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:
“Unionism seldom, if ever, uses such power as it has to insure better work; almost always it devotes a large part of that power to safeguarding bad work.”
—H.L. (Henry Lewis)
“There is never a beginning, there is never an end, to the inexplicable continuity of this web of God, but always circular power returning into itself.”
—Ralph Waldo Emerson (1803–1882)
“Every diminution of the public burdens arising from taxation gives to individual enterprise increased power and furnishes to all the members of our happy confederacy new motives for patriotic affection and support.”
—Andrew Jackson (1767–1845)