, "Generation of Mie size microdroplet aerosols with applications in laser-driven fusion experiments," Rev Sci. Instrum., 80, (2009 We have developed a tunable source of Mie scale microdroplet aerosols that can be used for the generation of energetic ions. To demonstrate this potential, a terawatt Ti: Al 2 O 3 laser focused to 2 ϫ 10 19 W / cm 2 was used to irradiate heavy water ͑D 2 O͒ aerosols composed of micron-scale droplets. Energetic deuterium ions, which were generated in the laser-droplet interaction, produced deuterium-deuterium fusion with approximately 2 ϫ 10 3 fusion neutrons measured per joule of incident laser energy.

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We have studied the explosion dynamics of methane clusters irradiated by intense, femtosecond, 38 nm (32.6 eV) XUV laser pulses. The ion time-of-flight spectrum measured with a Wiley-McLarentype time-of-flight spectrometer reveals undissociated molecular CH + 4 ions, fragments which are missing hydrogen atoms due to the breakage of one or more C-H bonds (CH + 3 , CH + 2 and CH + ) and the recombination product CH + 5 . Also visible on the time-of-flight traces are atomic and molecular hydrogen ions (H + and H + 2 ), carbon ions, and larger hydrocarbons such as C2H + 2 and C2H + 3 . No doubly-charged parent ions (CH 2+ 4 ) were detected. The time-of-flight results show that total and relative ion yields depend strongly on cluster size. The absolute yields of CH + 5 and H + scale linearly with the yields of the other generated fragments up to a cluster size of N = 70, 000 molecules, then begin to decrease, whereas the yields of the CH + n (n = 1 − 4) fragments plateau at this cluster size. The behavior of H + may be understood through the electron recombination rate, which depends on the electron temperature and the cluster average charge. Moreover, the CH + 5 behavior is explained by the depletion of both CH + 4 and H + via electron-ion recombination in the expanding nanoplasma.

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