Energy Density of Electric and Magnetic Fields
Electric and magnetic fields store energy. In a vacuum, the (volumetric) energy density (in SI units) is given by
where E is the electric field and B is the magnetic field. The solution will be in Joules per cubic metre. In the context of magnetohydrodynamics, the physics of conductive fluids, the magnetic energy density behaves like an additional pressure that adds to the gas pressure of a plasma.
In normal (linear) substances, the energy density (in SI units) is
where D is the electric displacement field and H is the magnetizing field.
Read more about this topic: Energy Density
Famous quotes containing the words energy, electric, magnetic and/or fields:
“A government deriving its energy from the will of the society, and operating, by the reason of its measures, on the understanding and interest of the society ... is the government for which philosophy has been searching and humanity been fighting from the most remote ages ... which it is the glory of America to have invented, and her unrivalled happiness to possess.”
—James Madison (1751–1836)
“That’s the down-town frieze,
Principally the church steeple,
A black line beside a white line;
And the stack of the electric plant,
A black line drawn on flat air.”
—Wallace Stevens (1879–1955)
“We are in great haste to construct a magnetic telegraph from Maine to Texas; but Maine and Texas, it may be, have nothing important to communicate.”
—Henry David Thoreau (1817–1862)
“When we walk, we naturally go to the fields and woods: what would become of us, if we walked only in a garden or a mall?”
—Henry David Thoreau (1817–1862)