Targets driven by dual-energy heavy ions

Abstract

Target designs that utilize heavy-ion beams with two substantially different particle energies are presented. Low-energy ions of moderate power are used to directly drive a spherical-shell target that is cryogenically layered with a deuterium-tritium (DT) mixture. The purpose of this first pulse is to compress the DT fuel and tamper; compressions of a hundred to a few hundred times solid density appear possible. Following compression the target is irradiated with a high-particle energy and high-power pulse. The main purpose of the second pulse is to bring the central DT region to ignition. Additional compression of no more •than 10 is needed. For targets with a low-Z pusher, gains greater than a hundred are possible with an ignition pulse of 1000 TW and a heavy-ion particle energy of 40 GeV. Pulse requirements, finite focusing effects, and symmetry requirements are discussed.

Hydrodynamic instability of shells accelerated by direct ion beam heating

“…By combining these numerical results for the linear growth rate with a qualitative analysis of the nonlinear regime, we deduce an enhancement factor of 1.5(h/d) for the distancemoved-over-thickness ratio relative to the classical RT case of a density jump with the Atwood number Aϭ1. This means that in our statement of the problem the stability issues favor large values of the absorber-to-payload mass ratio-a conclusion which is exactly opposite to the one reached by Magelssen 23 for the normal beam incidence in heavy ion ICF targets. With quite realistic values of h/d ϭ3 -5, one can count on the DMOT values that are no less than in the best cases of ablative stabilization-provided, of course, that a sufficiently low nonuniformity level of the beam deposition is ensured.…”

Determination of energy gain time dependent in D+T mixture with calculating total energy deposited of deuteron beam in hot spot

“…Or one might increase the expansion time by tamping the ignition region. In fact Magelssen published a paper in 1984 (Magelssen, 1984) in which he presented calculations of a target driven by ion beams having two very different energies. The lower energy ions arrived first and imploded the target to a spherical configuration with a rather dense pusher or tamper surrounding the fuel.…”

Assessment of Potential for Ion-Driven Fast Ignition

“…In both cases the electron conduction power, the alpha deposition power, and the bremsstrahlung power are smaller that the required beam power. At this level of approximation we ignore them leading to the following table: [7] in which he presented calculations of a target driven by ion beams having two very different energies. The lower energy ions arrived first and imploded the target to a spherical configuration with a rather dense pusher or tamper surrounding the fuel.…”