The Effective Temperature of Dust Impact Plasmas — Olivine Dust on Tungsten Target

2021 ◽  
Author(s):  
Jiří Pavlů ◽  
Samuel Kočiščák ◽  
Åshild Fredriksen ◽  
Michael DeLuca ◽  
Zoltan Sternovsky
Keyword(s):  
Negative Charge ◽  
Negative Ions ◽  
Charge Carriers ◽  
Dust Particles ◽  
Applied Bias ◽  
Control Grid ◽  
Impact Speed ◽  
Positive Ions ◽  
Effective Temperatures ◽  
The Impact

<p>We experimentally observe both positive and negative charge carriers in impact plasma and estimate their effective temperatures. The measurements are carried on a dust accelerator using polypyrrole (PPy)-coated olivine dust particles impacting tungsten (W) target in the velocity range of 2–18 km/s. We measure the retained impact charge as a function of applied bias potential to the control grid. The temperatures are estimated from the data fit. The estimated effective temperatures of the positive ions are approximately 7 eV and seems to be independent of the impact speed. The negative charge carriers' temperatures vary from as low as 1 eV for the lowest speeds to almost ten times higher speeds. The presented values differ significantly from previous studies using Fe dust particles. Yet, the discrepancy can be attributed to a larger fraction of negative ions in the impact plasma that likely originates from the PPy coating.</p>

THE IONIZATION OF THE ATMOSPHERE MEASURED FROM FLYING AIRCRAFT

1931 ◽  
Vol 5 (6) ◽  
pp. 625-635
Author(s):  
D. C. Rose
Keyword(s):  
Relative Humidity ◽  
Negative Ions ◽  
Ground Level ◽  
The State ◽  
Dust Particles ◽  
Measuring Apparatus ◽  
Positive Ions ◽  
Humidity Measurements ◽  
Water Drops ◽  
Atmospheric Ionization

The Gerdian type of atmospheric ionization measuring apparatus was attached to a cabin aeroplane so that the state of ionization of the atmosphere could be studied. The limitations of the apparatus for aeroplane use are discussed. Measurements were taken from ground level to heights of 15000 ft. The results are plotted in number of ions per cc. (separate curves for positive and negative) at different altitudes.The results indicate that at the cloud level there is an abnormal excess of small positive ions and a minimum in the excess of positive ions over negative ions from 4000–6000 ft. higher. This does not include large ions such as charged water drops or dust particles. The observations were taken in regions free from clouds, the cloud level being determined by observation on clouds in the sky, and by relative humidity measurements taken at the same time.

scholarly journals Measurement of Dust Electric Charges by the Ulysses and Galileo Dust Detectors

1996 ◽  
Vol 150 ◽  
pp. 481-484 ◽  
Author(s):  
J. Svestka ◽  
S. Auer ◽  
M. Baguhl ◽  
E. Grün
Keyword(s):  
Electric Field ◽  
Dust Particle ◽  
Time Of Flight ◽  
Opposite Polarity ◽  
Dust Particles ◽  
Impact Speed ◽  
The Impact

The Galileo and Ulysses dust detectors can detect electric charges of dust particles. Dust particles entering the sensor (see, e.g., Grün et al. 1992) may be detected by the charge Qp that they induce to the charge grid. All suitably massive dust particles - charged or uncharged - are then detected by the cloud of ions and electrons they produce during the impact on the hemispherical target after the time of flight between the charge grid and the target. After separation in the electric field, ions and electrons are collected by separate electrodes and produce two pulses of opposite polarity. From the two pulse heights and the rise times, the mass and impact speed of the dust particle are derived.

scholarly journals Potential distribution around a charged dust grain in an electronegative plasma

2010 ◽  
Vol 76 (5) ◽  
pp. 673-676 ◽  
Author(s):  
P. K. SHUKLA ◽  
L. STENFLO
Keyword(s):  
Potential Distribution ◽  
Negative Ions ◽  
Plasma Sheath ◽  
Dust Particles ◽  
Charged Dust ◽  
Electronegative Plasma ◽  
Positive Ions ◽  
Dust Grain ◽  
Bulk Plasma

AbstractThe potential distribution around a charged dust grain in an electronegative plasma is obtained by using the appropriate dielectric susceptibilities for the Boltzmann distributed electrons and negative ions, and for the inertial positive ions that are streaming from the bulk plasma into the electronegative plasma sheath. The existence of oscillatory ion wakefields is shown. Positive ions are trapped/focused in the ion wakefields, and subsequently the negative dust particles are attracted to each other, forming ordered dust structures.

scholarly journals Modeling of Spherical Dust Particle Charging due to Ion Attachment

