The Contribution of the Bulk Modes on Electrical Conductivity in 3D Topological Insulators

2015 ◽  
Author(s):  
Gulru Babac
Keyword(s):  
Electrical Conductivity ◽  
Magnetic Fields ◽  
Topological Insulators ◽  
Transport Coefficients ◽  
Main Difficulty ◽  
Size Dependent ◽  
Dependent Form ◽  
Hybridization Energy

Determination of transport coefficients in 3D topological insulators is one of the highlighted topics in the literature. The main difficulty of the calculation of transport coefficients comes from the contribution of bulk modes. In this work, electrical conductivity in 3D topologic insulators is considered under zero magnetic fields and it is written in a size dependent form. For this purpose, Weyl conjecture is used. The contribution of the bulk modes to electrical conductivity is analytically derived by depending on the material size, hybridization energy and degeneracy of the carriers.

Anomalous transport coefficients in a magnetized turbulent plasma

1982 ◽  
Vol 28 (2) ◽  
pp. 193-214 ◽  
Author(s):  
Qiu Xiaoming ◽  
R. Balescu
Keyword(s):  
Transport Coefficients ◽  
Collision Operator ◽  
Turbulent Plasma ◽  
Anomalous Transport ◽  
Weak Turbulence ◽  
Dissipative Effects ◽  
Dependent Transport ◽  
Two Fluid ◽  
Two Fluid Plasma

In this paper we generalize the formalism developed by Balescu and Paiva-Veretennicoff, valid for any kind of weak turbulence, for the determination of all the transport coefficients of an unmagnetized turbulent plasma, to the case of a magnetized one, and suggest a technique to avoid finding the inverse of the turbulent collision operator. The implicit plasmadynamical equations of a two-fluid plasma are presented by means of plasmadynamical variables. The anomalous transport coefficients appear in their natural places in these equations. It is shown that the necessary number of transport coefficients for describing macroscopically the magnetized turbulent plasma does not exceed the number for the unmagnetized one. The typical turbulent and gyromotion terms, representing dissipative effects peculiar to the magnetized system, which contribute to the frequency-dependent transport coefficients are clearly exhibited.

AMBIPOLAR DIFFUSION AND TURBULENT MAGNETIC FIELDS IN MOLECULAR CLOUDS

2011 ◽  
Vol 26 (04) ◽  
pp. 235-249 ◽  
Author(s):  
MARTIN HOUDE ◽  
TALAYEH HEZAREH ◽  
HUA-BAI LI ◽  
THOMAS G. PHILLIPS
Keyword(s):  
Magnetic Fields ◽  
Molecular Clouds ◽  
Ambipolar Diffusion ◽  
Star Forming ◽  
Star Forming Regions ◽  
Spin Interactions ◽  
Line Narrowing ◽  
Weakly Ionized ◽  
Novel Method

We review the introduction and development of a novel method for the characterization of magnetic fields in star-forming regions. The technique is based on the comparison of spectral line profiles from coexistent neutral and ion molecular species commonly detected in molecular clouds, sites of star formation. Unlike other methods used to study magnetic fields in the cold interstellar medium, this ion/neutral technique is not based on spin interactions with the field. Instead, it relies on and takes advantage of the strong cyclotron coupling between the ions and magnetic fields, thus exposing what is probably the clearest observational manifestation of magnetic fields in the cold, weakly ionized gas that characterizes the interior of molecular clouds. We will show how recent development and modeling of the ensuing ion line narrowing effect leads to a determination of the ambipolar diffusion scale involving the turbulent component of magnetic fields in star-forming regions, as well as the strength of the ordered component of the magnetic field.

scholarly journals Hydromagnetic dynamos in rotating spherical fluid shells in dependence on the Prandtl number, density stratification and electromagnetic boundary conditions

2014 ◽  
Vol 44 (4) ◽  
pp. 293-312 ◽  
Author(s):  
Tomáš Šoltis ◽  
Ján Šimkanin
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Magnetic Fields ◽  
Prandtl Number ◽  
Inner Core ◽  
Polar Regions ◽  
Number Density ◽  
Magnetic Diffusion ◽  
Spherical Fluid ◽  
The Magnetic Field

Abstract We present an investigation of dynamo in a simultaneous dependence on the non-uniform stratification, electrical conductivity of the inner core and the Prandtl number. Computations are performed using the MAG dynamo code. In all the investigated cases, the generated magnetic fields are dipolar. Our results show that the dynamos, especially magnetic field structures, are independent in our investigated cases on the electrical conductivity of the inner core. This is in agreement with results obtained in previous analyses. The influence of non-uniform stratification is for our parameters weak, which is understandable because most of the shell is unstably stratified, and the stably stratified region is only a thin layer near the CMB. The teleconvection is not observed in our study. However, the influence of the Prandtl number is strong. The generated magnetic fields do not become weak in the polar regions because the magnetic field inside the tangent cylinder is always regenerated due to the weak magnetic diffusion.

Determination of Insulating Properties of SO2 gas from BOLSIG+ Calculated Swarm Transport Coefficients

2021 ◽  
Author(s):  
Akhilesh Kumar Pandey ◽  
Pushpendra Singh ◽  
Mohd. Shahnawaz Khan ◽  
Jitendra Kumar Singh
Keyword(s):  
Transport Coefficients ◽  
Insulating Properties ◽  
So2 Gas
Sign in / Sign up

Export Citation Format

Share Document