The chaotic regime encountered in electrohydrodynamic instability of an insulating liquid subjected to space-charge-limited unipolar injection has been investigated experimentally. Two types of behavior of the power spectra of the intensity fluctuations have been characterized: an exponential decay obtained when viscous terms are dominant and a power-law decay obtained when inertial terms are dominant. Emphasis is put on the quasiuniversality of these behaviors and this is discussed in relation to the phenomenon of smallscale intermittency.

It is shown that many of the experimentally observed features of pattern formation in Rayleigh-Bénard convection near onset can be understood in terms of a two-dimensional relaxational equation. In particular, it is shown that disordered roll patterns follow a complicated dynamics that can require up to a hundred horizontal diffusion times to reach equilibrium.

Gain was measured for fast and slow waves propagating in a dielectric-loaded T${\mathrm{E}}_{01}$ axi-symmetric waveguide penetrated by an annular electron beam. This measurement is the first reported in the slow-wave regime, where axial velocity modulation dominates the azimuthal bunching. Small-signal gain at 6.0 GHz of over 30 dB, instantaneous bandwidth of 3.7%, and tuning bandwidth of over 11% are reported. In a feedback-amplifier configuration gain of 53 dB, power output of 20 kW, and 10% electronic efficiency are also reported.

Characteristics of plasmas in Tokapole II (a noncircular poloidal divertor tokamak) with directly measured $q$ as low as 0.4 are discussed. This is a $q$ regime bounded by well studied $q>\mathrm{}1\mathrm{}$ tokamaks and $q\approx 0.1$ reversed-field pinches. After $q$ drops below 1, soft-x-ray sawtooth oscillations begin. During the oscillations the central $q$ values remain stationary and below 1, while a small oscillation in the edge $q$ values near $q=1\mathrm{}$ is observed.

Fully ionized oxygen and carbon in PDX plasmas are detected via charge-exchange recombination reactions between the impurities and hydrogen atoms from a low-power neutral beam. The ${\mathrm{C}}^{6+}$ and ${\mathrm{O}}^{8+}$ ions are observed out to radii beyond the limiter, which is in contrast to expectations based on coronal equilibrium but consistent with a simple diffusive transport model. Central values of $Z_{\mathrm{eff}}$ obtained with these measurements agree with values obtained from plasma resistivity and visible bremsstrahlung measurements.

A method is proposed for injecting and trapping a high-current, high-energy, nonneutral electron beam into a modified betatron accelerator. The injection is substantially simplified as a result of the balancing of two effects that are prominent in high-current beams.

Sound attenuation has been measured at low and medium pressures down to $\frac{T}{T_c}\sim 0.4$ in the $A$ phase of superfluid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ stabilized by a magnetic field. Damping is due to Cooper pair breaking and constitutes a useful probe of the superfluid gap. The gap parameter is found to correspond to the weak-coupling value at high pressure but to be anomalously small at low pressure.

Nonconservation of photoelectron spin polarization during photoemission has been observed. Initially polarized electrons photoexcited in a germanium single crystal are completely depolarized by paramagnetic gadolinium atoms deposited on the surface of the sample.

An analytical procedure has been developed for calculating the localization length describing the exponential growth of the representative resistance in a one-dimensional disordered system and the associated residual resistance. The present results are compared to numerical simulations performed using a novel set of recurrence relations which provide a rapid and accurate method for computer studies of one-dimensional systems.

The method of moments of an absorption line is generalized to allow for a continuous level scheme. The range of problems which can be treated by this generalized method partially overlaps with those encountered by traditional perturbative methods. A test case consisting of an impurity ion that relaxes to conduction-electron bath is studied, and the compatibility of this method with other perturbative methods is demonstrated. It is also argued that this method is applicable to problems where density-matrix expansions are not valid. Further possible applications are discussed.

Numerical calculations on a model of localized interacting electrons are reported. A Coulomb gap is found in the density of states for bare and dressed single-particle excitations, which fills with increasing temperature. By making an analogy with a random-field Ising spin-glass with $\frac{1}{\mathcal{r}}$ interactions, evidence is found, in a modified Edwards-Anderson order parameter, of glasslike order at low temperatures.

