We report a study of electron density fluctuations in the adiabatic toroidal compressor tokamak using heterodyne detection to study the small-angle scattering of ${\mathrm{CO}}_2$ laser radiation. Data are presented for the frequencies, radial and poloidal wave vectors, and amplitudes of the turbulent low-frequency modes present in the adiabatic toroidal compressor. The results of searches are reported for scattering from the "thermal" ion feature and from a driven wave at 800 MHz (near the lower hybrid resonance).

I have considered the two-body problem in a uniform magnetic field. For the case of like-particle collisions, a resonance between the velocities transverse to the magnetic field of the test and field particles reduces the problem to that without a magnetic field for the relative-velocity scattering angle and scattering cross section. This resonance condition results in large changes in the test-particle collisional parameters. A secondary resonance for like-particle and resonances for unlike-particle collisions have also been found.

We report the observation of fast-electron emission (10-20 keV) from gaseous targets irradiated by a C${\mathrm{O}}_2$ laser pulse. The electrons are emitted in a direction 30° away from the electric vector, but in the plane of optical polarization. This is the first direct experimental observation of the resonant absorption effect, which has been proposed as being responsible for the efficiennt laser energy deposition in a plasma. In contrast, the parametric decay instability is not consistent with the observations.

We find that the normally stable configuration of substitutional hydrogen and deuterium in MgO becomes highly unstable during ionizing irradiation. The cross section for displacement of hydrogen is found to be a strong function of the irradiating temperature, being ∼ ${10}^8$ b at 290 K and ∼ ${10}^6$ b at 85 K. The displacement cross section of hydrogen at 290 K is shown to be twice that of deuterium.

The linewidth for electronic transitions in the image-induced potential well at the surface of liquid helium with a magnetic field applied parallel to the surface is observed to decrease as electron areal density increases. The interpretation is that the lines are motionally narrowed. The electron-velocity autocorrelation time is deduced from the data.

We report our preliminary results on a multiple-pulse spin-locking effect in dipolar solids. This effect has significant experimental advantages over prior techniques because of its high duty cycle for data collection. We show that the spin temperature assumption can be applied to explain the rather long-term behavior of the spin system. We also demonstrate how this method can be applied to obtain magnetization curves almost instantly for $T_{1\rho }$ decay and adiabatic demagnetization.

The technique of transient enhancement of initial ac susceptibility is introduced. The time dependence of the low-field ac susceptibility of ferromagnets is observed in the presence of a second time-varying field. The technique enables the diffusion of domain-wall pinning centers to be studied and also acts as a sensitive indicator of domain nucleation for magnetic critical-phenomena studies near the Curie temperature. Preliminary results for ferromagnetic gadolinium over the temperature range 240-292 K yield an activation energy for the pinning centers of ∼0.7 eV.

Ultraviolet photoelectron spectra of Cs evaporated onto Ag and oxidized under ultra-high-vacuum conditions have been measured. Time variation of the spectra indicates the formation of Cs suboxides (e.g., ${\mathrm{Cs}}_7$O, ${\mathrm{Cs}}_{11}$${\mathrm{O}}_3$). The high infrared photoelectric yield of Ag/O/Cs cathodes can be explained as due to the excitattion of surface plasmons in these compounds.

I show that spin-spin contact interactions occur in a quantum version of Einstein's conventional theory, which are of the same order of magnitude as those occurring in Einstein-Cartan-Sciama-Kibble (ECSK) theory. Thus, all the features which were thought to be peculiar to the ECSK theory—singularity behavior, possibility of stopping gravitational collapse, and so on—actually occur in Einstein's theory. In addition, I examine a contact term (independent of spin orientations and analogous to the Darwin term of quantum electrodynamics) which always gives rise to repulsive gravitation forces.

We have measured the neutron-proton charge-exchange differential cross section in the momentum interval 60 to 300 GeV/c, with squared four-momentum transfers 0.002 to 0.8 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$. Independent of incident momentum, the data are characterized by a sharp forward peak of width 0.02 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$, followed by a shoulder and gentler falloff at higher momentum transfers.

