scholarly journals Upgrade of the YerPhI polarization Lidar System for using Polarization of the Elastic and Raman Backscattered Beams

2019 ◽  
Vol 197 ◽  
pp. 03005
Author(s):  
A. Ghalumyan ◽  
K. Apresyan ◽  
A. Chilingaryan ◽  
V. Ghazaryan
Keyword(s):  
Electric Fields ◽  
Gamma Ray ◽  
Beam Polarization ◽  
Lidar System ◽  
Density Profiles ◽  
Electrical Fields ◽  
Polarized Beams ◽  
Electrical State ◽  
Atmospheric Backscatter ◽  
Telescope System

A powerful two-frequency lidar system using polarized beams has been developed at YerPhI. The system is completed with laser beam polarization changers and nitrogen and water Raman channels for investigation of the influence of atmospheric electric fields on the elastic and Raman backscattered beams polarization. At present, the system is being tuned for measuring vertical atmospheric backscatter profiles of aerosols and hydrometeors, analyze the depolarization ratio of elastic backscattered laser beams and investigate the influence of external factors on the beam polarization. Laser light that is reflected from the air and from clouds carries information on density profiles, aerosols and electrical fields. Applications of this system will be the investigation of the electrical state of the atmosphere during thunderstorms [1-3] on Mt Aragats, and, possibly the monitoring of the atmosphere at the site of the upcoming Cherenkov Telescope Array (CTA). CTA is expected to provide unprecedented sensitivity for gamma ray detection in the energy range of 30 GeV to 300 TeV. To fully exploit the potential of the telescope system it is important to characterize the optical and electrical properties of the atmosphere. A lidar system for the continuous monitoring of the atmosphere is the tool of choice.

scholarly journals Semicircular Patch-Embedded Vivaldi Antenna for Miniaturized UWB Radar Sensors

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 5988
Author(s):  
Jungwoo Seo ◽  
Jae Hee Kim ◽  
Jungsuek Oh
Keyword(s):  
Electric Fields ◽  
Impedance Matching ◽  
Low Frequency ◽  
Electrical Fields ◽  
Radar Sensors ◽  
Gain Enhancement ◽  
Uwb Radar ◽  
Vivaldi Antenna ◽  
Matching Techniques ◽  
Good Agreement

A microstrip-to-slot line-fed miniaturized Vivaldi antenna using semicircular patch embedment is proposed in this study. The conventional Vivaldi antenna has ultrawide bandwidth, but suffers from low gain in the low-frequency band. The proposed antenna topology incorporates the embedment of semicircular patch elements into the side edge of the antenna. This enables the phases of electric fields at both ends of the antenna to be out of phase. Since the distance between the two ends are λL/2 where λL is the wavelength at a low operating frequency, this antenna topology can achieve the constructive addition of electrical fields at the radiating end, leading to gain enhancement at the chosen low frequency. In comparison with the conventional Vivaldi antenna, the proposed antenna has a wider bandwidth from 2.84 to 9.83 GHz. Moreover, the simulated result shows a gain enhancement of 5 dB at low frequency. This cannot be realized by the conventional low-band impedance matching techniques only relying on slotted topologies. The measured results of this proposed antenna with a size of 45 × 40 × 0.8 mm3 are in good agreement with the simulated results.

Quantum field theory of optical birefringence phenomena II. Birefringence induced by static and optical electric fields

1968 ◽  
Vol 306 (1484) ◽  
pp. 119-134 ◽  
Keyword(s):  
Light Beam ◽  
Electric Fields ◽  
Kerr Effect ◽  
Optical Kerr Effect ◽  
Operator Formalism ◽  
Optical Birefringence ◽  
Electrical Fields ◽  
Intense Light ◽  
Intense Light Beam ◽  
Angle Of Rotation

The scattering matrix technique in conjunction with the Stokes’s operator formalism for characterizing the polarization of a light beam which was developed in a previous paper (Atkins & Barron 1968) is applied to the description of the optical birefringence induced in fluid materials by electrical fields. The fields considered are both static (the Kerr effect), arise from a second, intense light beam (the optical Kerr effect) or from the measuring beam itself. The last phenomenon causes the polarization ellipse to rotate and affects the angle of rotation induced by optically active molecules.

scholarly journals GRB spectral parameter modeling

2010 ◽  
Vol 6 (S274) ◽  
pp. 243-245
Author(s):  
Gregory D. Fleishman ◽  
Fedor A. Urtiev
Keyword(s):  
Synchrotron Radiation ◽  
Electric Fields ◽  
Large Scale ◽  
Gamma Ray ◽  
Small Scale ◽  
Random Waves ◽  
Spectral Parameters ◽  
Random Magnetic Field ◽  
Cross Correlations ◽  
Accelerated Particles

