scholarly journals Nonlinear evolution ofr-modes: The role of differential rotation

2005 ◽  
Vol 71 (4) ◽  
Author(s):  
Paulo M. Sá ◽  
Brigitte Tomé
Keyword(s):  
Differential Rotation ◽  
Nonlinear Evolution

scholarly journals Instabilities of Uniformly Rotating Disks

1996 ◽  
Vol 169 ◽  
pp. 349-350 ◽  
Author(s):  
P. Vauterin ◽  
H. Dejonghe
Keyword(s):  
Distribution Function ◽  
Differential Rotation ◽  
Mass Concentration ◽  
Expansion Method ◽  
Rotating Disks ◽  
Central Mass ◽  
Reasonable Approximation ◽  
Central Regions ◽  
Series Expansion Method

We explore a series expansion method to calculate the instabilities and the structure of the perturbations for a variety of uniformly rotating finite stellar disks. This survey focuses on the role of the distribution function in stability analyses. Although the potential does not show differential rotation, it will in many cases be a reasonable approximation for the disk in the central regions of galaxies without massive central mass concentration.

scholarly journals The role of rotation in Luminous Blue Variables

1989 ◽  
Vol 113 ◽  
pp. 205-210
Author(s):  
S.R. Sreenivasan ◽  
W.J.F. Wilson
Keyword(s):  
Significant Role ◽  
Differential Rotation ◽  
Luminous Blue Variables

AbstractWe demonstrate that differential rotation plays a significant role in the essential features of LBV’s, among other types of objects.

scholarly journals Relativistic filamentary equilibria

2010 ◽  
Vol 77 (2) ◽  
pp. 193-205 ◽  
Author(s):  
M. GEDALIN ◽  
A. SPITKOVSKY ◽  
M. MEDVEDEV ◽  
M. BALIKHIN ◽  
V. KRASNOSELSKIKH ◽  
...  
Keyword(s):  
Current Sheet ◽  
Inertial Confinement Fusion ◽  
Nonlinear Evolution ◽  
Analytical Description ◽  
Inertial Confinement ◽  
Collisionless Shocks ◽  
Confinement Fusion ◽  
Linear And Nonlinear ◽  
Periodic Current

AbstractPlasma filamentation is often encountered in collisionless shocks and inertial confinement fusion. We develop a general analytical description of the two-dimensional relativistic filamentary equilibrium and derive the conditions for existence of potential-free equilibria. A pseudopotential equation for the vector-potential is constructed for cold and relativistic Maxwellian distributions. The role of counter-streaming is explained. We present single current sheet and periodic current sheet solutions, and analyze the equilibria with electric potential. These solutions can be used to study linear and nonlinear evolution of the relativistic filamentation instability.

The role of proton injection processes in the nonlinear evolution of “pearls”

1979 ◽  
Vol 27 (2) ◽  
pp. 165-168
Author(s):  
Yu.G. Khabazin ◽  
O.A. Pokhotelov ◽  
A.V. Porotov
Keyword(s):  
Nonlinear Evolution

The role of magnetic reconnection and differential rotation in spheromak formation

1985 ◽  
Vol 28 (10) ◽  
pp. 3154 ◽  
Author(s):  
P. N. Guzdar ◽  
John M. Finn ◽  
K. W. Whang ◽  
A. Bondeson
Keyword(s):  
Magnetic Reconnection ◽  
Differential Rotation ◽  
Spheromak Formation

scholarly journals Hurricane Eyewall Evolution in a Forced Shallow-Water Model

2014 ◽  
Vol 71 (5) ◽  
pp. 1623-1643 ◽  
Author(s):  
Eric A. Hendricks ◽  
Wayne H. Schubert ◽  
Yu-Han Chen ◽  
Hung-Chi Kuo ◽  
Melinda S. Peng
Keyword(s):  
Shallow Water ◽  
Diabatic Heating ◽  
Nonlinear Evolution ◽  
Unstable Mode ◽  
Relative Vorticity ◽  
Stable Region ◽  
Water Model ◽  
Barotropic Instability ◽  
Shallow Water Model

