MadSci Network: Physics |
To learn some of the basics about plasmas, you should read previous answers here at MadSci by me and/or Mark Bachman. A search on the word "plasma" from the Mad Scientist Search Engine will also give you several other leads.
Yes, you could confine a plasma in the shape of a cylinder, like the shape of the movie light sabers. In practice, you need large magnetic fields, lots of energy, and a constant supply of new gas, because the plasma particles can only be contained for a few milliseconds before they escape.
The closest we can come to a light saber would be a plasma torch. This is an unconfined jet of plasma that is used for welding, cutting, and waste incineration. The picture at the above link for cutting looks the most like a light saber, though you'll notice the power cable. That undoubtedly runs to a rather large high-voltage, high-current power supply. The web site I mentioned for welding also has a short description of the technology behind plasma torches.
I hope this answers your question.
Try the links in the MadSci Library for more information on Physics.