and Ampère, and partially because of the Lorentz force experienced by a current-carrying body. The exact form of this interaction is analysed in detail in the following chapters, but perhaps it is worth stating now, without any form of proof, the nature of this coupling.
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- An Introduction to Magnetohydrodynamics , pp. 3 - 26Publisher: Cambridge University PressPrint publication year: 2001