Heating and acceleration of ions with Kappa distribution functions by low‐frequency Alfvén wave

2021 ◽  
Author(s):  
Kehua Li ◽  
Jingchun Li ◽  
Xingqiang Lu ◽  
Shijia Chen
Keyword(s):  
Low Frequency ◽  
Distribution Functions ◽  
Alfven Wave ◽  
Kappa Distribution

scholarly journals Statistical Uncertainties of Space Plasma Properties Described by Kappa Distributions

Entropy ◽  
2020 ◽  
Vol 22 (5) ◽  
pp. 541
Author(s):  
Georgios Nicolaou ◽  
George Livadiotis
Keyword(s):  
Accurate Determination ◽  
Space Plasma ◽  
High Energy ◽  
Distribution Functions ◽  
Kappa Distribution ◽  
Plasma Properties ◽  
Electrostatic Analyzer ◽  
Bulk Parameters ◽  
Plasma Bulk

The velocities of space plasma particles often follow kappa distribution functions, which have characteristic high energy tails. The tails of these distributions are associated with low particle flux and, therefore, it is challenging to precisely resolve them in plasma measurements. On the other hand, the accurate determination of kappa distribution functions within a broad range of energies is crucial for the understanding of physical mechanisms. Standard analyses of the plasma observations determine the plasma bulk parameters from the statistical moments of the underlined distribution. It is important, however, to also quantify the uncertainties of the derived plasma bulk parameters, which determine the confidence level of scientific conclusions. We investigate the determination of the plasma bulk parameters from observations by an ideal electrostatic analyzer. We derive simple formulas to estimate the statistical uncertainties of the calculated bulk parameters. We then use the forward modelling method to simulate plasma observations by a typical top-hat electrostatic analyzer. We analyze the simulated observations in order to derive the plasma bulk parameters and their uncertainties. Our simulations validate our simplified formulas. We further examine the statistical errors of the plasma bulk parameters for several shapes of the plasma velocity distribution function.

scholarly journals On the Determination of Kappa Distribution Functions from Space Plasma Observations

Entropy ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 212 ◽  
Author(s):  
Georgios Nicolaou ◽  
George Livadiotis ◽  
Robert T. Wicks
Keyword(s):  
Distribution Function ◽  
Velocity Distribution ◽  
Space Plasma ◽  
Distribution Functions ◽  
Specific Method ◽  
Kappa Distribution ◽  
Kappa Index ◽  
Velocity Distribution Functions ◽  
Bulk Parameters ◽  
Plasma Bulk

The velocities of space plasma particles, often follow kappa distribution functions. The kappa index, which labels and governs these distributions, is an important parameter in understanding the plasma dynamics. Space science missions often carry plasma instruments on board which observe the plasma particles and construct their velocity distribution functions. A proper analysis of the velocity distribution functions derives the plasma bulk parameters, such as the plasma density, speed, temperature, and kappa index. Commonly, the plasma bulk density, velocity, and temperature are determined from the velocity moments of the observed distribution function. Interestingly, recent studies demonstrated the calculation of the kappa index from the speed (kinetic energy) moments of the distribution function. Such a novel calculation could be very useful in future analyses and applications. This study examines the accuracy of the specific method using synthetic plasma proton observations by a typical electrostatic analyzer. We analyze the modeled observations in order to derive the plasma bulk parameters, which we compare with the parameters we used to model the observations in the first place. Through this comparison, we quantify the systematic and statistical errors in the derived moments, and we discuss their possible sources.

scholarly journals Nonlinear evolution of the parametric instability: numerical predictions versus observations in the heliosphere

2001 ◽  
Vol 8 (3) ◽  
pp. 159-166 ◽  
Author(s):  
F. Malara ◽  
L. Primavera ◽  
P. Veltri
Keyword(s):  
Large Scale ◽  
Parametric Instability ◽  
Low Frequency ◽  
Heliospheric Current Sheet ◽  
Mhd Equations ◽  
Alfven Wave ◽  
The Sun ◽  
High Latitudes ◽  
Initial Correlation ◽  
Numerical Predictions

