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:
“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)
“He made no resistance whatever, and was stabbed in the back.... I must not dwell upon the fearful repast.... Words have no power to impress the mind with the exquisite horror of their reality.”
—Edgar Allan Poe (1809–1849)
“The philosopher is like a man fasting in the midst of universal intoxication. He alone perceives the illusion of which all creatures are the willing playthings; he is less duped than his neighbor by his own nature. He judges more sanely, he sees things as they are. It is in this that his liberty consists—in the ability to see clearly and soberly, in the power of mental record.”
—Henri-Frédéric Amiel (1821–1881)