Magnetic field of a MRI...

[emunz]

(01-16-2016 08:52 PM)boby Wrote:  
So,is it possible to reverse the magnetic field of a MRI for a non-medical
application so that it repels the outside objects very strongly?
And how can do that?

No, ist's not possible. You are thinking about a magnetic monopole (attraction or repulsion), but a magnet is always (as far as we know) a dipole, i.e. attracting on one end and repulsing on the other end.
This interaction is only valid for other magnets, for magnetic materials (iron,.. =car) you have to unterstand that the magnetic material (iron) in a magnetic field is being magnetized and thereby becoming a magnet as long as it is in the magnetic field. The orientation of the magnetized material is dependent on its properties (para-, dia- or ferromagnetic).

So if you build a car from a diamagnetic material it will always be repulsed by the MRI-field, a car made out of para- or ferromagnetic material will always be attracted by it.