We report the excitation of lower-hybrid waves by a multiple-ring slow-wave structure (four waves, $\lambda =23\mathrm{}$ cm) in a magnetized plasma. Wavelengths measured parallel and perpendicular to the magnetic field were in agreement with the theoretical dispersion relation. The waves propagated in a packet defined by the axial length of the slow-wave structure.

The nonlinear phase shift which accompanies a large-amplitude electron plasma wave on a collisionless plasma column is demonstrated experimentally. The spatial evolution of the phase shift and the wave-number shift in a position-asymptotic limit are shown to be consistent with recent nonlinear theory.

A theory is presented for the rotation of the ion-sound spectrum with respect to the drift velocity as observed in perpendicular shocks. The results of simulation confirm the main points of the theory and represent a direct verification of perturbed-orbit theory of strong turbulence.

The 50% peak absorption predicted for resonant absorption in a linear density profile can be raised to above 90% if a different profile is used which involves a sharp jump in density along which a surface wave may propagate. Collisionless-plasma simulation studies show that at high intensities the energy goes into fast electrons which are accelerated back out of the plasma into the vacuum.

Magnetic fields in the megagauss range have been observed in the laser-produced plasma near the focus of a high-power laser pulse. Faraday-rotation measurements utilizing the light of a probing beam and the specularly reflected laser light both show the presence of these large fields.

Experimentalists studying the interaction of strong electromagnetic radiation with plasma have reported scattered asymmetric lines with frequency $2{\omega }_0$. This line and the neutron yield are correlated as a function of the peak intensity on the plasma profile. I show how the observed correlations between the $2{\omega }_0$ radiation and the neutron production can be explained by considering parametrics and linear effects in an inhomogeneous plasma. Scattered radiation and neutron output are discussed.

The large reverse isotope effect in the Pd-H(D) system is confirmed over a range of composition in samples prepared by cathodic charging. It is shown that by shifting the $T_c$-versus-composition curve for the deuteride by about 0.05 in atomic ratio it can be made to coincide with the data for the hydride. A qualitative explanation is given in terms of proposed differences between the hydride and the deuteride in electronic structure.

Phonon frequency distributions of bulk [$g^b\left(\omega \right)$] and microcrystalline [$g^m\left(\omega \right)$] titanium nitritde are obtained from neutron scattering experiments. The surface excess distribution $g^s\left(\omega \right)=g^m\left(\omega \right)-g^b\left(\omega \right)$ shows, at low energies, a positive region due to acoustic surface modes. A second positive region in $g^s\left(\omega \right)$ proves, for the first time experimentally, the existence of a band of surface vibrational modes bridging the acousto-optical gap of the bulk modes; the double-peak structure indicates two branches of surface modes.

Cyclotron resonance of electrons in an inversion layer on a Si (100) surface is studied in the regime of low electron densities ($n_s<{10}^{12}$ electrons/${\mathrm{cm}}^2$). A distinct and sample-dependent shift of the resonance to lower magnetic field is observed as $n_s$ is decreased and electron localization is expected to occur. We give a simple interpretation of the effect in terms of electronic states bound in a harmonic-oscillator potential.

We have calculated the dielectric response matrix ${\epsilon }_{\overrightarrow{G},{\overrightarrow{G}}^{\prime }}(\overrightarrow{\mathrm{q}}=0, \omega )$ for silicon and have obtained the macroscopic frequency-dependent dielectric function. Contrary to recent calculations, local-field corrections do not shift the prominent peak positions of the imaginary part of the dielectric function; further the calculated dielectric function is improved as compared with experiments at higher energies. In particular, agreement with measured energy-loss spectra is significantly better when local-field effects are included.

A strong population of the "$j$-forbidden" $4^{+}$ level at 4.25 MeV in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ is found in the reaction ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$(${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$)${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ at 46-, 58-, and 68-MeV incident energy. It provides evidence for a two-step process. This result was expected for structural and kinematical reasons.

High spin levels in ${}_{}{}^{91}{}_{}{}^{}\mathrm{Nb}$ and ${}_{}{}^{91}{}_{}{}^{}\mathrm{Zr}$ have been studied with the reactions ${}_{}{}^{88}{}_{}{}^{}\mathrm{Sr}({}_{}{}^6{}_{}{}^{}\mathrm{Li}, 3n){}_{}{}^{91}{}_{}{}^{}\mathrm{Nb}$ and ${}_{}{}^{88}{}_{}{}^{}\mathrm{Sr}({}_{}{}^6{}_{}{}^{}\mathrm{Li}, p2n){}_{}{}^{91}{}_{}{}^{}\mathrm{Zr}$ by pulsed-beam-$\gamma$, $\gamma -\gamma$, and $\gamma -W\left(\theta \right)$ measurements. Isomers were found which agree with theoretical predictions: a $\tau =5.42\mathrm{}\pm 0.18$-μ sec state at 2035 keV in ${}_{}{}^{91}{}_{}{}^{}\mathrm{Nb}$, $|{\left(g_{\frac{9}{2}}\right)}^2{p}_{\frac{1}{2}}, {\frac{17}{2}}^{-}〉$, and a $\tau =6.15\mathrm{}\pm 0.50$-μsec state at (3183) keV in ${}_{}{}^{91}{}_{}{}^{}\mathrm{Zr}$, $|{\left(g_{\frac{9}{2}}\right)}^2\times d_{\frac{5}{2}}, {\frac{21}{2}}^{+}〉$. The $|g_{\frac{9}{2}}{p}_{\frac{1}{2}}{d}_{\frac{5}{2}}, {\frac{15}{2}}^{-}〉$ state in ${}_{}{}^{91}{}_{}{}^{}\mathrm{Zr}$ was located at 2288 keV by a 28.1-keV decay $\gamma$ ray.

