Chandrasekhar number
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The Chandrasekhar number is a dimensionless quantity used in magnetoconvection to represent ratio of the Lorentz force to the viscous force. It is named after the Indian astrophysicist Subrahmanyan Chandrasekhar.
The number's principal function is as a measure of the magnetic field strength, being proportional to the square of a characteristic magnetic field strength in a system.
[edit] Definition
The Chandrasekar number is usually denoted by the letter Q, and is motivated by a dimensionless form of the Navier-Stokes equation in the presence of a magnetic force in the equations of magnetohydrodynamics:
where σ is the Prandtl number, and ζ is the magnetic Prandtl number.
The Chandrasekhar number is thus defined as [1]:
where μ0 is the magnetic permeability, ρ is the density of the fluid, ν is the kinematic viscosity, and λ is the magnetic diffusivity. B0 and d are a characteristic magnetic field strength and a length scale of the system respectively.
It is related to the Hartmann number, H, by the relation:
[edit] References
- ^ N.E. Hurlburt, P.C. Matthews and A.M. Rucklidge, "Solar Magnetoconvection," Solar Physics, 192, p109-118 (2000)
