scholarly journals General dispersion properties of magnetized plasmas with drifting bi-Kappa distributions. DIS-K: Dispersion Solver for Kappa Plasmas

2021 ◽  
Vol 87 (3) ◽  
Author(s):  
R.A. López ◽  
S.M. Shaaban ◽  
M. Lazar
Keyword(s):  
Dominant Role ◽  
High Energy ◽  
Distribution Functions ◽  
Magnetized Plasma ◽  
Unstable Wave ◽  
Space Plasmas ◽  
Good Representation ◽  
Particle Interactions ◽  
Particle Collisions ◽  
Dispersion Tensor

Space plasmas are known to be out of (local) thermodynamic equilibrium, as observations show direct or indirect evidences of non-thermal velocity distributions of plasma particles. Prominent are the anisotropies relative to the magnetic field, anisotropic temperatures, field-aligned beams or drifting populations, but also, the suprathermal populations enhancing the high-energy tails of the observed distributions. Drifting bi-Kappa distribution functions can provide a good representation of these features and enable for a kinetic fundamental description of the dispersion and stability of these collision-poor plasmas, where particle–particle collisions are rare but wave–particle interactions appear to play a dominant role in the dynamics. In the present paper we derive the full set of components of the dispersion tensor for magnetized plasma populations modelled by drifting bi-Kappa distributions. A new solver called DIS-K (DIspersion Solver for Kappa plasmas) is proposed to solve numerically the dispersion relations of high complexity. The solver is validated by comparing with the damped and unstable wave solutions obtained with other codes, operating in the limits of drifting Maxwellian and non-drifting Kappa models. These new theoretical tools enable more realistic characterizations, both analytical and numerical, of wave fluctuations and instabilities in complex kinetic configurations measured in-situ in space plasmas.

scholarly journals Middle-energy electron anisotropies in the auroral region

2004 ◽  
Vol 22 (1) ◽  
pp. 237-249 ◽  
Author(s):  
P. Janhunen ◽  
A. Olsson ◽  
H. Laakso ◽  
A. Vaivads
Keyword(s):  
Electron Distribution ◽  
Electron Flow ◽  
High Mobility ◽  
High Energy ◽  
Auroral Oval ◽  
Distribution Functions ◽  
Particle Interactions ◽  
Latitude Distribution ◽  
Field Lines ◽  
Auroral Phenomena

Abstract. Field-aligned anisotropic electron distribution functions of T∥ > T⊥ type are observed on auroral field lines at both low and high altitudes. We show that typically the anisotropy is limited to a certain range of energies, often below 1keV, although sometimes extending to slightly higher energies as well. Almost always there is simultaneously an isotropic electron distribution at higher energies. Often the anisotropies are up/down symmetrical, although cases with net upward or downward electron flow also occur. For a statistical analysis of the anisotropies we divide the energy range into low (below 100eV), middle (100eV–1keV) and high (above 1keV) energies and develop a measure of anisotropy expressed in density units. The statistical magnetic local time and invariant latitude distribution of the middle-energy anisotropies obeys that of the average auroral oval, whereas the distributions of the low and high energy anisotropies are more irregular. This suggests that it is specifically the middle-energy anisotropies that have something to do with auroral processes. The anisotropy magnitude decreases monotonically with altitude, as one would expect, because electrons have high mobility along the magnetic field and thus, the anisotropy properties spread rapidly to different altitudes. Key words. Magnetospheric physics (auroral phenomena). Space plasma physics (wave-particle interactions; changed particle motion and acceleration)

scholarly journals POLARIZED STRUCTURE FUNCTIONS AND SPIN PHYSICS

2002 ◽  
Vol 17 (23) ◽  
pp. 3220-3238
Author(s):  
UTA STÖSSLEIN
Keyword(s):  
Parton Distribution ◽  
Spin Structure ◽  
High Energy ◽  
Structure Functions ◽  
Distribution Functions ◽  
High Energy Particle ◽  
Particle Interactions ◽  
Parton Distribution Functions ◽  
Spin Physics ◽  
Further Development

Recent progress in the field of spin physics of high energy particle interactions is reviewed with particular emphasis on the spin structure functions as measured in polarized deep inelastic lepton-nucleon scattering (DIS). New measurements are presented to obtain more direct information on the composition of the nucleon angular momentum, with results from semi-inclusive DIS accessing flavour-separated parton distribution functions (PDF) and with first data from hard exclusive reactions which may be interpreted in terms of recently developed generalizations of parton distribution functions (GPD). Finally, experimental prospects are outlined which will lead to a further development of the virtues of QCD phenomenology of the spin structure of the nucleon.

