That being said, the plasma generated by an oxidation reaction (burning stuff) might be lucky if it gets up to a few thousand degrees.
The burny stuff inside the stars is a TAD hotter, generally on the order of millions of degrees.
In fact - that is what a plasma weapon is - and why it looks like a fluffy cloud being shot at you. It is the raw product of nuclear fusion being ejected from a mass driver (because plasma is also electrically charged).
So basically what you would be after is a higher refire, lower range version of the existing plasma weapons...