The ${\mathit{k}}^{\mathrm{-}3}$ spectrum, including the logarithmic correction, for the enstrophy range and the ${\mathit{k}}^{\mathrm{-}5/3}$ spectrum for the energy range of two-dimensional turbulence are derived using the renormalization-group method. The values of the Kolmogorov constants C’≃1.59 in the enstrophy range and C≃6.45 in the energy range are obtained without the need of adjustable parameters.

We have observed coherent patterns of the magnitude of the normalized vortex stretching vector ‖ω⋅∇u‖/‖ω‖ during the ‘‘bursting’’ reconnection phase of the evolution of identical initially orthogonally offset vortex tubes. We propose that the intensification and reconnection of initially tubelike vortex regions be viewed as a scattering process and that the topology of vortex lines during this phase of the process contributes to limiting vortex stretching (intensification). Furthermore, we advocate the use of these patterns (some rendered in color) as signatures of turbulent intermittency in exploring massive data sets.

We report heat transport measurements and optical shadowgraph visualization of rotating Rayleigh-Bénard convection. For dimensionless rotation rates 140<Ω<4300, the initial transition to convection, occurring at a Rayleigh number R much less than the linear-stability value for roll or vortex states, is a forward Hopf bifurcation to an azimuthally asymmetric state with mode number n. States with n=3, 4, 5, 6, and 7 exist at low to moderate R and precess with frequencies that depend on R and Ω. At higher R there is a continuous transition to a state with noisy, time-dependent heat transport, a distinct array of vortices in the central region, and a modulation of the precession speed of the outer structures.

A method is presented for evaluating the amplification of a three-wave parametric instability in a medium having a slow, locally linear variation in both time and space, and is applied to the specific case of stimulated Brillouin scattering (SBS) in a plasma undergoing an isothermal rarefaction. Time dependence can substantially alter the gain of such a parametric amplifier. For SBS in a subsonic rarefaction, inclusion of time dependence eliminates the absolute instability.

We analyze the new features of the low-frequency (ω<${\mathrm{\omega }}_{\mathit{p}}$) modes of wave propagation in a plasma-filled, spatially periodic structure. The spectrum of these modes is drastically modified by the periodic boundaries in a way that produces a fundamentally new kind of spectral behavior, a ‘‘dense spectrum.’’ The interaction of ballistic electron beam modes with the dense spectrum of plasma modes is shown to be unstable. These modes may play an important role in the area of plasma microwave electronics.

A model of edge localized modes in tokamak plasmas is presented. A limit-cycle solution is found in the transport equation (time-dependent Ginzburg-Landau type), which has a hysteresis curve for the gradient versus the flux. A periodic oscillation of the particle outflux and an L-H intermediate state are predicted near the L-H transition boundary. A mesophase in spatial structure appears near the edge.

Crystallization of two-dimensional domain in monolayer films of the soluble surfactant sodium dodecyl sulfate exhibits a smoth shape transition from disks to hexagons. This transition is experimentally proven to be mainly a kinetic effect. The appearance of negative curvature marks the onset of shape instabilities. A simple geometric model based on the local interplay between the line tension and crystalline anisotropy accounts for the observed behaviors. It is argued that the observed shapes are generic and insensitive to details of the actual mechanisms.

Finite-size scaling analysis is performed for one-dimensional Bose and Fermi systems with long-range interaction g/${\mathit{r}}^2$, based on the exact solution of Sutherland. The low-energy behavior of this model is shown to be described by the c=1 conformal field theory. Exact formulas for various correlation exponents are obtained. At a special point g=4, the model belongs to the same universality class as the Haldane-Shastry model, the effective theory of which is the level-1 SU(2) Kac-Moody theory.

The nuclear magnetic susceptibility of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ adsorbed on the surface of graphite, plated with a monolayer of solid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, has been measured at surface densities less than 0.055 Å ${}_{}{}^{\mathrm{-}2}{}_{}{}^{}$ and at temperatures down to 6 mK. A temperature-independent susceptibility is observed at low temperatures, which is strongly enhanced over the ideal-gas value, due to quasiparticle interactions. The inferred Landau-Fermi-liquid parameters allow a comparison with microscopic theories of interacting Fermi systems.

We report measurements of the NMR spin-lattice relaxation time, ${\mathit{T}}_1$, of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ in ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ films for 0.03<T<0.60 K as a function of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ coverage for 0.1 layer of adsorbed ${}_{}{}^3{}_{}{}^{}\mathrm{He}$. The results show thermally activated behavior for T>0.25 K and yield the energy difference, δε, between the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ ground state and the first excited state; δε shows substantial structure as a function of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ coverage.

