Dynamical Structure of Radiation‐dominated Pulsar Accretion Shocks

1998 ◽  
Vol 498 (2) ◽  
pp. 790-801 ◽  
Author(s):  
Peter A. Becker
Keyword(s):  
Dynamical Structure ◽  
Accretion Shocks

Effect of changes in pair potential on the dynamical structure factor of molecular crystals

1980 ◽  
Vol 40 (6) ◽  
pp. 1517-1521 ◽  
Author(s):  
C.S. Murthy ◽  
K. Singer ◽  
M.L. Klein ◽  
I.R. McDonald
Keyword(s):  
Structure Factor ◽  
Molecular Crystals ◽  
Pair Potential ◽  
Dynamical Structure ◽  
Dynamical Structure Factor

scholarly journals The Dynamical Structure of a Warm Core Ring as Inferred from Glider Observations and Along-Track Altimetry

2021 ◽  
Vol 13 (13) ◽  
pp. 2456
Author(s):  
Thomas Meunier ◽  
Enric Pallás Sanz ◽  
Charly de Marez ◽  
Juan Pérez ◽  
Miguel Tenreiro ◽  
...  
Keyword(s):  
Rotation Axis ◽  
Relative Vorticity ◽  
Dynamical Structure ◽  
Loop Current ◽  
Energy Partition ◽  
Warm Core ◽  
Warm Core Ring ◽  
Current Ring ◽  
Along Track ◽  
Pv Gradient

This study investigates the vertical structure of the dynamical properties of a warm-core ring in the Gulf of Mexico (Loop Current ring) using glider observations. We introduce a new method to correct the glider’s along-track coordinate, which is, in general, biased by the unsteady relative movements of the glider and the eddy, yielding large errors on horizontal derivatives. Here, we take advantage of the synopticity of satellite along-track altimetry to apply corrections on the glider’s position by matching in situ steric height with satellite-measured sea surface height. This relocation method allows recovering the eddy’s azimuthal symmetry, precisely estimating the rotation axis position, and computing reliable horizontal derivatives. It is shown to be particularly appropriate to compute the eddy’s cyclo-geostrophic velocity, relative vorticity, and shear strain, which are otherwise out of reach when using the glider’s raw traveled distance as a horizontal coordinate. The Ertel potential vorticity (PV) structure of the warm core ring is studied in details, and we show that the PV anomaly is entirely controlled by vortex stretching. Sign reversal of the PV gradient across the water column suggests that the ring might be baroclinically unstable. The PV gradient is also largely controlled by gradients of the vortex stretching term. We also show that the ring’s total energy partition is strongly skewed, with available potential energy being 3 times larger than kinetic energy. The possible impact of this energy partition on the Loop Current rings longevity is also discussed.

scholarly journals Dynamical structure of highly eccentric discs with applications to tidal disruption events

2020 ◽  
Vol 500 (3) ◽  
pp. 4110-4125
Author(s):  
Elliot M Lynch ◽  
Gordon I Ogilvie
Keyword(s):  
Thermal Instability ◽  
Vertical Structure ◽  
Scale Height ◽  
Accretion Discs ◽  
Radiative Cooling ◽  
Dynamical Structure ◽  
Tidal Disruption ◽  
The Subject ◽  
Stable Solutions ◽  
Physical Quantities

ABSTRACT Whether tidal disruption events circularize or accrete directly as highly eccentric discs is the subject of current research and appears to depend sensitively on the disc thermodynamics. One aspect of this problem that has not received much attention is that a highly eccentric disc must have a strong, non-hydrostatic variation of the disc scale height around each orbit. As a complement to numerical simulations carried out by other groups, we investigate the dynamical structure of TDE discs using the non-linear theory of eccentric accretion discs. In particular, we study the variation of physical quantities around each elliptical orbit, taking into account the dynamical vertical structure, as well as viscous dissipation and radiative cooling. The solutions include a structure similar to the nozzle-like structure seen in simulations. We find evidence for the existence of the thermal instability in highly eccentric discs dominated by radiation pressure. For thermally stable solutions many of our models indicate a failure of the α-prescription for turbulent stresses. We discuss the consequences of our results for the structure of eccentric TDE discs.

scholarly journals Philosophical Aspects of Astrobiology Revisited

Philosophies ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 55
Author(s):  
Rainer E. Zimmermann
Keyword(s):  
Dynamical Systems ◽  
First Principles ◽  
Special Form ◽  
Mathematical Representation ◽  
Dynamical Structure ◽  
Twistor Theory ◽  
Fundamental Physics ◽  
Physical Universe ◽  
The World ◽  
Traditional Sense

Given the idea that Life as we know it is nothing but a special form of a generically underlying dynamical structure within the physical Universe, we try to introduce a concept of Life that is not only derived from first principles of fundamental physics, but also metaphysically based on philosophical assumptions about the foundations of the world. After clarifying the terminology somewhat, especially with a view to differentiating reality from modality, we give an example for a mathematical representation of what the substance of reality (in the traditional sense of metaphysics) could actually mean today, discussing twistor theory as an example. We then concentrate on the points of structural emergence by discussing the emergence of dynamical systems and of Life as we know it, respectively. Some further consequences as they relate to meaning are discussed in the end.

Dynamical structure and function of purple membrane as seen by neutrons

1995 ◽  
Vol 213-214 ◽  
pp. 775-779 ◽  
Author(s):  
J. Fitter ◽  
M. Adams ◽  
G. Coddens ◽  
G. Büldt ◽  
N.A. Dencher ◽  
...  
Keyword(s):  
Structure And Function ◽  
Purple Membrane ◽  
Dynamical Structure ◽  
And Function

scholarly journals Trains of African Easterly Waves and Their Relationship to Tropical Cyclone Genesis in the Eastern Atlantic

2017 ◽  
Vol 145 (2) ◽  
pp. 599-616 ◽  
Author(s):  
Abdou L. Dieng ◽  
Saidou M. Sall ◽  
Laurence Eymard ◽  
Marion Leduc-Leballeur ◽  
Alban Lazar
Keyword(s):  
West African ◽  
Dynamical Structure ◽  
African Easterly Waves ◽  
The South ◽  
The West ◽  
Easterly Waves ◽  
West African Coast ◽  
African Coast ◽  
Tropical Depressions ◽  
The Relationship

In this study, the relationship between trains of African easterly waves (AEWs) and downstream tropical cyclogenesis is studied. Based on 19 summer seasons (July–September from 1990 to 2008) of ERA-Interim reanalysis fields and brightness temperature from the Cloud User Archive, the signature of AEW troughs and embedded convection are tracked from the West African coast to the central Atlantic. The tracked systems are separated into four groups: (i) systems originating from the north zone of the midtropospheric African easterly jet (AEJ), (ii) those coming from the south part of AEJ, (iii) systems that are associated with a downstream trough located around 2000 km westward (termed DUO systems), and (iv) those that are not associated with such a close downstream trough (termed SOLO systems). By monitoring the embedded 700-hPa-filtered relative vorticity and 850-hPa wind convergence anomaly associated with these families along their trajectories, it is shown that the DUO generally have stronger dynamical structure and statistically have a longer lifetime than the SOLO ones. It is suggested that the differences between them may be due to the presence of the previous intense downstream trough in DUO cases, enhancing the low-level convergence behind them. Moreover, a study of the relationship between system trajectories and tropical depressions occurring between the West African coast and 40°W showed that 90% of tropical depressions are identifiable from the West African coast in tracked systems, mostly in the DUO cases originating from the south zone of the AEJ.

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