Am I wrong on this?
Yes, you are wrong. The electric field exists between both electrodes, not between just one electrode and the water.
Thank you for your reply. I am just trying to understand something I have seen experimental evidence of, but obviously do not understand why. It seems that I often find myself in the position of knowing that, "I do not understand everything I know."
Yes, of course there is an electric field between the electrodes. If the two electrodes have a contact potential of 3.3Vdc (IIRC), then the effective resistance of the electrolyte between the electrode multiplied times the current must be an extra voltage drop in series with those two contact potentials.
Thus the electric field in the electrolyte would be the voltage drop per unit distance along this effective resistance of the electrolyte. (I realize that, for simplicity, I am reducing a 3 dimensional current flow and electric field to a simple 1 dimensional resistor, but perhaps this is not an erroneous simplification for this purpose.)
Thus the equivalent circuit I am imagining has these series components: an ohmic contact resistance at the anode to electrolyte, a contact potential at the anode to electrolyte, an effective resistance in the electrolyte to the vicinity of the cathode, a contact potential from electrolyte to the cathode, and an ohmic contact resistance at the cathode to electrolyte.
It has been explained to me by others that the motivation for a thinwire cathode is the limited surface area per length, thus more easily adjustable ohmic contact resistance to the electrolyte. That made sense as far as it goes....
If this equivalent circuit assumption is correct, an adjustment in the series ohmic contact resistance at the cathode will not appreciably change the existing electric field in the bulk of the electrolyte between the electrodes (and assuming constant current), or, if so, how? Seems as if it only changes the voltage drop across the cathode's ohnic contact resistance. So, what is wrong with this picture?
Again, I appreciate your reply but perhaps you can see I am hungry to understand more than has been explained (AFAIK) so far.
rogerw