To save this undefined to your undefined account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your undefined account.
Find out more about saving content to .
To save this article to your Kindle, first ensure firstname.lastname@example.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
A technique is demonstrated for optimally generating three-dimensional reconstructions of images formed using a minimal quantity of data. The results are illustrated using thermonuclear α-particles from laser-driven implosions. The images are generated with a maximum entropy deconvolution algorithm from sets of three or four penumbral imaging cameras. It is demonstrated that this approach provides superior resolution and reveals structures not visible from the corresponding two-dimensional reconstructions of the constituent data. This technique can be successfully applied even when the total number of particles recorded in the image is less than 1000.
For inertial confinement fusion (ICF), a focused light ion beam (LIB) is required to propagate stably through a chamber to a target. It is pointed out that the applied external magnetic field is important for LIB propagation. To investigate the influence of the external magnetic field on the LIB propagation, the electrostatic dispersion relation of the magnetized light ion beam-plasma system was analyzed. The particle in-cell (PIC) simulation results are presented for a light ion beam-plasma system with an external magnetic field.
Free electron lasers (FELs) place very stringent requirements on the quality of electron beams. Present techniques for commissioning and operating electron accelerators may not be optimized to produce the high brightness beams needed. Therefore, it is proposed to minimize the beamline errors in electron accelerator transport systems by minimizing the deviations between the experimentally measured and design transport matrices of each beamline section. The transport matrix for each section is measured using evoked responses. In addition, the transverse phase space of the beam is reconstructed by measuring the spatial distribution of the electrons at a number of different betatron phases and applying tomographic techniques developed for medical imaging.
It is not often that a new form of transportation suddenly appears and replaces what was hitherto regarded as mankind's only realistic option. In space and upper atmosphere transportation, chemical rockets have held center stage for over half a century. Tsiokolvsky's ideas led to Wernher von Braun's V2, which in turn led to the Soyuz, Apollo, and Ariane programs and the Space Shuttle. But recently theoretical and computational studies as well as a few initial experiments have pointed to a new option: laser impulse space propulsion (LISP). This may offer a more efficient and less ecologically damaging means of putting payloads into orbit. The world high-power laser community is well suited to following and aiding developments in LISP, though most practical research is still at an embryonic level. Obviously an effort of the size required to develop a laser-driven low-earth-orbit (LEO) launcher would require a multinational commitment. LISP could then be regarded as a parallel challenge to those of achieving ICF rriicrofusion yield and of improving X-ray lasers, especially in the “water window.” Any physicist or engineer involved with the latter projects would find many points in common with the former. It therefore seems appropriate to briefly review the progress made in LISP and also to communicate some recent results from high-power laser-matter experiments that have lead to conceptual designs.
A previous hydrodynamic model of the expansion of a laser-produced plasma, using classical (Spitzer) heat flux, is reconsidered with a nonlocal heat flux model. The nonlocal law is shown to be valid beyond the range of validity of the classical law, breaking down ultimately, however, in agreement with recent predictions.
The achievement of hypervelocities (40 km/s or more) is considered by the electrostatic simultaneous acceleration of dust particles positively and negatively charged. This ensures current neutralization. Beams carrying several grams of matter look feasible. The mutual impact of these macroparticles results in temperatures in the fusion range.
Results of the analysis and numerical calculations of continuous spectra of multicomponent multicharged plasma radiation are presented. Possibilities of control of the radiation spectrum by the mixture composition variation and programming in time the pulsed discharge current of the supply source are considered. Free and forced (by energy deposition or additional cooling) relaxation time estimations permit the definition of discharge parameters when plasma formation goes on under nonequilibrium conditions, leading to controlled energy redistribution over the spectrum.
It is the aim of this article to design a fusion power plant whose electric output power is 1 GW and find a way for breaking through fusion technically and energy economically. Proton beams whose total energy is 12 MJ, pulse width 30 ns, and beam number 6 are chosen here as the energy driver. Because of the low quality of these proton beams, the target should be indirect driven and its radius should be large. The target with the radius of 8.7 mm is the spherical cryogenic hollow one, which has double shells and five layers. The reactor has double solid walls. The inner wall rotates around the axis to induce a centrifugal acceleration. Flibe as the coolant protects the solid walls from damage and breeds tritium. The key technology of this power plant is for beam focusing and propagation. To suppress beam divergence by the electrostatic force due to unneutralized proton charge, simultaneous electron beam launching is proposed. When the excess electron beam current is –50 kA, the induced magnetic field in the azimuthal direction confines the beam in a radius of 5 mm, provided that the beam path is covered by the metal guide whose radius is 6 mm.
The interaction of femtosecond laser pulses with solid-state density plasmas in regime of normal skin effect is investigated by means of numerical simulation. For short-wavelength lasers and laser pulses with length ≲ 120 fs full width at half maximum, the regime of normal skin effect is shown to hold for peak intensities up to 1017 W/cm2. The basic characteristics of the interaction are revealed and certain departures from simplistic models in electron distribution function, in plasma dielectric constant, and in laser absorption are pointed out. Comparison with the published experimental results is made.
The application of random-phase plates in laser beams to improve the uniformity of target ablation is investigated by combining the simultaneous X-ray and particle emission measurements of ablation characteristics. It is shown that if some hot spots with dimensions of a few µm exist on target they persist at least during the initial stages of the laser interaction process, producing a local maximum in the ablation pressure. Lateral energy transport, inferred from the neutral particle measurements, has little influence on absorbed energy redistribution (only 1% of the energy is transported from the laser focal spot to an outer region of 2 mm size).