Progress towards a high-gain and robust target design for heavy ion fusion
- Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
Recently [E. Henestroza et al., Phys. Plasmas 18, 032702 (2011)], a new inertial-fusion target configuration, the X-target, using one-sided axial illumination has been explored. This class of target uses annular and solid-profile heavy ion beams to compress and ignite deuterium-tritium (DT) fuel that fills the interior of metal cases that have side-view cross sections in the shape of an 'X.' X-targets using all-DT-filled metal cases imploded by three annular ion beams resulted in fuel densities of {approx}50 g/cm{sup 3} at peak compression, and fusion gains of {approx}50, comparable to heavy ion driven hohlraum targets [D. A. Callahan-Miller and M. Tabak, Phys. Plasmas 7, 2083 (2000)]. This paper discusses updated X-target configurations that incorporate inside the case a propellant (plastic) and a pusher (aluminum) surrounding the DT fuel. The updated configurations are capable of assembling higher fuel areal densities {approx}2 g/cm{sup 2} using two annular beams to implode the target to peak DT densities {approx}100 g/cm{sup 3}, followed by a fast-ignition solid ion beam which heats the high-density fuel to thermonuclear temperatures in {approx}200 ps to start the burn propagation, obtaining gains of {approx}300. These targets have been modeled using the radiation-hydrodynamics code HYDRA [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] in two- and three- dimensions to study the properties of the implosion as well as the ignition and burn propagation phases. At typical Eulerian mesh resolutions of a few microns, the aluminum-DT interface shows negligible Rayleigh-Taylor (RT) and Richtmyer-Meshkov instability growth; also, the shear flow of the DT fuel as it slides along the metal X-target walls, which drives the RT and Kelvin Helmholtz instabilities, does not have a major effect on the burning rate. An analytic estimate of the RT instability process at the Al-DT interface shows that the aluminum spikes generated during the pusher deceleration phase would not reach the ignition zone in time to affect the burning process. Also, preliminary HYDRA calculations, using a higher resolution mesh to study the shear flow of the DT fuel along the X-target walls, indicate that metal-mixed fuel produced near the walls would not be transferred to the DT ignition zone (at maximum {rho}R) located at the vertex of the X-target.
- OSTI ID:
- 22085919
- Journal Information:
- Physics of Plasmas, Vol. 19, Issue 7; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
ALUMINIUM
CROSS SECTIONS
DEUTERIUM
HEAVY IONS
HELMHOLTZ INSTABILITY
HYDRODYNAMICS
ICF DEVICES
ILLUMINANCE
IMPLOSIONS
INERTIAL CONFINEMENT
ION BEAM TARGETS
ION BEAMS
PLASMA SIMULATION
RAYLEIGH-TAYLOR INSTABILITY
SHEAR
THERMONUCLEAR IGNITION
TRITIUM