scholarly journals Nonlinear Shift of Wave Parameters of Whistlers in the Ionosphere in the Presence of Negative Ions

1987 ◽  
Vol 40 (5) ◽  
pp. 665 ◽  
Author(s):  
AK Sur ◽  
PK Kashyapi ◽  
SN Paul ◽  
B Chakraborty
Keyword(s):  
Cyclotron Frequency ◽  
Negative Ions ◽  
Wave Frequency ◽  
Ion Concentration ◽  
Negative Ion ◽  
Wave Number ◽  
Wave Parameters ◽  
Ion Cyclotron

In this paper the nonlinear shift of the wave number of ion-cyclotron whistlers propagating through the ionosphere in the presence of negative ions is estimated. The results are discussed both numerically and graphically for the proton whistler. It is seen that under some physical situations the nonlinear shift of the wave number of the proton whistler is very significant. Furthermore, the nonlinear shift of the wave number depends significantly on the variation of negative ion concentration when the wave frequency is very close to an ion-cyclotron frequency.

Wavenumber shift of an obliquely propagating ion-cyclotron whistler

1989 ◽  
Vol 41 (1) ◽  
pp. 37-44 ◽  
Author(s):  
S. N. Paul ◽  
A. K. Sur ◽  
G. Pakira
Keyword(s):  
Cyclotron Frequency ◽  
Negative Ions ◽  
Ion Concentration ◽  
Negative Ion ◽  
Propagation Angle ◽  
Ion Cyclotron ◽  
Numerical Estimations

An expression for the nonlinear wavenumber shift of an obiquely propagating ion-cyclotron whistler in the presence of negative ions are derived. The effects of the intensity of the wave, the ion-cyclotron frequency, the negative-ion concentration and the propagation angle on the wavenumber shift of whistlers is discussed. Numerical estimations are also made of the wavenumber shift.

scholarly journals Novel internal measurements of ion cyclotron frequency range fast-ion driven modes

2021 ◽  
Author(s):  
Neal A Crocker ◽  
Shawn X Tang ◽  
Kathreen E Thome ◽  
Jeff Lestz ◽  
Elena Belova ◽  
...  
Keyword(s):  
Cyclotron Frequency ◽  
Harmonic Wave ◽  
Wave Number ◽  
Frequency Range ◽  
High Wave Number ◽  
Minor Radius ◽  
Ion Cyclotron ◽  
Cyclotron Emission ◽  
Edge Localized Modes ◽  
Fast Ion

Abstract Novel internal measurements and analysis of ion cyclotron frequency range fast-ion driven modes in DIII-D are presented. Observations, including internal density fluctuation (ñ) measurements obtained via Doppler Backscattering, are presented for modes at low harmonics of the ion cyclotron frequency localized in the edge. The measurements indicate that these waves, identified as coherent Ion Cyclotron Emission (ICE), have high wave number, _⊥ρ_fast ≳ 1, consistent with the cyclotron harmonic wave branch of the magnetoacoustic cyclotron instability (MCI), or electrostatic instability mechanisms. Measurements show extended spatial structure (at least ~ 1/6 the minor radius). These edge ICE modes undergo amplitude modulation correlated with edge localized modes (ELM) that is qualitatively consistent with expectations for ELM-induced fast-ion transport.

Solitary Wave with Quantisation of Electron’s Orbit in a Magnetised Plasma in the Presence of Heavy Negative Ions

2020 ◽  
Vol 75 (3) ◽  
pp. 211-223 ◽  
Author(s):  
Manoj Kr. Deka ◽  
Apul N. Dev
Keyword(s):  
Magnetic Field ◽  
Solitary Wave ◽  
Electron Density ◽  
Maximum Amplitude ◽  
Negative Ions ◽  
Ion Concentration ◽  
Negative Ion ◽  
Maximum Height ◽  
Degenerate Plasma ◽  
Analytical Scheme

AbstractThe propagation characteristics of solitary wave in a degenerate plasma in the presence of Landau-quantised magnetic field and heavy negative ion are studied. The nature of solitary wave in such plasma under the influence of magnetic quantisation and the concentration of both electrons and negative ions, as well as in the presence of degenerate temperature, are studied with the help of a time-independent analytical scheme of the solution of Zakharov–Kuznetsov equation. The electron density, as well as the magnetic quantisation parameter, has an outstanding effect on the features of solitary wave proliferation in such plasma. Interestingly, for any fixed electron density, the magnetic quantisation parameter has an equal control on the maximum height and dispersive properties of the solitary wave. Toward higher temperatures and higher magnetic fields, the width of the solitary wave decreases. For a lower magnetic field, the maximum amplitude of the solitary wave decreases rapidly at higher values of degenerate temperature and negative ion concentration; however, at a lower value of degenerate temperature, the maximum amplitude increases with increasing negative ion concentration.

