kiteman is on the right track. i think the confusion here is we are talking electrodynamics where you are talking electrostatics. we are both correct.
electrostatically, the charges in the conductor will move so as to neutralize any voltage gradients, thus moving so as to make themselves invisible to anything on the inside.
however, we are keeping the outer sphere at ground, and the inner sphere at a constant positive voltage relative to ground. as just mentioned, the charges will move so as to neutralize the voltage gradient. this means electrons will move from the outer sphere to the inner sphere. thus, we will not have this charge differential for very long. to get it back we have to move electrons from the inner sphere back to the outer sphere. when we say we are holding the inner and outer spheres at constant charge, that implies that we are doing precisely this.
so you see, while gauss' law (of course) accurately tells us what the system will be like when it reaches equillibrium, we are actively keeping the system _out_ of equilibrium by applying a current between the inner and outer spheres. this current constantly recharges the voltage gradient that the electrons are constantly neutralizing. if we turn the power off -- if we either unground the outer sphere or stop pumping electrons out of the inner sphere -- the electrons will quickly succeed in neutralizing the voltage gradient and we'd come to the situation described by you; by gauss's law. which means we would no longer have a charge differential between the two spheres (well, at least not one that can't be maintained electrostaticaly for very long). and the situation ipso facto would no longer be that which we seek to analyze.
sim needs faraday cage?
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Property Scaling Law Property Scaling Law
Voltage L Magnetic Fields L
Electric Resistance 1/L Magnetic Force LLLL
Electric Current LL Magnetic Energy LLLLL
Electric Current Density 1 Mag ERG Density LL
Electric Capacitance L
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- Joined: Wed Jul 14, 2010 5:27 pm
the goal of the grounded faraday cage is to go from a voltage gradient something like this:
no grounded cage:
v =
{magrid_radius < observation_radius : 1/(observation_radius-magrid_radius)^2
{obervation_radius < magrid_radius : 1
to one something like this:
grounded cage:
v =
{cage_radius < obervation_radius : 0
{magrid_radius < obervation_radius < cage_radius : (cage_radius-observation_radius)/(cage_radius-magrid_radius)
{obervation_radius < magrid_radius : 1
thus making the PE reach its extrema while the observation radius is still finite.
(i'd rather just draw a picture, but that's not so easy to do w/this medium!)
no grounded cage:
v =
{magrid_radius < observation_radius : 1/(observation_radius-magrid_radius)^2
{obervation_radius < magrid_radius : 1
to one something like this:
grounded cage:
v =
{cage_radius < obervation_radius : 0
{magrid_radius < obervation_radius < cage_radius : (cage_radius-observation_radius)/(cage_radius-magrid_radius)
{obervation_radius < magrid_radius : 1
thus making the PE reach its extrema while the observation radius is still finite.
(i'd rather just draw a picture, but that's not so easy to do w/this medium!)
No Cage:
With Cage:
Yah?
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- Posts: 1439
- Joined: Wed Jul 14, 2010 5:27 pm
KitemanSA wrote:No Cage:With Cage:Code: Select all
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Yah?Code: Select all
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YEP! Exactly! Thank you!
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- Posts: 1439
- Joined: Wed Jul 14, 2010 5:27 pm
So, given these items: Image magnet, MaGrid, Chamber... and if the MaGrid current and charge factors are both 1, then with a 0.5 scale image magnet, the two values should be -.25 and 0 while the Chamber with a size scale factor of 2 would have the two values 0 and -1.hj27 wrote:{x_start, y_start, z_start, x_end, y_end, z_end, current_multiplier, charge_multiplier}
How do I get this run?
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- Posts: 1439
- Joined: Wed Jul 14, 2010 5:27 pm
i've moved on. im all about my swarm wars game now.
i can picture it in my head w/the grounded chamber to improve recirculation and it works. nothing more to do on sims, imo. just have to wait until building and testing is all done. it works and we'll have a commercial reactor in the future. just have to wait a few years. which, of course, isn't the fun part.
if you can handle it and you've got an nvidia geforce 8800 or later, you can download the code and compile it yourself and run whatever you like (google sourceforge em-nbody for the code, you can download and run "eclipse" for the compiler, and you'll have to also install the sdk from nvidia and set up the compile chain. so it's not for the weak of heart. but sorry to disappoint but i don't feel like running it anymore.)
i can picture it in my head w/the grounded chamber to improve recirculation and it works. nothing more to do on sims, imo. just have to wait until building and testing is all done. it works and we'll have a commercial reactor in the future. just have to wait a few years. which, of course, isn't the fun part.
if you can handle it and you've got an nvidia geforce 8800 or later, you can download the code and compile it yourself and run whatever you like (google sourceforge em-nbody for the code, you can download and run "eclipse" for the compiler, and you'll have to also install the sdk from nvidia and set up the compile chain. so it's not for the weak of heart. but sorry to disappoint but i don't feel like running it anymore.)