when the thickness of air gap decrease, the self inductance (increase or decrease), how about the voltage increase or decrease?

 

This might help -

http://info.ee.surrey.ac.uk/Workshop/advice/coils/gap/index.html

https://www.researchgate.net/figure...ngth-varying-from-001-m-to-005_fig3_319991553


Regards, Dana.

 

There does not appear to be enough information to answer your question.

What voltage?

What is the circuit in which the inductor is being used?

Is there any external current limit to the inductor?+