We have examined the Newman-Penrose quantities for test fields in a Schwarzschild background. We find that, unless a static condition has prevailed in the infinite past, backscattered electromagnetic and gravitational waves make it impossible to define the quantities as limits at future null infinity. An operational definition in terms of observations at finite radii is possible, but yields quantities which are not conserved.

In huge magnetic fields ($B\gtrsim {10}^{12}$ G) matter forms a tightly bound, dense ($\gtrsim {10}^4$ g ${\mathrm{cm}}^{-3\mathrm{}}$) solid with properties of a one-dimensional metal and a work function of the order of a keV. Electron field emission from the sharp surface of a pulsar is much easier than ion emission; it is estimated to be cut off when the stellar rotation period exceeds several seconds.

The origin of high-energy cosmic electrons is considered. It is found that electrons of energies $\lesssim {10}^3$ GeV could have been produced by local supernovae associated with known radio remnants. At higher energies, observations of muon-poor air showers indicate the existence of electrons at ${10}^6$ GeV which may have originated entirely from the supernova Vela X.

We present distributions of transverse momentum squared and of longitudinal momentum in the laboratory, center-of-mass, and projectile frames for pions produced in $K^{-}p$ interactions at 9 $\frac{\mathrm{GeV}}{c}$. Comparisons made with the corresponding distributions published by other laboratories for pion production in $K^{+}p$, ${\pi }^{+}p$, $\mathrm{pp}$, and ${\pi }^{-}p$ interactions indicate that in the proton fragmentation region the distributions for pions produced from $K^{-}p$ interactions at 9 $\frac{\mathrm{GeV}}{c}$ have not yet reached a limiting behavior.

Inelastic effects ($\rho$ production, $\Delta$ production) and particle-exchange effects are shown to determine the major features of the $\pi -N{D}_{13}$, $D_{33}$, and $P_{13}$ waves. The $D_{33}\mathrm{}\left(1670\right)\mathrm{}$ is associated with a resonance pole but the $P_{13}\mathrm{}\left(1860\right)\mathrm{}$ is not.

A new kind of finite-energy sum rule is proposed that new dual amplitudes must satisfy in addition to the usual finite-energy sum rules. This new form of duality is suggested by general considerations on the common properties of the Regge-behaved dual models. Some phenomenological implications of this new concept are briefly discussed.

We report results for the circular polarization of photons emitted in the reaction $n+d\to {\mathrm{H}}^3+\gamma$ arising from parity nonconservation in the weak nucleon-nucleon interaction. Polarizations are found to be of the order ${10}^{-6\mathrm{}}$.

Group-theoretical analysis suggests the introduction of a new kinematical variable. Data on diffraction scattering exhibit remarkable universality in this variable. An $s$-dependent slope formula is obtained which fits both $K^{+}p$ and $\mathrm{pp}$ elastic scattering at all measured energies.

Mössbauer spectra of (salen) (pyrrolidinedithiocarbamato) Fe(III) show an abrupt change at $T=2.04\mathrm{}$°K. The spectra above this temperature are typical of paramagnetic relaxation and those below agree with calculated shapes for spin relaxation in the presence of an exchange field.

A divergence of electron paths from the cathode in short-duration, short-gap discharge between semimetal electrodes has been observed in air at atmospheric pressure. A suggested mechanism for this behavior involkes the action of a self-induced Hall effect in the cathode material.

We evaluate anomalous resistivity and steady-state turbulent spectra for ion-acoustic waves driven unstable by an electron drift. The model assumes that long-wavelength unstable waves couple to short-wavelength damped waves to reach a steady state. The anomalous resistivity turns out to be a very rapidly increasing function of the electron drift velocity.

The collisional diffusion coefficient is measured in the dc octopole plasma. All measurements indicate that the process is classical diffusion for the bulk of the plasma. The value of the coefficient agrees with the theoretical value within the experimental error. Also anomalous transport is observed in the average minimum-$B$ region which becomes large near the minimum-length flux line.

We have measured the spectrum of light scattered inelastically from thermal excitations on the surface of liquid xenon near its critical point, deduced the temperature dependence of the surface tension $\sigma$ and the effective kinematic viscosity $\overline{\nu }$, examined the Fisk-Widom relation between the surface tension and the long-range correlation length $\xi$, and obtained numerically the Kawasaki critical contribution to the thermal diffusivity. The surface tension and the effective kinematic viscosity along the coexistence curve may be represented by $\sigma =(62.9\mathrm{}\pm 1.8){(1-\frac{T}{T_c})}^{1.302\pm 0.006}$ dyn/cm and $\overline{\nu }=[448+12(T_c-T\left)\right]\pm 15$ microstokes.

We investigate the pressure-induced superfluid-solid transition of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ at $T=0\mathrm{}$. Neglecting the accidental instability against nucleation, we find a definite stability limit at which the superfluid phase becomes intrinsically unstable against a density fluctuation number $Q_L$. We find that the roton minimum with frequency $\omega \left(Q_L\right)$ is the soft mode associated with this stability limit. This interpretation reflects the observed pressure dependence both of the roton minimum and of the first maximum of the structure factor at $Q_L$.

A theory is derived which qualitatively and quantitatively explains the similarity between numerical simulations for electrostatic and perpendicular magnetic collisionless shocks for zero ion temperature and no anomalous resistance.

An exact solution has been obtained for the Korteweg—de Vries equation for the case of multiple collisions of $N$ solitons with different amplitudes.

The energy loss of ions channeled through the $〈111〉$ Si channel is studied in the energy range 0.9 to 5.0 MeV. The energy dependence of the ratio between channeling and random stopping power above 3 MeV shows an increase which can be interpreted in terms of core-electron excitation. The velocity dependence of the channeling stopping power is also studied.

A microscopic analysis of the differences in Gibbs free energy between covalent, ionic, and metallic forms of $A^N{B}^{8-N}$ compounds is described. The analysis explains the success of the spectroscopic theory of chemical bonds in predicting the covalent-ionic transition at zero pressure as a function of $A$ and $B$. It also suggests that bond charge may play the role of a microscopic order parameter which determines the magnitude of the differences in energy between ionic and covalent structures at zero pressure and temperature.

We report the first experimental determination of the microscopic strain fields surrounding substitutional impurities in a crystal. We have used pair spectra in GaP to reveal the splitting of Zn or C acceptor levels in the strain fields generated by O, S, Se, or Te donor ions. The anisotropic splitting, which agrees with a simple effective-mass theory, is the same for all four donors. We conclude that effects associated with the size of these impurities are distributed over a volume of the crystal extending more than 20 Å from the impurity.

We have applied Fourier analysis to our point-scattering theory of x-ray absorption fine structure to invert experimental data formally into a radial structure function with determinable structural parameters of distance from the absorbing atom, number of atoms, and widths of coordination shells. The technique is illustrated with a comparison of evaporated and crystalline Ge. We find that the first and second neighbors in amorphous Ge are at the crystalline distance within the accuracy of measurement (1%).