Use of TVD-schemes to simulate gasdynamic flows with spherical and cylindrical symmetry

1993 ◽  
Vol 65 (3) ◽  
pp. 861-866 ◽  
Author(s):  
I. M. Kozlov ◽  
G. S. Romanov ◽  
A. E. Suvorov
Keyword(s):  
Cylindrical Symmetry ◽  
Tvd Schemes ◽  
Spherical And Cylindrical Symmetry

scholarly journals 3D MHD simulations and synthetic radio emission from an oblique rotating magnetic massive star

2019 ◽  
Vol 489 (3) ◽  
pp. 3251-3268
Author(s):  
S Daley-Yates ◽  
I R Stevens ◽  
A ud-Doula
Keyword(s):  
Mass Loss ◽  
Massive Star ◽  
Thermal Emission ◽  
Mass Loss Rate ◽  
Cylindrical Symmetry ◽  
Phase Dependence ◽  
Spectral Flux ◽  
Oblique Rotator ◽  
Spherical And Cylindrical Symmetry

ABSTRACT We have performed 3D isothermal MHD simulation of a magnetic rotating massive star with a non-zero dipole obliquity and predicted the radio/sub-mm observable light curves and continuum spectra for a frequency range compatible with ALMA. From these results we also compare the model input mass-loss to that calculated from the synthetic thermal emission. Spherical and cylindrical symmetry is broken due to the obliquity of the stellar magnetic dipole resulting in an inclination and phase dependence of both the spectral flux and inferred mass-loss rate, providing testable predictions of variability for oblique rotator. Both quantities vary by factors between 2 and 3 over a full rotational period of the star, demonstrating that the role of rotation as critical in understanding the emission. This illustrates the divergence from a symmetric wind, resulting in a two-armed spiral structure indicative of an oblique magnetic rotator. We show that a constant spectral index, α, model agrees well with our numerical prediction for a spherical wind for ν < 103 GHz; however it is unable to capture the behaviour of emission at ν > 103 GHz. As such we caution the use of such constant α models for predicting emission from non-spherical winds such as those which form around magnetic massive stars.

scholarly journals Green's functions for polarized radiative transfer equation in different geometries

2011 ◽  
Vol 7 (S283) ◽  
pp. 358-359
Author(s):  
Juris Freimanis
Keyword(s):  
Radiative Transfer ◽  
Transfer Equation ◽  
Green's Functions ◽  
Radiative Transfer Equation ◽  
Green’S Functions ◽  
Analytic Solutions ◽  
Cylindrical Symmetry ◽  
Exact Analytic Solutions ◽  
Spherical And Cylindrical Symmetry ◽  
Stationary Vector

AbstractA review of some earlier exact analytic solutions of monochromatic stationary vector radiative transfer equation in homogeneous infinite medium is given. It is stressed that Green's functions for plane-parallel, spherical and cylindrical symmetry are expressed through derivatives and integrals from basically one and the same set of functions.

MAGNETIZATION REVERSAL BY NUCLEATION

1991 ◽  
Vol 05 (16) ◽  
pp. 1061-1064 ◽  
Author(s):  
W. BALTENSPERGER ◽  
J. S. BROZ ◽  
J. S. HELMAN
Keyword(s):  
Phenomenological Models ◽  
Magnetization Reversal ◽  
Cylindrical Symmetry ◽  
Critical Fields ◽  
Static Solutions ◽  
Spherical And Cylindrical Symmetry

The exact static solutions of the Landau-Lifshitz equations for the magnetization, which have been identified as describing nucleation centers for the magnetization reversal in ferromagnets, are compared with those of phenomenological models of spherical and cylindrical symmetry. It is found that the latter have higher critical fields.

Ray Paths in Media with Spherical and Cylindrical Symmetry

2002 ◽  
pp. 55-76
Author(s):  
Vasudevan Lakshminarayanan ◽  
Ajoy K. Ghatak ◽  
K. Thyagarajan
Keyword(s):  
Cylindrical Symmetry ◽  
Spherical And Cylindrical Symmetry ◽  
Ray Paths

scholarly journals Mass of dusty clumps with temperature and density structure

2019 ◽  
Vol 631 ◽  
pp. A65 ◽  
Author(s):  
R. Cesaroni
Keyword(s):  
Flux Density ◽  
Cylindrical Symmetry ◽  
Numerical Code ◽  
Effect Of Temperature ◽  
Density Gradients ◽  
Density Structure ◽  
The Stability ◽  
Spherical And Cylindrical Symmetry ◽  
Account Temperature ◽  
Approximate Expressions

We consider a dusty clump in two cases of spherical and cylindrical symmetry to investigate the effect of temperature and density gradients on the observed flux density. Conversely, we evaluate how the presence of these gradients affects the calculation of the clump mass from the observed flux. We provide approximate expressions relating flux density and mass in the optically thick and thin limits and in the Rayleigh-Jeans regime, and we discuss the reliability of these expressions by comparing them to the outcome of a numerical code. Finally, we present the application of our calculations to three examples taken from the literature, which shows how the correction introduced after taking into account temperature and density gradients may affect our conclusions on the stability of the clumps.

scholarly journals SOLITONS OF SCALAR FIELD WITH INDUCED NONLINEARITY AND THEIR STABILITY

2000 ◽  
Vol 15 (10) ◽  
pp. 1481-1496 ◽  
Author(s):  
BIJAN SAHA
Keyword(s):  
Electromagnetic Field ◽  
Gravitational Field ◽  
Finite Interval ◽  
Cylindrical Symmetry ◽  
Regular Solutions ◽  
Field System ◽  
Interaction Terms ◽  
Cylindrically Symmetric ◽  
Stable Solutions ◽  
Spherical And Cylindrical Symmetry

Exact particle-like static, spherically and/or cylindrically symmetric solutions to the equations of interacting scalar and electromagnetic field system have been obtained. We considered FRW and Gödel universes as external gravitational field with spherical and cylindrical symmetry respectively. Beside the usual solitons some special regular solutions know as droplets, antidroplets and hats (confined in finite interval and having trivial value beyond it) have been obtained. It has been shown that in FRW space–time equations with different interaction terms may have stable solutions while within the scope of Gödel model only the droplet-like and the hat-like configurations may be stable, providing they are located in the region where g00>0.

Probe size and 5th-order aberration

1987 ◽  
Vol 45 ◽  
pp. 134-135 ◽  
Author(s):  
Zhifeng Shao
Keyword(s):  
Electron Probe ◽  
Spherical Aberration ◽  
Wave Length ◽  
Cylindrical Symmetry ◽  
Electron Wave ◽  
Third Order ◽  
The Third ◽  
Probe Radius ◽  
Small Probe ◽  
Probe Size

A small electron probe has many applications in many fields and in the case of the STEM, the probe size essentially determines the ultimate resolution. However, there are many difficulties in obtaining a very small probe.Spherical aberration is one of them and all existing probe forming systems have non-zero spherical aberration. The ultimate probe radius is given byδ = 0.43Csl/4ƛ3/4where ƛ is the electron wave length and it is apparent that δ decreases only slowly with decreasing Cs. Scherzer pointed out that the third order aberration coefficient always has the same sign regardless of the field distribution, provided only that the fields have cylindrical symmetry, are independent of time and no space charge is present. To overcome this problem, he proposed a corrector consisting of octupoles and quadrupoles.

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