Thank you for the reply.
I was curious if the pulse would just propagate through the conductor like radio waves though space - without the need for or effect on electrons, but I just couldn't see there being this potential at some point in a conductor without an effect on the density of...
If I make a single, short (GHZ) negative voltage pulse propagate down a long, single wire which forms a closed circuit, will there be a corresponding negative charge density in the conductor (shown as bunched-up green electrons) which propagates with the pulse?