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The realization of an ideal volume compression of laser-irradiated fusion pellets (by C. Yamanaka) opens the possibility for an alternative to spark ignition proposed for many years for inertial confinement fusion. A re-evaluation of the difficulties of the central spark ignition of laser driven pellets is given. The alternative volume compression theory, together with volume burn and volume ignition (discovered in 1977), have received less attention and are re-evaluated in view of the experimental verification by Yamanaka, generalized fusion gain formulas, and the variation of optimum temperatures derived at self-ignition. Reactor-level DT fusion with MJ-laser pulses and volume compression to 50 times the solid-state density are estimated. Dynamic electric fields and double layers at the surface and in the interior of plasmas result in new phenomena for the acceleration of thermal electrons to suprathermal electrons. Double layers also cause a surface tension which stabilizes against surface wave effects and Rayleigh–Taylor instabilities.

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Volume compression and volume ignition of laser compressed pellets has an enormous advantage against spark ignition since the alpha self-heat substantially contributes as an additional stimulation of nuclear fusion reactions. We present here improved computations of volume ignition in agreement with the classical fact that the generated fusion energy is larger than the bremsstrahlung energy in DT only at temperatures above 4·5 keV. This result is in very close agreement with Kidder's (1974) values, and in agreement with recent computations of Mimaet al.(1987). The extension of these calculations to higher densities and input energies results in the self-absorption of bremsstrahlung at an initial temperature of about 1 keV only, much below the classical 4·5 keV. A fuel burnup fraction above 80% is shown to be possible.

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