scholarly journals Particle temperature and the chiral vortical effect in the early universe

2017 ◽  
Vol 32 (32) ◽  
pp. 1750178 ◽  
Author(s):  
Tamal K. Mukherjee ◽  
Soma Sanyal
Keyword(s):  
Early Universe ◽  
Beta Distribution ◽  
Magnetic Energy ◽  
Particle Temperature ◽  
Magnetized Plasma ◽  
Turbulent Dispersion ◽  
Temperature Dependent ◽  
Gaussian Peak ◽  
Magnetic Spectrum ◽  
Large Length

We study the effect of hotter or colder particles on the evolution of the chiral magnetic field in the early universe. We are interested in the temperature-dependent term in the chiral vortical effect (CVE). There are no changes in the magnetic energy spectrum at large length scales but in the Kolmogorov regime we do find a difference. Our numerical results show that the Gaussian peak in the magnetic spectrum becomes negatively skewed. The negatively skewed peak can be fitted with a beta distribution. Analytically, one can relate the non-Gaussianity of the distribution to the temperature-dependent vorticity term. The vorticity term is therefore responsible for the beta distribution in the magnetic spectrum. Since the beta distribution has already been used to model turbulent dispersion in fluids, hence it seems that the presence of hotter or colder particles may lead to turbulence in the magnetized plasma.

PHONON BROADENING OF IMPURITY SPECTRAL LINES: III. DIAGRAM TECHNIQUE

1966 ◽  
Vol 44 (1) ◽  
pp. 109-138 ◽  
Author(s):  
Robert Barrie ◽  
R. G. Rystephanick
Keyword(s):  
Shape Function ◽  
Particle Temperature ◽  
Spectral Lines ◽  
Diagram Technique ◽  
Temperature Dependent ◽  
Impurity Potential ◽  
Method Of Calculation ◽  
Double Time ◽  
Particle Propagator ◽  
Temperature Green’S Function

The theory of the phonon broadening of optical absorption lines associated with impurities in semiconductors is discussed, using the diagram technique for the evaluation of an appropriate two-particle temperature Green's function. The single-particle propagator for an electron moving in the impurity potential and simultaneously in interaction with the phonons is calculated and used. The interaction with the phonons is treated as weak. The line-shape function is found, and a comparison is made between this method of calculation and a previous one based on the decoupling of an infinite hierarchy of equations for double-time temperature-dependent Green's functions.

PHASE TRANSITIONS IN HIGHER DIMENSIONAL COSMOLOGY

2010 ◽  
Vol 25 (01) ◽  
pp. 113-122
Author(s):  
RIZWAN UL HAQ ANSARI ◽  
P. K. SURESH
Keyword(s):  
Phase Transitions ◽  
Early Universe ◽  
Higher Dimensions ◽  
Temperature Dependent ◽  
Loop Correction ◽  
Massive Scalar Field ◽  
Five Dimensions ◽  
Higher Dimensional Cosmology ◽  
Higher Dimensional ◽  
The One

We have considered five-dimensional massive scalar field coupled to gravity and evaluated the one-loop effective potential in higher dimensions. It is demonstrated that nonminimally coupled φ4 theory can be regularized in five dimensions. Temperature dependent one-loop correction and critical temperature βc are computed. The phase transitions in the early universe depend on the space–time curvature R and scalar gravitational coupling ξ. A brief discussion of symmetry restoration is also presented and the nature of phase transitions in the early universe is found to be of second order.

