Effect of high intensity electric and magnetic fields on gravity

[bwana]

Please forgive me if I am posting in the wrong forum. Also the board limits the length of the title. I wanted to ask about Effect of high intensity electric and magnetic fields on gravity.

To begin, 15 years ago this was published:

http://www.scientificamerican.com/article/do-electric-charges-and-m/

They refer to the "Reissner-Nordstrom" solution to Einstein's gravitational field equations. Basically what gravity would do near the surface of a very strong VanDe Graaf generator. They also mention the solution describing the special case in which the net electric charge is zero is the famous "Schwarzschild solution" to the gravitational field equations.

But I am more interested in what progress has been made in measuring the effect of a strong electric field. Is the prediction that it would increase gravity? or decrease it? or change the curvature of space so that gravity changes differently than the square of the radius between two masses?

Physical examples are not cited as they would be hard to find. But arent quasars a logical source of high intensity EM emissions? So the obvious question is:
Does light bend around a quasar differently than it bends around an equivalently massive but non radiating object?

 

[stedwards]

For a start, the gravitational contribution from electric and magnetic fields are expressed in the Electromagnetic Stress-Energy tensor.

From this is derived the Einstein field equation for gravity, with contributions from EM fields appearing explicitly in the last terms on the right hand side.

$F$ is the Faraday tensor constisting of the electric and magnetic field strengths.
The equation is cut and paste, so the term containing $\\rho$ is from combining EM contributions with "dust" where $rho$ the density of the dust.