Yeah DaveE...i guess I'm asking how do they create a "computer model of the field" ?
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And ok...i'll have a look at this "tomography " and see what that's about. I already checked out magnetometers or hall-effect sensors . And yes, they seem to be used to measure the field locally. But would be...
Ok, i see what you are saying.
But how do they analyse the field using computers.
I'm guessing that they must be able to create a model of the field "inside" the computer somehow...like how do they harness the information in the field...how do they get this information into the computer ?
Lets say we have a Direct Current (not an alternating current) going through a wire ; so there is a steady-state magnetic field created around the wire.
Then let's say we move some object into the magnetic field that disturbs the field.
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My question is : How do we/they get information...