Modified electron whistler dispersion law

2002 ◽  
Vol 67 (2-3) ◽  
pp. 149-161 ◽  
Author(s):  
B. V. LUNDIN ◽  
C. KRAFFT
Keyword(s):  
Cold Plasma ◽  
Wave Dispersion ◽  
Plasma Electron ◽  
Lower Hybrid ◽  
Analytical Treatment ◽  
Dispersion Law ◽  
Wide Range ◽  
Lightning Discharges ◽  
Ray Trajectories ◽  
Dynamical Spectra

A modified electron whistler dispersion law is derived in the cold-plasma approximation for analytical treatment and simplified numerical calculations of wave propagation in a wide range of ratios ωc/ωp of electron gyro- to plasma frequencies if the wave frequency is much less than ωp. The net contribution of ions to the wave dispersion law is expressed through the value of the lower-hybrid resonance frequency ωlhr only. This approximate dispersion law is valid in a wide frequency domain, that is, from the range of ωlhr until the domain where the contribution of ions can be neglected. A comparison of geometrical-optics ray trajectories calculated by the use of modified and total cold-plasma electron whistler dispersion laws is presented for the case of the Earth's plasma environment. Computer simulations of dynamical spectra of whistler waves excited by lightning discharges and registered in remote regions of the Earth's plasmasphere reveal good numerical stability of the developed ray-tracing code.

scholarly journals On the dispersion law of low-frequency electron whistler waves in a multi-ion plasma

2008 ◽  
Vol 26 (6) ◽  
pp. 1605-1615 ◽  
Author(s):  
B. V. Lundin ◽  
C. Krafft
Keyword(s):  
Cutoff Frequency ◽  
Low Frequency ◽  
Negative Ions ◽  
Plasma Electron ◽  
Lower Hybrid ◽  
Charged Dust ◽  
Whistler Waves ◽  
Dispersion Law ◽  
Ion Plasma ◽  
Lower Hybrid Resonance

Abstract. A new and simple dispersion law for extra-low-frequency electron whistler waves in a multi-ion plasma is derived. It is valid in a plasma with finite ratio ωc/ωpe of electron gyro-to-plasma frequency and is suitable for wave frequencies much less than ωpe but well above the gyrofrequencies of most heavy ions. The resultant contribution of the ions to the dispersion law is expressed by means of the lower hybrid resonance frequency, the highest ion cutoff frequency and the relative content of the lightest ion. In a frequency domain well above the ions' gyrofrequencies, this new dispersion law merges with the "modified electron whistler dispersion law" determined in previous works by the authors. It is shown that it fits well to the total cold plasma electron whistler dispersion law, for different orientations of the wave vectors and different ion constituents, including negative ions or negatively charged dust grains.

scholarly journals Reliable workflow for inversion of seismic receiver function and surface wave dispersion data: a “13 BB Star” case study

2019 ◽  
Vol 24 (1) ◽  
pp. 101-120
Author(s):  
Kajetan Chrapkiewicz ◽  
Monika Wilde-Piórko ◽  
Marcin Polkowski ◽  
Marek Grad
Keyword(s):  
Surface Wave ◽  
Inverse Problems ◽  
Receiver Function ◽  
Joint Inversion ◽  
Wave Dispersion ◽  
Receiver Functions ◽  
P Wave ◽  
Surface Wave Dispersion ◽  
Phase Velocity Dispersion ◽  
Wide Range

AbstractNon-linear inverse problems arising in seismology are usually addressed either by linearization or by Monte Carlo methods. Neither approach is flawless. The former needs an accurate starting model; the latter is computationally intensive. Both require careful tuning of inversion parameters. An additional challenge is posed by joint inversion of data of different sensitivities and noise levels such as receiver functions and surface wave dispersion curves. We propose a generic workflow that combines advantages of both methods by endowing the linearized approach with an ensemble of homogeneous starting models. It successfully addresses several fundamental issues inherent in a wide range of inverse problems, such as trapping by local minima, exploitation of a priori knowledge, choice of a model depth, proper weighting of data sets characterized by different uncertainties, and credibility of final models. Some of them are tackled with the aid of novel 1D checkerboard tests—an intuitive and feasible addition to the resolution matrix. We applied our workflow to study the south-western margin of the East European Craton. Rayleigh wave phase velocity dispersion and P-wave receiver function data were gathered in the passive seismic experiment “13 BB Star” (2013–2016) in the area of the crust recognized by previous borehole and refraction surveys. Final models of S-wave velocity down to 300 km depth beneath the array are characterized by proximity in the parameter space and very good data fit. The maximum value in the mantle is higher by 0.1–0.2 km/s than reported for other cratons.