Physics of particle collisions at high energies: Limits to phenomenology, Part 1

2008 ◽  
Vol 86 (7) ◽  
pp. 883-897 ◽  
Author(s):  
G Sau ◽  
S K Biswas ◽  
B De ◽  
P Guptaroy ◽  
A Bhattacharya ◽  
...  
Keyword(s):  
Good Description ◽  
Heavy Ion ◽  
High Energy ◽  
Data Sets ◽  
Particle Interactions ◽  
Power Law Model ◽  
Particle Collisions ◽  
Relativistic Heavy Ion Collider ◽  
High Energies ◽  
200 Gev

Interpretation and understanding of high-energy PP data in a clear, consistent, and comprehensive manner is crucial for making valid claims to build up any successful theoretical framework for particle interactions. We have tried here to analyze the various sets of PP data available from the pre-ISR days to the latest PP collisions at the relativistic heavy ion collider (RHIC) experiment at [Formula: see text] = 200 GeV in the light of a power-law model. Both mid-rapidity and high-rapidity data sets have been dealt with by applying the same working formula. It is found that the working formula used provides a good description of these wide ranging data sets; but hardly throws any deep insights into the nature of particle interactions that force us to question the worth and rigour of phenomenological studies.PACS Nos.: 13.60.Hb, 13.60.Le, 13.85.Ni

Particle acceleration in plasmas by perpendicularly propagating waves

2000 ◽  
Vol 64 (4) ◽  
pp. 481-487 ◽  
Author(s):  
R. BINGHAM ◽  
R. A. CAIRNS ◽  
J. T. MENDONÇA
Keyword(s):  
Particle Acceleration ◽  
Laboratory Experiments ◽  
Plasma Waves ◽  
High Energy ◽  
Relativistic Plasma ◽  
Magnetized Plasma ◽  
Space Plasmas ◽  
Astrophysical Plasmas ◽  
Present Test ◽  
Propagating Waves

The acceleration of particles to high energy by relativistic plasma waves has received a great deal of attention lately. Most of the particle-acceleration schemes using relativistic plasma waves rely either on intense terawatt or petawatt lasers or on electron beams as the driver of the acceleration wave. These laboratory experiments have attained accelerating fields as high as 1 GeV cm−1 with the electrons being accelerated to about 100 MeV in millimetre distances. In space and astrophysical plasmas, relativistic plasma waves can also be important for acceleration. A process that is common to both laboratory and space plasmas is the surfatron concept, which operates as a wave acceleration mechanism in a magnetized plasma. In this paper, we present test-particle results for the surfatron process.

scholarly journals High-energy operator product expansion at sub-eikonal level

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Giovanni Antonio Chirilli
Keyword(s):  
Operator Product Expansion ◽  
Evolution Equations ◽  
Energy Operator ◽  
High Energy ◽  
Structure Functions ◽  
Distribution Functions ◽  
Impact Factors ◽  
Operator Product ◽  
The Impact ◽  
New Distribution

Abstract The high energy Operator Product Expansion for the product of two electromagnetic currents is extended to the sub-eikonal level in a rigorous way. I calculate the impact factors for polarized and unpolarized structure functions, define new distribution functions, and derive the evolution equations for unpolarized and polarized structure functions in the flavor singlet and non-singlet case.

scholarly journals The theory of cosmic ray scattering on pre-existing MHD modes meets data

2021 ◽  
Vol 502 (4) ◽  
pp. 5821-5838
Author(s):  
Ottavio Fornieri ◽  
Daniele Gaggero ◽  
Silvio Sergio Cerri ◽  
Pedro De La Torre Luque ◽  
Stefano Gabici
Keyword(s):  
Diffusion Coefficients ◽  
Galactic Halo ◽  
Dominant Role ◽  
Cosmic Ray ◽  
High Energy ◽  
Scattering Rate ◽  
Equilibrium Spectrum ◽  
Galactic Cosmic Ray ◽  
Comprehensive Study ◽  
Ray Scattering

ABSTRACT We present a comprehensive study about the phenomenological implications of the theory describing Galactic cosmic ray scattering on to magnetosonic and Alfvénic fluctuations in the GeV−PeV domain. We compute a set of diffusion coefficients from first principles, for different values of the Alfvénic Mach number and other relevant parameters associated with both the Galactic halo and the extended disc, taking into account the different damping mechanisms of turbulent fluctuations acting in these environments. We confirm that the scattering rate associated with Alfvénic turbulence is highly suppressed if the anisotropy of the cascade is taken into account. On the other hand, we highlight that magnetosonic modes play a dominant role in Galactic confinement of cosmic rays up to PeV energies. We implement the diffusion coefficients in the numerical framework of the dragon code, and simulate the equilibrium spectrum of different primary and secondary cosmic ray species. We show that, for reasonable choices of the parameters under consideration, all primary and secondary fluxes at high energy (above a rigidity of $\simeq 200 \, \mathrm{GV}$) are correctly reproduced within our framework, in both normalization and slope.

