scholarly journals Charged dust in the D-region incoherent scatter spectrum

2021 ◽  
Vol 87 (5) ◽  
Author(s):  
Tinna L. Gunnarsdottir ◽  
Ingrid Mann
Keyword(s):  
Electromagnetic Waves ◽  
Dust Particles ◽  
Charged Dust ◽  
Vhf Radar ◽  
Model Calculations ◽  
Incoherent Scatter ◽  
D Region ◽  
Dust Detection ◽  
Dust Component ◽  
Scatter Spectrum

We investigate the influence of charged dust on the incoherent scatter from the D-region ionosphere. Incoherent scatter is observed with high-power, large aperture radars and results from electromagnetic waves scattering at electrons that are coupled to other charged components through plasma oscillations. The influence of charged dust can hence be considered an effect of dusty plasma. The D-region contains meteoric smoke particles that are of nanometre size and form from incoming ablating meteors. Detection of such charged dust in the incoherent scatter spectrum from the D-region has previously been proposed and studied to some degree. We here present model calculations to investigate the influence of the charged dust component with a size distribution, instead of the one size dust components assumed in other works. The developed code to calculate the incoherent scatter spectrum from the D-region including dust particles with different sizes and different positive and negative charge states is made available (https://doi.org/10.18710/GHZIIY). We investigate how sizes, number density and charge state of the dust influence the spectrum during different ionospheric conditions. We consider the ionospheric parameters for the location of the EISCAT VHF radar during a year and find that conditions are most suitable for dust detection in winter below 80 km at times with increased electron densities. The prospects to derive dust parameters increase, when the incoherent scatter observations are combined with those of other instruments to provide independent information on electron density, neutral density and temperature.

Model Calculations on the Influence of Charged Mesospheric dust on the Incoherent Radar Spectrum

2020 ◽  
Author(s):  
Tinna Gunnarsdottir ◽  
Ingrid Mann ◽  
Wojciech Miloch
Keyword(s):  
Dust Particles ◽  
Radar Signal ◽  
Charged Dust ◽  
Large Set ◽  
Model Calculations ◽  
Radar Systems ◽  
Altitude Dependence ◽  
Dust Detection ◽  
Dust Component ◽  
Scatter Spectrum

<p>Detection of charged dust in the spectrum of incoherent radars has previously been proposed and examined to some degree. These dust particles are of nanometer size and reside at mesospheric altitudes due to incoming ablating meteors. They are difficult to detect and thus their influence on atmospheric processes is hard to determine. Theoretical studies suggest that charged nanometer sized dust in the mesosphere can be successfully detected in the radar spectrum. However, current radar systems like EISCAT are not capable to distinguish adequately the dust signal from the main signal because the influence is small. We expect however, that the upcoming new EISCAT_3D radar will improve the observation conditions. We here present model calculations to examine the influence of the charged dust component on the radar signal, a so-called dusty plasma effect. Instead of the previously assumed one size dust component, we simulate the incoherent scatter spectrum including a large set of dust size bins. We show that different sizes, number density and charge of dust influence the signal in different ways, either causing a narrowing or broadening of the spectrum. Here the results are presented in a systematic way and specific conditions identified that provide the largest chance of dust detection in the signal. A simple charging model is used to model the most probable charge and altitude dependence to simulate realistic dust distributions that are then used as input to the radar spectrum model. These results can then be used to compare with actual radar measurements. Off which the new EISCAT_3D radar system, ready in 2022, might provide the adequate resolution for these requirements.</p>

scholarly journals Enhanced incoherent scatter plasma lines

1996 ◽  
Vol 14 (12) ◽  
pp. 1462-1472 ◽  
Author(s):  
H. Nilsson ◽  
S. Kirkwood ◽  
J. Lilensten ◽  
M. Galand
Keyword(s):  
High Plasma ◽  
Collision Term ◽  
Vhf Radar ◽  
Detailed Model ◽  
Model Calculations ◽  
Incoherent Scatter ◽  
Incoherent Scatter Radars ◽  
Plasma Line ◽  
E Region ◽  
Radar Measurements

