Nuclear Fusion Driven by Coulomb Explosion of Deuterated Methane Clusters in an Intense Femtosecond Laser Field

We have made experimental studies on the generation of deuterium-deuterium fusion neutrons from intense Coulomb explosions (CE) of large-size (CD4)N cluster jets under the irradiation of intense femtosecond laser pulses. By optimizing the propagation of a laser pulse in the cluster gas and the time delay between the laser pulse and the gas flow, the maximum neutron yield of 2:5×10^5, which corresponds to a conversion efficiency of 2:1×10^6 fusion neutrons per joule of incident laser energy, has been obtained with a 120-mJ, 60-fs laser pulse and cluster jets with an average molecular density of 3:6×10^(18) cm^(-3) and cluster radius of 7 nm. We have demonstrated that the neutron yields can be dramatically increased by using heteronuclear (CD4)N clusters as compared with the similar sized homonuclear (D2)N clusters. This enhancement is attributed to the significant increase in the deuteron kinetic energies due to energetic boosting and overrun effects during CE of heteronuclear clusters.