Drift waves and transport

Drift waves occur universally in magnetized plasmas producing the dominant mechanism for the transport of particles, energy and momentum across magnetic field lines. A wealth of information obtained from quasistationary laboratory experiments for plasma confinement is reviewed for drift waves driven unstable by density gradients, temperature gradients and trapped particle effects. The modern understanding of Bohm transport and the role of sheared flows and magnetic shear in reducing the transport to the gyro-Bohm rate are explained and illustrated with large scale computer simulations. The types of mixed wave and vortex turbulence spontaneously generated in nonuniform plasmas are derived with reduced magnetized fluid descriptions. The types of theoretical descriptions reviewed include weak turbulence theory, Kolmogorov anisotropic spectral indices, and the mixing length. A number of standard turbulent diffusivity formulas are given for the various space-time Scales of the drift-wave turbulent mixing. [S0034-6861(99)00803-X].Physic

Nonlinear aspects of quantum plasma physics

Dense quantum plasmas are ubiquitous in planetary interiors and in compact astrophysical objects, in semiconductors and micro-mechanical systems, as well as in the next generation intense laser-solid density plasma interaction experiments and in quantum x-ray free-electron lasers. In contrast to classical plasmas, one encounters extremely high plasma number density and low temperature in quantum plasmas. The latter are composed of electrons, positrons and holes, which are degenerate. Positrons (holes) have the same (slightly different) mass as electrons, but opposite charge. The degenerate charged particles (electrons, positrons, holes) follow the Fermi-Dirac statistics. In quantum plasmas, there are new forces associated with i) quantum statistical electron and positron pressures, ii) electron and positron tunneling through the Bohm potential, and iii) electron and positron angular momentum spin. Inclusion of these quantum forces provides possibility of very high-frequency dispersive electrostatic and electromagnetic waves (e.g. in the hard x-ray and gamma rays regimes) having extremely short wavelengths. In this review paper, we present theoretical backgrounds for some important nonlinear aspects of wave-wave and wave-electron interactions in dense quantum plasmas. Specifically, we shall focus on nonlinear electrostatic electron and ion plasma waves, novel aspects of 3D quantum electron fluid turbulence, as well as nonlinearly coupled intense electromagnetic waves and localized plasma wave structures. Also discussed are the phase space kinetic structures and mechanisms that can generate quasi-stationary magnetic fields in dense quantum plasmas. The influence of the external magnetic field and the electron angular momentum spin on the electromagnetic wave dynamics is discussed.Comment: 42 pages, 20 figures, accepted for publication in Physics-Uspekh

Acoustic Waves

The concept of acoustic wave is a pervasive one, which emerges in any type of medium, from solids to plasmas, at length and time scales ranging from sub-micrometric layers in microdevices to seismic waves in the Sun's interior. This book presents several aspects of the active research ongoing in this field. Theoretical efforts are leading to a deeper understanding of phenomena, also in complicated environments like the solar surface boundary. Acoustic waves are a flexible probe to investigate the properties of very different systems, from thin inorganic layers to ripening cheese to biological systems. Acoustic waves are also a tool to manipulate matter, from the delicate evaporation of biomolecules to be analysed, to the phase transitions induced by intense shock waves. And a whole class of widespread microdevices, including filters and sensors, is based on the behaviour of acoustic waves propagating in thin layers. The search for better performances is driving to new materials for these devices, and to more refined tools for their analysis

Wave Spectra in Dusty Plasmas of Nuclear Fusion Devices

Wave’s spectra are investigated through an equilibrium molecular dynamic (EMD) simulation of three-dimensional (3D) strongly-coupled complex-dusty plasmas (SCCDPs). In this chapter, we have analyzed the correlation functions over a wide range of plasma parameters of Γ (≡1, 100) and of κ (≡4.5, 5.5) along with a higher wave’s numbers of k (≡1, 4). In EMD simulations, we have examined the propagation modes of wave in the longitudinal CL(k, t) and transverse CT(k, t) current direction at higher screening (κ). We have also analyzed the wave’s spectra in different regimes of plasma states of SCCDPs. A new simulation shows that the longitudinal (CL) and transverse (CT) waves in SCCDPs are damped for low values of Γ. However, these damping affects decrease comparatively with an increasing Γ. Outcomes show that amplitude and frequency modes of the CL and CT depend on κ, Γ, k and probably on a number of particles (N). The results obtained from EMD are in reasonable agreement with earlier known theoretical and experimental data. It has been shown that the present EMD method is the best tool for computing CL and CT in the SCCDPs over a suitable range of plasma parameters

Nonlinear wave structures of the soliton and vortex types in complex continuous media: Theory, simulation, applications

This edition of the Lecture Notes of TICMI is devoted to the problems of study of nonlinear wave structures of the soliton and vortex types in complex continuous media including theory and simulation of these processes and also some applications of the results in real physical media such as space plasma and plasma of the ionosphere and magnetosphere of the Earth. The results obtained in the collaborative works of the Kazan Federal University, Russia and I. Vekua Institute of Applied Mathematics, I. Javakhishvili Tbilisi State University, Georgia are presented. Some of them were discussed on special session of the VIII Annual Meeting of the Georgian Mechanical Union dedicated to the 110th Birthday Anniversary of Ilia Vekua on September 27-29, 2017, Tbilisi, Georgia. This edition consists of two parts devoted to the nonlinear wave structures and vortical structures in complex continuous media, respectively.9

Physics Department. Annual progress report, 1 January - 31 December 1977

Research in the Physics Department at Risø covers three main fields:Solid-state physics (neutron scattering)Plasma physicsMeteorologyThe principal activities in these fields are presented in this report that covers the period from 1 January to 31 December 1977. Introductions to the work in each of the main fields are given in the respective sections of the report. The contributionsmarked with § are abstracts of published articles. References to these articles are given in section 5.2

Theoretical and computational studies of magnetized dusty plasmas

This dissertation documents my mathematical and computational research on plasmas which contain small, charged particulate matter (dust) in the presence of magnetic fields. Phenomena from two limiting cases of dust dominance are considered, these being where the grains are plentiful enough to introduce new collective plasma behaviours and sparse enough such that the grains are effectively passengers in the plasma. The study into the former limit looks at the effect which immobile dust grains have on transversely and obliquely propagating Alfv´enic solitary waves, with application to cometary and planetary magnetospheres. The spatial structure and permissible range of speeds is derived for the transverse wave. For oblique waves the problem is partially solved, with necessary, but not sufficient, restrictions on the wave speed and direction being found. Next is a study where dust is not dominant, looking at the plasma structure near to a conducting wall which has an embedded magnetic dipole oriented perpendicular to the surface, with application to dusty crystal experiments and lunar swirls. A study of electron kinetic behaviour is carried out and a novel way to calculate their density is formulated. Once implemented into a sheath model this reveals that a ring of positive space charge appears in the sheath which is capable of influencing dust grain dynamics and repelling incoming ions.Open Acces

NASA Thesaurus. Volume 2: Access vocabulary

The NASA Thesaurus -- Volume 2, Access Vocabulary -- contains an alphabetical listing of all Thesaurus terms (postable and nonpostable) and permutations of all multiword and pseudo-multiword terms. Also included are Other Words (non-Thesaurus terms) consisting of abbreviations, chemical symbols, etc. The permutations and Other Words provide 'access' to the appropriate postable entries in the Thesaurus