If I understand correctly, a regular solenoid like this one
does not have a permanent magnet as core and as such it doesn't matter with what polarity it is activated (please correct me if that's wrong).
Since the current in the winding takes some time to decay, it's apparently possible to release the solenoid faster by applying reverse voltage (to "flush out" the current)
but since the polarity doesn't matter to activate the solenoid, I assume that there is a specific duration for which this reversed polarity should be applied or otherwise the magnetic field just builds up again in the other direction and pulls the solenoid back in.
How can I compute the duration for which the reversed polarity should be applied (based on rated voltage and current of the solenoid as well as number of windings) in order to achieve fastest release?