Numerical model for low-frequency ion waves in magnetized dusty plasmas

2000 ◽  
Vol 28 (5) ◽  
pp. 1694-1705 ◽  
Author(s):  
Gyoo-Soo Chae ◽  
W.A. Scales ◽  
G. Ganguli ◽  
P.A. Bernhardt ◽  
M. Lampe
Keyword(s):  
Numerical Model ◽  
Low Frequency ◽  
Dusty Plasmas ◽  
Ion Waves

Ion plasma waves in dusty plasmas: Halley's comet

1988 ◽  
Vol 40 (3) ◽  
pp. 399-406 ◽  
Author(s):  
U. de Angelis ◽  
V. Formisano ◽  
M. Giordano
Keyword(s):  
Acoustic Waves ◽  
Low Frequency ◽  
Dusty Plasmas ◽  
Dust Particles ◽  
Charged Dust ◽  
Ion Acoustic Waves ◽  
Common Space ◽  
Halley's Comet ◽  
Homogeneous Background ◽  
Ion Waves

We investigate ion waves in a plasma in the presence of massive charged dust particles, a common space-plasma component now known to exist also in planetary rings and comets. We derive an equation describing low-frequency electrostatic perturbations on a non-homogeneous background, where the inhomogeneity is due to a distribution of charged grains, each surrounded by an equilibrium statistical distribution of plasma particles. This model is then applied to propose an interpretation of some recent data from the Vega and Giotto space probes to Halley's comet the increase of the low-frequency electrostatic noise (ion-acoustic waves) in the region of increased dust.

Low frequency waves in streaming quantum dusty plasmas

2017 ◽  
Vol 24 (9) ◽  
pp. 093702 ◽  
Author(s):  
Ch. Rozina ◽  
M. Jamil ◽  
Arroj A. Khan ◽  
I. Zeba ◽  
J. Saman
Keyword(s):  
Low Frequency ◽  
Dusty Plasmas ◽  
Low Frequency Waves

A theory for Langmuir solitons

1982 ◽  
Vol 27 (1) ◽  
pp. 95-120 ◽  
Author(s):  
N. Nagesha Rao ◽  
Ram K. Varma
Keyword(s):  
Mach Number ◽  
A Priori ◽  
Low Frequency ◽  
Analytic Solutions ◽  
Smooth Transition ◽  
Langmuir Waves ◽  
Method Of Solution ◽  
Mach Numbers ◽  
Ion Waves ◽  
Langmuir Solitons

A systematic and self-consistent analysis of the problem of Langmuir solitons in the entire range of Mach numbers (0 < M < 1) has been presented. A coupled set of nonlinear equations for the amplitude of the modulated, high-frequency Langmuir waves and the associated low-frequency ion waves is derived without using the charge neutrality condition or any a priori ordering schemes. A technique has been developed for obtaining analytic solutions of these equations where any arbitrary degree of ion nonlinearity consistent with the nonlinearity retained in the Langmuir field can be taken into account self-consistently. A class of solutions with non-zero Langmuir field intensity at the centre (ξ = 0) are found for intermediate values of the Mach number. Using these solutions, a smooth transition from single-hump solitons to the double-hump solitons with respect to the Mach number has been established through the definitions of critical and cut-off Mach numbers. Further, under appropriate limiting conditions, various solutions discussed by other authors are obtained. Sagdeev potential analyses of the solutions for the Langmuir field as well as the ion field are carried out. These analyses confirm the transition from single-hump solitons to the double-hump solitons with respect to the Mach number. The existence of many-hump solitons for higher-order nonlinearities in the low-frequency ion wave potential has been conjectured. The method of solution developed here can be applied to similar equations in other fields.

scholarly journals Dynamic Pulse Buckling of Composite Stanchions in the Sub-Cargo Floor Area of a Civil Regional Aircraft