We show that an ion carried through an electric field by a quantized vortex ring in helium II will cause a symmetric change in the radius of the ring, even though the ion is located asymmetrically on the core of the vortex ring. The localized force on the ion will combine with a specific series of vortex waves to give a uniform growth of the ring with a small component of drift velocity perpendicular to the applied electric field. This type of energy transfer may also play an important role in superfluid turbulence. Our calculations should be valid for localized forces on thin-core classical vortices as well.

Observations have been made of the incorporation of single iridium atoms into ascending as well as descending steps at iridium clusters on Ir(111). At ascending steps, incorporation occurs once diffusion of adatoms becomes significant. At descending steps, it is more complicated, and proceeds differently on large compared to small (12-atom) clusters. The mechanism of incorporation has been tested in experiments with tungsten atoms. These reveal that incorporation at descending steps can occur by exchange of the adatom with a cluster atom rather than by simple jumps.

Steplike behavior of the perpendicular lattice strain in ${\mathrm{Ge}}_{\mathit{x}}$${\mathrm{Si}}_{1\mathrm{-}\mathit{x}}$ alloy layers, grown epitaxially on Si(001), is revealed by real-time x-ray scattering during rapid thermal annealing. A cooperative pin-slip mechanism is proposed which accounts for the observed kinetic effects including the coexistence of domains with different states of strain.

Direct evidence for the creation of oxygen-vacancy, oxygen-interstitial pairs in ${\mathrm{SiO}}_2$ glasses by an excitonic mechanism is developed from an electron-spin-resonance study of high-purity fused silicas exposed to highly focused 6.4-eV excimer laser light.

The binding energy of the diamond 1s core exciton has a measured value of 0.2 eV, in marked contrast to the 1.7-eV binding energy of the physically similar nitrogen donor in diamond. Using the local-density approximation to study the core exciton, we find the shallow exciton binding energy is explained by dipole selection rules which prohibit occupation of a deep exciton gap state in single-photon excitation. This deep state has not yet been observed experimentally, and the calculation predicts a binding energy in the range of 0.8–1.7 eV.

The field dependence of the anisotropic second moment of the nuclear dipolar field distribution in rhombohedral Bi at 11 K observed by muon-spin relaxation in a single-crystal sample is in complete contrast to the results of well established calculations. A phenomenological model of an electric field gradient rotated by the external magnetic field allows description of the data; its physical justification, however, is not clear.

Measurements of coplanar current fluctuations in n-type hydrogenated amorphous silicon (a-Si:H) find that the spectral density of the noise accurately obeys a 1/f frequency dependence for frequency f in the range 1<f<${10}^3$ Hz over a temperature range 300≤T≤450 K. The noise power density displays a power-law dependence on the dc current, where the power-law exponent b increases with temperature from b∼1 at 350 K to ∼2.5 at 450 K. These results are discussed in terms of models for noise in composite and inhomogeneous materials.

Depositing alkali metal into a molecular oxygen layer dispersed on a Kr film produces alkali-metal superoxides containing the ${\mathrm{O}}_2^{\mathrm{-}}$ species for photoemission and near-edge study. The O K-edge spectrum of ${\mathrm{LiO}}_2$, ${\mathrm{KO}}_2$, and ${\mathrm{CsO}}_2$ is in good agreement with theoretical calculations for the free ${\mathrm{O}}_2^{\mathrm{-}}$ ion. The O K edge for the superoxide strongly resembles that observed for ${\mathrm{O}}_2$, which is nondissociatively adsorbed on a metal surface.

The low-temperature phase of a model of pinned, two-dimensional flux lines is analytically shown to be glassy. Typical energy barriers L diverge as (lnL${)}^{1/2}$ as the length scale L→∞. This implies a voltage-current relation of the form V=${\mathit{C}}_1$I exp{-${\mathit{C}}_2$[ln(${\mathit{I}}_0$/I)${]}^{1/2}$. The growth velocity ${\mathit{V}}_{\mathit{G}}$ of the surface of a disordered crystal is given by ${\mathit{V}}_{\mathit{G}}$=${\mathit{c}}_3$Δμ exp{-${\mathit{C}}_4$[ln(Δ${\mathrm{\mu }}_{\mathit{c}}$/Δμ)${]}^{1/2}$}, where Δμ is the crystal-liquid chemical-potential difference. Similar results hold for 2D charge-density waves, if dislocations in the charge-density wave are ignored.

Through numerical simulations and diagrammatical calculation, we find a metal-insulator transition in two-dimensional disordered systems where the scattering impurities are fractally correlated. The transition is accessible through the variation of either the Fermi energy or the impurity-scattering strength, and in the metallic regime the electronic transport is shown to be superdiffusive in nature.