Fusion for Energy:

Fusion for Energy: Plasma Confinement, Bubble Collapse, and Laser Beams
At this point there are a number of avenues of fusion energy research, but currently the magnetic plasma confinement (i.e. tokamak), bubble collapse (i.e. sonofusion), and laser ignition (i.e. inertial confinement) methods are receiving the most attention. Laser and sonofusion techniques rely on lasers and acoustic bubble collapse, respectively, to produce the necessary temperature and pressure for nuclear fusion. Laser ignition research is currently being pursued at the Lawrence Livermore National Laboratory's National Ignition Facility (on wikipedia).

Sonofusion, an off-shoot of sonoluminescence research begun in the 1990s hypothesizes that fusion occurs when bubbles generated by acoustic waves in fluid solutions implode violently (image of sonoluminescence credit: Kenneth S. Suslick UIUC). Magnetic plasma confinement fusion research began in the 1970s and has since improved to the point where significant amounts of energy can be produced at almost the same level as energy is input to keep the fusion going. In light of these successes and the preliminary state of research in the other areas, I'll focus the rest of this entry on magnetic plasma confinement.

The two fusion techniques seemingly most capable of producing excess energy useful for power generation are the laser-ignition and plasma confinement methods . Both methods require massive infrastructure, enormous startup costs, and plenty of opportunity for high-profile failure. The laser-ignition method relies on focusing hundreds of very high power lasers on a tiny pellet of deuterium that then implodes on itself in a fashion not unlike that in a hydrogen bomb. The image on the right is of the 10-meter target chamber at the National Ignition Facility. The combined output of these lasers for the brief pulses they are active is over 1 Petawatt (1 x 10^15 watts). Plasma confinement methods require enormous magnetic fields on the order of 20 Tesla (thousands of times stronger than Earth's field) and very large and complicated tritium breeding systems, neutron absorbing blankets, and associated facilities. Government research will need to reduce the costs of these methods by several orders of magnitude before they become commercially viable, and international cooperation is seen as the only means to share the expenses.