# maximum positive electric charge of solid body

What are the limiting factors on the positive charge of a solid body? If I assume a 'perfect insulator' environment that would not exchange charge with my solid body, I would guess that I can remove electrons from the body until it's internal chemical bond structure made by them breaks down and the body disintegrates. Are there any other other limits that would be hit first? How to calculate the charge at which the body breaks away?

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## 1 Answer

According to http://erps.spacegrant.org/uploads/images/images/iepc_articledownload_1988-2007/2009index/IEPC-2009-010.pdf , "The electric charge on a microparticle is limited by two processes which become important at very high electric field strength on the particle surface... For negative charges electron field emission begins at $|E_p| > 10^9 Vm^{−1}$. For positive charges field evaporation destroys the particle, if $|E_p| > 10^{10} Vm^{−1}$. In case of materials with low tensile strength or fluffy grains, charges of both signs are able to fragment the particles (“Coulomb explosion”)... already at lower field strengths."

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Are those $Vm^{-1}$ values theoretical ones or in reach for experimental techniques? –  dronus Aug 18 '12 at 12:11
There is a reference to a certain article in the link above (Erwin W. M¨uller. Field desorption. Phys. Rev. 102, 618, 1956). I looked at it, and it looks like those values are experimental (though the values in the article are smaller), although I would suspect that there might be at least some primitive theory - for field emission, see e.g. en.wikipedia.org/wiki/Field_electron_emission –  akhmeteli Aug 18 '12 at 12:41
Could you explain a little bit about the difference between field evaporation and Coulomb explosion? It seems like the former involves the atom-by-atom surface evaporation of ions/charge and the latter involves the entire particle. Is this right? –  AlanSE Aug 18 '12 at 16:56
I guess so. It is my understanding that Coulomb explosion takes place when the stress caused by Coulomb repulsion exceeds the tensile strength. –  akhmeteli Aug 18 '12 at 18:37
What kind of setup could achieve that charges? –  dronus Feb 17 '13 at 22:15
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