Bose-Einstein condensation (BEC) has been observed in a dilute gas of sodium atoms. A Bose-Einstein condensate consists of a macroscopic population of the ground state of the system, and is a coherent state of matter. In an ideal gas, this phase transition is purely quantum-statistical. The study of BEC in weakly interacting systems which can be controlled and observed with precision holds the promise of revealing new macroscopic quantum phenomena that can be understood from first principles.

Bose-Einstein condensation in a gas of sodium atoms

Preface. 1. Plasmas and Dust. 2. Charging Mechanisms and Experiments. 3. Space Observations. 4. Multispecies Formalism and Waves. 5. Electrostatic Modes. 6. Electromagnetic Modes. 7. Fluctuating Dust Charges. 8. Self-Gravitation. 9. Mass and Size Distributions. 10. Other Modes. 11. Conclusions and Outlook. Bibliography. Index.

https://physicstoday.scitation.org/doi/pdf/10.1063/1.1404853

Waves in Dusty Space Plasmas

[1] Comets, planetary rings, exposed dusty surfaces, and the zodiacal dust cloud are all examples of environments where dusty plasma effects establish the size and spatial distributions of small grains. Simultaneously, dust often influences the composition, density, and temperature of the plasma surrounding it. The dynamics of charged dust particles can be surprisingly complex and fundamentally different from the well-understood limits of gravitationally dominated motions of neutral particles or the adiabatic motion of electrons and ions in electromagnetic fields that dominate gravity. In this review we focus on observations that are best explained by theories concerning dusty plasma effects at Saturn. In addition to presenting our current models we also discuss our expectations for new discoveries based on existing observations at Jupiter or on purely theoretical considerations. Our intent is to give an up-to-date overview of dusty plasma effects in Saturn's magnetosphere and to draw attention to several outstanding problems that could be resolved by the Cassini mission.

Dusty plasma effects in Saturn's magnetosphere

In recent years, there has been a wealth of new science involving low-energy antimatter (i.e., positrons and antiprotons) at energies ranging from 10 to less than 10 eV. Much of this progress has been driven by the development of new plasma-based techniques to accumulate, manipulate and deliver antiparticles for specific applications. This article focuses on the advances made in this area using positrons. However many of the resulting techniques are relevant to antiprotons as well. An overview is presented of relevant theory of single-component plasmas in electromagnetic traps. Methods are described to produce intense sources of positrons and to efficiently slow the typically energetic particles thus produced. Techniques are described to trap positrons efficiently and to cool and compress the resulting positron gases and plasmas. Finally, the procedures developed to deliver tailored pulses and beams (e.g., in intense, short bursts, or as quasi-monoenergetic continuous beams) for specific applications are reviewed. The status of development in specific application areas is also reviewed. One example is the formation of antihydrogen atoms for fundamental physics [e.g., tests of invariance under charge conjugation, parity inversion and time reversal (the CPT theorem), and studies of the interaction of gravity with antimatter]. Other applications discussed include atomic and materials physics studies and study of the electron-positron many-body system, including both classical electron-positron plasmas and the complementary quantum system in the form of Bose-condensed gases of positronium atoms. Areas of future promise are also discussed. The review concludes with a brief summary and a list of outstanding challenges. ∗ Contact information: jrdanielson@ucsd.edu † Contact information: ddubin@ucsd.edu ‡ Contact information: rgreaves@fpsi.edu § Contact information: csurko@ucsd.edu

https://link.aps.org/accepted/10.1103/RevModPhys.87.247

Plasma and trap-based techniques for science with positrons

Spherical Kadomtsev-Petviashvili equation and nebulons for dust ion-acoustic waves with symbolic computation

The head-on collision of ion acoustic solitary waves in a three-component unmagnetized plasma with cold ions, Boltzmann distributed positrons, and superthermal electrons is investigated using the extended Poincare–Lighthill–Kuo method. The effects of the ratio of electron temperature to positron temperature, the spectral index, κ, of the electron kappa distribution, and fractional concentration of positron component (p) on the phase shift are studied. It is found that the presence of superthermal electrons play a significant role on the collision of ion acoustic solitary waves.

Head-on collision of ion acoustic solitary waves in an electron-positron-ion plasma with superthermal electrons

The effects of unbounded planar geometry and bounded nonplanar geometry on quantum ion acoustic shock waves (QIASWs) in unmagnetized plasmas, where plasma kinematic viscosities are taken into account, are investigated. By the reductive perturbation method, deformed Korteweg–de Vries Burger (dKdVB), cylindrical, and spherical dKdVB equations are obtained for quantum ion acoustic shock waves in an unmagnetized two-species quantum plasma system, comprising electrons and ions. The properties of quantum ion acoustic shock waves are studied taking into account the quantum-mechanical effects in planar and nonplanar geometry. It is shown that quantum ion acoustic shock waves in nonplanar geometry differ from planar geometry. We have studied the change of QIASW structure due to the effect of the geometry, quantum parameter H, and ion kinematic viscosities by numerical calculations of the planar dKdVB, cylindrical, and spherical dKdVB equations.

Quantum ion acoustic shock waves in planar and nonplanar geometry

The properties of cylindrical and spherical dust acoustic (DA) solitary and shock waves in an unmagnetized electron depleted dusty plasma consisting of inertial dust fluid and ions featuring Tsallis statistics are investigated by employing the reductive perturbation technique. A Korteweg-de Vries Burgers (KdVB) equation is derived and its numerical solution is obtained. The effects of ion nonextensivity and dust kinematic viscosity on the basic features of DA solitary and shock waves are discussed in nonplanar geometry. It is found that nonextensive nonplanar DA waves behave quite differently from their one-dimensional planar counterpart.

https://www.tpbin.com/Uploads/Subjects/1f9787c1-0be8-49d8-9141-f39a533c2124.pdf

Nonextensive dust acoustic solitary and shock waves in nonplanar geometry

Cylindrical and spherical modified Korteweg–de Vries (KdV) equations are derived for dust ion acoustic waves. It is shown that a suitable coordinate transformation reduces the cylindrical KdV equation into the ordinary KdV equation which can be solved analytically. A completely different analytical solution is obtained using the group analysis method. However, for cylindrical and spherical modified KdV equations group analysis method yields trivial analytical solutions. Numerically, solutions to these modified KdV equations are obtained assuming initial profiles similar to those in one-dimensional soliton solutions.

Exact solutions of cylindrical and spherical dust ion acoustic waves

The problem of arbitrary amplitude electron acoustic solitary waves (EASWs) are discussed using Sagdeev’s pseudopotential technique for a plasma comprising cold electrons, superthermal hot electrons, and stationary ions. The standard normal-mode analysis is used to study the dispersion relation for linear waves. It is found that the present plasma model supports EASWs having negative potential. The influence of superthermal hot electrons on the present plasma model is investigated for the existence of solitary waves. The investigation shows that the solitary structure ceases to exist when the parameter κ crosses a certain limit. It is also found that the small amplitude double layer solution can exist in such a plasma system in some parametric regions. It is shown that solitary structures and double layers are affected by superthermality, as well as by relevant plasma parameters.

Biswajit Sahu

Papers

Head-on collision of ion acoustic solitary waves in an electron-positron-ion plasma with superthermal electrons

Quantum ion acoustic shock waves in planar and nonplanar geometry

Nonextensive dust acoustic solitary and shock waves in nonplanar geometry

Exact solutions of cylindrical and spherical dust ion acoustic waves

Electron acoustic solitary waves and double layers with superthermal hot electrons