Power
Dielectric heating must be distinguished from Joule heating of conductive media, which is caused by induced electric currents in the media. For dielectric heating, the generated power density per volume is given by
where is the angular frequency of the exciting radiation, is the imaginary part of the complex relative permittivity of the absorbing material, is the permittivity of free space and the electric field strength. The imaginary part of the (frequency-dependent) relative permittivity is a measure for the ability of a dielectric material to convert electromagnetic field energy into heat.
If the conductivity of the material is small, or the frequency is high, such that (with ), then dielectric heating is the dominant mechanism of loss of energy from the electromagnetic field into the medium.
Read more about this topic: Dielectric Heating
Famous quotes containing the word power:
“Poetry is above all a concentration of the power of language, which is the power of our ultimate relationship to everything in the universe.”
—Adrienne Rich (b. 1929)
“Even voting for the right is doing nothing for it. It is only expressing feebly your desire that it should prevail. A wise man will not leave the right to the mercy of chance, nor wish it to prevail through the power of the majority.”
—Henry David Thoreau (1817–1862)
“What is genius—but the power of expressing a new individuality?”
—Elizabeth Barrett Browning (1806–1861)