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 and/or magnetic:
“The scholar may be sure that he writes the tougher truth for the calluses on his palms. They give firmness to the sentence. Indeed, the mind never makes a great and successful effort, without a corresponding energy of the body.”
—Henry David Thoreau (1817–1862)
“Wisdom is like electricity. There is no permanently wise man, but men capable of wisdom, who, being put into certain company, or other favorable conditions, become wise for a short time, as glasses rubbed acquire electric power for a while.”
—Ralph Waldo Emerson (1803–1882)
“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)