Two-dimensional simulations of plastic-shell, direct-drive implosions on OMEGA

Abstract

Multidimensional hydrodynamic properties of high-adiabat direct-drive plasticshell implosions on the OMEGA laser system [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)] are investigated using the multidimensional hydrodynamic code, DRACO.Multimode simulations including the effects of nonuniform illumination and target roughness indicate that shell stability during the acceleration phase plays a critical role in determining target performance. For thick shells that remain integral during the acceleration phase, target yields are significantly reduced by the combination of the longwavelength ( < 10) modes due to surface roughness and beam imbalance and the intermediate modes (20 ≤ ≤ 50) due to single-beam nonuniformities. The neutronproduction rate for these thick shells truncates relative to one-dimensional (1-D) predictions. The yield degradation in the thin shells is mainly due to shell breakup at short wavelengths (λ ~ ∆, where ∆ is the in-flight shell thickness). The neutron-rate curves for the thinner shells have significantly lower amplitudes and a fall-off that is less steep than 1-D rates. DRACO simulation results are consistent with experimental observations. 2

SPECT3D – A multi-dimensional collisional-radiative code for generating diagnostic signatures based on hydrodynamics and PIC simulation output

“…SPECT3D is currently being used to post-process output from a variety of 1-D, 2-D, and 3-D RH codes, including ALEGRA [7], DRACO [8], CTH [9], and HELIOS-CR [10]. In addition, SPECT3D has recently been upgraded to post-process LSP [11,12] PIC simulation results.…”

Inelastic X-Ray Scattering from Shocked Liquid Deuterium

“…Two-dimensional hydrodynamic simulations of the experiment were performed with the DRACO code, which uses the SESAME EOS, a three-dimensional (3-D) laser ray trace model that calculates the laser absorption via inverse bremsstrahlung, a flux-limited thermal-transport approximation with a flux limiter of 0.06, and a multigroup diffusion radiation transport approximation using opacity tables created for astrophysics [23]. The simulation results shown in Fig.…”

Measured dependence of nuclear burn region size on implosion parameters in inertial confinement fusion experiments

“…[4][5][6][7][8][9]10 Figure 6a shows the effect upon R burn (diamonds). The trend of these data is more fully revealed by averaging the data over capsules with similar shell thicknesses (Fig.…”

“…[1][2][3] In the direct-drive approach to ICF, a spherical capsule containing fuel is compressed and heated by direct illumination of laser beams focused on the capsule surface in a nominally uniform fashion. 2 Hydrodynamic instabilities, drive characteristics, and capsule structure affect the performance of these implosions, [2][3][4][5][6][7][8][9][10] ultimately determining the size, symmetry, and yield of the nuclear burn region. This article, the third in a series about proton emission imaging, [11][12] presents the first comprehensive studies of D 3 He burn region sizes in nominally symmetric direct-drive implosions with diverse capsule and drive conditions.…”