Steady-state model of the corona of spherical laser targets allowing for energy transfer by fast electrons

Abstract

The (2 + p)-satisfiability (SAT) problem interpolates between different classes of complexity theory and is thought to be of basic interest in understanding the onset of typical case complexity in random combinatorics. In this paper, a tricritical point in the phase diagram of the random (2 + p)-SAT problem is analytically computed using the replica approach and found to lie in the range 2 5 p 0 0.416. These bounds on p 0 are in agreement with previous numerical simulations and rigorous results. §

Laser-driven ablation through fast electrons in PALS-experiment at the laser radiation intensity of 1–50 PW/cm2

“…In the presence of the resonance absorption of the laser radiation, such conditions correspond to relatively small values of the parameter I L λ 2 (I L and λintensity and wavelength of laser radiation), which should not exceed the value of 10 14 Wμm 2 /cm 2 . In the middle of the 1980s, analyses of experimental results (McCall et al, 1983;Tan et al, 1983) concerning the compression of spherical targets by a long-wavelength radiation CO 2 lasers have shown that for I L λ 2 ≈ 10 15-17 Wμm 2 /cm 2 and the laser energy above 100 kJ, the dimensional parameters of ICF target and a range of the fast electrons can be chosen in such a way to exclude preheating of the compressed part of the target (Volosevich & Rozanov, 1981;Gus'kov et al, 1983;1987). It was also shown that under these conditions the fast electron energy transfer from the critical density region to more dense plasma areas increases the ablation pressure and thereby plays a positive role in the target compression.…”

Effect of ‘wandering’ and other features of energy transfer by fast electrons in a direct-drive inertial confinement fusion target

“…Expression (18), written at the maximum energy of fast electrons got into the region 2. These particles were slowed down with a minimum surface density of the region 3 ρr min 3 = 7 • 10 −4 g/cm 2 .…”

“…These particles were slowed down with a minimum surface density of the region 3 ρr min 3 = 7 • 10 −4 g/cm 2 . So, expression (18) determines the initial energy of fast electrons, at which they will not hit into the DT-layer:…”

“…Thus, for the considered target, the transfer of a significant fraction of energy to the region of the evaporated part of ablator with overcritical density will partially compensate a negative effect of heating of the compressed shell. For the first time, the contribution of energy transfer by fast electrons to ablation pressure was discussed in [18] as applied to the long-wavelength CO 2 laser interaction with matter. At present time it is paid much attention to the study of this effect in relation to the promising approach to ICF target ignition known as "shock ignition" [19,20].…”

Direct-drive inertial confinement fusion: A review

“…810,840 Indeed, several researchers have indicated that electrons of such energies may be beneficial to SI since they deposit energy near the shock-formation region and, therefore, may amplify the shock pressures above those anticipated by including only inverse bremsstrahlung absorption and flux-limited thermal heat conduction. 809,810,812,[840][841][842][843] Some authors have gone further to propose using hot electrons as the primary shock-launching mechanism. 844,845 D. Experiments SI-relevant experiments have been performed at various facilities, examining target stability and yield, strong-shock generation, and laser-plasma interactions at spike-pulse laser intensities.…”