Walter W. Simpson

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An inertial-confinement-fusion (ICF) concept using two 60-MA Z pinches to drive a cylindrical hohlraum to 220 eV has been recently proposed. The first capsule implosions relevant to this concept have been performed at the same physical scale with a lower 20-MA current, yielding a 70+/-5 eV capsule drive. The capsule shell shape implies a polar radiation(More)
Sympathetic nerves are known to reach the heart via classical vagal pathways. Bilateral cervicothoracic sympathectomy (CS) might be expected therefore to leave significant amounts of releasable catecholamines in the myocardium if the vagi are left intact. Cardiac responses to tyramine (500 micrograms intracoronary) were compared in animals with CS,(More)
Monochromatic x-ray backlighting of wire-array z-pinch plasmas using spherically bent quartz crystals D. B. Sinars, M. E. Cuneo, G. R. Bennett, D. F. Wenger, L. E. Ruggles, M. F. Vargas, J. L. Porter, R. G. Adams, D. W. Johnson, K. L. Keller, P. K. Rambo, D. C. Rovang, H. Seamen, W. W. Simpson, I. C. Smith, and S. C. Speas Sandia National Laboratories, P.(More)
We have measured the x-ray power and energy radiated by a tungsten-wire-array z pinch as a function of the peak pinch current and the width of the anode-cathode gap at the base of the pinch. The measurements were performed at 13- and 19-MA currents and 1-, 2-, 3-, and 4-mm gaps. The wire material, number of wires, wire-array diameter, wire-array length,(More)
Previous reports of cardiac beta to alpha adrenoceptor interconversion secondary to hypothyroidism left open the alternative possibility of a functional influence by hypothyroidism on the inotropic and chronotropic effects of adrenergic amines through a different mechanism. To test this possibility, the effects of hypothyroidism (thyroidectomy) were(More)
Evidence suggests that the combined alpha and beta adrenergic agonist phenylephrine influences cardiac tissue through stimulation of both alpha and beta adrenoceptors. Phenylephrine effected a positive inotropic and chronotropic response in paced (1 Hz) left and spontaneously beating right atria, respectively. In the presence of the combined alpha and beta(More)
Simulations of a double Z-pinch hohlraum, relevant to the high-yield inertial-confinement-fusion concept, predict that through geometry design the time-integrated P2 Legendre mode drive asymmetry can be systematically controlled from positive to negative coefficient values. Studying capsule elongation, recent experiments on Z confirm such control by varying(More)
A double Z pinch driving a cylindrical secondary hohlraum from each end has been developed which can indirectly drive intertial confinement fusion capsule implosions with time-averaged radiation fields uniform to 2%-4%. 2D time-dependent view factor and 2D radiation hydrodynamic simulations using the measured primary hohlraum temperatures show that capsule(More)
A new analytical model, derived rigorously from scalar diffraction theory, accurately fits soft-x-ray measurements of symmetrical profile gold transmission gratings in all diffracted orders. The calibration system selects numerous photon energies by use of a high-resolution grazing-incidence monochromator and a dc e-beam source. Fine-period free-standing(More)