According to this release, bubble fusion (i.e. using ultrasonic waves to induce the rapid collapse of bubbles causing the atoms at the center to fuse), has been convincingly demonstrated in the laboratory. http://www.rpi.edu/web/News/press_releases/2004/lahey.htm#cool At least two movies (The Saint and one other one whose name escapes me at the moment) have featured this as a premise, and one prior experiment suggested the phenomena was present but not very convincingly. This is, of course, notable, because the equipment needed to produce the effect is far less costly than plama containment equipment. Don't, however, count on this as a useful energy source any time soon.