2021 ◽  
Vol 9 ◽  
Author(s):  
Sotirios A. Mallios ◽  
Georgios Papangelis ◽  
George Hloupis ◽  
Athanasios Papaioannou ◽  
Vasiliki Daskalopoulou ◽  
...  
Keyword(s):  
Electric Field ◽  
Large Scale ◽  
Negative Ions ◽  
Particle Dynamics ◽  
Electrical Charge ◽  
Dust Particles ◽  
Electrical Force ◽  
Force Magnitude ◽  
Ion Attachment ◽  
The Impact

The attachment of positive and negative ions to settling spherical dust particles is studied. A novel 1D numerical model has been developed to parameterize the charging process in the presence of a large-scale electric field. The model is able to self-consistently calculate the modification of atmospheric ion densities in the presence of the dust particles, and the consequent alteration of the atmospheric electrical conductivity and the large-scale electric field. Moreover, the model estimates the acquired electrical charge on the dust particles and calculates the electrical force that is applied on them. Using observed dust size distributions, we find that the particles can acquire electrical charge in the range of 1–1,000 elementary charges depending on their size and number density. The particles become mainly negatively charged, but under specific conditions giant mode particles (larger than 50 μm radius) can be positive. Moreover, the large-scale electric field can increase up to 20 times as much as the fair weather value. However, our approach shows that the resultant electrical force is not enough to significantly influence their gravitational settling, as the ratio between the electrical force magnitude and the gravity magnitude does not exceed the value of 0.01. This indicates that the process of ion attachment alone is not sufficient to create strong electrical effects for the modification of particle dynamics. Therefore, other processes, such as the triboelectric effect and updrafts, must be included in the model to fully represent the impact of electricity on particle dynamics.

scholarly journals Adsorption at a water surface. Part I

1929 ◽  
Vol 122 (790) ◽  
pp. 622-633 ◽  
Keyword(s):  
Negative Charge ◽  
Selective Adsorption ◽  
Negative Ions ◽  
Bubble Surface ◽  
Negative Ion ◽  
Water Molecules ◽  
Air Bubbles ◽  
Surface Molecules ◽  
Positive Ions ◽  
Positive Ion

It has already been shown that the charge acquired by small air bubbles in water is due to the selective adsorption of ions by the surface molecules. The bubble surface is considered to consist of water molecules which are partly or completely orientated. These, owing to their polar nature, have a resultant electric field and therefore attract ions of one sign while repelling those of the opposite sign. In the case of water the orientation is such as to attract negative ions from the water. These ions are adsorbed on to the surface of the bubble and give it a negative charge. At the same time some of the negative ions already adsorbed will be removed by the thermal agitation of the liquid and an equilibrium state will eventually be reached in which the number striking the surface per second is equal to the number re-evaporated from it. This adsorption of negative ions is accompanied by the capture of positive ions from the liquid. Any such positive ion striking an adsorbed negative ion may be bound to it by the electrostatic attraction so that a number of the negative ions are covered by positive ions and the charge on the bubble is due to the remaining uncovered negative ions.

scholarly journals Positive and negative role of negative ions in cosmic exploration

2021 ◽  
Vol 69 (3) ◽  
pp. 607-637
Author(s):  
Leonid Gretchikhin
Keyword(s):  
Heat Transfer ◽  
Radiative Heat Transfer ◽  
Radiative Heat ◽  
Negative Ions ◽  
Dust Particles ◽  
Compression Waves ◽  
A Value ◽  
Negative Role ◽  
Small Parts ◽  
The Impact

Introduction/purpose: At altitudes of 80 to 40 km, while the spacecraft made of duralumin without a thermal-protective coating was descending from the flight orbit at the first and second cosmic velocities, data were obtained on the increase in density, pressure, and temperature behind the shock front, as well as on the backout of the shock wave from the surface of the descending spacecraft. Methods: Calculations were made of the energy fluxes on the surface of the spacecraft for every 10 km, for convective and radiative heat transfer, as well as for the impact of electrons produced due to ionization of negative ions. Results: At the first cosmic velocity, the greatest energy flux is realized under the influence of an electron flux, and at the second cosmic velocity, radiative heat transfer occurs. In the shock-compressed gas at all the considered altitudes, pressure increases instantly to a value of 109 ÷ 1011 Pa, which leads to a sequential explosion with increasing power resulting in shock waves in the surrounding atmosphere and compression waves in the entire aircraft structure. The last most powerful explosion occurs at an altitude of approx. 40 km. Conclusion: The descending aircraft is destroyed into separate small parts to the size of small dust particles.

scholarly journals Drift wave excitation in a collisional dusty magnetoplasma with multi-ion species

2009 ◽  
Vol 75 (2) ◽  
pp. 153-158 ◽  
Author(s):  
P. K. SHUKLA ◽  
M. ROSENBERG
Keyword(s):  
Negative Ions ◽  
Magnetized Plasma ◽  
Dust Particles ◽  
Charged Dust ◽  
Dust Grains ◽  
Wave Excitation ◽  
Drift Wave ◽  
Positive Ions ◽  
Dissipative Instability ◽  
Ion Species

AbstractWe investigate the drift dissipative instability in a non-uniform magnetized plasma composed of electrons, positive ions, negative ions and negatively charged dust particles. We use a multi-fluid plasma model and derive a dispersion relation for the electrostatic drift waves with frequencies much smaller than the ion gyrofrequencies and wavelengths longer than the ion gyroradii. The presence of the negatively charged, massive dust grains affects the drift wave frequency and the growth rate of the drift dissipative instability. The present results may be relevant to space and laboratory magnetoplasmas containing negative ions and charged dust grains.

