Auroral electrodynamics---investigation by a dual sounding rocket experiment

2020 ◽  
Author(s):  
Hassanali Akbari ◽  
Robert Pfaff ◽  
Keyword(s):  
Electric Fields ◽  
Sounding Rocket ◽  
Sounding Rockets ◽  
Neutral Winds ◽  
Incoherent Scatter ◽  
Ac Electric Fields ◽  
Numerical Studies ◽  
Rocket Experiment ◽  
N Wave

<p>We present results from a 2017 sounding rocket experiment in which two NASA sounding rockets were simultaneously launched into the auroral ionosphere. The rockets included comprehensive instrumentation to measure DC and AC electric fields, magnetic fields, energetic particles, plasma density, and neutral winds, among other parameters, and achieved apogees of 190 and 330 km. This unprecedented collection of in-situ measurements obtained at two altitudes over an auroral arc, along with conjugate ground-based measurements by the Poker Flat incoherent scatter radar and all-sky cameras, enable us to investigate the behavior of an aurora arc and its associated electrodynamics. A prominent feature of our observations is the presence of localized, large-amplitude Alfvén wave structures observed in both the electric field and magnetometers at altitudes as low as 190 km in the vicinity of up- and down-ward current regions. The observations are discussed in the context of ionospheric feedback instability. The results are compared to predictions of previously published numerical studies and other sounding rocket observations.</p>

scholarly journals Signatures of mesospheric particles in ionospheric data

2009 ◽  
Vol 27 (2) ◽  
pp. 823-829 ◽  
Author(s):  
M. Friedrich ◽  
K. M. Torkar ◽  
W. Singer ◽  
I. Strelnikova ◽  
M. Rapp ◽  
...  
Keyword(s):  
Electron Density ◽  
Indirect Evidence ◽  
Meteor Radar ◽  
Sounding Rockets ◽  
Close Vicinity ◽  
Incoherent Scatter ◽  
Summer Echoes ◽  
In Situ Observations ◽  
Mf Radar

Abstract. The state of the ionosphere during the 2007 ECOMA/MASS campaign is described by in-situ observations by three sounding rockets launched from the Andøya Rocket Range and by ground based observations. The ground based measurements included the incoherent scatter radar EISCAT near Tromsø (both on UHF and VHF), as well as an MF radar, a meteor radar and an imaging riometer all located in the close vicinity of the rocket range. The pronounced electron density bite-outs seen by two of the rockets could not be detected from the ground, but the associated PMSE (Polar Mesospheric Summer Echoes) provide indirect evidence of pronounced perturbations of mesospheric electron densities.

AC Electrophoresis, a New Technique for Deposition of Ceramic Nanoparticles; Introduction, Application and Mechanism

2012 ◽  
Vol 507 ◽  
pp. 41-45 ◽  
Author(s):  
Reza Riahifar ◽  
Babak Raissi ◽  
Ehsan Marzbanrad ◽  
Cyrus Zamani
Keyword(s):  
Electric Fields ◽  
Applied Field ◽  
Aqueous Suspension ◽  
Mutual Effect ◽  
Device Fabrication ◽  
Frequency Range ◽  
Ceramic Nanoparticles ◽  
Ac Electric Fields ◽  
A New Technique

Deposition of ceramic nanoparticles (dispersed in non-aqueous suspension) on in-plane electrodes and under the influence of AC electric fields in the frequency range of 0.01 Hz - 10 kHz is investigated. Analysis of the particle response to the applied field is a difficult task due to the mutual effect of electric and hydrodynamic forces which are present in the system. In this work, however, we show the possibility of dividing the frequency range into four domains with four distinct governing mechanisms. Possible mechanisms are suggested and dominant forces are determined for each domain. In situ optical microscopy observations are used for visualization of nanoparticles´ movement dispersed in liquid medium. These observations show that applying AC electrophoresis at frequencies below 10 kHz is an effective way for manipulating ceramic nanoparticles and device fabrication.

scholarly journals Calculation of meridional neutral winds in middle latitudes from the Irkutsk incoherent scatter radar data

2015 ◽  
Vol 1 (3) ◽  
pp. 37-48
Author(s):  
Александр Щербаков ◽  
Aleksandr Shcherbakov ◽  
Андрей Медведев ◽  
Andrey Medvedev ◽  
Дмитрий Кушнарев ◽  
...  
Keyword(s):  
Electric Fields ◽  
Radar Data ◽  
Special Technique ◽  
Incoherent Scatter Radar ◽  
Neutral Winds ◽  
Incoherent Scatter ◽  
Plasma Drift ◽  
Middle Latitudes ◽  
Scatter Radar ◽  
The Impact

The paper sequentially presents technique for determining velocity of meridional neutral winds from the Irkutsk Incoherent Scatter Radar (IISR) data. Due to IISR specific features effective at other IS radars, techniques for determining ionosphere parameters, in particular plasma drift velocities, resulted in considerable variance of defined parameters. To measure the plasma drift velocity taking into account such IISR features, we have developed a special technique based on phase analysis of autocorrelation function of incoherent scatter signal. The technique needs to be tested, and for this purpose, an experiment was carried out to measure velocities of low-orbit satellites. However, methods for meridional neutral wind calculations used by many authors [Evans, 1970] with the use of drift velocities obtained before, resulted in great disagreements with empirical HWM93 and HWM07 wind models. In addition, simultaneous measurements at two frequencies at IISR showed that it was difficult to explain such differences without taking into account the cross-field movements. Possible underestimation of the impact of movements generated by electric fields can result in serious error in determining wind velocities. The paper considers improvements for methods of calculating winds, and shows that the results obtained with it are in a better agreement with wind models.