Simulation and Experimental Studies of Particles Interaction with Plasma Jet in Vacuum Plasma Spraying Processes

2000 ◽  
Author(s):  
A. Ilyuschenko ◽  
V. Okovity ◽  
S. Kundas ◽  
V. Gurevich
Keyword(s):  
Particle Temperature ◽  
Experimental Studies ◽  
Al2o3 Particle ◽  
Temperature Dependent ◽  
Vacuum Plasma Spraying ◽  
Program Complex ◽  
Real Process ◽  
Process Error ◽  
Temperature Dependent Properties ◽  
Intensity Radiation

Abstract Mathematical and computer models of movement and heating of particles in low pressure conditions are developed. The mathematical models are based on the molecular-kinetics theory of gases. A program complex for computer realization of models is developed. It contains a built-in data base of temperature dependent properties of substances, system of processing and graphic visualization of simulation results. For verification of the developed models, computer simulation and experimental measurements of Al2O3 particle temperature and velocity are conducted. These materials were sprayed with Plasma-Technik equipment at pressure 60 mBar in argon. Particle velocity was measured with a special optical device, particle temperature was defined by intensity radiation method. It was established that the developed models are adequate to real process (error of 5-8 %) and may be used for study and improvement of VPS processes.

scholarly journals SSX MHD plasma wind tunnel

2015 ◽  
Vol 81 (3) ◽  
Author(s):  
Michael R. Brown ◽  
David A. Schaffner
Keyword(s):  
Wind Tunnel ◽  
Energy Density ◽  
Thermal Energy ◽  
Magnetic Energy ◽  
Flow Speed ◽  
Magnetized Plasma ◽  
Drift Region ◽  
Order Unity ◽  
Plasma Gun ◽  
Background Magnetic Field

A new turbulent plasma source at the Swarthmore Spheromak Experiment (SSX) facility is described. The MHD wind tunnel configuration employs a magnetized plasma gun to inject high-beta plasma into a large, well-instrumented, vacuum drift region. This provides unique laboratory conditions approaching that in the solar wind: there is no applied background magnetic field in the drift region and has no net axial magnetic flux; the plasma flow speed is on the order of the local sound speed (M ~ 1), so flow energy density is comparable to thermal energy density; and the ratio of thermal to magnetic pressure is of order unity (plasma β ~ 1) so thermal energy density is also comparable to magnetic energy density. Results presented here and referenced within demonstrate the new capabilities and show how the new platform is proving useful for fundamental plasma turbulence studies.

scholarly journals Radiation and Polarization Signatures from Magnetic Reconnection in Relativistic Jets. II. Connection with γ-Rays

2022 ◽  
Vol 924 (2) ◽  
pp. 90
Author(s):  
Haocheng Zhang ◽  
Xiaocan Li ◽  
Dimitrios Giannios ◽  
Fan Guo ◽  
Hannes Thiersen ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Magnetic Energy ◽  
High Energy ◽  
Magnetized Plasma ◽  
Emission Region ◽  
Polarization Angle ◽  
Optical Polarization ◽  
Particle Distributions ◽  
Particle In Cell ◽  
Very High Energy

Abstract It is commonly believed that blazar jets are relativistic magnetized plasma outflows from supermassive black holes. One key question is how the jets dissipate magnetic energy to accelerate particles and drive powerful multiwavelength flares. Relativistic magnetic reconnection has been proposed as the primary plasma physical process in the blazar emission region. Recent numerical simulations have shown strong acceleration of nonthermal particles that may lead to multiwavelength flares. Nevertheless, previous works have not directly evaluated γ-ray signatures from first-principles simulations. In this paper, we employ combined particle-in-cell and polarized radiation transfer simulations to study multiwavelength radiation and optical polarization signatures under the leptonic scenario from relativistic magnetic reconnection. We find harder-when-brighter trends in optical and Fermi-LAT γ-ray bands as well as closely correlated optical and γ-ray flares. The swings in optical polarization angle are also accompanied by γ-ray flares with trivial time delays. Intriguingly, we find highly variable synchrotron self-Compton signatures due to inhomogeneous particle distributions during plasmoid mergers. This feature may result in fast γ-ray flares or orphan γ-ray flares under the leptonic scenario, complementary to the frequently considered minijet scenario. It may also imply neutrino emission with low secondary synchrotron flux under the hadronic scenario, if plasmoid mergers can accelerate protons to very high energy.

