scholarly journals Transport coefficients in Lorentz plasmas with the power-law kappa-distribution

2013 ◽  
Vol 20 (9) ◽  
pp. 092901 ◽  
Author(s):  
Du Jiulin
Keyword(s):  
Power Law ◽  
Transport Coefficients ◽  
Kappa Distribution

scholarly journals Landauer-Datta-Lundstrom Generalized Transport Model for Nanoelectronics

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Yuriy Kruglyak
Keyword(s):  
Electron Transport ◽  
Band Structure ◽  
Free Path ◽  
Power Law ◽  
Linear Response ◽  
Transport Model ◽  
Transport Coefficients ◽  
Mean Free Path ◽  
Linear Dispersion ◽  
Thermoelectric Transport

The Landauer-Datta-Lundstrom electron transport model is briefly summarized. If a band structure is given, the number of conduction modes can be evaluated and if a model for a mean-free-path for backscattering can be established, then the near-equilibrium thermoelectric transport coefficients can be calculated using the final expressions listed below for 1D, 2D, and 3D resistors in ballistic, quasiballistic, and diffusive linear response regimes when there are differences in both voltage and temperature across the device. The final expressions of thermoelectric transport coefficients through the Fermi-Dirac integrals are collected for 1D, 2D, and 3D semiconductors with parabolic band structure and for 2D graphene linear dispersion in ballistic and diffusive regimes with the power law scattering.

Debye length in a kappa-distribution plasma

1996 ◽  
Vol 56 (1) ◽  
pp. 87-93 ◽  
Author(s):  
D. A. Bryant
Keyword(s):  
Velocity Distribution ◽  
Power Law ◽  
Debye Length ◽  
Space Plasmas ◽  
Kappa Distribution ◽  
Number Density ◽  
Electrons And Ions ◽  
Modified Power Law

The Debye length, the characteristic shielding distance in a plasma, is, when the electrons and ions have Maxwellian velocity distributions, determined by the ratio of the temperatures of these components, to the electron (or ion) number density. Plasmas encountered in space, however, commonly exhibit non-Maxwellian velocity distributions, where the evaluation of an appropriate ‘temperature’ from an observed velocity distribution is no longer a recognized procedure. This paper evaluates the shielding distance for a plasma having a modified power-law, or kappa, family of distribuitons characteristic of some space plasmas.

VALUES OF THE TRANSPORT COEFFICIENTS IN A PLASMA FOR ANY DEGREE OF IONIZATION BASED ON A MAXWELLIAN DISTRIBUTION

1961 ◽  
Vol 39 (11) ◽  
pp. 1619-1703 ◽  
Author(s):  
I. P. Shkarofsky
Keyword(s):  
Power Law ◽  
Collision Frequency ◽  
Transport Coefficients ◽  
Temperature Gradients ◽  
Electron Collision ◽  
Density Gradients ◽  
Ionized Gas ◽  
Degree Of Ionization ◽  
Coulomb Collisions ◽  
Neutral Particles

Values are presented for the electronic conductivity for any degree of ionization, radio frequency, and d-c. magnetic field strength, and various electron speed power law variations of the electron collision frequency with neutral particles. Also, the other transport coefficients, such as electron current due to electron density gradients and temperature gradients, and energy flow due to an electric field and due to density gradients and temperature gradients, are tabulated.The analysis is based on substitution of the usual series expansion of Laguerre polynomials into the Fokker–Planck equation for Coulomb collisions and into the Boltzmann equation for electron collisions with neutral particles. For Coulomb effects, the expressions are the same as those derived by Landshoff. Collisions of electrons with neutral particles are included in addition to ions, and a-c. electric fields are treated as well as d-c. magnetic fields. In the limit of a completely ionized gas, the results also agree with those of Spitzer and Harm and of Kaufman. For a slightly ionized gas, the results are compared with Allis' treatment and with calculations using the Dingle integrals. It is found that the Laguerre convergence is inadequate for large angular frequencies when the power law is less than −2 and for small angular frequencies when the power law is greater than 1.The final results can be put in a form which yields two factors, multiplying, respectively, the average collision frequency and radian frequency, to give correct results from simple equations. These factors are usually of order one, and are functions of three parameters, proportional to angular frequency, ratio of electron–neutral to ion averaged collision frequency, and ion charge number.

