I am rewinding a solenoid for the fuel control on a truck injector  
system.
A slug that is restrained by a small spring is pulled into the
solenoid to allow fuel to flow.

Since I have a fixed amount of space, I am wondering if it
is better to have many windings of a smaller gauge wire or
fewer windings of a larger gauge wire.  I am not worried about
inductance or ease of winding.

I am seeking the optimum tradeoff between heat dissipated
by the coil and maximum magnetic field inside the solenoid.

I am guessing that the amount of heat dissipated is inversely
related to the square of the diameter of the wire ( holding
everything else constant ).

The B-field seems as though it would also be related to the
inverse of the square of the wire diameter.  ( divide the diameter
by two and get 4 times as many windings. )

If I keep everything constant except I vary the current through the
solenoid, the B-field seems to vary linearly with the current while
the heat dissipated by the solenoid seems to vary the square
of the current.  Would this suggest that lowering the current and
increasing the number of windings would improve the solenoid
capabilities.

I feel I have made a mistake here somewhere since a gazillion
windings and nearly zero current would give me the magnetic
field I want.

Of course there must be some amount of energy required to
move the slug into the solenoid.


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