Abstract A forced shallow-water model is used to understand the role of diabatic and frictional effects in the generation, maintenance, and breakdown of the hurricane eyewall potential vorticity (PV) ring. Diabatic heating is parameterized as an annular mass sink of variable width and magnitude, and the nonlinear evolution of tropical storm–like vortices is examined under this forcing. Diabatic heating produces a strengthening and thinning PV ring in time due to the combined effects of the mass sink and radial PV advection by the induced divergent circulation. If the forcing makes the ring thin enough, then it can become dynamically unstable and break down into polygonal asymmetries or mesovortices. The onset of barotropic instability is marked by simultaneous drops in both the maximum instantaneous velocity and minimum pressure, consistent with unforced studies. However, in a sensitivity test where the heating is proportional to the relative vorticity, universal intensification occurs during barotropic instability, consistent with a recent observational study. Friction is shown to help stabilize the PV ring by reducing the eyewall PV and the unstable-mode barotropic growth rate. The radial location and structure of the heating is shown to be of critical importance for intensity variability. While it is well known that it is critical to heat in the inertially stable region inside the radius of maximum winds to spin up the hurricane vortex, these results demonstrate the additional importance of having the net heating as close as possible to the center of the storm, partially explaining why tropical cyclones with very small eyes can rapidly intensify to high peak intensities.

scholarly journals The Suppression and Promotion of Magnetic Flux Emergence in Fully Convective Stars

2016 ◽  
Vol 12 (S328) ◽  
pp. 85-92
Author(s):  
Maria A. Weber ◽  
Matthew K. Browning ◽  
Suzannah Boardman ◽  
Joshua Clarke ◽  
Samuel Pugsley ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Differential Rotation ◽  
Flux Emergence ◽  
Surface Magnetism ◽  
Flux Tubes ◽  
Cool Stars ◽  
M Dwarf ◽  
Insight Into ◽  
Individual Flux

AbstractEvidence of surface magnetism is now observed on an increasing number of cool stars. The detailed manner by which dynamo-generated magnetic fields giving rise to starspots traverse the convection zone still remains unclear. Some insight into this flux emergence mechanism has been gained by assuming bundles of magnetic field can be represented by idealized thin flux tubes (TFTs). Weber & Browning (2016) have recently investigated how individual flux tubes might evolve in a 0.3M⊙ M dwarf by effectively embedding TFTs in time-dependent flows representative of a fully convective star. We expand upon this work by initiating flux tubes at various depths in the upper ~50-75% of the star in order to sample the differing convective flow pattern and differential rotation across this region. Specifically, we comment on the role of differential rotation and time-varying flows in both the suppression and promotion of the magnetic flux emergence process.

scholarly journals Progression of Aortic Dissection: An Application of Soliton Solutions of Nonlinear Evolution Equation in (3+1)-Dimensions

2021 ◽  
Author(s):  
VISHAKHA JADAUN ◽  
Nitin Singh
Keyword(s):  
Differential Equation ◽  
Aortic Dissection ◽  
Evolution Equation ◽  
Nonlinear Evolution Equation ◽  
Nonlinear Evolution ◽  
Early Stage ◽  
Nonlinear Partial Differential Equation ◽  
Aortic Tissue ◽  
The Impact

Abstract Aortic dissection is a serious pathology involving the vessel wall of the aorta with significant societal impact. To understand aortic dissection we explain the role of the dynamic pathology in the absence or presence of structural and/or functional abnormalities. We frame a differential equation to evaluate the impact of mean blood pressure on the aortic wall and prove the existence and uniqueness of its solution for homeostatic recoil and relaxation for infinitesimal aortic tissue. We model and analyze generalized (3+1)-dimensional nonlinear partial differential equation for aortic wave dynamics. We use the Lie group of transformations on this nonlinear evolution equation to obtain invariant solutions, traveling wave solutions including solitons. We find that abnormalities in the dynamic pathology of aortic dissection act as triggers for the progression of disease in early-stage through the formation of soliton-like pulses and their interaction. We address the role of unstable wavefields in waveform dynamics when waves are unidirectional. Moreover, the notion of dynamic pathology within the domain of vascular geometry may explain the evolution of aneurysms in cerebral arteries and cardiomyopathies even in the absence of anatomical and physiological abnormalities.

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