scholarly journals Die hard holographic phenomenology of cuprates

2021 ◽  
Vol 61 (1) ◽  
Author(s):  
D.V. Khveshchenko
Keyword(s):  
Power Law ◽  
Transport Coefficients ◽  
Approximate Power

We discuss the attempts of fitting a number of the approximate power-law dependences observed in the cuprates into one consistent holographic or holographically inspired hydrodynamic framework. Contrary to the expectations, the goal of reproducing as many as possible of the established behaviours of the thermodynamic and transport coefficients appears to be achievable within the picture of a non-degenerate fermion fluid with quadratic dispersion. While not immediately elucidating the essential physics of the cuprates, this observation suggests a possible reason for which the previous attempts towards that goal have so far remained inconclusive.

Analysis of power law assumptions for short-period comets and Kuiper bodies

1999 ◽  
Vol 173 ◽  
pp. 289-293 ◽  
Author(s):  
J.R. Donnison ◽  
L.I. Pettit
Keyword(s):  
Power Law ◽  
Pareto Distribution ◽  
Limited Data ◽  
Short Period ◽  
Probability Plots ◽  
Exponential Probability

AbstractA Pareto distribution was used to model the magnitude data for short-period comets up to 1988. It was found using exponential probability plots that the brightness did not vary with period and that the cut-off point previously adopted can be supported statistically. Examination of the diameters of Trans-Neptunian bodies showed that a power law does not adequately fit the limited data available.

Hearing in Mice by GSR Audiometry: II. Magnitude of Unconditioned GSR as a Function of Intensity and Frequency Interactions

1968 ◽  
Vol 11 (1) ◽  
pp. 169-178 ◽  
Author(s):  
Alan Gill ◽  
Charles I. Berlin
Keyword(s):  
Power Law ◽  
Response Magnitude ◽  
Single Units ◽  
Spectral Content ◽  
Hearing Sensitivity ◽  
Subjective Magnitude ◽  
Orderly Fashion ◽  
Viiith Nerve

The unconditioned GSR’s elicited by tones of 60, 70, 80, and 90 dB SPL were largest in the mouse in the ranges around 10,000 Hz. The growth of response magnitude with intensity followed a power law (10 .17 to 10 .22 , depending upon frequency) and suggested that the unconditioned GSR magnitude assessed overall subjective magnitude of tones to the mouse in an orderly fashion. It is suggested that hearing sensitivity as assessed by these means may be closely related to the spectral content of the mouse’s vocalization as well as to the number of critically sensitive single units in the mouse’s VIIIth nerve.

How Useful is the Power Law of Practice for Recognizing Practice in Concentration Tests?

2007 ◽  
Vol 23 (3) ◽  
pp. 157-165 ◽  
Author(s):  
Carmen Hagemeister
Keyword(s):  
Logistic Regression ◽  
Reaction Time ◽  
Power Law ◽  
Error Rate ◽  
Reaction Times ◽  
Practice Effect ◽  
Practice Effects ◽  
Rate Decrease ◽  
Small Practice

Abstract. When concentration tests are completed repeatedly, reaction time and error rate decrease considerably, but the underlying ability does not improve. In order to overcome this validity problem this study aimed to test if the practice effect between tests and within tests can be useful in determining whether persons have already completed this test. The power law of practice postulates that practice effects are greater in unpracticed than in practiced persons. Two experiments were carried out in which the participants completed the same tests at the beginning and at the end of two test sessions set about 3 days apart. In both experiments, the logistic regression could indeed classify persons according to previous practice through the practice effect between the tests at the beginning and at the end of the session, and, less well but still significantly, through the practice effect within the first test of the session. Further analyses showed that the practice effects correlated more highly with the initial performance than was to be expected for mathematical reasons; typically persons with long reaction times have larger practice effects. Thus, small practice effects alone do not allow one to conclude that a person has worked on the test before.

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