Is Air Used as Plasma Armature?

A railgun still launches a projectile using gas (plasma) pressure. This fantasy wishes to hurl lightning bolts. An electron beam in the air will scatter quickly.

"... A railgun still launches a projectile using gas (plasma) pressure...."

Does it?

It is difficult to imagine how <...plasma...> can exist at standard temperature and pressure.

Conditions usually have to be somewhat severe...

I know that by applying high voltage across electrodes can make plasma in air at STP.

To understand this effect, read up on Paschen's Law, remembering that you need TWO electrodes. A "Projectile-less Rail Gun" concept (as I interpret what you are after) presumes the "target" is electrically the other end of an electrode pair. How are you going to get the target to cooperate?

As to air being used as a plasma conduit, observe lightning for an idea on how difficult that would be. Millions of volts does allow the bolt to travel through air at "standard" pressure but the destination (earth as the second electrode) is still random and very difficult to predict.

I built a Jacob's Ladder once, using an oil furnace ignition transformer and a couple of straightened wire coat hangers. Of course, the plasma has very little mass, so very little momentum. Not much of a gun.

Yes maybe, but the range would be very short and ineffectual....

I would like to know on what basis you said yes.

Just for curiosity.

I said yes because it is possible ....but on a hobbyist level, not enough power. unless your expectations are very limited....

https://en.wikipedia.org/wiki/MARAUDER

https://www.military.com/video/off-duty/tech/new-progress-on-plasma-weapons/2324951333001

Plasma cutters create a plasma using high voltage and air.They will cut through nearly anything,but the distances involved are very limited.

Here is a link with details:https://home.howstuffworks.com/plasma-cutter.htm