- #1
yungman
- 5,741
- 294
Poynting Theorem:
\frac {dW}{dt} \;=\; \int _{v'} (\vec E \cdot \vec J) d \vec {v'} \;=\; -\frac 1 2 \frac {\partial}{\partial t} \int _{v'} ( \epsilon_0 E^2 +\frac 1 {\mu_0} B^2) d \vec {v'}\;-\;\frac 1 {\mu_0} \int _{s'} (\vec E X \vec B) d \vec {s'}
In Cheng's "Field and Wave Electromagnetics", it interpret this is ohmic loss because:
\vec E \cdot \vec J \;=\; \sigma E^2
Which is the ohmic loss.
I don't see it described like this in Griffiths. Can anyone comment what this term really means?
\frac {dW}{dt} \;=\; \int _{v'} (\vec E \cdot \vec J) d \vec {v'} \;=\; -\frac 1 2 \frac {\partial}{\partial t} \int _{v'} ( \epsilon_0 E^2 +\frac 1 {\mu_0} B^2) d \vec {v'}\;-\;\frac 1 {\mu_0} \int _{s'} (\vec E X \vec B) d \vec {s'}
In Cheng's "Field and Wave Electromagnetics", it interpret this is ohmic loss because:
\vec E \cdot \vec J \;=\; \sigma E^2
Which is the ohmic loss.
I don't see it described like this in Griffiths. Can anyone comment what this term really means?
