We derive an expression for the generalized radia heat flux which is defined by the fourth moment of the particle distribution function $f_a$, namely $q_a$,r=0.05${\mathrm{m}}_{\mathrm{a}}$ F (v-〈${\mathrm{v}}_{\mathrm{r}}$〉${)}^2$(${\mathrm{v}}_{\mathrm{r}}$-〈${\mathrm{v}}_{\mathrm{r}}$〉)f ${\mathrm{d}}^3$v . .sp Our result holds for a two-component, moderately non-Maxwellian, spherically symmetric pelletlike plasma in which each component a is described by the first six moments of $f_a$. Special attention is given to the electron-ion plasma case. Our generalized expression (which reduces to the familiar Fourier law) contains contributions due to the following deviations from equilibrium: temperature gradients, radial streaming velocities, thermal anisotropies, temperature differences, relative radial heat fluxes(or, equivalently, relative radial skewness of the distribution functions), and the ‘‘reduced’’ fifth moments ${\xi }_a$ (${\xi }_a$>0 represents elongated, i.e., longer than Maxwellian, tails; ${\xi }_a$<0 corresponds to truncated tails).

Contrary to the well-known (Denisov) resonance absorption of obliquely incident p-polarized laser light on plasma, we derive and evaluate a second-harmonic resonance for perpendicular incidence at four times the critical density, from hydrodynamics, including unrestricted electric fields.

A systematic approximation which consists of neglecting long-time memory effects for the entropy in chaotic systems is studied and its fast convergence is demonstrated. We determine the Lyapunov exponent for some one-dimensional maps with a high precision. For example the Lyapunov exponent of the logistic map at the first band merging point is obtained as λ=0.342 172 7. . . .

The classical string equations are cast into a simple nonlinear complex wave equation that admits a class of explicitly solvable solutions.

We derive precisely the results of streaming ($V_0$${\Omega }_e$) and Alfvén’s (ω<${\Omega }_I$) mode. The electroncyclotron resonance reveals that the phase velocity (ω/k) is of the order of the velocity of light, and the refractive index is unity for moderate streaming velocity. However, for ion fusion mode, the corresponding ω/k approaches ${10}^2$ in a dense refractive medium for low ion cyclotron frequency. Moreover, with ${\Omega }_I$${=10\mathrm{}}^4$ rad/sec, luminous waves are generated. Early isotropic results are also recovered in our analysis.

We comment on comparisons made by Ben-Misrachi and Procaccia [Phys. Rev. A 27, 2126 (1983)] between their and our works. We clarify the reported discrepancies and point out a real difference with respect to flow alignment.

Several relations between the binding energy and the electrostatic potential at the nucleus of a neutral atom are obtained by truncating the $Z^{\mathrm{-}1}$ perturbation expansion at zero, first, and approximately second order. These relations are then used to estimate the coefficient of the leading correction to the Thomas-Fermi energy, which is found to increase as more terms of the $Z^{\mathrm{-}1}$ expansion are included. This observation suggests that the limiting value of the coefficient is probably higher than the value of 0.4701 recently derived by Tal and Levy [Phys. Rev. A 25, 1838 (1982)].

The effect of diffusion upon drift-velocity measurements in electron-conductance-transient experiments is analyzed analytically, and the correction procedure employed by Wada and Freeman is argued to be inappropriate.

The effects of excitation pulse duration and electron diffusion upon drift-velocity measurements are described. The correction procedure employed by Wada and Freeman is at least as accurate as that proposed by Cassidy and by Robson, but was perhaps not previously illustrated in enough detail.

It is shown that in the limit in which the cholesteric pitch is large compared with the coherence length, the blue-phase region of the phase diagram is richer than two recent publications might suggest.

Conditional probability distributions for the valence electrons of alkaline-earth atoms in their ground and valence excited states are constructed using large-basis Sturmlan configuration-interaction wave functions for two electrons in frozen, effective-core potentials. The distributions indicate that the ground states of Be, Mg, Ca, Sr, and Ba, and the valence excited states of Be, are much more like linear triatomic molecules, akin to doubly excited He, than like independent-particle systems such as the ground states of He and He-like ions.

The eikonal theory of electron capture by relativistic projectiles has been formulated, and calculations are presented for 140- to 2100-MeV/amu C, Ne, and Ar projectiles incident on a series of target atoms between Al and U. The eikonal calculations are in good agreement with measurements at high relative velocities.

A mathematical treatment is presented in order to obtain the autocorrelation function necessary in hydrogen Stark profiles calculations. The method reduces the size of the differential-equation systems appearing in those ones, according to the SO(4) symmetry group for hydrogen. This technique suits for computer-simulated calculations.

Squeezed states of light have been predicted to be generated by four-wave mixing in cavity configurations. Any noise fields in the cavity can degrade or modify these squeezed states. An experiment using a Na atomic beam as the nonlinear mixing medium shows that spontaneous emission from the excited atoms results in a broadband frequency spectrum of noise in the cavity used for squeezing. The limits this noise places on the observed amount of squeezing and possible techniques for avoiding this noise source are discussed.

An equation of state for a single polymer chain can be established with use of either a constant force or a constant length ensemble. These two equations of state, often regarded as equivalent, are shown here to be fundamentally different in the weak-stretching (Hooke’s law) regime. In this limit, the equation derived from the force ensemble is unrelated to Hooke’s law. Various calculations of the influence of the excluded volume interaction on the equation of state are discussed.

Longitudinal-acoustic-wave oscillations on circular and linear segments of DNA are analyzed for a Boussinesq model which includes both the effects of dispersion and of anharmonicity. Expressions are obtained for the frequency spectra of anharmonic (soliton) modes. These results may help to explain details of the microwave absorption spectra of DNA.

Previous renormalization analyses have demonstrated universal properties for the quasiperiodic transition to chaos. These theories have the unpleasant feature that universal properties depend on the winding number. We modify the renormalization transformation so that it has stable attractors. This allows us to study nonlocal properties by solving the equations numerically without linearizing. The resulting universal strange attractor contains the unstable fixed points of previous theories and has exponents that are independent of winding number.

A retarded backward equation for a non-Markovian process induced by dichotomous noise (the random telegraphic signal) is deduced. The mean-first-passage time of this process is exactly obtained. The Gaussian white noise and the white shot noise limits are studied. Explicit physical results in first approximation are evaluated.

We investigate the random-trapping problem in disordered one-dimensional quasilocalized systems in the presence of a bias field. We obtain for the survival probability of the random walker a power-law decay in contrast to the exponential law which is found in the problem of ordered hopping rates. The power-law decay is a consequence of the anomalous slow exploration of the hopping sites in quasilocalized systems. The method we use combines an exact treatment of the trap statistics with an effective-medium approximation for the disorder in the hopping rates leading to the exact asymptotic long-time behavior of the physical quantities.