What they need is a way to control the plasma because a 3 foot torch alone could be dangerous.

• They need to create a ceramic rod to control the plasma
• A powerful battery that can heat plasma to 12,000 degrees but it can’t be big
• Brian Wardle from MIT shows the narrator how to build carbon nanotubes which may help with the size issue of normal batteries
• Apparently some of the military applications are top secret and the researcher can not talk about

So how do these carbon nanotubes help power the lightsaber?  Carbon nanotubes can apparently conduct 1,000 times more electricity than copper.  Regular carbon is not a conductor.  And apparently they are able to make a lot of these nanotubes hence a lightsaber.