scholarly journals Whistler instability threshold condition of energetic electrons by kappa distribution in space plasmas

2006 ◽  
Vol 111 (A8) ◽  
Author(s):  
Fuliang Xiao ◽  
Qinghua Zhou ◽  
Huinan Zheng ◽  
Shui Wang
Keyword(s):  
Instability Threshold ◽  
Space Plasmas ◽  
Threshold Condition ◽  
Kappa Distribution ◽  
Energetic Electrons

Proton Cyclotron Instability Threshold Condition of Suprathermal Protons by Kappa Distribution

2007 ◽  
Vol 9 (5) ◽  
pp. 545-549 ◽  
Author(s):  
Xiao Fuliang ◽  
Zhou Qinghua ◽  
He Huiyong ◽  
Tang Lijun ◽  
Fang Jiayuan
Keyword(s):  
Instability Threshold ◽  
Threshold Condition ◽  
Kappa Distribution ◽  
Cyclotron Instability ◽  
Proton Cyclotron

scholarly journals Derivation of the entropic formula for the statistical mechanics of space plasmas

2018 ◽  
Vol 25 (1) ◽  
pp. 77-88 ◽  
Author(s):  
George Livadiotis
Keyword(s):  
Statistical Mechanics ◽  
Canonical Ensemble ◽  
Space Plasmas ◽  
Kappa Distribution ◽  
Physical Origin ◽  
Nonextensive Statistical Mechanics

Abstract. Kappa distributions describe velocities and energies of plasma populations in space plasmas. The statistical origin of these distributions is associated with the framework of nonextensive statistical mechanics. Indeed, the kappa distribution is derived by maximizing the q entropy of Tsallis, under the constraints of the canonical ensemble. However, the question remains as to what the physical origin of this entropic formulation is. This paper shows that the q entropy can be derived by adapting the additivity of energy and entropy.

A dielectric tensor for a uniform magnetoplasma with a generalized Lorentzian distribution

1996 ◽  
Vol 55 (3) ◽  
pp. 415-429 ◽  
Author(s):  
R. L. Mace
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Magnetized Plasma ◽  
Space Plasmas ◽  
Dielectric Tensor ◽  
Kappa Distribution ◽  
Numerical Studies ◽  
Starting Point ◽  
Limiting Case ◽  
The Magnetic Field

It is demonstrated that the dielectric tensor for a non-relativistic magnetized plasma whose particle velocity distributions can be modelled by isotropic kappa, or generalized Lorentzian, distributions admits an expression similar to that obtained by Trubnikov for a relativistic plasma. The kappa distribution is a useful distribution for modelling space plasmas containing significant numbers of superthermal particles, i.e. those that have energies in excess of the thermal energy. The dielectric tensor is valid for arbitrary wavevectors, and is shown to reproduce the known limiting case of wave propagation parallel to the magnetic field. Even in this limiting case, the results obtained represent a generalization of previous results to arbitrary real values of the index K, the parameter that shapes the superthermal tail on the distribution. The expression for the dielectric tensor might be useful as a starting point for numerical studies of waves and instabilities in plasmas containing superthermal particles.

scholarly journals Derivation of the entropic formula for the statistical mechanics of space plasmas

2017 ◽  
Author(s):  
George Livadiotis
Keyword(s):  
Statistical Mechanics ◽  
Canonical Ensemble ◽  
Space Plasmas ◽  
Kappa Distribution ◽  
Physical Origin

Abstract. Kappa distributions describe velocities and energies of plasma populations in space plasmas. The statistical origin of these distributions is the non-extensive statistical mechanics. Indeed, the kappa distribution is derived by maximizing the q-entropy of Tsallis under the constraints of canonical ensemble. However, there remains the question what is the physical origin of this entropic formulation. This paper shows that the q-entropy can be derived by adapting the additivity of energy and entropy.

Skew-Kappa distribution functions & whistler-heat flux instability in the solar wind

2021 ◽  
Author(s):  
Bea Zenteno-Quinteros ◽  
Adolfo F. Viñas ◽  
Pablo S. Moya
Keyword(s):  
Heat Flux ◽  
Solar Wind ◽  
Electron Velocity ◽  
Marginal Stability ◽  
Threshold Condition ◽  
Kappa Distribution ◽  
Particle Interactions ◽  
Whistler Mode ◽  
Electron Heat ◽  
Wave Particle Interactions

<p>Electron velocity distributions in the solar wind are known to have field-aligned skewness, which has been observationally characterized by the presence of secondary populations such as the halo and strahl electron components. This non-thermal feature provides energy for the excitation of electromagnetic instabilities that may play a role in regulating the electron heat flux in the solar wind by wave-particle interactions. Among the wave modes excited in regulating the electron non-thermal features is the whistler-mode and its so-called whistler heat-flux instability (WHFI). In this work, we use kinetic linear theory to analyze the stability of the WHFI in a solar wind like plasma where the electrons are described as a single population modeled by a Kappa distribution to which an asymmetry term has been added. We solve the dispersion relation numerically for the parallel propagating whistler-mode and study its linear stability for different plasma parameters. We also show the marginal stability thresholds for this instability as a function of the electron beta and the parallel electron heat flux and present a threshold condition for instability that can be modeled to compare with observational data. The principal result is that the WHFI can develop in this system; however, the heat flux parameter is not a good predictor of how unstable this wave mode will be. This is because different plasma states, with different stability to WHFI, can have the same initial heat flux. Thus, systems with high <img title="This is the rendered form of the equation. You can not edit this directly. Right click will give you the option to save the image, and in most browsers you can drag the image onto your desktop or another program." src="https://latex.codecogs.com/gif.latex?q_%7B%5Cparallel%20e%7D/q_0"> can be stable enough to WHFI so that it cannot effectively modify the heat flux values through wave-particle interactions</p>

scholarly journals A universal mirror wave-mode threshold condition for non-thermal space plasma environments

2002 ◽  
Vol 9 (2) ◽  
pp. 75-78 ◽  
Author(s):  
M. P. Leubner ◽  
N. Schupfer
Keyword(s):  
Wave Mode ◽  
Instability Threshold ◽  
Velocity Space ◽  
Space Distribution ◽  
Instability Criterion ◽  
Threshold Condition ◽  
Magnetic Fluctuations ◽  
Plasma Parameters ◽  
Energy Principle ◽  
Loss Cone

Abstract. Magnetic fluctuations are recognized in a large variety of space plasmas by increasingly high resolution, in situ observations as mirror wave mode structures. A typical requirement for the excitation of mirror modes is a dominant perpendicular pressure in a high-beta plasma environment. Contrary, we demonstrate from a realistic kinetic analysis how details of the velocity space distributions are of considerable significance for the instability threshold. Introducing the most common characteristics of observed ion and electron distributions by a mixed suprathermal-loss-cone, we derive a universal mirror instability criterion from an energy principle for collisionless plasmas. As a result, the transition from two temperature Maxwellians to realistic non-thermal features provides a strong source for the generation of mirror wave mode activity, reducing drastically the instability threshold. In particular, a number of space-related examples illuminate how the specific structure of the velocity space distribution dominates as a regulating excitation mechanism over the effects related to changes in the plasma parameters.

Marginal instability threshold condition of the aperiodic ordinary mode in equal-mass plasmas

2014 ◽  
Vol 21 (10) ◽  
pp. 104504 ◽  
Author(s):  
S. Vafin ◽  
R. Schlickeiser ◽  
P. H. Yoon
Keyword(s):  
Equal Mass ◽  
Instability Threshold ◽  
Threshold Condition ◽  
Ordinary Mode
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