Total scattering experiments on glass and crystalline materials at the ESRF on the ID11 Beamline

2014 ◽  
Vol 30 (S1) ◽  
pp. S2-S8 ◽  
Author(s):  
Andrea Bernasconi ◽  
Jonathan Wright ◽  
Nicholas Harker
Keyword(s):  
High Energy ◽  
Real Space ◽  
European Synchrotron Radiation Facility ◽  
Small Sample ◽  
Distribution Functions ◽  
Total Scattering ◽  
Crystalline Materials ◽  
Space Resolution ◽  
Atomic Pair ◽  
Counting Statistics

ID11 is a multi-purpose high-energy beamline at the European Synchrotron Radiation Facility (ESRF). Owing to the high-energy X-ray source (up to 140 keV) and flexible, high-precision sample mounting which allows small sample–detector distances to be achieved, experiments such as total scattering in transmission geometry are possible. This permits the exploration of a wide Q range and so provides high real-space resolution. A range of samples (glasses and crystalline powders) have been measured at 78 keV, first putting the detector as close as possible to the sample (~10 cm), and then moving it vertically and laterally with respect to the beam in order to have circular and quarter circle sections of diffraction rings, with consequent QMAX at the edge of the detector of about 16 and 28 Å−1, respectively. Data were integrated using FIT2D, and then normalized and corrected with PDFgetX3. Results have been compared to see the effects of Q-range and counting statistics on the atomic pair distribution functions of the different samples. A Q of at least 20 Å−1 was essential to have sufficient real-space resolution for both type of samples while statistics appeared more important for glass samples rather than for crystalline samples.

scholarly journals Analytic slowing-down distributions as modified by turbulent transport

2018 ◽  
Vol 84 (6) ◽  
Author(s):  
G. J. Wilkie
Keyword(s):  
Particle Density ◽  
Plasma Heating ◽  
Turbulent Transport ◽  
A Priori ◽  
High Energy ◽  
Relative Strength ◽  
Distribution Functions ◽  
Toroidal Plasmas ◽  
Model Distribution ◽  
Phase Space Transport

The effect of electrostatic microturbulence on fast particles rapidly decreases at high energy, but can be significant at moderate energy. Previous studies found that, in addition to changes in the energetic particle density, this results in non-trivial changes to the equilibrium velocity distribution. These effects have implications for plasma heating and the stability of Alfvén eigenmodes, but make multiscale simulations much more difficult without further approximations. Here, several related analytic model distribution functions are derived from first principles. A single dimensionless parameter characterizes the relative strength of turbulence relative to collisions, and this parameter appears as an exponent in the model distribution functions. Even the most simple of these models reproduces key features of the numerical phase-space transport solution and provides a useful a priori heuristic for determining how strong the effect of turbulence is on the redistribution of energetic particles in toroidal plasmas.

Assessment of Power Consumption of an Electrodynamic Dust Shield to Clean Solar Panels

2016 ◽  
Author(s):  
Jennifer K. W. Chesnutt ◽  
Bing Guo ◽  
Chang-Yu Wu
Keyword(s):  
Power Consumption ◽  
Dielectric Material ◽  
Average Power ◽  
Experimental Studies ◽  
Particle Interactions ◽  
Solar Panels ◽  
Particle Collisions ◽  
Monodisperse Particles ◽  
Power Requirement ◽  
Transport Distance

Substantial time and money have been directed toward photovoltaic solar power. However, mitigation of dust on solar panels has been largely neglected. The objective of this research was to determine the performance and power consumption of an electrodynamic dust shield (EDS) to clean solar panels as a function of dust particle size. We utilized a discrete element method to computationally simulate the transport, collision, and electrodynamic interactions of particles subjected to electrodynamic waves generated by an EDS. The EDS consisted of electrodes embedded within a dielectric material. 1250 monodisperse particles with diameters of 30–50 μm were simulated. In the absence of particle-particle interactions, an increase in diameter increased particle transport distance due to increased particle charge. However, inclusion of particle-particle collisions produced interactions such that an intermediate diameter yielded the smallest transport distance. Average power required to lift a particle off the surface was smallest with the smallest particle; however, power requirement decreased with diameter with a constant loading of particles on the EDS. Calculated from our simulation data, power consumption per unit area of an experimental EDS agreed with previous experimental studies. Our study elucidated important aspects of EDS operation and power consumption to mitigate dust on solar panels.

scholarly journals Generation of shocked hot regions in black hole magnetosphere

2006 ◽  
Vol 2 (S238) ◽  
pp. 367-368
Author(s):  
Keigo Fukumura ◽  
Masaaki Takahashi ◽  
Sachiko Tsuruta
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Event Horizon ◽  
Accretion Disk ◽  
High Energy ◽  
Magnetized Plasma ◽  
Shock Formation ◽  
Poloidal Magnetic Field ◽  
High Energy Radiation ◽  
Plausible Mechanism

AbstractWe study magnetohydrodynamic (MHD) standing shocks in ingoing plasmas in a black hole (BH) magnetosphere. We find that low or mid latitude (non-equatorial) standing MHD shocks are both physically possible, creating very hot and/or magnetized plasma regions close to the event horizon. We also investigate the effects of the poloidal magnetic field and the BH spin on the properties of shocks and show that both effects can quantitatively affect the MHD shock solutions. MHD shock formation can be a plausible mechanism for creating high energy radiation region above an accretion disk in AGNs.

Sign in / Sign up

Export Citation Format

Share Document