I remember reading about an experiment where fine rods of tungsten were super-heated with millions of amps of electricity, melting them into ionised gas and were then compressed (by magnetic fields?) into plasma.
The plasma heated up to temperatures never before reached. I can't remember exactly, but I believe it was a few billion degrees fahrenheit.
It was a number of years ago - and I can't find the report via a search engine.
Is there a limit to the temperature of plasma? What's the current highest recorded temperature of plasma? Is it hotter than nuclear reactions?