Imagine electric conductor,copper wire for example,that is fully coated with thin teflon coating and this coated wire is surrounded by air.

The classis high voltage air ionisation happens when the electrons start to escape naked non-insulated conductor and go into the air,its called corona discharge.

My question is,is it possible to cause ionisation of air by high voltage conductor that is fully coated by thin layer of strong insulator like teflon?

I think it my work in following way,near the insulated high voltage conductor,close to its surface there exist strong electric field that can accelerate positive ions or electrons,ofcourse,molecules and atoms of air are neutral,but its a fact that cosmic radiation,radon gas and ultraviolet light causes constant ionisation of air in the enviroment where we live,its very small amount but it exist and these small ionisation events,while invisible happen relatively often.

I think that maybe if one ionisation event happens near the insulated conductor where the electric field is strong,the field might be strong enough at that location to accelerate that electron to such degree it will cause ionisation by colliding with neutral air atom thus causing sort of avalanche where more electrons are ejected,they are accelerated and they ionise more atoms and it repeats and grows exponentialy.

Could all this happen like I described it? Could teflon insulated conductor really cause air ionisation without any current flowing from it into air?