The discussion centers on whether a square loop of steady current radiates electromagnetic energy, drawing comparisons to the well-known behavior of circular loops. Participants explore the conditions under which radiation occurs, particularly focusing on the nature of the current and the motion of charges within the loop.
Participants generally disagree on whether a square loop of steady current radiates, with some asserting that it does not while others introduce conditions under which radiation might occur, such as varying currents or fast-moving electrons.
The discussion includes assumptions about the nature of current, the behavior of electric fields, and the conditions necessary for radiation, which remain unresolved and dependent on specific definitions and contexts.
Imagine the static field of the charges in the wire. The lines of force point radially outwards everywhere, and are always normal to the wire. Even when it goes round a corner they are normal to the wire. To have radiation, they need to be not normal but pushed to one side a bit. In this way a transverse component of field is created, the radiated E-field. This only occurs if the current is varied, as with AC or at switch-on.How about a loop of steady current that is shaped in a square? Does this structure radiate?
and i guess radiated power will be given by Larmor's formula ?tech99 said:Further to my reply, if the electrons can move fast enough with a steady current it is possible to obtain cyclotron radiation. But electrons in a wire are only traveling at, say, 1 mm an hour. In a vacuum tube it is possible for them to go round millions of times a second, and then cyclotron radiation can be seen at the rotation frequency.
Yes, taking the radial acceleration.debajyoti datta said:and i guess radiated power will be given by Larmor's formula ?