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:
“You don’t have power if you surrender all your principles—you have office.”
—Ron Todd (b. 1927)
“In this our talking America, we are ruined by our good nature and listening on all sides. This compliance takes away the power of being greatly useful.”
—Ralph Waldo Emerson (1803–1882)
“I hate this shallow Americanism which hopes to get rich by credit, to get knowledge by raps on midnight tables, to learn the economy of the mind by phrenology, or skill without study, or mastery without apprenticeship, or the sale of goods through pretending that they sell, or power through making believe you are powerful, or through a packed jury or caucus, bribery and “repeating” votes, or wealth by fraud.”
—Ralph Waldo Emerson (1803–1882)