The formation and propagation of ion-acoustic solitons are observed experimentally. The character of a solitary pulse is observed to follow the predictions of the Kortewegde Vries equation with respect to the shape and velocity of the soliton. The interaction between two solitons is modified significantly by dissipation. However, the nonlinear nature of the interactions is confirmed for solitons moving in the same direction. Solitons moving in the opposite direction and colliding have very little effect on each other.

Conservation of canonical angular momentum is shown to require that all trapped particles drift towards the magnetic axis with velocity $\frac{c{E}_{\varphi }}{B_{\theta }}$ ($E_{\varphi }$ is the toroidal electric field; $B_{\theta }$ the poloidal magnetic field). This property, plus an amplification process for the number of trapped particles, will explain the relaxation oscillations which occur for $q<\mathrm{}3\mathrm{}$. In addition, there is experimental evidence that it is an important contribution to the good containment when $q>\mathrm{}3\mathrm{}$.

The nonlinear integral equation that describes correlation functions of a quasisteady Langmuir turbulence is investigated by the use of a computer. We obtain the form and width of the Fourier component of the space-time correlation function for various values of the wave number. The correlation-curve width is determined (in the case in question) by four-plasmon interactions and can be significant even for a quite small turbulence level. The method developed permits us to determine the level of the turbulence energy by the width of the correlation curve.

A thin disk surrounded by a polyatomic gas has been found to experience a force in a direction normal to its surface when a thermal gradient and an external magnetic field are applied. This force has been measured as a function of field and pressure for oxygen. The nature of the field and pressure dependence indicates that this force effect has its origin in the same molecular-collision processes as does the field-induced decrease of the viscosity (Senftleben-Beenakker effect).

Using de Vries's model, we predicted theoretically that phase matching of optical third-harmonic generation can be achieved in cholesteric liquid crystals. The prediction was verified by measurements of third-harmonic generation from a mixture of cholesteryl chloride and cholesteryl myristate.

Propagation of heat pulses in NaF has been studied to higher temperatures in a purer crystal than studied by McNelly et al. At the highest temperatures the second-sound velocity fails to level off at the theoretically predicted limiting value.

The results of a phase-shift analysis of the Fermi surface of copper using the Korringa-Kohn-Rostoker method are reported. The values of the first four phase shifts and the Fermi energy differ from those obtained recently by Lee from an augmented-plane-wave calculation.

Previous work on investigations of spectral lines emitted from low-energy ${\mathrm{He}}^{+}$ +Ar collisions has indicated the presence of emission solely from Ar II. We have extended these investigations to show that both Ar I and He I spectra are also present and have measured the relative excitation cross sections for the 7635- and 5876-ÅA lines of these two species for energies less than 700 eV.

Within the droplet model for the Ising spin system it is shown that the magnetic specific heat $C_p$ and the susceptibility ${\chi }_p$ for constant vanishing pressure and magnetic field remain finite in a compressible lattice as the critical point $T_c$ is approached from below. This regularization of $C_p$ and ${\chi }_p$ is caused by the long-range indirect spin-spin interaction, which is a consequence of the dependence of the exchange integral on the lattice spacing.

Adjustments to proton-proton elastic scattering data at 9.690 and 9.918 MeV have apparently resolved a discrepancy between the data and current energy-dependent phase-shift analyses. New data at 13.600 MeV are also presented and are compatible with the phenomenological analysis. These results indicate that the energy-dependent fitting of $p+p$ data in the region of 10 MeV is now satisfactory.

The reaction ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}\mathrm{}(d,p)\mathrm{}{}_{}{}^{41}{}_{}{}^{}\mathrm{Ca}$ has been studied with vector-polarized deuterons of an energy of 11 MeV. The measured vector analyzing power was used to make angular momentum assignments to states in ${}_{}{}^{41}{}_{}{}^{}\mathrm{Ca}$ at $E_x=3.62,4.62, \mathrm{and} 4.77$ MeV. Two of the present $j$ assignments are in disagreement with results obtained by other methods. Further experiments are needed to investigate the reliability of different methods of determining angular momenta of nuclear energy levels.

