We propose an experiment for the measurement of gravitational effect on cold atoms by applying a one-dimensional vertically sinusoidal oscillation to the magneto-optical trap, and observe the signature of low quantum energy shift of quantum-bound states as a consequence of gravitational fluctuation. To this end, we present brief details of the experiment on a Bose–Einstein condensate (BEC), and a simplistic calculation of the Gross–Pitaevskii solution using the Thomas–Fermi approximation with focus on the density of the BEC for the time-dependent perturbation. Moreover, we calculate the power induced by quantum gravity on a generic atomic ensemble. We also address the possible challenges for the measurement of the expected results. Finally, we discuss the prospect of further developing this experiment toward measuring the effect of quantum spacetime fluctuations on cold atoms.

I–V characteristics of air glow discharge, ionic liquid–contact air glow discharge and ionic liquid–air glow discharge are presented and photographs of the discharges are shown. It is found that the I–V characteristics of the air glow discharge always obey Ohm's law but I–V characteristics of the ionic liquid–contact air glow discharge and ionic liquid–air glow discharge obey Ohm's law only up to a particular voltage. A sudden burst of the electrolyte is observed for currents above a critical current.

Some years ago, a group including the present author and Padma Shukla showed that a suitable non-thermal electron distribution allows the formation of ion sound solitary waves with either positive or negative density perturbations, whereas with Maxwellian electrons only a positive density perturbation is possible. The present paper discusses the qualitative features of this distribution allowing the negative waves and shared with suitable two-temperature distributions.

A theoretical investigation of both deterministic and statistical approaches to modulational instability arising in the cylindrical nonlinear von Neumann equation (CNLvNE) is carried out. This is done on the basis of a recently discovered exact mapping that relates the CNLvNE to the standard one. We show that the dispersion relations of the cylindrical case (for the examples considered here) do not depend explicitly on time and their functional forms do not change with respect to the corresponding standard cases. These results differ from the previous investigations.

Supersolitons are a form of soliton characterised, inter alia, by additional local extrema superimposed on the usual bipolar electric field signature. Previous studies of supersolitons supported by three-component plasmas have dealt with ion-acoustic structures. An analogous problem is now considered, namely, dust-acoustic supersolitons in a plasma composed of fluid negative dust grains and two kappa-distributed positive ion species. Calculations illustrating some supersoliton characteristics are presented.

The non-thermal shielding effects on the Ramsauer phenomena for the electron–atom-induced dipole scattering are investigated in Lorentzian plasmas. The phase theory and the modified Buckingham-type potential are employed to obtain phase shift and collision cross section as functions of spectral index, scattering length, polarizability, collision energy, and the Debye radius. It is found that the non-thermal effect enhances the collision cross section below the Ramsauer energy and suppresses the collision cross section above the Ramsauer energy. In addition, it is found that the non-thermal effect enhances the Ramsauer energy in Lorentzian plasmas.

Using the reductive perturbation approach, dust–ion acoustic solitons and double layers (DLs) have been studied in a dust–electron–positron–ion (d-e-p-i) plasma composed of q-distributed electrons and positrons, warm fluid ions, and a fraction of immobile dust grains. Existence domains of either solitary waves or DLs are presented and their parametric dependence determined. It is found that particle non-extensivity, dust concentration and positron concentration may drastically affect these existence domains and may play a key role in defining the polarity of these localized structures. Our results should assist in interpreting the nonlinear structures that may occur in astrophysical environments.

A spiraling ion beam propagating through a magnetized plasma cylinder containing K+ light positive ions, electrons, and C7F14− heavy negative ions drives electrostatic ion–cyclotron waves to instability via cyclotron interaction. Higher harmonics of the beam cyclotron frequency can be generated in this way. The unstable mode frequencies and growth rates of both unstable light positive ions and heavy negative ions increase with the relative density of heavy negative ions. Moreover, the growth rate of unstable modes scales as the one-third power of the beam density. The growth rate of unstable modes increases with harmonic number. The frequencies of both unstable modes also increase with magnetic fields. In addition, the real part of both unstable modes (K+ and C7F14−) increases with the beam energy and scales as almost one-half power of the beam energy.

X-ray and extreme ultraviolet emission from galaxy clusters can be interpreted as thermal emission from a hot plasma gravitationally bound to the cluster and constituting a significant amount of the mass of the cluster. The origin of this plasma and its thermal energy content can be linked to the formation process through the theory of self-organization of these structures.