Abstract. Low-frequency turbulence in the solar wind is characterized by a high degree of Alfvénicity close to the Sun. Cross-helicity, which is a measure of Alfvénic correlation, tends to decrease with increasing distance from the Sun at high latitudes as well as in slow-speed streams at low latitudes. In the latter case, large scale inhomogeneities (velocity shears, the heliospheric current sheet) are present, which are sources of decorrelation; yet at high latitudes, the wind is much more homogeneous, and a possible evolution mechanism is represented by the parametric instability. The parametric decay of an circularly polarized broadband Alfvén wave is then investigated, as a source of decorrelation. The time evolution is followed by numerically integrating the full set of nonlinear MHD equations, up to instability saturation. We find that, for <beta>  ~ 1, the final cross-helicity is ~ 0.5, corresponding to a partial depletion of the initial correlation. Compressive fluctuations at a moderate level are also present. Most of the spectrum is dominated by forward propagating Alfvénic fluctuations, while backscattered fluctuations dominate large scales. With increasing time, the spectra of Elsässer variables tend to approach each other. Some results concerning quantities measured in the high-latitude wind are reviewed, and a qualitative agreement with the results of the numerical model is found.

scholarly journals Reduced models accounting for parallel magnetic perturbations: gyrofluid and finite Larmor radius–Landau fluid approaches

2016 ◽  
Vol 82 (6) ◽  
Author(s):  
E. Tassi ◽  
P. L. Sulem ◽  
T. Passot
Keyword(s):  
Fluid Model ◽  
Collisionless Plasma ◽  
Low Frequency ◽  
Wave Model ◽  
Plasma Phys ◽  
Alfven Wave ◽  
Larmor Radius ◽  
Closure Relation ◽  
Reduced Models ◽  
Finite Larmor Radius

Reduced models are derived for a strongly magnetized collisionless plasma at scales which are large relative to the electron thermal gyroradius and in two asymptotic regimes. One corresponds to cold ions and the other to far sub-ion scales. By including the electron pressure dynamics, these models improve the Hall reduced magnetohydrodynamics (MHD) and the kinetic Alfvén wave model of Boldyrev et al. (2013 Astrophys. J., vol. 777, 2013, p. 41), respectively. We show that the two models can be obtained either within the gyrofluid formalism of Brizard (Phys. Fluids, vol. 4, 1992, pp. 1213–1228) or as suitable weakly nonlinear limits of the finite Larmor radius (FLR)–Landau fluid model of Sulem and Passot (J. Plasma Phys., vol 81, 2015, 325810103) which extends anisotropic Hall MHD by retaining low-frequency kinetic effects. It is noticeable that, at the far sub-ion scales, the simplifications originating from the gyroaveraging operators in the gyrofluid formalism and leading to subdominant ion velocity and temperature fluctuations, correspond, at the level of the FLR–Landau fluid, to cancellation between hydrodynamic contributions and ion finite Larmor radius corrections. Energy conservation properties of the models are discussed and an explicit example of a closure relation leading to a model with a Hamiltonian structure is provided.

scholarly journals On the coupling between unstable magnetospheric particle populations and resonant high <i>m</i> ULF wave signatures in the ionosphere

2005 ◽  
Vol 23 (2) ◽  
pp. 567-577 ◽  
Author(s):  
L. J. Baddeley ◽  
T. K. Yeoman ◽  
D. M. Wright ◽  
K. J. Trattner ◽  
B. J. Kellet
Keyword(s):  
Wave Energy ◽  
Low Frequency ◽  
Distribution Functions ◽  
Wave Number ◽  
Particle Interactions ◽  
Ion Distribution ◽  
M Wave ◽  
Ulf Wave ◽  
Energy Dissipated ◽  
Giant Pulsations

Abstract. Many theories state that Ultra Low Frequency (ULF) waves with a high azimuthal wave number (m) have their energy source in wave-particle interactions, yet this assumption has been rarely tested numerically and thus many questions still remain as to the waves' exact generation mechanism. For the first time, this paper investigates the cause and effect relationship between the driving magnetospheric particle populations and the ULF wave signatures as observed in the conjugate ionosphere by quantitatively examining the energy exchange that occurs. Firstly, a Monte Carlo method is used to demonstrate statistically that the particle populations observed during conjugate ionospheric high m wave events have more free energy available than populations extracted at random. Secondly, this paper quantifies the energy transferred on a case study basis, for two classes of high m waves, by examining magnetospheric Ion Distribution Functions, (IDFs) and directly comparing these with the calculated wave energy dissipated into the conjugate ionosphere. Estimates of the wave energy at the source and the sink are in excellent agreement, with both being of the order of 1010J for a typical high m wave. Ten times more energy (1011J) is transferred from the magnetospheric particle population and dissipated in the ionosphere when considering a subset of high m waves known as giant pulsations (Pgs). Previous work has demonstrated that 1010J is frequently available from non - Maxwellian IDFs at L=6, whereas 1011J is not. The combination of these studies thus provides an explanation for both the rarity of Pgs and the ubiquity of other high m waves in this region.