We have analyzed 25 000 $K_{e3\mathrm{}}$ decays, reconstructed to the center of mass by measurement of the ${K_L}^0$ momentum from time of flight and measurement of the $\pi$ and $e$ momenta with a spark-chamber-magnet spectrometer. Using the linear parametrization of the vector form factor $f_{+}\left(q^2\right)=1+{\lambda }_{+}\left(\frac{q^2}{{m_{\pi }}^2}\right)$ we find ${\lambda }_{+}=0.0270\mathrm{}\pm 0.0028$. Upper limits for the scalar ($f_s$) and tensor ($f_t$) form factors at the 68% confidence level are $\frac{f_s}{f_{+}}<0.04\mathrm{}$, $\frac{f_t}{f_{+}}<0.23\mathrm{}$, corresponding to intensity ratios $\frac{I_s}{I_v}=0.3\%$ and $\frac{I_t}{I_v}<0.4\%$.

The picture that charmed quarks are interacting with each other through a linear potential is used to analyze the particle spectrum in the high-energy annihilation process $e^{+}{e}^{-}\to \mathrm{hadrons}$. With the newly found resonances at 3.1 and 3.7 GeV as input, we predict other resonances (in particular, one at approximately 4.0 GeV) and determine the hadronic width of the 3.1 and leptonic widths of the 3.1 and 3.7 resonances. Extending the linear potential to quarks without charm enables us to predict the charmed-particle threshold to be approximately 5 GeV.

Analyses of measurements of muons produced directly, in the forward direction, by the interaction of 28-GeV protons with uranium show that the muon/pion production ratio for negative particles is 13×${10}^{-5\mathrm{}}$ for 11.6-GeV particles, 2.6×${10}^{-5\mathrm{}}$ at 20.3 GeV, 1.3×${10}^{-5\mathrm{}}$ at 23.5 GeV, and 7.0×${10}^{-6\mathrm{}}$ at 25 GeV. The largest ratio is similar to ratios measured at higher energies and large transverse momenta and none of the ratios are easily explained in terms of conventional mechanisms.

I present a model of hadrons composed of relativistic quarks in bound oscillator states. The model gives a good account of the multiplicity, distribution in momentum, and particle ratios for high-energy proton-proton collisions.

If there is a high density of ambient neutrinos—a "neutrino sea"—then on the conventional weak-interaction theory two types of possibly measurable effects exist. In one the spin direction of a transversely polarized moving electron rotates in field-free space. In the other the motion of the earth creates a torque on a ferromagnet.

The $K=0\mathrm{}\to 1$ pure rotational spectrum of C${\mathrm{O}}^{+}$ ($X{}_{}{}^2{}_{}{}^{}\Sigma$, $v=0\mathrm{}$) has been detected in a direct absorption experiment, in which microwave radiation is passed through a $3\frac{1}{2}$-m-long dc glow discharge in carbon monoxide or a helium-carbon-monoxide mixture. The discharge tube is cooled with liquid nitrogen, and the signal is detected with source modulation and computer-controlled signal averaging. The measured frequencies are 117 692.55 MHz ($J=\frac{1}{2}\to \frac{1}{2}$) and 118 101.99 MHz ($J=\frac{1}{2}\to \frac{3}{2}$).

The existence of directional anisotropies in quasimolecular $K$-x-ray emission has been independently confirmed in experiments on the C-C, O-C, Al-Al, and Si-Al collision systems. Anisotropies ranging from zero to substantially larger values than measured by Greenberg, Davis, and Vincent for the Ni-Ni system are strongly dependent on beam energy (0.06-2 MeV/amu). The C-C and O-C anisotropies decrease with energy. The Al-Al and Si-Al anisotropies increase with energy, in accord with a dependence predicted theoretically.

Photons resulting from ${\mathrm{C}}^{+}$-${\mathrm{H}}_2$ collisions have been studied in order to determine which electronic states of the product C${\mathrm{H}}^{+}$ are formed. The $A{}_{}{}^1{}_{}{}^{}\Pi$, $b{}_{}{}^3{}_{}{}^{}\Sigma$, and $B{}_{}{}^1{}_{}{}^{}\Delta$ states are observed; relative intensities depend on kinetic energy. No emission is unambiguously attributable to CH. These results complement earlier kinematic studies, and represent the first system for which luminescence has been used to distinguish among states suggested by kinematic analyses of reactive collisions.