Linear and nonlinear obliquely propagating ion-acoustic waves in magnetized negative ion plasma with non-thermal electrons

2013 ◽  
Vol 79 (5) ◽  
pp. 893-908 ◽  
Author(s):  
M. K. MISHRA ◽  
S. K. JAIN
Keyword(s):  
Acoustic Waves ◽  
Kdv Equation ◽  
Negative Ions ◽  
Ion Concentration ◽  
Negative Ion ◽  
Slow Mode ◽  
Ion Temperature ◽  
Ion Acoustic ◽  
Ion Acoustic Solitons ◽  
Ion Species

AbstractIon-acoustic solitons in magnetized low-β plasma consisting of warm adiabatic positive and negative ions and non-thermal electrons have been studied. The reductive perturbation method is used to derive the Korteweg–de Vries (KdV) equation for the system, which admits an obliquely propagating soliton solution. It is found that due to the presence of finite ion temperature there exist two modes of propagation, namely fast and slow ion-acoustic modes. In the case of slow-mode if the ratio of temperature to mass of positive ion species is lower (higher) than the negative ion species, then there exist compressive (rarefactive) ion-acoustic solitons. It is also found that in the case of slow mode, on increasing the non-thermal parameter (γ) the amplitude of the compressive (rarefactive) soliton decreases (increases). In fast ion-acoustic mode the nature and characteristics of solitons depend on negative ion concentration. Numerical investigation in case of fast mode reveals that on increasing γ, the amplitude of compressive (rarefactive) soliton increases (decreases). The width of solitons increases with an increase in non-thermal parameters in both the modes for compressive as well as rarefactive solitons. There exists a value of critical negative ion concentration (αc), at which both compressive and rarefactive ion-acoustic solitons appear as described by modified KdV soliton. The value of αc decreases with increase in γ.

scholarly journals Negative Ion Purifier Effects on Indoor Particulate Dosage to Small Airways

2021 ◽  
Vol 19 (1) ◽  
pp. 264
Author(s):  
Mengjie Duan ◽  
Lijuan Wang ◽  
Xingyan Meng ◽  
Linzhi Fu ◽  
Yi Wang ◽  
...  
Keyword(s):  
Indoor Air ◽  
Indoor Air Pollution ◽  
Disease Risk ◽  
Negative Ions ◽  
Underlying Mechanism ◽  
Small Airway ◽  
Ion Concentration ◽  
Negative Ion ◽  
Small Airways

Indoor air quality is an important health factor as we spend more than 80% of our time indoors. The primary type of indoor pollutant is particulate matter, high levels of which increase respiratory disease risk. Therefore, air purifiers are a common choice for addressing indoor air pollution. Compared with traditional filtration purifiers, negative ion air purifiers (NIAPs) have gained popularity due to their energy efficiency and lack of noise. Although some studies have shown that negative ions may offset the cardiorespiratory benefits of air purifiers, the underlying mechanism is still unclear. In this study, we conducted a full-scale experiment using an in vitro airway model connected to a breathing simulator to mimic inhalation. The model was constructed using computed tomography scans of human airways and 3D-printing technology. We then quantified the effects of NIAPs on the administered dose of 0.5–2.5 μm particles in the small airway. Compared with the filtration purifier, the NIAP had a better dilution effect after a 1-h exposure and the cumulative administered dose to the small airway was reduced by 20%. In addition, increasing the negative ion concentration helped reduce the small airway exposure risk. NIAPs were found to be an energy-efficient air purification intervention that can effectively reduce the small airway particle exposure when a sufficient negative ion concentration is maintained.

scholarly journals On the influence of fuel sulfur induced stable negative ion formation on the total concentration of ions emitted by an aircraft gas turbine engine: comparison of model and experiment

2003 ◽  
Vol 3 (6) ◽  
pp. 6001-6018
Author(s):  
A. Sorokin ◽  
F. Arnold ◽  
P. Mirabel
Keyword(s):  
Gas Turbine ◽  
Total Concentration ◽  
Negative Ions ◽  
Aircraft Engine ◽  
Ion Concentration ◽  
Negative Ion ◽  
Test Facility ◽  
Turbine Engine ◽  
Formation And Evolution ◽  
Neutralization Rate

Abstract. A model which considers the formation and evolution of combustion ions in a combustor of an aircraft engine in dependence on the electron detachment efficiency from negative ions is presented. It is a further development of the model reported by (Sorokin et al., 2003). The model allows to consider the effect of the transformation of primary negative ions to more stable secondary negative ions with a much higher electron affinity and as a consequence a greater stability with respect to electron thermal detachment. The formed stable negative ions most probably are sulfur-bearing ions. This effect slows down the charged particle neutralization rate leading to an increase of the concentration of positive and negative ions at the combustor exit. The results of the simulation and their comparison with the ground-based experimental data obtained within the framework of the project PartEmis (Particle emission, measurements and predictions of emission of aerosols and gaseous precursors from gas turbine engines; coordinator: C. Wilson) at the QinetiQ test facility at Pyestock, UK (Wilson et al., 2003) support the above hypothesis, i.e. the increase of the fuel sulfur content leads to an increase of the ion concentration at the combustor exit.

