Tehnoman

Well, plasma physics is plasma physics. I can't see any reason, why we should use it if we got no plasma whatsoever. If we want to redefine term "plasma", then it is whole different question.

And all in all - it is not important to what we believe, in physics it is the description that matters, and all arising practical consequences.

Have you heard anything about quantum physics? In such description there is particle/wave duality - electron acts like nothing but a wave, although it can have only one amount of charge, that is characteristic to particles.

Wave theory part doesn't explain why electron have this elementary charge (experimentally no other results are obtained).

Particle theory part doesn't explain how electron behaves, why there is such "forbidden" zone, why they can interfere.

Nobody has come up with a better description, so in present it is believed that quantum physics holds key to future. Of course, theory is far from complete and TOE (theory of everything) is yet to be formulated.

That is true, these "theoretical" values of inductance will be even more away from actual value. Approximate value we can get out of it, but just in cases which are relatively simple. Like finite size cylinder-type coil. In that case the theoretical formula is:

L = mi0*mi*n^2*S/(h+0.45*d), where mi - core magnetic coefficient, n - wire turn count, S - area of coil's cross-section, h - coil's length (cylinder height), d - coil's diameter (cylinder diameter).

As for other configurations - in ideal toroidal case there is appropriate to use infinite long magnet inductance formula and that is it.

About capacitance - it exists at every frequency, but effect may show up only at higher frequencies. But in this case I doubt that parasitic capacitance would mess things up.

The simplest way to do it is to use AC with known frequency together with variable resistor to determine coil impedance from Ohm's law, then use multimeter to determine it's active resistance, from that - coil's inductive resistance, and from AC frequency - inductance. Bear in mind, that if frequency will be relative low together with coil's active resistance relative high, result error will be quite high.

U - effective AC voltage over coil, I - effective AC current, Z - impedance, XL - inductive resistance, R - active resistance, f - frequency, L - inductance.

Z=U/I
XL = SQRT(Z^2-R^2)
XL = 2*PI*f*L
L = XL / (2*PI*f)

result - AVERAGE(L);

Better yet - if you have signal generator, measure impedance in respect to frequency. Accuracy would be way higher.