We examine the dependence of the $n$-$p$ charge-exchange cross section on the squared four-momentum transfer and on the incident momentum, and include some comparisons with data from lower energies. Implications for the difference between $n$-$p$ and $p$-$p$ total cross sections are presented.

It is shown that the four-particle $S$ matrix of pure supergravity and of the recently constructed theory of extended supergravity with O(2) internal symmetry is one-loop finite. An explicit calculation of photon-photon scattering confirms this latter result.

Our high-statistics experiment on ${\pi }^{-}p\to K^{-}{K}^{+}n$ and ${\pi }^{+}n\to K^{-}{K}^{+}p$ at 6 GeV/c confirms the $\overline{K}K$ $S$-wave enhancement near 1300 MeV recently observed by Cason et al. in ${\pi }^{-}p\to K_S^{}{}_{}{}^{0}K_S^{}{}_{}{}^{0}n$. Using the $P$-wave amplitude and the isospin dependence of interfering $\overline{K}K$ states, we resolve partial-wave ambiguities and find the $S$ wave to be dominantly isospin $I=0$, with a slow variation of phase. This excludes the interpretation of Cason et al. that the $S$ wave enhancement is a narrow $I=1$ state.

We construct a new theory of supergravity which is invariant under complex local supersymmetry transformations. This theory is obtained by coupling the massless spin-($\frac{3}{2},1$) multiplet of ordinary global supersymmetry to the spin-($2,\frac{3}{2}$) gauge multiplet of previous supergravity.

The vector analyzing power of the ($d,{}_{}{}^3{}_{}{}^{}\mathrm{He}$) reaction leading to the ground state of ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$ and the first excited states of ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}$ and ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$ has been measured. The analyzing powers strongly suggest that the admixture of $d_{\frac{3}{2}}$ into $d_{\frac{5}{2}}$ transfer strength to the first excited states of these nuclei is small. This result contrasts with recent calculations using the overlap representation which raised the possibility that this admixture might be large (≳ 40%).

$K$ Auger electrons from C bound in C${\mathrm{H}}_4$, ${\mathrm{C}}_2$${\mathrm{H}}_2$, and C${\mathrm{O}}_2$ molecules, from N bound in N${\mathrm{H}}_3$ and ${\mathrm{N}}_2$, and from Ne, induced by ${\mathrm{Ar}}^{12+}$ (56 MeV) bombardment, were recorded with an electrostatic energy analyzer. The $K$ Auger spectra from atoms in different chemical compounds exhibit significantly different line intensities and linewidths. Linewidths of metastable states are explained by the Doppler broadening arising from Coulomb explosion of the target molecule.

In order to observe energy-level splittings in free ions, we used a new technique based upon the superposition of a fixed-frequency c.w. laser beam and of a post-accelerated (or -decelerated) fast ion beam. Narrow spectral features observed in fluorescence under these conditions are easily identified within a simple hole-burning model. Implications of our results for high-resolution spectroscopy of free ions are discussed and an application is given in the case of hyperfine-structure measurements.

We report on ruby-laser scattering measurements of Langmuir turbulence excited in a high-density plasma by a C${\mathrm{O}}_2$ laser pump. The observations are reasonably consistent with a new theoretical treatment of the convective electron-ion decay instability at equal electron and ion temperatures.

In the presence of a large-amplitude electron plasma wave showing amplitude oscillations, measurements are made on test waves launched at various positions. The results give a two-branch dispersion relation, which is explained by production of detrapped electrons due to an initial damping of the large-amplitude wave.

We report the observation of wave-packet splitting due to bifurcation as predicted by the modulation theory of nonlinear dispersive waves. To our knowledge, this is the first experimental observation of this effect. The observation was made on a glow discharge plasma column with a 200-G axial field surrounded by a conducting wave guide. This observation is of importance since it provides an assessment of the modulation theory.