- #1
devd
- 47
- 1
Suppose we have a charge, ##q## and a magnetic dipole moment, ##\vec m##. They don't move, nothing changes with time, in short, a static situation.
Now, we have at least some regions of space where both the electric field, ##\vec E## and the magnetic field, ##\vec B## are non-zero. That means in those regions, the poynting vector, ##\vec S## is non-zero.
Now according to the interpretation of ##\vec S## as energy flux density, that is energy per unit area per unit time, energy is flowing between the regions. How is this true? What is the source of this energy? Am i missing something trivial?
Now, we have at least some regions of space where both the electric field, ##\vec E## and the magnetic field, ##\vec B## are non-zero. That means in those regions, the poynting vector, ##\vec S## is non-zero.
Now according to the interpretation of ##\vec S## as energy flux density, that is energy per unit area per unit time, energy is flowing between the regions. How is this true? What is the source of this energy? Am i missing something trivial?