I have noted three different phenomena due to high electric fields in air. 1. When I run a ten-stage voltage multiplier I get sparking and crackling. 2. When I run the multiplier but current limit the output with ten 720k resistors in series, I get a violet arc that is sometimes smooth and quiet and sometimes jagged and hissy. 3. When I run a Jacob's Ladder from a flyback transformer (driver draws around 5A) I get a whitish flame-like arc. Can anyone enlighten me as to what is going on at the molecular level to give these three different phenomena? Thanks for reading.