Questions regarding electrostatic charge decay.

[wiredGuy]

Hi,

I've had a pretty good experience with physics forum in the past, so when I ran across something I couldn't find an answer to on the web, I figured why not ask it here..

I found a great introduction to electrostatic charge decay located at http://www.ce-mag.com/archive/2000/marapril/mrstatic.html .. after reading the article I was left with a few questions.

1) Since the article was written eight years ago, I was wondering if we've made any progress in terms of determining how much charge will be collected when two materials are rubbed against each other.

2) Is there any way to prevent static charge decay? one underlying thing I think the article points out is that the decay occurs as electrons pass through surrounding material to neutralize the charge on the substance in question. This movement occurs as magnetic fields push the electrons around eventually leading to a neutralization over time.

3) if the charge was well insulated, or surrounded by elements that are more extreme on the triboelectric scale wouldn't this force the charge to be retained even if a magnetic field passed through the substance? (Unless the field was strong enough to overcome to overcome the resistance provided by the surrounding substances).
I would also appreciate greatly if anyone could tell me how I can calculate static charges accurately. Or reproduce similar charges consistently (Like, doing a, b and c ensures at least x coulombs of charge are present on block A for T seconds).

 

[snapback]

Hi,

1) Since the article was written eight years ago, I was wondering if we've made any progress in terms of determining how much charge will be collected when two materials are rubbed against each other.

I think, the methods are similar to those used 8 years ago, but maybe the measurement setups got better. But I don't know whether it is what you meant with progress ;-) ?

2) Is there any way to prevent static charge decay? one underlying thing I think the article points out is that the decay occurs as electrons pass through surrounding material to neutralize the charge on the substance in question. This movement occurs as magnetic fields push the electrons around eventually leading to a neutralization over time.

Do you really mean "magnetic" and not "electric" fields ?

Generally the higher the resistance of the material, the longer it takes static charge to decay. So if you take good insulator like teflon (and clean it very well for removal of any dirt, fingerprints, fat etc) and put a cahrged thing on a teflon plate in dry air (20% air humidity or less), you can keep the charge on a charged device for a fairly long time (the electric field from this charge can be monitored, e.g. by a field meter, like in the article you have mentioned)

cheers