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3594
Author(s):  
Andrea Sellitto ◽  
Francesco Di Caprio ◽  
Michele Guida ◽  
Salvatore Saputo ◽  
Aniello Riccio
Keyword(s):  
Numerical Model ◽  
Numerical Models ◽  
Low Frequency ◽  
Time Dependent ◽  
Structural Behavior ◽  
Cyclic Loads ◽  
Civil Aircraft ◽  
Compressive Loads ◽  
Pulse Buckling ◽  
Implicit And Explicit

This work is focused on the investigation of the structural behavior of a composite floor beam, located in the cargo zone of a civil aircraft, subjected to cyclical low-frequency compressive loads with different amplitudes. In the first stage, the numerical models able to correctly simulate the investigated phenomenon have been defined. Different analyses have been performed, aimed to an exhaustive evaluation of the structural behavior of the test article. In particular, implicit and explicit analyses have been considered to preliminary assess the capabilities of the numerical model. Then, explicit non-linear analyses under time-dependent loads have been considered, to predict the behavior of the composite structure under cyclic loading conditions. According to the present investigation, low-frequency cyclic loads with peak values lower than the static buckling load value are not capable of triggering significant instability.

scholarly journals Comparative study of dust acoustic solitons in two-temperature ion homogeneous and inhomogeneous plasmas

2020 ◽  
Vol 14 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Rashmi Srivastava ◽  
Hitendra K. Malik ◽  
Devi Singh
Keyword(s):  
Solitary Waves ◽  
Inhomogeneous Plasma ◽  
Low Frequency ◽  
Soliton Solutions ◽  
Dusty Plasmas ◽  
Number Density ◽  
Dust Charge ◽  
Plasma Species ◽  
Dust Acoustic ◽  
Two Temperature

AbstractThe dust acoustic solitary waves are theoretically investigated in dusty plasmas for different cases of with and without density gradients. These low-frequency solitary waves are studied using appropriate Korteweg–de Vries equations obtained using relevant stretched coordinates. The soliton solutions in homogeneous plasma, weakly inhomogeneous plasma and strongly inhomogeneous plasma, are thoroughly investigated for studying the effect of different parameters like dust charge and density of all the plasma species on the soliton profiles. The combination of the dust charge with its number density changes the dynamics of the solitons and that is further affected by the number density of the hot ion with respect to the cold ions.

scholarly journals Properties of the singing comet waves in the 67P/Churyumov-Gerasimenko plasma environment as observed by the Rosetta mission

2019 ◽  
Vol 630 ◽  
pp. A39 ◽  
Author(s):  
H. Breuillard ◽  
P. Henri ◽  
L. Bucciantini ◽  
M. Volwerk ◽  
T. Karlsson ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Low Frequency ◽  
Compressional Waves ◽  
Weibel Instability ◽  
Plasma Environment ◽  
Background Magnetic Field ◽  
Rosetta Mission ◽  
Ion Waves ◽  
Plasma Coupling

Using in situ measurements from different instruments on board the Rosetta spacecraft, we investigate the properties of the newly discovered low-frequency oscillations, known as singing comet waves, that sometimes dominate the close plasma environment of comet 67P/Churyumov-Gerasimenko. These waves are thought to be generated by a modified ion-Weibel instability that grows due to a beam of water ions created by water molecules that outgass from the comet. We take advantage of a cometary outburst event that occurred on 2016 February 19 to probe this generation mechanism. We analyze the 3D magnetic field waveforms to infer the properties of the magnetic oscillations of the cometary ion waves. They are observed in the typical frequency range (~50 mHz) before the cometary outburst, but at ~20 mHz during the outburst. They are also observed to be elliptically right-hand polarized and to propagate rather closely (~0−50°) to the background magnetic field. We also construct a density dataset with a high enough time resolution that allows us to study the plasma contribution to the ion cometary waves. The correlation between plasma and magnetic field variations associated with the waves indicates that they are mostly in phase before and during the outburst, which means that they are compressional waves. We therefore show that the measurements from multiple instruments are consistent with the modified ion-Weibel instability as the source of the singing comet wave activity. We also argue that the observed frequency of the singing comet waves could be a way to indirectly probe the strength of neutral plasma coupling in the 67P environment.

