Hi. I am not too sure about the electric field from AC overhead lines, I understand an electric field from a charged particle but not too sure when there are electrons moving back and forward quickly as in AC what the field looks like??
Can someone please explain to me what the electric field from overhead lines looks like, is it just away from the conductor core radially (can anyone refer me to a diagram for this) and why is it so. Is the electric field alternating ? Do you need current to flow for the field to exist or does it exist just with a potential?

 

From NEETS Module 2 - AC and Transformers, Chapter 1

MAGNETIC FIELDS

In 1819 Hans Christian Oersted, a Danish physicist, found that a definite relationship exists between magnetism and electricity. He discovered that an electric current is always accompanied by certain magnetic effects and that these effects obey definite laws.

MAGNETIC FIELD AROUND A CURRENT-CARRYING CONDUCTOR

If a compass is placed in the vicinity of a current-carrying conductor, the compass needle will align itself at right angles to the conductor, thus indicating the presence of a magnetic force. You can demonstrate the presence of this force by using the arrangement illustrated in figure 1-2. In both (A) and (B) of the figure, current flows in a vertical conductor through a horizontal piece of cardboard. You can determine the direction of the magnetic force produced by the current by placing a compass at various points on the cardboard and noting the compass needle deflection. The direction of the magnetic force is assumed to be the direction in which the north pole of the compass points.


The relation between the direction of the magnetic lines of force around a conductor and the direction of electron current flow in the conductor may be determined by means of the LEFT-HAND RULE FOR A CONDUCTOR: if you grasp the conductor in your left hand with the thumb extended in the direction of the electron flow (current) (− to +), your fingers will point in the direction of the magnetic lines of force. Now apply this rule to figure 1-2. Note that your fingers point in the direction that the north pole of the compass points when it is placed in the magnetic field surrounding the wire.

An arrow is generally used in electrical diagrams to denote the direction of current in a length of wire (see figure 1-3(A)). Where a cross section of a wire is shown, an end view of the arrow is used. A cross-sectional view of a conductor that is carrying current toward the observer is illustrated in figure 1-3(B). Notice that the direction of current is indicated by a dot, representing the head of the arrow. A conductor that is carrying current away from the observer is illustrated in figure 1-3(C). Note that the direction of current is indicated by a cross, representing the tail of the arrow. Also note that the magnetic field around a current-carrying conductor is perpendicular to the conductor, and that the magnetic lines of force are equal along all parts of the conductor.

Here are the graphics

 

Is the electric field alternating ?

Yes, because the voltage is alternating.

 

Ok. So would it be correct to say that there is an electric field (albeit weaker) a fair distance away from a current carrying conductor because of the electromagnetism? Would it be correct to view it like that in the sense that the electric field exists as a result of the propagation of the magnetic field surrounding the conductor?
I guess the concept of the electric field existing a certain distance away from a conductor is just hard to understand intuitively.

 

Ok. So would it be correct to say that there is an electric field (albeit weaker) a fair distance away from a current carrying conductor because of the electromagnetism? Would it be correct to view it like that in the sense that the electric field exists as a result of the propagation of the magnetic field surrounding the conductor?
I guess the concept of the electric field existing a certain distance away from a conductor is just hard to understand intuitively.

Not really.

Magnetic fields are generated by current flow in a wire and are proportional to the amount of current.

Electric fields are generated by and are proportional to the potential (voltage) in a wire and are independent of current or the magnetic field.

Both decrease with distance from the wire.

If the voltage in a wire is alternating, then so will the associated electric and magnetic fields.

Of course an alternating electric and magnetic field also generates an electromagnetic (radio) wave which propagates through space to a much greater distance then the magnetic and electric field do.

 

Both decrease with distance from the wire.

But magnetic fields are a lot harder to shield......

 

Ok. But what actually constitutes of the electric field, how does the electric field exist lets say several metres away from the overhead line, if I hypothetically placed an electron a few metres away from the overhead line what (is the physics behind it that) makes the electron to be pushed/pulled according to the electric field??

 

Don't touch that: https://www.youtube.com/watch?v=Gz5ffSYsd7Y

Just saying. Could be 10MW or more.

 

Sometimes we pull up our sailboats on to a beach where there are HV transmission lines very high overhead. I talking about those huge power transmission pylons.

If you were to touch the metal masts or stays of the sailboats you would get an electrical shock.

 

But what actually constitutes of the electric field, how does the electric field exist lets say several metres away from the overhead line, if I hypothetically placed an electron a few metres away from the overhead line what (is the physics behind it that) makes the electron to be pushed/pulled according to the electric field??

 

Google Maxwell's Equations.

 

But what actually constitutes of the electric field, how does the electric field exist lets say several metres away from the overhead line, if I hypothetically placed an electron a few metres away from the overhead line what (is the physics behind it that) makes the electron to be pushed/pulled according to the electric field??

I'm not sure what you mean by "how does the electric field exist". It exists by virtue of the electrons in the wire and the charge on each electron. It has been experimentally determined by numerous experimenters that an electron generates an electric field in it's vicinity which decreases with distance from the electron. In a conductor, the field is proportional to the voltage between the conductor and ground. Also this electron field repels other electrons, thus a negative electric field from an excess of electrons will repel electrons (otherwise all the electrons in the universe would be lumped together in one very large sphere).

If you want to know why or how an electron generates an electric field that's getting into metaphysics (or perhaps string theory, I'm not sure which).