Inhomogeneity scale lengths between critical and quarter-critical densities have been obtained by photographing laser-produced plasmas in emitted light at twice and three-halves the laser frequency. The displacements of the harmonic-light images were measured on photographs taken from a position below spherical targets irradiated by four Nd: glass-laser beams. Over the range of 5 to 20 J absorbed (in 200 to 600 psec) by 70-100-μm-diam glass shells, this scale length increased linearly from 10 to 30 μm.

Whereas experiments on the ST Tokamak demonstrated fast-Alfvén-wave cavity resonances to be sharp and resolvable and suggested highly efficient coupling could be obtained for plasma heating, warm-plasma effects appropriate to fusion plasmas suggest such resonances will not be resolvable and that the characteristic mode structure will be significantly modified through the coupling to ion-Bernstein modes unless the heating is shifted to higher harmonics of the ion-cyclotron frequency.

Nonequilibrium hydro-burn simulations of early laser-driven-compression experiments indicate that low-energy photons from the vicinity of the ablation surface are preheating the microballoon pushers, thereby severely limiting the compression achieved (similar degradation may result from 1-4% energy deposition by superthermal electrons). This implies an 8- to 27-fold increase in the energy requirements for breakeven, unless radiative preheat can be drastically reduced by, say, the use of composite ablator pushers.

The plasma thermal conductivity has been measured in a C${\mathrm{O}}_2$-laser-heated $Z$ pinch at a number density of 8 × ${10}^{16}$ ${\mathrm{cm}}^{-3\mathrm{}}$. Ruby-laser scattering was used to monitor the heating and rarefaction. Comparison with a numerical simulation indicates that the thermal conductivity is about a factor of 2 below that predicted by classical theory.

Measurements of the pressure gradient accompanying thermal counterflow in helium II have been made for both glass and metal flow tubes. A pressure in addition to that from the laminar Poiseuille flow of the normal fluid is observed when mutual friction is observed to be present. This excess pressure is described in terms of an eddy viscosity due to the interactions between the vortex lines. The eddy viscosity is found to depend only on the density of vortex lines present.

Inelastic neutron scattering from bcc ${\mathrm{Zr}}_{0.92}$${\mathrm{Nb}}_{0.08}$ at 965°C reveals features in the inelastic response which lack the average cubic symmetry of the lattice. This can be understood as arising from phonon modulation of quasistatic short-range order representing fluctuations into an incipient "$\omega$" phase.

It is shown that a three-band model (i.e., inclusion of $5d_{z^2}$, $6s$, and $6p_z$ states) for the linear Pt chains in ${\mathrm{K}}_2$Pt${\mathrm{}\left(\mathrm{CN}\right)\mathrm{}}_4$${\mathrm{Br}}_{0.3}$·3${\mathrm{H}}_2$O is inappropriate for a description of the electronic structure. The chemical effects of the ligands force an $s-d$ hybridization which is $k$ independent and leads to free-electron-like bands within a basically tight-binding scheme. This results in an explanation of the band structure deduced experimentally. A highly simplified model is also presented to explain the partial occupancy ($\frac{5}{6}$ full) of the band.

The size of small electron-hole drops near threshold is investigated in Ge using a small shift of their main luminescence line due to their surface energy $\sigma$. The smallest radii measured at different temperatures are compared with the minimum stable radii given by a model taking $\sigma$ and the drop binding energy $\varphi$ into account. We find an excellent agreement if we use the spectroscopic value of $\varphi$ (23 K).

At the orbit of Skylab we observed steeply falling energy spectra of nuclei with $Z>~8$ and $10\lesssim E\lesssim 40$ MeV/amu at intensities much higher than seen outside the magnetosphere. The composition is O: Ne: [Na-Si]: Fe = 100:33:13:(∼2), consistent with that of the solar corona. We suggest that heavy solar-wind ions enter the magnetosphere, are accelerated, and populate the inner radiation belt.

We have measured the inclusive scattering of muons of average energy 7.2 GeV from a variety of nuclear targets in the four-momentum-transfer range $0.6<\mathrm{}{Q}^2<4.0\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$. We find that the data can be well represented as an incoherent sum of muon-proton and muon-neutron scattering except in the region $x(\equiv \frac{1}{\omega }=\frac{Q^2}{2m\nu })<\mathrm{}0.1\mathrm{}$. A fit in this region by the form $A_{\mathrm{eff}}=\frac{{\sigma }_A}{\left[\right(\frac{Z}{A}){\sigma }_p+(\frac{N}{A}\left){\sigma }_n\right]}=A^{\rho }$ yields a value of the exponent $\rho$ of 0.963 ±0.006.

