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:
“He has served me too well; by increasing my power he has stolen it away: he is now my subject only so long as he pleases.”
—Pierre Corneille (1606–1684)
“Power is not of a man. Wealth does not center in the person of the wealthy. Celebrity is not inherent in any personality. To be celebrated, to be wealthy, to have power requires access to major institutions.”
—C. Wright Mills (1916–1962)
“Compared to other parents, remarried parents seem more desirous of their child’s approval, more alert to the child’s emotional state, and more sensitive in their parent-child relations. Perhaps this is the result of heightened empathy for the child’s suffering, perhaps it is a guilt reaction; in either case, it gives the child a potent weapon—the power to disrupt the new household and come between parent and the new spouse.”
—Letty Cottin Pogrebin (20th century)