We present experimental results on the ground-state bands of light even-even nuclei produced in the primary fission of ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$. The systematics of the energy spacings and lifetimes are similar to those of deformed nuclei in the rare earth and actinide regions.

Evidence is presented from the reaction ${}_{}{}^{152}{}_{}{}^{}\mathrm{Sm}\mathrm{}(p,t)\mathrm{}{}_{}{}^{150}{}_{}{}^{}\mathrm{Sm}$ for the existence of an excited rotational band based on the 1.256-MeV $0^{+}$ state of ${}_{}{}^{150}{}_{}{}^{}\mathrm{Sm}$, with $2^{+}$ and $4^{+}$ members at 1.417 and 1.819 MeV.

A reasonable fit to the observed high-energy proton distribution in the inner zone of the Van Allen radiation belt is obtained when the mechanism of radial diffusion is added to a cosmic-ray-produced albedo-neutron-decay source and an atmospheric collision loss mechanism. The radial diffusion mechanism transports protons inward from the outer zone to make up the serious deficiency of the albedo-neutron source at low magnetic moments, and at the same time redistributes protons of high magnetic moment in a way that is consistent with experimental observations.

Channeling of positrons in silicon single crystals has been observed in transmission and scattering measurements for incident energies from 16 to 28 MeV. In addition, the forward bremsstrahlung intensity has been established as a new observable of the channeling phenomenon. Enhancement of the low-energy portion of the bremsstrahlung spectrum ($E_{\gamma }<1\mathrm{}$ MeV) has been observed with both positron and electron beams incident along the crystal axes; this enhancement is attributed to coherence effects in bremsstrahlung production.

Pion pair production is studied in the pure state of isospin $T=0\mathrm{}$ using the reaction $\mathrm{dd}\to \mathrm{dd}\pi \pi$ in a bubble chamber experiment. The data are compared in detail with a one-pion-exchange and a Reggeized one-pion-exchange model including proper Bose symmetrization and the effects of the deuteron spin. No additional $\pi \pi$ interaction is necessary to explain our data. A $\pi \pi$ mass plot in bins close to our experimental resolution is presented as an incentive for bump hunters.

Evidence is presented for production of the $L$ meson ($M=1745\mathrm{}\pm 20$ MeV and $\Gamma =100\mathrm{}\pm 50$ MeV) in the reaction $K^{-}p\to K^{-}{\pi }^{+}{\pi }^{-}p$ at an incident momentum of 4.6 $\frac{\mathrm{GeV}}{c}$. It decays mainly into $K^{-}{\pi }^{+}{\pi }^{-}$, of which (20±20)% goes via the $K\left(1420\right)\mathrm{}\pi$ state. No significant evidence is found for $K\left(890\right)\mathrm{}\pi$, $K\omega$, $K\varphi$, or $K\eta$ decay modes. We do not observe $K\pi \pi$ threshold enhancements for arbitrary $K\pi$ mass selections.

We present confirmation for the existence of two $\Sigma \mathrm{}\left(1670\right)\mathrm{}$ resonances on the basis of their different production angular distributions. One of these decays predominantly into $\Lambda \mathrm{}\left(1405\right)\mathrm{}\pi$ and is produced much more peripherally than the second, whose principal decay mode is $\Sigma \pi$.

Production of heavy bosons is studied in $\overline{p}p$ six-prong annihilations at 6.94 $\frac{\mathrm{GeV}}{c}$. Evidence is presented for the existence of a heavy boson with a mass of 3.035 GeV and a full width of 0.200 GeV decaying into four and six pions. The possible existence of another boson at 3.4 GeV is also discussed.

Using chiral SU(2) current algebra, we have derived a dynamical equation for the form factor which describes the sigma-field matrix element between single-pion states. With the aid of the model of Gell-Mann, Oakes, and Renner, we solve this equation in an effective-range approximation, and from unitarity deduce the $T=J=0\mathrm{} \pi \pi$ phase shift. Our analysis strongly favors the "up-down" set of phenomenological $\pi \pi$ phase shifts, and rules out a narrow $\epsilon$ resonance.