Low-frequency electrostatic instabilities in strongly coupled dusty plasmas

2001 ◽  
Vol 29 (2) ◽  
pp. 226-230 ◽  
Author(s):  
Baisong Xie ◽  
Zhaoyang Chen ◽  
M.Y. Yu
Keyword(s):  
Low Frequency ◽  
Dusty Plasmas ◽  
Strongly Coupled

scholarly journals Establishment of a Numerical Model to Design an Electro-Stimulating System for a Porcine Mandibular Critical Size Defect

2019 ◽  
Vol 9 (10) ◽  
pp. 2160 ◽  
Author(s):  
Hendrikje Raben ◽  
Peer W. Kämmerer ◽  
Rainer Bader ◽  
Ursula van Rienen
Keyword(s):  
Numerical Model ◽  
Critical Size ◽  
Healing Process ◽  
Low Frequency ◽  
Implant Design ◽  
Tissue Properties ◽  
Stimulation Parameters ◽  
Promising Therapeutic Approach ◽  
Stimulation System

Electrical stimulation is a promising therapeutic approach for the regeneration of large bone defects. Innovative electrically stimulating implants for critical size defects in the lower jaw are under development and need to be optimized in silico and tested in vivo prior to application. In this context, numerical modelling and simulation are useful tools in the design process. In this study, a numerical model of an electrically stimulated minipig mandible was established to find optimal stimulation parameters that allow for a maximum area of beneficially stimulated tissue. Finite-element simulations were performed to determine the stimulation impact of the proposed implant design and to optimize the electric field distribution resulting from sinusoidal low-frequency ( f = 20 Hz ) electric stimulation. Optimal stimulation parameters of the electrode length h el = 25 m m and the stimulation potential φ stim = 0.5 V were determined. These parameter sets shall be applied in future in vivo validation studies. Furthermore, our results suggest that changing tissue properties during the course of the healing process might make a feedback-controlled stimulation system necessary.

scholarly journals A study of seasonal variations of gravity wave intensity in thelower thermosphere using LF D1 wind observations and a numerical model

2004 ◽  
Vol 22 (1) ◽  
pp. 35-45 ◽  
Author(s):  
N. M. Gavrilov ◽  
Ch. Jacobi
Keyword(s):  
Numerical Model ◽  
Drift Velocity ◽  
Seasonal Variations ◽  
Middle Atmosphere ◽  
Low Frequency ◽  
Internal Gravity Waves ◽  
Short Period ◽  
Summer Maximum ◽  
E Region ◽  
Standard Deviations

Abstract. The data of the regular low-frequency D1 E-region observations at Collm, Germany (52°N, 15°E) in 1983–1999 are used for estimations of the intensity of short-period perturbations of the horizontal drift velocity at 85–110 km altitude. A simple half-hourly-difference numerical filter is used to extract perturbations with time scales of 0.7–3 h. The average monthly standard deviations of short-period perturbations of the zonal velocity near altitude 83 km have a main maximum in summer, a smaller maximum in winter, and minimum values at the equinoxes. At higher altitudes the summer maximum is shifted towards the spring months, and a second maximum of perturbation amplitudes appears in autumn at altitudes near and above 100 km. The seasonal changes in the standard deviations of meridional velocity show the maxima in spring and summer. A numerical model describing the propagation of a set of harmonics modeling a spectrum of internal gravity waves in the atmosphere is used for the interpretation of observed seasonal variations of wind perturbation intensity. Numerical modeling reveals that the observed altitude changes in the seasonal variations of the drift velocity standard deviations may be explained by a superposition of IGWs generated at different levels in the troposphere and middle atmosphere. IGWs generated in the stratospheric and mesospheric jet stream may have substantial amplitudes at altitudes near and above 100 km, where they may modify the seasonal variations, which are typical for IGWs propagating from the troposphere. Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides) – Ionosphere (ionospheric irregularities)

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