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 power confided in me will be used to hold, occupy and possess the property and places belonging to the government, and to collect the duties and imposts.”
—Abraham Lincoln (1809–1865)
“I never saw love as luck, as that gift from the gods which put everything else in place, and allowed you to succeed. No, I saw love as reward. One could find it only after one’s virtue, or one’s courage, or self-sacrifice, or generosity, or loss, has succeeded in stirring the power of creation.”
—Norman Mailer (b. 1923)
“I know not whether the remark is to our honour or otherwise, that lessons of wisdom have never such power over us, as when they are wrought into the heart, through the ground-work of a story which engages the passions: Is it that we are like iron, and must first be heated before we can be wrought upon?”
—Laurence Sterne (1713–1768)