Assumption:
Current is flowing in an isolated coil in space. The connection at both ends is suddenly removed so the coil become truely isolated.
G8RPI said:
the current flow will charge up the self capacitance of the coil.
OK. There is some form of energy stored. Then what next?
After some hours later, i.e. steady state, what happens?
This "special capacitor" is unlike a normal capacitor consists of two plates with opposite charges.
The capacitance is distributed through out the coil since one turn lies next to those beside it and above the ones under it, etc. The electric field is due to the potential difference across the coil due to its resistance and the current flowing. The "capacitor" now changed into a single electrode fromed by the coil made up of metal. No potential difference can exists on different part of a metal object because it is now isolated in space, with no current flowing.
There is a current flowing, ie. the current that was flowing at the instant the circuit was opened. And there is a potential difference across the coil since it has resistance. So the stored energy immediately during the disconnection may well have become a static charge on the isolated coil or have gone all together and lost as heat in oscillation.
As I wrote previously, it will oscillate and the energy will be dissipated as heat due to the resistance of the coil.
Would there be a net charge on the coil?
No. When an LC circuit oscillates, the energy is transferred from the magnetic field to the electric field and vice versa. So eventually, all the energy will be dissipated. There cannot be a static charge left since the coil is a conductor. If so, does the polarity of this charge related to the direction of the original current direction?