AbstractFireball model of the gamma-ray bursts (GRBs) predicts generation of numerous internal shocks, which efficiently accelerate charged particles and generate relatively small-scale stochastic magnetic and electric fields. The accelerated particles diffuse in space due to interaction with the random waves and so emit so called Diffusive Synchrotron Radiation (DSR) in contrast to standard synchrotron radiation they would produce in a large-scale regular magnetic fields. In this contribution we present key results of detailed modeling of the GRB spectral parameters, which demonstrate that the non-perturbative DSR emission mechanism in a strong random magnetic field is consistent with observed distributions of the Band parameters and also with cross-correlations between them.

Electrically Assisted Aerosol Reactors using Ring Electrodes

1998 ◽  
Vol 520 ◽  
Author(s):  
H. Briesen ◽  
A. Fuhrmann ◽  
S. E. Pratsinis
Keyword(s):  
Particle Size ◽  
Electric Fields ◽  
Optical Fibers ◽  
Total Production ◽  
Electrical Fields ◽  
Synthesis Of Nanoparticles ◽  
Practical Applications ◽  
Electrically Assisted ◽  
Aerosol Reactors ◽  
Electrostatic Dispersion

ABSTRACTNanostructured materials have distinctly different properties than the bulk because the number of atoms or molecules on their surface is comparable to that inside the particles creating a number of new materials and applications. Despite this potential for nanoparticles, very few practical applications have been developed because of the current high cost of these materials ($100/lb). On the other hand, flame aerosol reactors are routinely used for inexpensive production (∼$1/lb) of submicron sized commodities such as carbon blacks, pigmentary titania, fumed silica and preforms for optical fibers in telecommunications. Flame technology can be used also for synthesis of nanoparticles with precisely controlled characteristics. In these reactors, gas mixing is used to widely control the primary particle size and crystallinity of product powders while electric fields can be used to narrowly control the primary, and aggregate particle size and crystallinity. Here the application of axial electrical fields on a silica producing flame using hexamethyldisiloxane (HMDS) as precursor is presented. Experiments varying the precursor delivery rate corresponding to total production rates of 10, 20 and 30 g/h are presented. Electric fields decreased the particle size by electrostatic dispersion and repulsion of charged particles and by the reduced particle residence time inside the flame.

scholarly journals An investigation of the influence of electric fields on spectral lines: preliminary note

1906 ◽  
Vol 78 (521) ◽  
pp. 80-81
Keyword(s):  
Electric Fields ◽  
Electric Discharge ◽  
Wave Length ◽  
Spectral Lines ◽  
Mercury Vapour ◽  
Special Design ◽  
Preliminary Note ◽  
Electrical Fields ◽  
Interference Fringes ◽  
Discharge Tubes

In general the electrical fields used were those concomitant with the luminous electric discharge. An interferometer of the Michelson form and an echelon spectroscope of 18 plates were used to analyse the radiations. The results may be summarised as follows:— (1) End-on discharge tubes of special design, in which the light-source was a uniform column of luminous mercury vapour viewed in the direction of discharge, showed no change of wave-length as great as 1 part in 4,000,000 when the direction of the discharge was reversed. The pressure in the tube was varied from a few millimetres to a vacuum so high that there was but little luminosity. (2) The passage of Röntgen rays through the tube did not alter the wave-length nor the width of the mercury lines, to an extent sufficient to affect the visibility of interference fringes formed with a difference of path of 400,000 waves. When the luminous column was viewed at right angles to the direction of the discharge no polarisation effects in the radiation from it, due to the passage of the Röntgen rays, could be detected by a sensitive Savart plate and Nicol prism.

