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I have a coaxial cylinder with a cooper wire inside which is corona discharge happening. enter image description here

Corona discharge is happening after ionization in this coaxial cylinder. My question is about calculating E (electric field)and Q (Amount of charge) in ionization area! enter image description here Would really appreciate if your help is included the process before ionization (E and Q).
Thanks in advance for your help!

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  • \$\begingroup\$ Please provide some more details. Are you simulating or conducting an experiment? \$\endgroup\$ – vindarmagnus Nov 18 '16 at 10:38
  • \$\begingroup\$ Yours may be more appropriate as a physics question, or even surface chemist/plasma chemist. It appears to involve the time-evolution of initial breakdown in a gas-discharge tube, not an EE topic unless merc-vapor thyratrons. Also, the values won't be obvious, since the equilibrium state will be sensitive to gas mix, temperature, pressure, surface roughness, oxide layer, ion chemistry, etc. Possible lit-search keyword: langmuir probe \$\endgroup\$ – wbeaty Dec 22 '16 at 11:31
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Corona discharge is due to a gas transferring phases from a gas to a plasma. From wikipedia:

The positive charge in ions is achieved by stripping away electrons from atomic nuclei. The number of electrons removed is related to either the increase in temperature or the local density of other ionized matter. This also can be accompanied by the dissociation of molecular bonds,[10] though this fundamental process is distinctly different from chemical processes of ion interactions in liquids or the behavior of ions existing in metals. A significant number of highly charged particles together make plasma electrically conductive so that it responds strongly to electromagnetic fields.

So just some background to get you started (plasma physics is an entire field and it will be difficult to explain in just one answer)

There exists a Debye Sheath around the outer conductor, because the electrons are repelled by the charge from the outer conductor.

The wire in the middle is like a Langmuir Probe and the plasma has an IV relationship similar to a diode.

You will need to know the density of plasma and the molecular weights of the plasma ion species (the problem will get harder the more ion species there are), and the potential of the inner and outer conductor. You will also need to assume that that magnetic field is zero. And you will need to read sections 1, 2, and 3 of this if you don't know about plasma physics.

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Measurement

Corona discharge represent an actual charge transfer. So you will have to very carefully measure the currents passing in the ground conductor and through the wire itself. With knowledge of I=dQ/dt you can find the amount of charge in the corona discharge path by integration.

Simulation

I guess you are interested in the distribution of charge and electric field. With the measurement above you have a good basis for veryfing a FEM model which will give you the distributions. If you have access to COMSOL Multiphysics I know they have a plasma module which can be used for this. Otherwise, the equations and setup are explained in detail here, which can be applied to any general FEM solver.

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