scholarly journals Kinetic theory of electrostatic ion cyclotron waves (QPESIC) in multicomponent plasmas with negative ions

2007 ◽  
Vol 5 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Darko Simic ◽  
Dragan Gajic
Keyword(s):  
Kinetic Theory ◽  
Negative Ions ◽  
Negative Ion ◽  
Bgk Model ◽  
Maxwellian Plasma ◽  
Ion Cyclotron ◽  
Model Collision ◽  
Weakly Ionized ◽  
Component Plasma ◽  
Ion Species

The instabilities of the quasi-perpendicular electrostatic (?B = 0) ioncyclotron waves (QPESIC) are investigated. The kinetic theory with BGK model collision integrals is used to estimate the critical electron drift velocity in the presence of positively or negatively charged resonant ions in multi-component plasma. Analytical evaluation for the ion-cyclotron modes and instabilities in the long-wave range in a weakly-ionized Maxwellian plasma with two positive ion species, one negative ion species and with electrons, drifting along magnetic lines of force is demonstrated. The spectrum in these situations is also given. It is shown that the critical drift decreases as the state of plasma approaches the isothermic state.

Propagation of nonlinear electrostatic drift solitary waves in a collisionless plasma consisting of two ion species

1977 ◽  
Vol 55 (10) ◽  
pp. 861-865
Author(s):  
S. G. Tagare
Keyword(s):  
Solitary Wave ◽  
Solitary Waves ◽  
Collisionless Plasma ◽  
Argon Plasma ◽  
Negative Ions ◽  
Ionic Species ◽  
Ion Concentration ◽  
Negative Ion ◽  
Light Ions ◽  
Ion Species

A modified two-dimensional Korteweg – de Vries equation for a collisionless plasma consisting of two distinct ionic species and isothermal electrons has been derived. The effect of concentration of light ions on the amplitude and the width of the drift solitary wave is examined for an argon plasma and a helium plasma with hydrogen ion impurities. Similarly the effect of concentration of negative ions on the amplitude of the drift solitary wave is examined and it is shown that when negative ions are present one gets the usual compressive drift solitary waves with positive amplitude as well as rarefactive drift solitary waves with negative amplitude depending on the negative ion concentration.

Magnetohydrodynamic wave propagation from a localized source including hall effect

1968 ◽  
Vol 263 (1137) ◽  
pp. 119-147 ◽  
Keyword(s):  
Wave Propagation ◽  
Wave Amplitude ◽  
Cyclotron Frequency ◽  
Asymptotic Expression ◽  
Wave Frequency ◽  
Laboratory Plasma ◽  
Magnetohydrodynamic Wave ◽  
Localized Source ◽  
Ion Cyclotron ◽  
Finite Electrical Conductivity

Lighthill’s theorem on magnetohydrodynamic wave propagation from a localized source gives an asymptotic expression for the wave amplitude at large distance from the source and this theorem is applied to a laboratory plasma. Attention is focused mainly on conditions where the Alfven speed is large compared with the sound speed and where the wave frequency is of the same order as the ion cyclotron frequency. These conditions are also typical of certain natural plasmas. The manner in which the wave amplitude depends on the direction of propagation and on the ratio of the wave frequency to the ion cyclotron frequency is examined and illustrated by graphs which also cover a range of source sizes. An extension is made into a two-fluid theory such that electron inertia and electron source terms can be included and the effect of finite electrical conductivity is considered.

scholarly journals Effect of Negative Ions on the Instability of Ion-acoustic Waves in a Relativistic Plasma

1997 ◽  
Vol 50 (2) ◽  
pp. 319 ◽  
Author(s):  
K. K. Mondal ◽  
S. N. Paul ◽  
A. Roychowdhury
Keyword(s):  
Dispersion Relation ◽  
Acoustic Wave ◽  
Acoustic Waves ◽  
Negative Ions ◽  
Ion Concentration ◽  
Negative Ion ◽  
Relativistic Velocity ◽  
Ion Acoustic Waves ◽  
Ion Acoustic Wave ◽  
Ion Acoustic

The dispersion relation of an ion-acoustic wave propagating through a collisionless, unmagnetised plasma, having warm isothermal electrons and cold positive and negative ions has been derived. It is seen that the ion-acoustic wave will be unstable in the presence of streaming of ions. Instability of the wave is graphically analysed for the plasma having (H+, O¯) ions, (H+, O2¯) ions, (H+, SF5¯) ions, (He+, Cl¯) ions and (Ar+, O¯) ions with different negative ion concentration and relativistic velocity.

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