Optical optimization of organic solar cell with bulk heterojunction

2014 ◽  
Vol 22 (2) ◽  
Author(s):  
E. Gondek
Keyword(s):  
Electric Fields ◽  
Active Layer ◽  
Organic Solar Cell ◽  
Bulk Heterojunction ◽  
Photovoltaic Cell ◽  
Antireflection Coating ◽  
Generation Rate ◽  
Electrical Fields ◽  
Optical Transfer ◽  
The Relationship

AbstractThe work is devoted to the optimization of layer thickness in an organic photovoltaic cell. It presents the applied calculation method which is based on the optical transfer matrix 2×2 formalism. We present the influence of thickness of a PEDOT:PSS layer and of an active layer on the normalized modulus squared of optical electric fields distribution inside devices and on the distributions of exciton generation rate. We present the relationship between optimal thicknesses of the PEDOT:PSS layer and the active layer. We also present the influence of antireflection coating on distributions of optical electrical fields, as well as the distributions of exciton generation rate. Perpendicular and oblique illumination of the photovoltaic structure is discussed.

scholarly journals A Complete Mission Concept Design and Analysis of the Student-Led CubeSat Project: Light-1

Aerospace ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 247
Author(s):  
Aaesha Almazrouei ◽  
Aaliya Khan ◽  
Abdullah Almesmari ◽  
Ahmed Albuainain ◽  
Ahmed Bushlaibi ◽  
...  
Keyword(s):  
United Arab Emirates ◽  
Electric Fields ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Thunderstorm Activity ◽  
Low Earth Orbit ◽  
Concept Design ◽  
Silicon Photomultipliers ◽  
Strong Electric Fields ◽  
Future Plans

Terrestrial gamma ray flashes (TGF) are intense and prompt bursts of X- and gamma-rays of up to 100 MeV of energy. Typically associated with thunderstorm activity, TGFs are produced by bremsstrahlung effects of electrons accelerated in strong electric fields generated by lightning. TGFs can be effectively targeted by gamma detectors with enhanced time stamping capabilities onboard of satellites operating at near-Earth low obits (LEO) [1]. Light-1 is a miniature satellite, a 3U CubeSat designed to detect, monitor and study terrestrial gamma ray flashes in low Earth orbit. The two payload detectors are composed of a photomultiplier tube and silicon photomultipliers. The two detectors are mounted at two ends of the CubeSat and the proposed orientation of the CubeSat will ensure maximum TGF detection probability. To allow an increased frequency of data downlink, Khalifa University has collaborated with NanoAvionics Corp, and hence Light-1 has access to three ground stations situated across the map, Abu Dhabi in United Arab Emirates, Vilnius in Lithuania, and Aalborg in Denmark. The satellite expected to launch in late-2021 is currently in its assembly and integration phase. This paper describes mission, concept, objectives, success criteria, design, analysis, status, and the future plans of Light-1 satellite.

Seismo-ionospheric precursors of the 14 November 2019 M7.1 Indonesia Earthquake detected by FORMOSAT-7/COSMIC-2

2020 ◽  
Author(s):  
Jann-Yenq Liu ◽  
Chi-Yen Lin ◽  
Fu-Yuan Chang ◽  
Yuh-Ing Chen
Keyword(s):  
Electron Density ◽  
Electric Fields ◽  
Radio Occultation ◽  
Electron Content ◽  
Ion Temperature ◽  
Density Profiles ◽  
Ion Density ◽  
Total Electron ◽  
Ion Velocity ◽  
Electron Density Profiles

<p>FORMOSAT-7/COSMIC-2 (F7/C2), with the mission orbit of 550 km altitude, 24-deg inclination, and a period of 97 minutes, was launched on 25 June 2019.  Tri-GNSS Radio occultation System (TGRS), Ion Velocity Meter (IVM), and RF beacon onboard F7/C2 six small satellites allow scientists to observe the plasma structure and dynamics in the mid-latitude, low-latitude, and equatorial ionosphere in detail.  F7/C2 TGRS sounds ionospheric RO (radio occultation) electron density profiles, while F7/C2 IVM probes the ion density, ion temperature, and ion velocity at the satellite altitude.  The F7/C2 electron density profiles and the ion density, ion temperature, and ion velocity, as well as the global ionospheric map (GIM) of the total electron content (TEC) derived from global ground-based GPS receivers are used to detect seismo-ionospheric precursors (SIPs) of the 14 November 2019 M7.1 Indonesia Earthquake.  The GIM TEC and F7/C2 RO NmF2 significantly increase specifically over the epicenter on 25-26 October, which indicates SIPs of the 14 November 2019 M7.1 Indonesia Earthquake being detected.  The F7/C2 RO electron density profiles upward motions suggest that the eastward electric fields have been enhanced during the SIP days of the 2019 M7.1 Indonesia earthquake.  The seismo-generated electric fields of the 2019 M7.1 Indonesia earthquake are 0.34-0.64 mV/m eastward.  The results demonstrate that F7/C2 can be employed to detect SIPs in the ionospheric plasma, which shall shed some light on earthquake prediction/forecast.</p>

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