The basic features of dust shear Alfvén (DSA) solitary structures formed in an opposite polarity dust medium (containing positively and negatively charged dust fluids) have been investigated by using the reductive perturbation method. The derivative nonlinear Shrödinger equation and its stationary solitary wave solution are obtained for this investigation. It is shown that the opposite polarity dust medium under consideration supports the compressive DSA solitary structures having new features with new time and length scales. The implications of our results in space environments and laboratory devices are briefly discussed.

Relativistically hot electron–positron–ion (EPI) plasmas in the presence of relativistic intense electromagnetic (EM) radiation that are not in thermal equilibrium are studied by following a modified plasma particle distribution function. By means of a kinetic description, soliton solution is obtained for a small amplitude EM wave, whereas for large amplitude EM waves a cusp soliton solution is obtained. A general expression of positron density oscillations is obtained for long wavelength in comparison with the Debye length of electrons, and is discussed for special cases. Dispersion relations for a new type of longitudinal waves with slow damping is formulated as a consequence of resonant wave–particle interaction, and the necessary conditions for the existence of positron sound waves are obtained. Furthermore, for ultrarelativistic electrons and non-relativistic positrons, quasi positron sound waves dispersion relation in the intermediate wave range is obtained. It is shown that the modulation of amplitude of relativistic EM waves leads to instability for the rare plasma. Finally, we have obtained the relativistic kinetic nonlinear Schrödinger equation (KNLS) with local and non-local nonlinearities. The KNLS equation depicts nonlinear Landau damping rates for intense EM waves, and these damping rates are also examined.

The generation of ion-acoustic rogue waves in ultracold neutral plasmas (UNPs) composed of ion fluids and nonextensive electron distribution is investigated. For this purpose, basic equations are reduced to a nonlinear Schrödinger equation (NLSE) using a reductive perturbation technique. The existence region for the rogue waves defined precisely in terms of the critical wavenumber threshold kc. It is found that increasing the nonextensive parameter q would lead to a decrease of kc until q approaches to its critical value qc, then further increase of q beyond qc enhances kc; however, kc shrinks with the increase of the ions effective temperature ratio σ∗. The dependence of the first- and second-order rational solutions profile on the UNP parameters is numerically examined. It is noticed that near to the critical nonextensive parameter qc, the rogue wave amplitude becomes smaller, but it enhances whenever we stepped away from qc. However, the enhancement of the temperature ratio σ∗ and the wavenumber k reduces the envelope rogue wave amplitudes.

Volume 79, issue 3, of the Journal of Plasma Physics, contained two papers (Allen, 2013; Lehnert, 2013), which were intended for publication in volume 79, issue 4, a thematic issue dedicated to ‘Advanced Plasma Concepts’.

The Press apologises to the authors concerned, the guest editors of issue 4 and the readers for this error.

Turbulence in the interstellar medium has been an active field of research in the last decade. Numerical simulations are the tool of choice in most cases. However, while there are a number of simulations on the market, some questions have not been answered finally. In this paper, we examine the influence of compressible and incompressible driving on the evolution of turbulent spectra in a number of possible interstellar medium scenarios. We conclude that the driving has an influence not only on the ratio of compressible to incompressible component but also on the anisotropy of turbulence.

The dynamics of solitons is considered in the framework of the extended nonlinear Schrödinger equation (NLSE), which is derived from a system of Zakharov's type for the interaction between high-frequency (HF) and low-frequency (LF) waves, in which the LF field is subject to diffusive damping. The model may apply to the propagation of HF waves in plasmas. The resulting NLSE includes a pseudo-stimulated-Raman-scattering (PSRS) term, i.e. a spatial-domain counterpart of the SRS term, which is well known as an ingredient of the temporal-domain NLSE in optics. Also included is inhomogeneity of the spatial second-order diffraction (SOD). It is shown that the wavenumber downshift of solitons, caused by the PSRS, may be compensated by an upshift provided by the SOD whose coefficient is a linear function of the coordinate. An analytical solution for solitons is obtained in an approximate form. Analytical and numerical results agree well, including the predicted balance between the PSRS and the linearly inhomogeneous SOD.

We consider the excitation and dispersion of ion acoustic waves in expanding ultracold plasmas, taking into account the influence of boundary conditions. A cylindrical plasma geometry is assumed. We show that temporal changes in the medium lead to a wave frequency shift, associated with an evolving radial and standing wave mode structure, and to the temporal change of the background plasma parameters. A non-collisional model for the cylindrical geometry is also proposed.