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:
“Then Jesus called the twelve together and gave them power and authority over all demons and to cure diseases, and he sent them out to proclaim the kingdom of God and to heal.”
—Bible: New Testament, Luke 9:1,2.
“Don’t you see what my power does for me? I could sit in on the councils of kings and dictators. It makes me king. It makes me—Nemesis.”
—Lester Cole (1904–1985)
“It recognizes no morality but a sham morality meant for deceit, no honor even among thieves and of a thievish sort, no force but physical force, no intellectual power but cunning, no disgrace but failure, no crime but stupidity.”
—Woodrow Wilson (1856–1924)