Determination of wave growth from measured distribution functions and transport theory

1980 ◽  
Vol 23 (1) ◽  
pp. 91-113 ◽  
Author(s):  
C. T. Dum ◽  
E. Marsch ◽  
W. Pilipp
Keyword(s):  
Acoustic Waves ◽  
Transport Theory ◽  
Low Frequency ◽  
Distribution Functions ◽  
Ion Acoustic Waves ◽  
Wave Growth ◽  
Ion Cyclotron Waves ◽  
Precise Shape ◽  
The Magnetic Field

A stability analysis which directly uses particle distribution functions determined from experiments or transport theory, rather than model distributions, is carried out. The features of distribution functions relevant to whistlers, ion cyclotron waves, including their low-frequency extensions for propagation along the magnetic field, and to ion-acoustic waves are analyzed in detail. The dependence of wave growth on the precise shape of the distributions and the numerical feasibility of the method is demonstrated by the use of measured solar wind distributions.

Alfvén Wave Heating Experiment of Field-Reversed Configuration Plasma in the Fix Device Using Low Frequency Magnetic Pulse

2001 ◽  
Vol 39 (1T) ◽  
pp. 370-383
Author(s):  
Koji Yamanaka ◽  
Satoru Yoshimura ◽  
Shinichi Yamamoto ◽  
Shigefumi Okada ◽  
Seiichi Goto
Keyword(s):  
Low Frequency ◽  
Alfven Wave ◽  
Magnetic Pulse ◽  
Field Reversed Configuration ◽  
Wave Heating

Clarity Index Analysis and Modeling Using Probability Distribution Functions in Campo Grande-MS, Brazil

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Amaury de Souza ◽  
Razika Ihaddadene ◽  
Nabila Ihaddadene ◽  
Pelumi E. Oguntunde
Keyword(s):  
Low Frequency ◽  
Distribution Functions ◽  
Data Sets ◽  
Atmospheric Conditions ◽  
Mato Grosso ◽  
Clear Sky ◽  
Probability Distribution Functions ◽  
Index Analysis ◽  
Sky Conditions ◽  
Mato Grosso Do Sul

The importance of statistical analysis in the field of energy for environmental engineering is shown in this research paper, in which the adequacy of the data sets of clarity index with the model of “best” probability (based on the criteria used) was studied. In Campo Grande which is the capital of the Brazilian state of Mato Grosso do Sul, located in the Center-West region of the country, there is a predominance of the atmospheric conditions of low cloudiness, with a high frequency of days with a clear sky and in consequence a low-frequency of days with cloudy sky. The aerosols resulting from the burning of sugarcane influence the sky conditions in Campo Grande thus reducing the frequency of the clear sky.

Shear Alfvén Wave with Quantum Exchange-Correlation Effects in Plasmas

2017 ◽  
Vol 72 (10) ◽  
pp. 891-898 ◽  
Author(s):  
Zahid Mir ◽  
M. Jamil ◽  
A. Rasheed ◽  
M. Asif
Keyword(s):  
Low Frequency ◽  
Phase Speed ◽  
Alfven Wave ◽  
Exchange Potential ◽  
Correlation Effects ◽  
Long Wavelength ◽  
Exchange Correlation ◽  
Exchange Correlation Potential ◽  
Dust Charge ◽  
Correlation Potential

AbstractThe dust shear Alfvén wave is studied in three species dusty quantum plasmas. The quantum effects are incorporated through the Fermi degenerate pressure, tunneling potential, and in particular the exchange-correlation potential. The significance of exchange-correlation potential is pointed out by a graphical description of the dispersion relation, which shows that the exchange potential magnifies the phase speed. The low-frequency shear Alfvén wave is studied while considering many variables. The shear Alfvén wave gains higher phase speed at the range of small angles for the upper end of the wave vector spectrum. The increasing dust charge and the external magnetic field reflect the increasing tendency of phase speed. This study may explain many natural mechanisms associated with long wavelength radiations given in the summary.

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