shape the field...
I dont have pictures or plans, but this is a one you can do easy, just be carefull...
it is not a tesla, but is similar, get a flyback, feed it with fast dc pulses, 20 khz or up, yes dc, not ac,properlly drive it,better use a 12volts dc battery to drive the flyback and circuit ,(easy 555 and 2n3054 or a solid state relay) at the secundary output connect aluminum foil paper, the one from the kitchen, put one at the floor connected to the ground of the secundary, and the other to other piece of alum foil paper, flat it like envelopes and face them one to the other you can stick it with glue, secure them with wood, pvc or starboard so they dont move or blow away, separe them enough , i dont know how much, because I am giving the main idea and depend of your flyback...then, get a tank of argon, yes, the one for mig welding, dont get the huge one, get a small one, then power up the thing , turn off the light, and open the argon valve, blow in between the alum paper plates and enjoy.(dont blow to close and use a pvc water pipe 1/2 inch to drive the gas to , so you dont get zap)...I did this long time ago when i was a kid, dont fear electricity, fear your mistakes, mix theory and use your fingers...now what you got? plasma?? try it....think but dont burn your head...