### magnetic energy spectrum

(spatial spectral density of the energy associated with magnetic fields)

The term **magnetic energy spectrum** can perhaps have more
than one meaning in astronomy. One usage is
the spatial spectral density (like the power
spectrum of the cosmic microwave background, but an **energy spectral density**)
regarding the energy
associated with magnetic fields over a sphere.

The sphere could be associated with a planet,
i.e., centered on the planet, and encompass
a given range of radii, or it could be
the celestial sphere, with some similar
kind of specification of distance.

A magnetic field's energy (**magnetic energy**)
is essentially the minimal amount of work
sufficient to construct the magnetic field.
**Magnetic energy density** is a measure of
magnetic energy per unit volume. This
is equal to the **magnetic pressure**,
the pressure implied by the internal pressure
of plasma compressed by the magnetic field.

(*physics,magnetism*)
http://en.wikipedia.org/wiki/Magnetic_energy

http://en.wikipedia.org/wiki/Spectral_density

https://arxiv.org/abs/astro-ph/0404221

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