J. Zweiback

Detailed study of nuclear fusion from femtosecond laser-driven explosions of deuterium clusters

Recent experiments on the interaction of intense, ultrafast pulses with large van der Waals bonded clusters have shown that these clusters can explode with sufficient kinetic energy to drive nuclear fusion. Irradiating deuterium clusters with a 35 fs laser pulse, it is found that the fusion neutron yield is strongly dependent on such factors as cluster size, laser focal geometry, and deuterium gas jet parameters. Neutron yield is shown to be limited by laser propagation effects as the pulse traverses the gas plume. From the experiments it is possible to get a detailed understanding of how the laser deposits its energy and heats the deuterium cluster plasma. The experiments are compared with simulations.

Nuclear fusion in gases of deuterium clusters heated with a femtosecond laser

Recent experiments on the interaction of intense, ultrafast pulses with large van der Waals bonded clusters have shown that these clusters can explode with substantial kinetic energy. Producing explosions in deuterium clusters with a 35 fs laser pulse, deuterium ions were accelerated to sufficient kinetic energy to drive deuterium–deuterium (DD) nuclear fusion. By diagnosing the fusion yield through measurements of 2.45 MeV fusion neutrons, over 104 neutrons per laser shot were measured when 100 mJ of laser energy is used.

Femtosecond laser energy deposition in strongly absorbing cluster gases diagnosed by blast wave trajectory analysis

An intense ultrafast laser pulse can be very strongly absorbed in a moderate density gas composed of van der Waals bonded clusters. In this paper, the deposition of the energy of intense 30 fs light pulses in a gas of deuterium clusters has been diagnosed using a technique based on analysis of the trajectories of the resulting cylindrically symmetric blast waves. Using the well-known relation between blast wave velocity and energy deposition in gas, the laser energy deposited per unit length as a function of distance in gas jet plume was measured. These measurements were conducted in jets containing either deuterium clusters or simple deuterium molecules.

Resonance in scattering and absorption from large noble gas clusters.

Light scattering in large noble gas clusters irradiated by intense laser pulses was studied and compared to absorption measurements. The scattering signal shows the presence of a peak, when the pulse width was varied, similar to one previously reported in absorption measurements. The peak of the scattering, however, occurs at a longer pulse width than for absorption. This result disagrees with a simple simulation and may be due to propagation or non-linear effects not included in the model.

Nuclear fusion from coulomb explosions of D2 clusters ionized by a femtosecond laser

Recent experiments on the interaction of intense, ultrafast pulses with large van der Waals bonded clusters have shown that these clusters can explode with substantial kinetic energy. Producing Coulomb explosions in deuterium clusters with a 35 fs laser pulse, we have accelerated ions to sufficient kinetic energy to drive DD nuclear fusion. By diagnosing the fusion yield through measurements of 2.45 MeV fusion neutrons, we have measured the production of over 104 neutrons per laser shot when 100 mJ of laser energy is used.

Nuclear fusion driven by Coulomb explosions of deuterium clusters

We have examined the interaction of deuterium clusters with high intensity, ultrafast laser radiation. Upon irradiation a hot plasma is created with a sufficient temperature to produce nuclear fusion. We have seen that larger clusters produce more fusion neutrons than small er clusters, consistent with a Coulomb explosion model. Fusion yields is currently limited by propagation effects. Using interferometric imaging we have examined the laser propagation and found that the laser energy is absorbed before it penetrates to the center of the gas jet.

Deuterium cluster fusion driven by Coulomb explosions

Summary form only given. A number of experiments have been conducted in recent years examining the interactions of intense femtosecond laser pulses with large (10/sup 2/-10/sup 6/ atoms) van der Waals bonded clusters. Many research groups have reported that these interactions can be very energetic. Perhaps most remarkable has been the discovery that these large clusters, when irradiated at intensity above 10/sup 15/ W/cm/sup 2/, eject ions with substantial kinetic energy; ions with energy as high as 1 MeV have been seen from exploding Xe clusters. This large release of kinetic energy in fast ions can be harnessed to drive nuclear fusion if deuterium clusters are irradiated in a gas of sufficient average density. Indeed, we have recently observed these fusion reactions in deuterium clusters with an average size of roughly 5 nm diameter.

Experimental observation of resonance effects in intensely irradiated atomic clusters

We have resolved the expansion of intensely irradiated atomic clusters on a femtosecond time scale. These data show evidence for resonant heating, similar to resonance absorption, in spherical cluster plasmas.