PLASMA PHYSICS
'(<a href="http://www.j-archive.com/media/2007-03-01_DJ_06.jpg" target="_blank">Cheryl of the Clue Crew presents from the Plasma Physics Lab at Princeton.</a>)  To produce energy, scientists are experimenting with plasma, a charged medium, sometimes called the fourth one of these after solid, liquid & gas'
phase of matter (or state of matter)