Here's an experiment for Chris to try.
An external magnetic field in opposition to the magnetic field of a solenoidal inductor will delay magnetic saturation of that inductor and thus increase the inductance, while also changing the time constant curve of that inductor.
Now, what happens when the inductor moves closer to that magnet as it's being energized, and farther away as it's being deenergized? We also get a generator effect!
So the coil, sliding upon the core and biased with a lightly-tensioned spring, acting against a permanent magnet, can have its inductance and time constant curve tailored to fit any application by substituting a stronger or weaker permanent magnet, and a stronger or weaker spring.
In addition, since the permanent magnet's bound electrons are inherently undergoing virtual photon exchange with the quantum vacuum, and thus can receive energy from the quantum vacuum, this opens up interesting possibilities for extraction of energy from the quantum vacuum.