"Why is this plasma so hot? Physicists aren't sure. What is known for sure is that the Z Machine running at Sandia National Laboratories created a plasma that was unexpectedly hot. The plasma reached a temperature in excess of two billion Kelvin, making it arguably the hottest human made thing ever in the history of the Earth, and, for a brief time, hotter than the interior of stars...? http://antwrp.gsfc.nasa.gov/apod/astropix.html
That's amazing that they can do that without burning down the building it's in!
BTW, Wikipedia suggests this explanation as to why it got so hot:
In 2006, the Z Machine produced plasmas with temperatures in excess of 2 GK (109 K) or 3.6 billion oF. Project scientists were doubtful about the results, but after fourteen months of computer modeling and further tests, they have concluded that the results are, indeed, valid. It is believed the high temperature plasmas were achieved by using a slightly larger spool of wires with thicker steel wires substituted for the usual tungsten wires.
Now, what I'm wondering about is, if they can get so much energy relative to the amount they put in, what if we came up with a way to capture some of it? It said it put out 80 times the world's power usage for a fraction of a second. Even grabbing 1 percent of that would be amazing. AND it could even be safer than a nuclear plant (depending on the technologies used).