Could a planet with a strong magnetic field exert a diamagnetic force on an orbiting moon? Here is a question from the world building stack exchange.
https://worldbuilding.stackexchange.com/questions/79003/making-a-slow-orbit-around-a-large-gas-giant
Requested: a means to have a moon of Jupiter orbit closely but slowly.  Gravity precludes this.  
If there were some force that opposed gravity, making the attractive force weaker, then closer slower orbits become possible.  If gravity were completely opposed the object could hover.
Which is like diamagnetic levitation.  The question: 


*

*Is the magnetic field (magnetic gradient?) of Jupiter adequate to exert a repulsive force on a hypothetical diamagnetic satellite?  

*A superconducting satellite?  

*Could this force be on the order of gravity such that a slower orbit for this satellite is possible at the same distance from Jupiter?
 A: A nice, realistic example of this is for Ganymede at Jupiter.  The Jovian magnetic field is ~0.42 mT at the planet's equator and the orbital speed of Ganymede is roughly 10 km/s.  If we take a hand-wavy approach with the Lorentz force assuming a 1 coulomb charge, we get a maximum force of ~4 newtons.
For Ganymede this corresponds to an acceleration of ~10-23 m -2 (note that gravitational acceleration on Earth's surface is ~24 orders of magnitude larger than this).

Is the magnetic field (magnetic gradient?) of Jupiter adequate to exert a repulsive force on a hypothetical diamagnetic satellite?

Yes, it can exert a force but the result is negligible.

A superconducting satellite?

What type of superconductor?  A Type-I superconductor expells magnetic fields.

Could this force be on the order of gravity such that a slower orbit for this satellite is possible at the same distance from Jupiter?

If we assume the magnetic field is in the positive z-direction and the orbit is circular, thus the velocity in the azimuthal direction, then at the equator the Lorentz force would be directed radially for positive charge.  The problem is that the magnitude of the force depends upon the speed of the charged body with respect to the magnetic field.  So if the planet moves slower, the Lorentz force gets weaker.
Side Note:  In the case of Jupiter, I did not point out that the planet rotates faster than the moons orbit, so in the magnetic field rest frame the planet would actually move in the opposite direction to its orbit.
A: May be if the satellite have some electric charge the Lorentz's force applies, and act in the radial direction.
I think that to have a diamagnetic satellite has any effect in radial acceleration, may be in $\hat{\phi}$ direction (in spherical coordinate system with the origin in Jupiter's center).
