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:
“The older I get, the greater power I seem to have to help the world; I am like a snowball—the further I am rolled the more I gain.”
—Susan B. Anthony (1820–1906)
“The least one can say of power is that a vocation for it is suspicious.”
—Jean Rostand (1894–1977)
“Nothing is quite so wretchedly corrupt as an aristocracy which has lost its power but kept its wealth and which still has endless leisure to devote to nothing but banal enjoyments. All its great thoughts and passionate energy are things of the past, and nothing but a host of petty, gnawing vices now cling to it like worms to a corpse.”
—Alexis de Tocqueville (1805–1859)