Progress in direct-drive inertial confinement fusion

Abstract

A model of crossed-beam energy transfer has been developed to explain the observed scattered-light spectrum and laser-target coupling. Experiments show that its impact can be mitigated by changing the ratio of the laser beam to target diameter. Progress continues in the development of the polar-drive concept that will allow direct-drive-ignition experiments to be conducted on the National Ignition Facility using the indirect-drive-beam layout.

An easily assembled double T-shape for the preparation of submillimeter-sized hollow polyacrylonitrile (PAN) microcapsules for inertial confinement fusion (ICF) project

“…In this experiment, a two-step method of droplets formation at T-junction microchannel was adopted [35]. At the first T-junction, the inner oil phase drop was enclosed by the middle water phase stream, and then at the next T-junction, the water phase drop with oil phase drop inside was enclosed by the outer oil phase stream, and then the double emulsion have been formed.…”

Spectral and temporal properties of optical signals with multiple sinusoidal phase modulations

“…These parameters were determined by simulations to optimize the on-target smoothing, including the engineering constraints related to potential implementation on the NIF [13]. Small relative changes to these frequencies would not affect the smoothing, but they have been chosen as multiples of a reference clock available in the Omega Laser Facility [2] because this allows them to be temporally synchronized to the optical pulse. The microwave frequencies are commensurate, but the integer multiples linking them are so large that no effect of commensurability has been observed in simulations.…”

“…One application of these lasers is inertial confinement fusion (ICF)-a strategy for producing energy by compressing targets composed of hydrogen isotopes and starting a chain reaction [1,2]. Laser systems developed for ICF are large-scale complex optical systems that must produce temporally shaped optical pulses containing megajoules of energy in the ultraviolet (UV) [3,4].…”

“…In this approach, phase modulation at a single frequency with a modulation index of a few radians is sufficient for SSD when implemented with angular dispersion in only one direction. In the direct-drive approach to ICF, the optical pulses directly compress the target [2]. If SSD is implemented in only one direction, modulation at multiple frequencies is required, at least during the low-energy portion of the pulse shape [11,13].…”

Hundred picoseconds laser pulse amplification based on scalable two-cells Brillouin amplifier

“…In 2007, Betti et al (2007) came up with shock ignition in order to achieve inertial confinement fusion, and it has high neutron efficiency McCrory et al, 2008). In the process of shock ignition, how to obtain the desired high peak power laser pulse and how to get 100 ps laser pulse amplification with high efficiency are key problems that need to be solved.…”