Origins of Cosmic magnetism

2018 ◽  
Vol 14 (A30) ◽  
pp. 291-294
Author(s):  
Kandaswamy Subramanian
Keyword(s):  
Kinetic Energy ◽  
Magnetic Fields ◽  
Early Universe ◽  
Magnetic Energy ◽  
Turbulent Dynamo ◽  
Degree Of Coherence ◽  
Seed Field ◽  
Standard Picture

AbstractThe standard picture for the origin of magnetic fields in astrophysical systems involves turbulent dynamo amplification of a weak seed field. Dynamos convert kinetic energy of motions to magnetic energy. While it is relatively easy for magnetic energy to grow, explaining the observed degree of coherence of cosmic magnetic fields generated by turbulent dynamos, remains challenging. We outline potential resolution of these challenges. Another intriguing possibility is that magnetic fields originated at some level from the early universe.

scholarly journals Avalanches of Magnetic Reconnection

1993 ◽  
Vol 141 ◽  
pp. 112-114
Author(s):  
Edward T. Lu
Keyword(s):  
Magnetic Field ◽  
Magnetic Reconnection ◽  
Energy Release ◽  
Power Law ◽  
Magnetic Energy ◽  
Magnetized Plasma ◽  
Release Process ◽  
3 Dimensional ◽  
Convective Motions ◽  
The Magnetic Field

AbstractActive region coronal magnetic fields are expected to be in a twisted tangled state due to photospheric convective motions. These motions can drive the magnetic field to a statistically steady state where energy is released impulsively (Lu and Hamilton 1991). These relaxation events in the magnetic field can be interpreted as avalanches of many small reconnection events. We argue that the frequency distribution of these magnetic reconnection avalanches must be a power law. Furthermore, we calculate the expected distributions in a simple model of magnetic energy release events in a 3-dimensional complex magnetized plasma, and compare these to the distributions of solar flares. These distributions are found to match the observed power law distributions of solar flare energies, peak fluxes, and durations. This model implies that the energy-release process is fundamentally the same for flares of all sizes. Observational predictions of this model are discussed.

Properties of Alfvén solitons in a finite-beta plasma

1982 ◽  
Vol 27 (2) ◽  
pp. 193-198 ◽  
Author(s):  
Steven R. Spangler ◽  
James P. Sheerin
Keyword(s):  
Functional Form ◽  
Magnetic Energy ◽  
Potential Method ◽  
Reductive Perturbation Method ◽  
Magnetized Plasma ◽  
Envelope Soliton ◽  
Magnetic Energy Density ◽  
Pseudo Potential ◽  
The Magnetic Field ◽  
Two Fluid

The properties of Alfvén solitons are examined (solitons propagating parallel to the magnetic field in a magnetized plasma) in the case when the plasma possesses a finite pressure. Starting from a two-fluid system of equations, the reductive perturbation method is used to derive a derivative nonlinear Schr ödinger equation, which is solved by a pseudo-potential method. An envelope soliton is found which possesses a width –amplitude relationship. The same functional form for the envelope of the magnetic energy density is obtained regardless of the value of the plasma &bgr;.

Evolution of Turbulent Magnetic Fields – Approach to a Steady State

1971 ◽  
Vol 43 ◽  
pp. 487-504
Author(s):  
S. Nagarajan
Keyword(s):  
Magnetic Field ◽  
Steady State ◽  
Magnetic Fields ◽  
Magnetic Energy ◽  
Dynamical Evolution ◽  
Magnetic Excitation ◽  
Electrically Conducting ◽  
Electrically Conducting Fluid ◽  
Turbulent Dynamo ◽  
Magnetic Spectrum

The dynamical evolution of a weak, random, magnetic excitation in a turbulent electrically-conducting fluid is examined under varying kinematic conditions. It is found that the results of an earlier paper (Kraichnan and Nagarajan, 1967) can be reliably extended to a stage of evolution wherein the magnetic spectrum has reached local equipartition with the velocity. The transfer of the magnetic energy to smaller wavenumbers (larger scales) is considerable and significant. This result is highly pertinent to the turbulent dynamo question, which has been variously investigated recently. The relevance of the coupling of the rms magnetic field to the magnetic modes of all scales in deciding the efficiency of this transfer is discussed.

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