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:
“It is in this power of saying everything, and yet saying nothing too plainly, that the perfection of art ... consists.”
—John Ruskin (1819–1900)
“True freedom is to have power over oneself for everything.”
—Michel de Montaigne (1533–1592)
“For the first time in the history of mankind, one generation literally has the power to destroy the past, the present and the future, the power to bring time to an end.”
—Hubert H. Humphrey (1911–1978)