On the minima of Markov and Lagrange Dynamical Spectra

Astérisque ◽  
2020 ◽  
Vol 415 ◽  
pp. 45-57
Author(s):  
Carlos Gustavo MOREIRA
Keyword(s):  
2015 ◽  
Vol 70 (4) ◽  
pp. 466-473 ◽  
Author(s):  
G. G. Valyavin ◽  
A. O. Grauzhanina ◽  
G. A. Galazutdinov ◽  
D. R. Gadelshin ◽  
R. Ya. Zhuchkov ◽  
...  

2022 ◽  
pp. 34-48
Author(s):  
Aamir Shahzad ◽  
Zakia Rafiq ◽  
Alina Manzoor ◽  
Muhammad Kashif

Equilibrium molecular dynamics (EMD) simulation has been employed to explore the dynamical structure factors (DSFs) of two-dimensional (2D) dusty plasma systems for a wide domain of plasma parameters of Coulomb coupling (Γ) and Debye screening strength (κ). The influence of varying wave vectors (k) on plasma DSFs S (k, ω) have been reported with different combinations of plasma state points (Γ, κ). New simulations have been tested for the influence of different wave vectors on plasma density S (k, ω) in addition to different combinations of plasma state points. New results of plasma density S (k, ω) show that amplitude of oscillation and frequency will vary with increasing value of Coulomb coupling parameter (Γ) and Debye screening strength (κ). These simulation techniques show that transient behavior has been reported for frequency (ω) with various values of Debye screening strength (κ) and number of particles (N). Moreover, EMD simulation has been checked in order to investigate the behavior of plasma DSFs with increasing number of particles (N). The outcomes of EMD simulations are matched to earlier known numerical and experimental data. It has been shown that fluctuation of dynamical density increases at intermediate to higher values of coupling parameter. However, it shows less fluctuation at higher values of Debye screening strength (κ).


2020 ◽  
pp. 2140001
Author(s):  
Michael Baake ◽  
Natalie Priebe Frank ◽  
Uwe Grimm

Several variants of the classic Fibonacci inflation tiling are considered in an illustrative fashion, in one and in two dimensions, with an eye on changes or robustness of diffraction and dynamical spectra. In one dimension, we consider extension mechanisms of deterministic and of stochastic nature, while we look at direct product variations in a planar extension. For the pure point part, we systematically employ a cocycle approach that is based on the underlying renormalization structure. It allows explicit calculations, particularly in cases where one meets regular model sets with Rauzy fractals as windows.


2009 ◽  
Vol 27 (6) ◽  
pp. 2341-2359 ◽  
Author(s):  
D. Nunn ◽  
O. Santolik ◽  
M. Rycroft ◽  
V. Trakhtengerts

Abstract. This paper presents a study of the use of a one-dimensional Vlasov Hybrid Simulation (VHS) computer code to simulate the dynamical spectra (i.e. frequency versus time spectrograms) of ELF/VLF chorus signals (from ~a fraction to ~10 kHz). Recently excellent measurements of chorus have been made in the source region close to the geomagnetic equator aboard the four spacecraft Cluster mission. Using Cluster data for wave amplitude, which is up to 300 pT, local gyrofrequency, cold plasma density, and L-shell, observed chorus signals are reproduced with remarkable fidelity and, in particular, sweep rates in the range 1–10 kHz result as observed. Further, we find that the sweep rate is a falling function of increasing cold plasma density, again in accord with observations. Finally, we have satisfactorily simulated the rather rare falling frequency elements of chorus which are sometimes observed aboard Cluster in the generation region. For both rising and falling chorus we have presented detailed structural analyses of the generation regions. The main contributor to the frequency sweep rate is primarily the establishment of wave number/frequency gradients across the generation region by the out of phase component of the resonant particle current. The secondary contributor is the shortening of the wavelength of resonant particle current relative to that of the wave field. In view of the close agreement between observation and simulation, we conclude that nonlinear electron cyclotron resonance is indeed the mechanism underlying the generation of chorus signals just outside the plasmasphere.


2018 ◽  
Vol 57 (2) ◽  
pp. 269-292
Author(s):  
Carlos Gustavo T. Moreira ◽  
Maria José Pacifico ◽  
Sergio Romaña Ibarra

Astérisque ◽  
2020 ◽  
Vol 415 ◽  
pp. 45-57
Author(s):  
Carlos Gustavo MOREIRA
Keyword(s):  

Author(s):  
C. Efthymiopoulos ◽  
N. Voglis ◽  
G. Contopoulos
Keyword(s):  

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