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IEVref: | 121-14-09 | ID: | |

Language: | en | Status: Standard | |

Term: | Alfvén wave velocity | ||

Synonym1: | Alfvén velocity | ||

Synonym2: | |||

Synonym3: | |||

Symbol: | ${v}_{A}$ | ||

Definition: | propagation velocity of Alfvén waves
${v}_{A}=B/\sqrt{\rho \mu {}_{0}}$ where
Note 1 to entry: The phase velocity of Alfvén waves is $c}_{\phi}=\frac{{c}_{0}^{}{v}_{A}^{}}{\sqrt{\left({c}_{0}^{2}+{v}_{A}^{2}\right)}$ where ${v}_{A}$ is the Alfvén wave velocity
The Alfvén wave velocity does not depend on the wavelength, so it shows no dispersion. Note 2 to entry: The coherent SI unit of the Alfvén wave velocity is metre per second, m/s. | ||

Publication date: | 2021-03 | ||

Source: | ISO 80000-11:2019, item 11–8.4, Remarks | ||

Replaces: | |||

Internal notes: | |||

CO remarks: | |||

TC/SC remarks: | |||

VT remarks: | |||

Domain1: | |||

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Domain5: |

${v}_{A}=B/\sqrt{\rho \mu {}_{0}}$

where

** B** is the magnetic flux density

*ρ* is the mass density

*μ*_{0} is the magnetic constant

Note 1 to entry: The phase velocity of Alfvén waves is

$c}_{\phi}=\frac{{c}_{0}^{}{v}_{A}^{}}{\sqrt{\left({c}_{0}^{2}+{v}_{A}^{2}\right)}$

where

${v}_{A}$ is the Alfvén wave velocity

*c*_{0} is the speed of light in vacuum.

The Alfvén wave velocity does not depend on the wavelength, so it shows no dispersion.

Note 2 to entry: The coherent SI unit of the Alfvén wave velocity is metre per second, m/s.