The large unexplained deviations of the experimental muonic 4-3 transitions in Ba and 5-4 transitions in Pb from calculations were found not to be existent. The absolute energies of these transitions agree, on the average, with theory to within 10 eV: The differences between experimental and calculated energies $E^{\mathrm{calc}}-E^{\exp }$ are +2±13 and -2 ±12 eV for the ${\mu }^{-}$-Ba $4f_{\frac{5}{2}}-3\mathrm{}{d}_{\frac{3}{2}}$ and $4f_{\frac{7}{2}}-3\mathrm{}{d}_{\frac{5}{2}}$ transitions, respectively, and 10±16 and -13±14 eV for the ${\mu }^{-}$-Pb $5g_{\frac{7}{2}}-4\mathrm{}{f}_{\frac{5}{2}}$ and $5g_{\frac{9}{2}}-4\mathrm{}{f}_{\frac{7}{2}}$ transitions, respectively.

The amplitude and phase for coherent regeneration in hydrogen and deuterium have been measured for six momentum bins in the range 3.5-10.5 GeV/c. Over this region the phase, ${\varphi }_f$, is consistent with being constant and has the value - 60°±8° for hydrogen and - 46°±8° for deuterium. Power-law fits of the form ${p_{\mathrm{lab}}}^n$ for the amplitudes when combined with other data give $n=-0.60\mathrm{}\pm 0.02$ for hydrogen and $n=-0.52\mathrm{}\pm 0.02$ for deuterium.

We report here on an experiment done at the 30-GeV proton synchrotron at Brookhaven National Laboratory using a large-acceptance ($\Delta m=1\mathrm{}$ GeV) pair spectrometer with a mass resolution of ±5 MeV, to search for additional long-lived particles which decay into $K^{-}{\pi }^{+}$, $K^{+}{\pi }^{-}$, $\overline{p}p$, $K^{+}{K}^{-}$, ${\pi }^{+}{\pi }^{-}$, $K^{-}p$, ${\pi }^{-}p$, $K^{+}\overline{p}$, or ${\pi }^{+}\overline{p}$. The result, based on 2×${10}^7$ events, shows that, to a sensitivity comparable to or lower than the production of $J$ particles [(production) × (decay branching ratio) ≈ ${10}^{-34\mathrm{}}$ ${\mathrm{cm}}^2$], no additional states were found.

It is shown that the $O$ meson, the $J^P=1^{-}$ daughter of the Pomeron, is quite successful in predicting a number of rates for duality-violating processes.

A new model-independent method for determining the parity of a state as either $\pi ={\mathrm{}(-)\mathrm{}}^J$ or $\pi ={\mathrm{}(-)\mathrm{}}^{J+1\mathrm{}}$ in odd-odd nuclei is described. The technique requires a polarized deuteron beam to initiate a ($d, \alpha$) reaction on an even-even target with detection of the reaction products near 0° or 180°. The method is demonstrated using the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(d, \alpha ){}_{}{}^{10}{}_{}{}^{}\mathrm{B}$.

Results for the elastic scattering of 50-MeV ${\pi }^{+}$ on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ are presented. Contrary to experience at energies above 100 MeV, simple optical models (with parameters derived from $\pi -N$ phase shifts) give poor fits to the data. Forcing good fits yields potentials that are pion producing or in violation of unitarity. We conclude that improved optical potentials will be required to describe low-energy data.

The polarization in proton-proton scattering at 10.0 MeV has been measured at seven angles with an accuracy of ±2×${10}^{-4\mathrm{}}$. Model-independent values of the phase shifts at 10 MeV are deduced from an analysis of the cross-section and polarization data. The implications for existing energy-dependent phase-shift sets are examined.

We show that the presence of the recently discovered phase transition in the Dicke Hamiltonian is due entirely to the absence of the $A^2$ terms from the interaction Hamiltonian.

We consider plasma conditions leading to a population inversion with respect to the ground state of an ion and problems arising in the measurement of gain in laser-produced plasmas. These considerations indicate that recent reports of superradiant emission in a laser-produced aluminum plasma at 117.41 Å might be subject to reinterpretation.

We report experimental results of hydrogen-plasma heating using very intense relativistic electron beams with $\frac{\nu }{\gamma }$ up to 10. The beam-plasma interaction process is found to be plasma-return-current heating with strongly anomalous plasma resistivity. Peak plasma energy is 1.5×${10}^{19}$ eV/${\mathrm{cm}}^3$, corresponding to $T_e=2.2\mathrm{}$ keV at $n_e=6.7\mathrm{}\times {10}^{15}$ ${\mathrm{cm}}^{-3\mathrm{}}$.