Conventional laser radiation intensity was too low to trigger the processes prior to the current work.
XFEL and electron beams to assist fusion reactions
This could all change in the near future: With X-ray free-electron lasers (XFEL) it is already possible to achieve power densities of 10^20 watts per square centimeter. This is the equivalent of approximately a thousand times the energy of the sun hitting the earth, concentrated on the surface of a one-cent coin. "We are now advancing into areas that suggest the possibility of assisting these tunneling processes with strong X-ray lasers," says Schützhold.
The strong electric field causing the nuclei repulsion is superimposed with a weaker, but rapidly changing, electromagnetic field that can be produced with the aid of an XFEL. The Dresden researchers investigated the process theoretically for the fusion of the hydrogen isotopes deuterium and tritium. This reaction is currently considered to be one of the most promising candidates for future fusion power plants. The results show that it should be possible to increase the tunneling rate in this way; a sufficiently high number of tunneling processes could eventually facilitate a successful, controlled fusion reaction.