Flux density vector B is it constant in my design?

I'm in the process of writing a Model for a electromechanic Device
which is basically an air coil in front of a ceramic magnet .Now i know the
residual Br of the magnet .. When the coil is ENERGISED it develops a force F
that is in function of the physical aspect of the COIL and the current .. But also proportional to the flux density B from the magnet . Now i don't undertsand if that B is constant or if it changes in fucntion of the current applied to the coil
I reason that the coil develops a Field intensity H that plays against the Magnet B
bringing that B vector from Br to Hc . so basically B = f( i) i the current of the coil?
But if the field B is in fuction of the current so is H = NI/l
so i get the problem who drives who ?
The problem is that in function of the coil current the coil is pushed .. by getting farther the field path P is also modified which also modifies H .. but will do it to B?

Magnetic fields are linear so superposition holds. The net field at any point will be the sum of the field at that point if the solenoid and the permanent magnet were there alone.

The force acting between the two will be the difference in energy of the field between two positions dx apart. This is because energy = force x distance.

Hi FLATULENT .. how many beers DO I OWE YOU NOW ??
Great this confirms my feeling i have to go with a rate of differentials to find my actual position ...!
ok that'zs all i need it to know..


You know all this now makes sense !
though is a little harder on COMPUTATION