# Equipment to measure strong constant (in time) and slowly changing electric fields

I would like to measure the electric field in the vicinity of an object of interest. I would like to have decent spatial resolution (i.e. be able to pinpoint a measurement to a point in space within an inch or so). The electric field might be (time) constant, or it might be changing slowly (up to several kHz). If the same piece of equipment can't handle both, I will be completely satisfied if it is able to measure constant field. It doesn't have to be too sensitive - the fields I expect are on the order of kV/m. I've been searching the internet for a piece of equipment to do this, but without much luck. Here are a few things I found:

1. I found this straightforward application in a book but I can't seem to find any equipment employing this idea.
2. I could use a sensitive electrometer to measure induced charge on an antenna, which should be proportional to the electric field. I'm not sure how well it will cope with changing field.
3. An electric field mill, which is a similar idea to the electrometer, but the ones I saw were quite bulky, intended for atmospheric measurements.

What would you recommend?

• How sensitive do you want it to be? Don't say "very", think about a number. – Andy aka May 14 '17 at 9:10
• @Andyaka not very :P Seriously. The fields are supposed to be quite strong, on the order of kV/m. I guess 10V/m is more than enough. I'd probably settle for 100V/m as well. Edited the question. – Slava P May 14 '17 at 11:47
• Is the medium around the object air or vacuum, or can it be made slightly conductive, like an electrolyte? This is how field measurements were done before computers, by measuring the potential around the scale model, with an (automated) probe, in a bath of conductive fluid. With computers it might be simplest to measure the voltage and then simulate the field. If your object can be well described, dimensions and permittivity, at or near DC it's a trivial problem and simulations will be very accurate. – tomnexus May 14 '17 at 12:01
• @tomnexus The medium is air. It has to be air, I can't put it in a bath. I've simulated with a model (that's where I have the kV/m ballpark figures from) but the actual object is quite complicated geometrically. What SW would you recommend for the simulations (if Matlab, maybe you can direct me towards a relevant implementation)? – Slava P May 14 '17 at 12:51
• Matlab has some examples. I always start with Quickfield, it's simple to learn and the free version is reasonably capable. – tomnexus May 14 '17 at 13:33