Abstract. Detailed model calculations of auroral secondary and photoelectron distributions for varying conditions have been used to calculate the theoretical enhancement of incoherent scatter plasma lines. These calculations are compared with EISCAT UHF radar measurements of enhanced plasma lines from both the E and F regions, and published EISCAT VHF radar measurements. The agreement between the calculated and observed plasma line enhancements is good. The enhancement from the superthermal distribution can explain even the very strong enhancements observed in the auroral E region during aurora, as previously shown by Kirkwood et al. The model calculations are used to predict the range of conditions when enhanced plasma lines will be seen with the existing high-latitude incoherent scatter radars, including the new EISCAT Svalbard radar. It is found that the detailed structure, i.e. the gradients in the suprathermal distribution, are most important for the plasma line enhancement. The level of superthermal flux affects the enhancement only in the region of low phase energy where the number of thermal electrons is comparable to the number of suprathermal electrons and in the region of high phase energy where the suprathermal fluxes fall to such low levels that their effect becomes small compared to the collision term. To facilitate the use of the predictions for the different radars, the expected signal- to-noise ratios (SNRs) for typical plasma line enhancements have been calculated. It is found that the high-frequency radars (Søndre Strømfjord, EISCAT UHF) should observe the highest SNR, but only for rather high plasma frequencies. The VHF radars (EISCAT VHF and Svalbard) will detect enhanced plasma lines over a wider range of frequencies, but with lower SNR.

scholarly journals Physical Processes in Cometary Atmospheres

1972 ◽  
Vol 45 ◽  
pp. 253-259 ◽  
Author(s):  
A. Z. Dolginov
Keyword(s):  
Rotation Period ◽  
Dust Particles ◽  
Molecular Flow ◽  
Physical Parameters ◽  
Charged Dust ◽  
Nuclear Surface ◽  
Cometary Dust ◽  
Meteor Streams ◽  
Cometary Tail ◽  
Dust Component

Formulae are obtained for the distribution of molecules in the cometary head, taking into account the conditions of hydrodynamic and free molecular flow in various regions around the nucleus. Experimental data are used to derive physical parameters near the nuclei of comets 1952 III, 1955 V, 1957 III, and 1960 II and the rate of decrease of mass. The possibility of chemical reactions in the region close to the nucleus is discussed. Gas condensation is shown to be a possible cause of dust formation under the conditions existing near the nucleus, and this process may be responsible for the major portion of the cometary dust component. The observed grouping of synchrones in the cometary tail can be explained on the assumption that the nuclear surface comprises two (or more) areas differing essentially in evaporation rate, the amount of matter ejected varying over the rotation period of the nucleus. Charged dust particles are shown to form, with electrons and ions, a common medium, i.e., dust plasma, which can be treated by the same methods used for ordinary plasma. Special investigations appear to be desirable when comets intersect meteor streams.

scholarly journals New incoherent scatter diagnostic methods for the heated D-region ionosphere

2008 ◽  
Vol 26 (8) ◽  
pp. 2273-2279 ◽  
Author(s):  
A. Kero ◽  
J. Vierinen ◽  
C.-F. Enell ◽  
I. Virtanen ◽  
E. Turunen
Keyword(s):  
Electron Temperature ◽  
Signal To Noise Ratio ◽  
Diagnostic Technique ◽  
Diagnostic Methods ◽  
Maximum Effect ◽  
Ion Chemistry ◽  
Vhf Radar ◽  
Incoherent Scatter ◽  
Target Plasma ◽  
D Region