A rigorous procedure is devised for generating quantum transport equations in an arbitrarily strong uniform electric field. An analytic implementation of the procedure is possible for the case of electrons scattering off a dilute random distribution of resonant-level impurities. In the limit of local scattering, the collision integral assumes a relaxation form, with a field-dependent relaxation time, thus reducing the calculation of the current to quadrature.

Let $G$ be the time-dependent quantum mechanical propagator for a particle that is free except for a half-plane barrier with a straight edge. A closed-form exact expression for $G$ is presented in terms of the Fresnel integral for the case where the initial and final positions lie in a plane perpendicular to the edge. $G$ is not expressible as a sum over classical paths.

Analytic results have been obtained for the thermodynamics of the two-dimensional $S=\frac{1}{2}$ $X-Y$ model using the simplest form of the generalized Trotter formula for the partition function. The model exhibits a phase transition of unconventional nature. It is claimed that this is one of the best descriptions given so far of the critical thermodynamics of the $S=\frac{1}{2}$ two-dimensional $X-Y$ model. Central in the present approach is the mapping of a family of two-dimensional $S=\frac{1}{2}$ models on staggered eight-vertex models having unconventional weights.

Irrational decimation schemes are constructed for functional integrals with the very interesting feature of preserving several distinct site Hamiltonians into the fixed-point limit. This method is applied to the quasiperiodicity transition to turbulence in order to compute the effects of external noise.

A measurement is presented of inclusive charged $D^{*}\mathrm{}\left(2010\right)\mathrm{}$ production from nonresonant $e^{+}{e}^{-}$ annihilation in the center-of-mass energy ($W$) range $10.2 \mathrm{GeV}<W<\mathrm{}10.6\mathrm{} \mathrm{GeV}$. Charged $D^{*}$ mesons are identified by the decays $D^{*+}\to D^0{\pi }^{+}\to K^{-}{\pi }^{+}{\pi }^{+}$ and the charge conjugate mode. It is found that 40 ± 7 ± 13% of the charm quarks from the process $e^{+}{e}^{-}\to c\overline{c}$ result in $D^{*}$ mesons with $z>\mathrm{}0.7\mathrm{}$ ($z=\frac{2E}{W}$, where $E$ is the $D^{*}$ energy).

A new formulation of lattice gauge theory without explicit path integrals or sums is obtained by using the microcanonical ensemble of statistical mechanics. Expectation values in the new formalism are calculated by solving a large set of coupled, nonlinear, ordinary differential equations. The average plaquette for compact electrodynamics calculated in this fashion agrees with standard Monte Carlo results. Possible advantages of the microcanonical method in applications to fermionic systems are discussed.

The branching ratio of $\Upsilon \mathrm{}\left(3S\right)\mathrm{}\to {\pi }^{+}{\pi }^{-}\Upsilon \mathrm{}\left(1S\right)\mathrm{}$ has been measured to be (4.9 ± 0.9 ± 0.5)%. The di-pion invariant-mass distribution for this decay is flatter than that for the decays $\Upsilon \mathrm{}\left(2S\right)\mathrm{}\to {\pi }^{+}{\pi }^{-}\Upsilon \mathrm{}\left(1S\right)\mathrm{}$ and ${\psi }^{\prime }\to {\pi }^{+}{\pi }^{-}\psi$.

A reduced, quenched, large-$N$ model which is identical with the infinite-volume lattice chiral theory in any number of dimensions for both strong and weak couplings is proposed. It is shown to provide numerical evidence for the existence of a first-order phase transition in the large-$N$ limit of the two-dimensional case.

It is shown that in spite of their unconventional experimental properties the scalar mesons $\epsilon$, $\delta$, $\kappa$, and $S^{*}$ can be understood as the unitarized remnants of conventional $q\overline{q}$ states. The $S^{*}$ and $\delta$ have large components of $q\overline{q}q\overline{q}$ in the form of virtual two-meson states (mainly $K\overline{K}$).