@motorollin
If it works, I'd expect the potassium to give a lilac coloured flame characteristic of its main (visible) emission spectrum, just as it would in the traditional flame test.
Potassium ought to be easier to excite than sodium, it might produce a more pronounced flame effect for the same energy input but it doesn't imply it would be more energetic than sodium. This isn't a chemical reaction in the common understanding of the word, more a physical reaction of the atoms/ions that get created in the plasma.