Abstract. A new incoherent scatter (IS) diagnostic technique for the actively heated D-region ionosphere is presented. In this approach, an exponential autocorrelation function (ACF) was fitted to the data by using a Markov Chain Monte Carlo (MCMC) inversion and the Sodankylä Ion Chemistry model (SIC). The method was applied for a set of combined EISCAT heating and VHF radar experiments carried out in November 2006. A newly designed radar experiment, sippi, based on optimised phase codes and direct sampling of the transmitted and the received IS signal, was used to produce ACF estimates of the target plasma. Systematic features associated with the heating were found by comparing the mean ACFs corresponding to heated and unheated periods. However, the data analysis revealed reasonable electron temperature estimates at the altitudes of the expected maximum effect (70–75 km) only in three cases out of six, corresponding to the highest signal-to-noise ratio (SNR) conditions. In two of these cases, the electron temperature was increased by a factor of 5 to 7, which is in a good agreement with the theoretical heating modelling. In the case of the first presented data example, the model overestimates the effect. These are the first successful IS observations of the HF-induced maximum electron temperature enhancements in the D-region ionosphere.

scholarly journals First EISCAT measurement of electron-gas temperature in the artificially heated D-region ionosphere

2000 ◽  
Vol 18 (9) ◽  
pp. 1210-1215 ◽  
Author(s):  
A. Kero ◽  
T. Bösinger ◽  
P. Pollari ◽  
E. Turunen ◽  
M. Rietveld
Keyword(s):  
Electron Temperature ◽  
Electron Gas ◽  
Density Wave ◽  
Integration Time ◽  
Maximum Effect ◽  
Gas Temperature ◽  
Plasma Parameters ◽  
Vhf Radar ◽  
Incoherent Scatter ◽  
D Region

Abstract. The ionospheric electron gas can be heated artificially by a powerful radio wave. According to our modeling, the maximum effect of this heating occurs in the D-region where the electron temperature can increase by a factor of ten. Ionospheric plasma parameters such as Ne, Te and Ti are measured by EISCAT incoherent scatter radar on a routine basis. However, in the D-region the incoherent scatter echo is very weak because of the low electron density. Moreover, the incoherent scatter spectrum from the D-region is of Lorentzian shape which gives less information than the spectrum from the E- and F-regions. These make EISCAT measurements in the D-region difficult. A combined EISCAT VHF-radar and heating experiment was carried out in November 1998 with the aim to measure the electron temperature increase due to heating. In the experiment the heater was switched on/off at 5 minute intervals and the integration time of the radar was chosen synchronously with the heating cycle. A systematic difference in the measured autocorrelation functions was found between heated and unheated periods.Key words: Ionosphere (active experiments; plasma temperature and density; wave propagation)

Scattering of electromagnetic waves by a distribution of charged dust particles in space plasmas

1992 ◽  
Vol 97 (A5) ◽  
pp. 6261 ◽  
Author(s):  
U. de Angelis ◽  
A. Forlani ◽  
V. N. Tsytovich ◽  
R. Bingham
Keyword(s):  
Electromagnetic Waves ◽  
Dust Particles ◽  
Space Plasmas ◽  
Charged Dust

Antiprobcotron magnetic trap for charged dust particles in space experiments

2019 ◽  
pp. 20-29
Author(s):  
Lev G. D’YACHKOV ◽  
Mikhail M. VASILYEV ◽  
Oleg F. PETROV ◽  
Sergey F. SAVIN ◽  
Igor V. CHURILO
Keyword(s):  
Magnetic Trap ◽  
Space Station ◽  
Coulomb Systems ◽  
Inhomogeneous Magnetic Field ◽  
Dust Particles ◽  
Charged Dust ◽  
Magnetic Traps ◽  
Space Experiments ◽  
Microgravity Conditions ◽  
New Space

