Modern high-power lasers can generate extreme states of matter that are relevant to astrophysics, equation-of-state studies and fusion energy research. Laser-driven implosions of spherical polymer shells have, for example, achieved an increase in density of 1,000 times relative to the solid state. These densities are large enough to enable controlled fusion, but to achieve energy gain a small volume of compressed fuel (known as the 'spark') must be heated to temperatures of about 108 K (corresponding to thermal energies in excess of 10 keV). In the conventional approach to controlled fusion, the spark is both produced and heated by accurately timed shock waves, but this process requires both precise implosion symmetry and a very large drive energy. In principle, these requirements can be significantly relaxed by performing the compression and fast heating separately; however, this 'fast ignitor' approach also suffers drawbacks, such as propagation losses and deflection of the ultra-intense laser pulse by the plasma surrounding the compressed fuel. Here we employ a new compression geometry that eliminates these problems; we combine production of compressed matter in a laser-driven implosion with picosecond-fast heating by a laser pulse timed to coincide with the peak compression. Our approach therefore permits efficient compression and heating to be carried out simultaneously, providing a route to efficient fusion energy production.

Rapid heating of a compressed fusion fuel by a short-duration laser pulse is a promising route to generating energy by nuclear fusion, and has been demonstrated on an experimental scale using a novel fast-ignitor geometry. Here we describe a refinement of this system in which a much more powerful, pulsed petawatt (10(15) watts) laser creates a fast-heated core plasma that is scalable to full-scale ignition, significantly increasing the number of fusion events while still maintaining high heating efficiency at these substantially higher laser energies. Our findings bring us a step closer to realizing the production of relatively inexpensive, full-scale fast-ignition laser facilities.

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Articles you may be interested inA highly miniaturized electron and ion energy spectrometer prototype for the rapid analysis of space plasmas Rev. Sci. Instrum. 85, 023305 (2014); 10.1063/1.4865842 High energy electron crystal spectrometer Rev. Sci. Instrum. 80, 076106 (2009); 10.1063/1.3170508 Absolute calibration of an electron spectrometer using high energy electrons produced by the laser-plasma interaction Rev. Sci. Instrum. 79, 083301 (2008); 10.1063/1.2969655 Absolute calibration of image plates for electrons at energy between 100 keV and 4 MeV Rev. Sci. Instrum. 79, 033301 (2008); 10.1063/1.2885045 A high sensitivity electron momentum spectrometer with simultaneous detection in energy and momentum Rev.A high energy electron spectrometer has been designed and tested using imaging plate (IP). The measurable energy range extends from 1 to 100 MeV or even higher. The IP response in this energy range is calibrated using electrons from L-band and S-band LINAC accelerator at energies 11.5, 30, and 100 MeV. The calibration has been extended to 0.2 MeV using an existing data and Monte Carlo simulation Electron Gamma Shower code. The calibration results cover the energy from 0.2 to 100 MeV and show almost a constant sensitivity for electrons over 1 MeV energy. The temperature fading of the IP shows a 40% reduction after 80 min of the data taken at 22.5°C. Since the fading is not significant after this time we set the waiting time to be 80 min. The oblique incidence effect has been studied to show that there is a 1 / cos relation when the incidence angle is .

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