Asteroid and Comet Impact Speeds upon Mars: Significance for Panspermia and the Supply of Organics

1997 ◽  
Vol 161 ◽  
pp. 197-201 ◽  
Author(s):  
Duncan Steel
Keyword(s):  
Probability Distributions ◽  
Regions Of Interest ◽  
Significant Fraction ◽  
Organic Chemicals ◽  
Impact Speed ◽  
The Mean ◽  
The Impact

AbstractWhilst lithopanspermia depends upon massive impacts occurring at a speed above some limit, the intact delivery of organic chemicals or other volatiles to a planet requires the impact speed to be below some other limit such that a significant fraction of that material escapes destruction. Thus the two opposite ends of the impact speed distributions are the regions of interest in the bioastronomical context, whereas much modelling work on impacts delivers, or makes use of, only the mean speed. Here the probability distributions of impact speeds upon Mars are calculated for (i) the orbital distribution of known asteroids; and (ii) the expected distribution of near-parabolic cometary orbits. It is found that cometary impacts are far more likely to eject rocks from Mars (over 99 percent of the cometary impacts are at speeds above 20 km/sec, but at most 5 percent of the asteroidal impacts); paradoxically, the objects impacting at speeds low enough to make organic/volatile survival possible (the asteroids) are those which are depleted in such species.

Numerical Simulation of Leakage Current on Conductive Insulator Surface

2019 ◽  
Vol 8 (4) ◽  
pp. 9487-9492
Keyword(s):  
Numerical Simulation ◽  
Electric Field ◽  
Leakage Current ◽  
Method Of Lines ◽  
Electron Attachment ◽  
Negative Ions ◽  
Conduction Current ◽  
Insulator Surface ◽  
Finite Difference Approximations ◽  
Positive Ions

The outdoor insulator is commonly exposed to environmental pollution. The presence of water like raindrops and dew on the contaminant surface can lead to surface degradation due to leakage current. However, the physical process of this phenomenon is not well understood. Hence, in this study we develop a mathematical model of leakage current on the outdoor insulator surface using the Nernst Planck theory which accounts for the charge transport between the electrodes (negative and positive electrode) and charge generation mechanism. Meanwhile the electric field obeys Poisson’s equation. Method of Lines technique is used to solve the model numerically in which it converts the PDE into a system of ODEs by Finite Difference Approximations. The numerical simulation compares reasonably well with the experimental conduction current. The findings from the simulation shows that the conduction current is affected by the electric field distribution and charge concentration. The rise of the conduction current is due to the distribution of positive ion while the dominancy of electron attachment with neutral molecule and recombination with positive ions has caused a significant reduction of electron and increment of negative ions.

scholarly journals Effect of Low-Pressure Plasma Treatment Parameters on Wrinkle Features

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3852
Author(s):  
Bongjun Gu ◽  
Dongwook Ko ◽  
Sungjin Jo ◽  
Dong Choon Hyun ◽  
Hyeon-Ju Oh ◽  
...  
Keyword(s):  
Power Flow ◽  
Treatment Time ◽  
Argon Plasma ◽  
Negative Ions ◽  
Low Pressure ◽  
Nitrogen Plasma ◽  
Pressure Plasma ◽  
Positive Ions ◽  
Low Pressure Plasma ◽  
Optical Adhesive

Wrinkles attract significant attention due to their ability to enhance the mechanical and optical characteristics of various optoelectronic devices. We report the effect of the plasma gas type, power, flow rate, and treatment time on the wrinkle features. When an optical adhesive was treated using a low-pressure plasma of oxygen, argon, and nitrogen, the oxygen and argon plasma generated wrinkles with the lowest and highest wavelengths, respectively. The increase in the power of the nitrogen and oxygen plasma increased the wavelengths and heights of the wrinkles; however, the increase in the power of the argon plasma increased the wavelengths and decreased the heights of the wrinkles. Argon molecules are heavier and smaller than nitrogen and oxygen molecules that have similar weights and sizes; moreover, the argon plasma comprises positive ions while the oxygen and nitrogen plasma comprise negative ions. This resulted in differences in the wrinkle features. It was concluded that a combination of different plasma gases could achieve exclusive control over either the wavelength or the height and allow a thorough analysis of the correlation between the wrinkle features and the characteristics of the electronic devices.

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