We discuss the possibility of using static magnetic traps as an alternative to electrostatic traps for forming and confining structures of charged dust particles in a gas discharge plasma in the context of our study of strongly interacting Coulomb systems. Some advantages of confining structures in magnetic traps over electrostatic ones are shown. Also we provide a review of the related researches carried out first in laboratory conditions, and then under microgravity conditions including the motivation of performing the experiments aboard the International Space Station (ISS). The preparations of a new space experiment «Coulomb-magnet» as well as the differences of a new equipment from previously used are described. We proposed the main tasks of the new experiment as a study of the dynamics and structure of active monodisperse and polydisperse macroparticles in an inhomogeneous magnetic field under microgravity conditions, including phase transitions and the evolution of such systems in the kinetic heating of dust particles by laser radiation. Key words: Coulomb structures, magnetic trap, antiprobotron, diamagnetic particles, dust particles, microgravity.

scholarly journals A new method of inferring the size, number density, and charge of mesospheric dust from its in situ collection by the DUSTY probe

2019 ◽  
Vol 12 (3) ◽  
pp. 1673-1683 ◽  
Author(s):  
Ove Havnes ◽  
Tarjei Antonsen ◽  
Gerd Baumgarten ◽  
Thomas W. Hartquist ◽  
Alexander Biebricher ◽  
...  
Keyword(s):  
New Method ◽  
Production Model ◽  
Dust Particles ◽  
Bottom Plate ◽  
Charged Dust ◽  
Fundamental Parameters ◽  
Dust Charge ◽  
Analysis Technique ◽  
June July ◽  
The Impact

Abstract. We present a new method of analyzing measurements of mesospheric dust made with DUSTY rocket-borne Faraday cup probes. It can yield the variation in fundamental dust parameters through a mesospheric cloud with an altitude resolution down to 10 cm or less if plasma probes give the plasma density variations with similar height resolution. A DUSTY probe was the first probe that unambiguously detected charged dust and aerosol particles in the Earth's mesosphere. DUSTY excluded the ambient plasma by various biased grids, which however allowed dust particles with radii above a few nanometers to enter, and it measured the flux of charged dust particles. The flux measurements directly yielded the total ambient dust charge density. We extend the analysis of DUSTY data by using the impact currents on its main grid and the bottom plate as before, together with a dust charging model and a secondary charge production model, to allow the determination of fundamental parameters, such as dust radius, charge number, and total dust density. We demonstrate the utility of the new analysis technique by considering observations made with the DUSTY probes during the MAXIDUSTY rocket campaign in June–July 2016 and comparing the results with those of other instruments (lidar and photometer) also used in the campaign. In the present version we have used monodisperse dust size distributions.

Future lunar missions and investigation of dusty plasma processes on the Moon

2013 ◽  
Vol 79 (4) ◽  
pp. 405-411 ◽  
Author(s):  
SERGEY I. POPEL ◽  
LEV M. ZELENYI
Keyword(s):  
Dusty Plasma ◽  
Lunar Surface ◽  
Dust Particles ◽  
Maximum Height ◽  
Charged Dust ◽  
The Moon ◽  
Plasma System ◽  
Lunar Dust ◽  
The Impact ◽  
Dusty Plasma System

AbstractFrom the Apollo era of exploration, it was discovered that sunlight was scattered at the terminators giving rise to “horizon glow” and “streamers” above the lunar surface. Subsequent investigations have shown that the sunlight was most likely scattered by electrostatically charged dust grains originating from the surface. A renaissance is being observed currently in investigations of the Moon. The Luna-Glob and Luna-Resource missions (the latter jointly with India) are being prepared in Russia. Some of these missions will include investigations of lunar dust. Here we discuss the future experimental investigations of lunar dust within the missions of Luna-Glob and Luna-Resource. We consider the dusty plasma system over the lunar surface and determine the maximum height of dust rise. We describe mechanisms of formation of the dusty plasma system over the Moon and its main properties, determine distributions of electrons and dust over the lunar surface, and show a possibility of rising dust particles over the surface of the illuminated part of the Moon in the entire range of lunar latitudes. Finally, we discuss the effect of condensation of micrometeoriod substance during the expansion of the impact plume and show that this effect is important from the viewpoint of explanation of dust particle rise to high altitudes in addition to the dusty plasma effects.

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