The collisional drift instability is remotely feedback stabilized by irradiating the plasma with microwaves to heat the electrons locally, by upper-hybrid resonance absorption, at interior plasma locations. The phase and amplitude of the feedback-modulated heating necessary for stabilization agree qualitatively with a linear theory, which includes a feedback-controlled heat source.

One-dimensional numerical calculations have been made of the heating of a thick target of solid-density deuterium by focused subnanosecond pulses of neodymium-glass laser light. The conditions for neutron emission were found to be produced by two different mechanisms. The results are found to be in semiquantitative agreement with recent experimental results.

Containment of a gun-injected hydrogen plasma in the dc octopole has been studied. The plasma parameters are $n={10}^8-{10}^{11}$ ${\mathrm{cm}}^{-3\mathrm{}}$, $T_e=1-5\mathrm{}$ eV. The confinement of 300 Bohm times is observed. The plasma losses across the magnetic field are comparable to the support loss. In high-density regimes the loss process is found to be due to classical diffusion.

The method of ionic thermocurrents has been applied to count selectively the number of ${\mathrm{Ce}}^{3+}$ ions in tetragonal sites in Ca${\mathrm{F}}_2$ through the reorientation of the electric dipole associated with the (${\mathrm{Ce}}^{3+}$: ${\mathrm{F}}^{-}$ interstitial) center. The oscillator strength of its associated optical absorption at 305 nm has been measured. Activation energies and relaxation times for dipole reorientation have also been evaluated.

The electron $g$ factor is calculated to a high degree of accuracy for the ground state of hydrogenic atoms. In addition to binding corrections of order ${\left(Z\alpha \right)}^2$, ${\left(Z\alpha \right)}^2\frac{m}{M}$, and ${\left(Z\alpha \right)}^2{\left(\frac{m}{M}\right)}^2$, radiative level shifts of order $\alpha {\left(Z\alpha \right)}^2$ and $\alpha {\left(Z\alpha \right)}^2\frac{m}{M}$ are obtained. These level shifts differ from those previously given in the literature. The origin of the discrepancies is discussed in some detail.

Energy spectra of electrons ejected from autoionization states in helium excited by electron impact have been measured at bombarding energies from 65 to 250 eV as a function of the angle to the primary electron beam.

The height of peaks of the energy spectra due to optically forbidden transitions from the ground state compared with those due to optically allowed transitions increases as the impact energy is reduced; this trend was most marked for the triplet-state $\mathrm{}\left(2s2p\right)\mathrm{}{}_{}{}^3{}_{}{}^{}P$ excitation.

We show a way of attacking elastic atomic collisions on the grounds of classical physics.

The liquid-droplet model is used to derive a formula relating the exponent $\delta$ and the compressibility factor $\frac{P_c}{k_{\mathrm{B}}{T}_c{\rho }_c}$ at the critical point of a fluid. For fluids (the van der Waals continuum, the Bragg-Williams lattice gas, and Ising lattice gases) where both these quantities are known, the proposed relation is in agreement with experiment and theoretical prediction. Therefore, in other cases this relation may be used to predict $\delta$ from the known $P_c$, $T_c$, and ${\rho }_c$. On this basis we predict a $\delta$ between 4.2 and 4.5 for nonpolar molecules, about 5 for hydrocarbons, and larger than 5 for polar molecules.

A comparison between He II when the normal fluid is clamped and the superconducting state of metals leads to an extension of the two-fluid equations of London. The following consequences are discussed: (a) A nonstationary thermal emf (thermal electric effect) can exist in a superconductor, (b) a stationary potential difference (not an emf) can exist.

Superconductivity has been found to occur in samples of TlBi${\mathrm{Te}}_2$ with nominal carrier densities of approximately 6 × ${10}^{20}$ holes per ${\mathrm{cm}}^3$. The superconducting transition temperature is 0.14°K and the upper critical magnetic field at the absolute zero of temperature is 10 Oe. Replacing Bi with Sb produces the compound TlSb${\mathrm{Te}}_2$ which remains normal down to 0.015°K.

Measurements of the angular correlation of annihilation radiation from oriented single crystals of ${\mathrm{V}}_3$Si are reported, exhibiting marked anisotropies. These anisotropies are interpreted as hole pockets in the Fermi surface and are compared with the predictions of the linear chain model.

${\mathrm{Co}}^{59}$ NMR of Co impurities dissolved in Nb-Mo and Ti-Mo hosts is used to provide the first direct evidence in support of the Jaccarino-Walker hypothesis that moment formation in binary hosts is a discontinuous process in which the impurity moment is either zero or a fixed, maximum value depending upon the local atomic environment.

A theory of inelastic scattering of electrons by surface plasma oscillation is presented for low-energy electron diffraction and photoemission. The calculations give results which lend quantitative support to the interpretations of some prominent inelastic effects as due to surface plasmon excitation in recent experiments by Lander and Morrison in low-energy electron diffraction and by Smith and Spicer in photoemission.

Evidence for the decay of surface plasmons into one-electron excitations has been obtained in photoemission measurements from a slightly roughened surface of aluminum. A simple theory has been developed which explains the resultant photoyield in terms of both the drop in reflectance resulting from roughness-aided plasmon coupling, and the relative penetration depth of the fields associated with these excited plasmons.

A magnetic critical phase transition which involves no change in symmetry is described theoretically. In the example, ${\mathrm{Yb}}_6$${\mathrm{Fe}}_{10}$${\mathrm{O}}_{24}$ with applied field along [100], a critical point is predicted at $T^c=7.51\mathrm{}°$K and $H^c=43\mathrm{}640$ Oe. There is a large associated anomaly in $C_H: C_H(H=H^c)\approx 0.3{(T-T^c)}^{\frac{1}{\delta }-1\mathrm{}}R$ ${\mathrm{mole}}^{-1\mathrm{}}$, where $\delta$ should realize the classical value 3.

We use the low-energy pion-nucleus interaction as a means for investigating the distribution of nucleons in nuclei. An optical-model analysis of existing experimental data on pionic atoms is used to study possible differences in the rms radii of the neutron and proton densities. The difference in these radii, assumed to be independent of mass number, was found to be -0.01 ± 0.16 F. The absence of any significant difference in these radii should be considered an average behavior for a wide range of nuclei.

The charge radii of ${}_{}{}^{16,17,18}{}_{}{}^{}\mathrm{O}$ have been determined by elastic electron scattering using a gas target system. The result obtained is $R_{17}<R_{16}<R_{18}$.

A way is indicated to construct a general solution of the Einstein equations with a singularity, starting from a previously known solution of a lesser degree of generality. A qualitative description is given of the evolution of the metric in this general solution towards the singularity, which is of a complex, oscillatory nature.

Using the quoted ${\mu }^{+}$-to-${\mu }^{-}$ ratio obtained from the Berne-CERN-Fribourg neutrino experiment, the upper limit of $C_M$ was estimated to be of the order of $5C_V$, where $C_V$ is the universal vector-coupling constant of $\beta$ decay, and $C_M$ characterizes the coupling strength of a four-fermion weak interaction vertex only allowed by a multiplicative lepton-number conservation law.

Charge-transfer cross sections of ${\mathrm{Cs}}^{+}$ + Cs and ${\mathrm{K}}^{+}$ + K are calculated by the impact-parameter method using suitable atomic wave functions. The theoretical cross sections as a function of ion velocity show oscillatory structure in qualitative agreement with the experimental values given by Perel and co-workers.