PMWE creation mechanism inferred from sounding rocket measurements

2021 ◽  
Author(s):  
Boris Strelnikov ◽  
Keyword(s):  
Electron Density ◽  
Current Knowledge ◽  
Sounding Rocket ◽  
Small Scale ◽  
Sounding Rockets ◽  
Smoke Particles ◽  
The North ◽  
Air Turbulence ◽  
Rocket Measurements

<p>A first sounding rocket campaign dedicated to investigate the creation mechanism of Polar Mesosphere Winter Echoes (PMWE) was conducted in April 2018 from the north Norwegian Andøya Space Center (69°N, 16°E). Two instrumented sounding rockets were launched on 13th and 18th of April under PMWE and no-PMWE conditions, respectively.</p><p>In this paper we give a brief summary of our current knowledge of PMWE and an overview of the PMWE sounding rocket mission. We describe and discuss some results of combined in situ and ground-based measurements which allow <span>to</span> <span>check</span> the existing PMWE theories.</p><p>Our measurements clearly show that the coherent structures in refractive index variations (forming PMWE) are accompanied by neutral air turbulence, which is reflected in small-scale structures (down to some meters) of neutral and electron density. We show that the behavior of the structures under investigation together with the atmospheric background is consistent with the interpretation, that PMWE were created by turbulence. Rocket measurements ultimately show that polar winter mesosphere is abounded with meteor smoke particles (MSP) and intermittent turbulent layers. Furthermore, it becomes clear that charged Meteor Smoke Particles (MSP) and background electron density can only enhance SNR, while turbulence is a prerequisite for their formation.</p>

scholarly journals In-flight calibration of double-probe DC electric field measurements on Cluster

2014 ◽  
Vol 4 (1) ◽  
pp. 85-107
Author(s):  
Y. V. Khotyaintsev ◽  
P.-A. Lindqvist ◽  
C. M. Cully ◽  
A. I. Eriksson ◽  
M. André
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Field Measurements ◽  
Calibration Procedure ◽  
Double Probe ◽  
Ac Electric Fields ◽  
Dc Electric Field ◽  
Electric Field Measurements

Abstract. Double-probe electric field instrument with long wire booms is one of the most popular techniques for in situ measurement of DC and AC electric fields in plasmas on spinning spacecraft platforms, which have been employed on a large number of space missions. Here we present an overview of the calibration procedure used for the EFW instrument on Cluster, which involves spin fits of the data and correction of several offsets. We also describe the procedure for the offset determination and present results for the long-term evolution of the offsets.

scholarly journals Piezoelectric Properties of Pb1−xLax(Zr0.52Ti0.48)1−x/4O3 Thin Films Studied by In Situ X-ray Diffraction

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3338
Author(s):  
Thomas W. Cornelius ◽  
Cristian Mocuta ◽  
Stéphanie Escoubas ◽  
Luiz R. M. Lima ◽  
Eudes B. Araújo ◽  
...  
Keyword(s):  
Thin Films ◽  
Electric Fields ◽  
Lead Zirconate Titanate ◽  
Piezoelectric Properties ◽  
Lead Zirconate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ac Electric Fields ◽  
Zirconate Titanate

The piezoelectric properties of lanthanum-modified lead zirconate titanate Pb1−xLax(Zr0.52Ti0.48)1−x/4O3 thin films, with x = 0, 3 and 12 mol% La, were studied by in situ synchrotron X-ray diffraction under direct (DC) and alternating (AC) electric fields, with AC frequencies covering more than four orders of magnitude. The Bragg reflections for thin films with low lanthanum concentration exhibit a double-peak structure, indicating two contributions, whereas thin films with 12% La possess a well-defined Bragg peak with a single component. In addition, built-in electric fields are revealed for low La concentrations, while they are absent for thin films with 12% of La. For static and low frequency AC electric fields, all lanthanum-modified lead zirconate titanate thin films exhibit butterfly loops, whereas linear piezoelectric behavior is found for AC frequencies larger than 1 Hz.

Fabrication of ZrO 2 /rGO nanocomposites by flash sintering under AC electric fields

2021 ◽  
Author(s):  
Xinghua Su ◽  
Mengying Fu ◽  
Gai An ◽  
Zhihua Jiao ◽  
Qiang Tian ◽  
...  
Keyword(s):  
Electric Fields ◽  
Ac Electric Fields ◽  
Flash Sintering
Sign in / Sign up

Export Citation Format

Share Document