Multifluid interpenetration mixing in directly driven inertial confinement fusion capsule implosions

Mixing between the shell and fuel in directly driven single shell capsule implosions causes changes in yield, burn history, burn temperature, areal density, x-ray image shape, and the presence of atomic mix. Most observations are consistent with a mix model using the same values of its single free parameter as with indirectly driven single shell and double shell capsules. Greater mixing at lower gas pressure fills reduces capsule yield. Time dependent mixing growth causes truncation of the burn history. This emphasizes early yield from the center of the capsule, raising the observed burn temperature. Mixed fuel areal densities are lower because fuel moves through the shell and the observation weights earlier times when areal density is lower. Shell x-ray emission mixing into the fuel fills in the limb brightened image to produce a central peak. Implosions of 3He filled capsules with a layer of deuterated plastic show substantial atomic mix.

[1]  P. B. Radha,et al.  Time-resolved areal-density measurements with proton spectroscopy in spherical implosions. , 2003, Physical review letters.

[2]  H. Brysk,et al.  Fusion neutron energies and spectra , 1973 .

[3]  Anthony J. Scannapieco,et al.  A multifluid interpenetration mix model , 2002 .

[4]  Gregory A. Moses,et al.  Inertial confinement fusion , 1982 .

[5]  Andrew J. Schmitt,et al.  Simulations of high-gain direct-drive inertial confinement fusion targets , 2004 .

[6]  R. Town,et al.  Core performance and mix in direct-drive spherical implosions with high uniformity , 2001 .

[7]  Stephen D. Jacobs,et al.  Direct‐drive laser‐fusion experiments with the OMEGA, 60‐beam, >40 kJ, ultraviolet laser system , 1996 .

[8]  P B Radha,et al.  Measuring implosion dynamics through rhoR evolution in inertial-confinement fusion experiments. , 2003, Physical review letters.

[9]  Paul A. Jaanimagi,et al.  Characterization of direct-drive-implosion core conditions on OMEGA with time-resolved Ar K-shell spectroscopy , 2002 .

[10]  Nelson M. Hoffman,et al.  Degradation of radiatively driven inertial confinement fusion capsule implosions by multifluid interpenetration mixing , 2003 .

[11]  J. Nuckolls,et al.  Laser Compression of Matter to Super-High Densities: Thermonuclear (CTR) Applications , 1972, Nature.

[12]  D. Phillion,et al.  25 ps neutron detector for measuring ICF‐target burn history , 1995 .

[13]  R. Town,et al.  Analysis of a direct-drive ignition capsule designed for the National Ignition Facility , 2001 .

[14]  R. Town,et al.  Inference of mix in direct-drive implosions on OMEGA , 2002 .

[15]  Denis G. Colombant,et al.  Direct-drive laser fusion: status and prospects , 1998 .

[16]  F. J. Marshall,et al.  The influence of asymmetry on mix in direct-drive inertial confinement fusion experiments , 2004 .

[17]  R. Town,et al.  Direct-drive high-convergence-ratio implosion studies on the OMEGA laser system* , 2000 .

[18]  P. B. Radha,et al.  Shell mix in the compressed core of spherical implosions. , 2002, Physical review letters.