Non-Thermal Food Preservation Methods in the Meat Industry

2020 ◽  
pp. 44-64
Author(s):  
Basak Gokce Col ◽  
Sergen Tuggum ◽  
Seydi Yıkmış
Keyword(s):  
Cold Plasma ◽  
Meat Products ◽  
Food Preservation ◽  
Enzymatic Reactions ◽  
Meat Industry ◽  
Chemical Additives ◽  
Preservation Methods ◽  
Wide Range ◽  
Meat Preservation ◽  
Novel Approaches

The most commonly used meat preservation methods include cooling, freezing, drying, vacuum packing, and curing. Meat quality is impaired by a wide range of changes including physical, chemical, microbiological, and enzymatic reactions. Food manufacturers focus on processes that require fewer chemical additives to meet the increased demand of consumers and to obtain more natural, healthy, and nutritious meat products. Non-thermal food preservation methods are one of the new trends to minimise thermal effects on texture, nutritional value, and flavor losses of meats. The chapter focuses on two novel approaches; non-thermal (Pulsed Electric Field) and Atmospheric Pressure Cold Plasma (APCP) Technologies.

Ergodic behavior of lower hybrid decay wave ray trajectories in toroidal geometry

1978 ◽  
Vol 21 (12) ◽  
pp. 2263 ◽  
Author(s):  
Jean-Marie Wersinger ◽  
Edward Ott ◽  
John M. Finn
Keyword(s):  
Lower Hybrid ◽  
Wave Ray ◽  
Ergodic Behavior ◽  
Ray Trajectories ◽  
Toroidal Geometry

Reflection of Conductive Plane Covered by Double Inhomogeneous Plasma Slab

2012 ◽  
Vol 229-231 ◽  
pp. 941-944
Author(s):  
Fei Yan ◽  
Zhong Cai Yuan ◽  
Yong Wang ◽  
Shi Lian Gong ◽  
Zheng Li
Keyword(s):  
Functional Dependence ◽  
Inhomogeneous Plasma ◽  
Plasma Electron ◽  
Reflection Coefficients ◽  
Frequency Range ◽  
Wide Range ◽  
Plasma Slab ◽  
Electromagnetic Signals ◽  
Set Up ◽  
Plasma Electron Density

This paper presents numerical results in the form of graphs of the power reflection coefficients for electromagnetic signals normally incident upon a conductive plane covered with two layers of inhomogeneous plasma slabs. The plasma electron density varies only in the direction perpendicular to the plane. Parameters considered in the computation cover a relatively wide range and the functional dependence of the power reflection coefficients on these parameters is studied. The results indicate that in a rather broad frequency range, the electromagnetic attenuations by the double slabs obviously excel the sum of attenuations resulted from two plasma layers when each layer exits respectively. The structure presented is easy to set up, which is instructive for plasma stealth.

scholarly journals On the numerical modelling of VLF chorus dynamical spectra

2009 ◽  
Vol 27 (6) ◽  
pp. 2341-2359 ◽  
Author(s):  
D. Nunn ◽  
O. Santolik ◽  
M. Rycroft ◽  
V. Trakhtengerts
Keyword(s):  
Plasma Density ◽  
Cold Plasma ◽  
Electron Cyclotron Resonance ◽  
Source Region ◽  
Computer Code ◽  
Sweep Rate ◽  
Wave Number ◽  
Generation Region ◽  
Dynamical Spectra ◽  
Particle Current

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.

Comment on paper by Bhartendu, "A study of atmospheric pressure variations from lightning discharges"

1968 ◽  
Vol 46 (20) ◽  
pp. 2333-2334 ◽  
Author(s):  
R. A. McCrory ◽  
C. R. Holmes
Keyword(s):  
Time Series ◽  
Power Spectra ◽  
Power Spectral Analysis ◽  
Sound Level ◽  
Hot Wire ◽  
Power Spectral ◽  
Wide Range ◽  
Spectral Components ◽  
Lightning Discharges ◽  
Level Meter

Bhartendu uses two types of microphones to provide the time series for his power spectral investigations of thunder, the hot wire microphone and a wide-range crystal microphone with amplification provided by a sound-level meter. He then takes power spectra calculated from these time series and states conclusions regarding the power spectrum of thunder. Data and discussion are presented here to demonstrate that one cannot use a single-grid hot-wire microphone for power spectral analysis without introducing spurious spectral components.

Electrostatic instabilities in anti-loss-cone plasma

1978 ◽  
Vol 19 (2) ◽  
pp. 193-199 ◽  
Author(s):  
K. G. Bhatia ◽  
G. S. Lakhina
Keyword(s):  
Plasma Density ◽  
Growth Rates ◽  
Cold Plasma ◽  
Lower Hybrid ◽  
Loss Cone ◽  
Trapped Electrons ◽  
A Value ◽  
Acoustic Instabilities ◽  
Electron Acoustic

It is shown that both lower hybrid and modified electron acoustic instabilities can be excited in a hot anti-loss-cone plasma co-existing with a rarefied cold plasma, provided the anti-loss-cone factor, ρ, exceeds a value Tm/Tt, where Tm and Tt are the parallel temperatures of missing and trapped electrons respectively. These instabilities are excited in a bounded range of wavenumbers and the growth rates are enhanced with the increase of cold plasma density. ForTm/Tt < ρ > (Tm/Tt)½both the instabilities are of resonant type whereas for ρ > (Tm/Tt)½ both may be converted into non-resonant types. These instabilities are expected to give rise to the heating of protons as well as electrons in the magnetosphere beyond the plasmapause.

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