Journal articles: 'Coherent Microwave Scattering'

1

Duan, Xueyang, and Cathleen E. Jones. "Coherent Microwave Scattering Model of Marsh Grass." Radio Science 52, no. 12 (December 2017): 1578–95. http://dx.doi.org/10.1002/2017rs006325.

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Yang, Yuqi, Wei Luo, Bo Yin, and Yi Ren. "Electromagnetic Scattering of Rough Ground Surface Covered by Multilayers Vegetation." International Journal of Antennas and Propagation 2019 (April 11, 2019): 1–12. http://dx.doi.org/10.1155/2019/9413058.

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A microwave scattering model is proposed for the ground surface covered with multilayers vegetation. The vegetation leaves are simulated with the discrete elliptical particles in layers, which are randomly distributed above the randomly rough surface. The finite element method is applied to solve the scattering magnetic field equation based on the Dirichlet boundary, and the relationship between the radar cross section and bidirectional reflectance distribution function is deduced with the coherent scattering field. The internal mechanism of microwave scattering of multilayers vegetation is explored with the numerical results, and the relationship of vegetation growing parameter with scattering characteristic is established.

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Wu, Xuerui, Wenxiao Ma, Junming Xia, Weihua Bai, Shuanggen Jin, and Andrés Calabia. "Spaceborne GNSS-R Soil Moisture Retrieval: Status, Development Opportunities, and Challenges." Remote Sensing 13, no. 1 (December 24, 2020): 45. http://dx.doi.org/10.3390/rs13010045.

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Soil moisture is the most active part of the terrestrial water cycle, and it is a key variable that affects hydrological, bio-ecological, and bio-geochemical processes. Microwave remote sensing is an effective means of monitoring soil moisture, but the existing conventional radiometers and single-station radars cannot meet the scientific needs in terms of temporal and spatial resolution. The emergence of GNSS-R (Global Navigation Satellite Systems Reflectometry) technology provides an alternative method with high temporal and spatial resolution. An important application field of GNSS-R is soil moisture monitoring, but it is still in the initial stage of research, and there are many uncertainties and open issues. Based on a review of the current state-of-the-art of soil moisture retrieval using GNSS-R, this paper points out the limitations of existing research in observation geometry, polarization, and coherent and non-coherent scattering. The smooth surface reflectivity model, the random rough surface scattering model, and the first-order radiation transfer equation model of the vegetation, which are in the form of bistatic and full polarization, are employed. Simulations and analyses of polarization, observation geometry (scattering zenith angle and scattering azimuth angle), Brewster angle, coherent and non-coherent component, surface roughness, and vegetation effects are carried out. The influence of the EIRP (Effective Isotropic Radiated Power) and the RFI (Radio Frequency Interference) on soil moisture retrieval is briefly discussed. Several important development directions for space-borne GNSS-R soil moisture retrieval are pointed out in detail based on the microwave scattering model.

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Wu, Yue, Zhili Zhang, and Steven F. Adams. "O2 rotational temperature measurements by coherent microwave scattering from REMPI." Chemical Physics Letters 513, no. 4-6 (September 2011): 191–94. http://dx.doi.org/10.1016/j.cplett.2011.07.092.

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Tu, Hai-Tao, Kai-Yu Liao, Zuan-Xian Zhang, Xiao-Hong Liu, Shun-Yuan Zheng, Shu-Zhe Yang, Xin-Ding Zhang, Hui Yan, and Shi-Liang Zhu. "High-efficiency coherent microwave-to-optics conversion via off-resonant scattering." Nature Photonics 16, no. 4 (February 28, 2022): 291–96. http://dx.doi.org/10.1038/s41566-022-00959-3.

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Zhang, Zhili. "Quantitative Microplasma Electron Number Density Measurement by Coherent Microwave Rayleigh Scattering." IEEE Transactions on Plasma Science 39, no. 1 (January 2011): 593–95. http://dx.doi.org/10.1109/tps.2010.2088407.

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Wu, Yue, Jordan Sawyer, Zhili Zhang, Mikhail N. Shneider, and Albert A. Viggiano. "Measurement of sodium-argon cluster ion recombination by coherent microwave scattering." Applied Physics Letters 100, no. 11 (March 12, 2012): 114108. http://dx.doi.org/10.1063/1.3695064.

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Kapilevich, B., B. Litvak, T. Ben Yehuda, and O. Shotman. "Comparative characteristics of coherent and incoherent microwave scattering in dense inhomogeneous layers." Russian Physics Journal 49, no. 9 (September 2006): 913–16. http://dx.doi.org/10.1007/s11182-006-0201-y.

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Liao, Jingjuan, Tao Xu, and Guozhuang Shen. "Simulating Microwave Scattering for Wetland Vegetation in Poyang Lake, Southeast China, Using a Coherent Scattering Model." Remote Sensing 7, no. 8 (July 31, 2015): 9796–821. http://dx.doi.org/10.3390/rs70809796.

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Ranjan, Apoorv, Adam Patel, Xingxing Wang, and Alexey Shashurin. "Thomson microwave scattering for diagnostics of small plasma objects enclosed within glass tubes." Review of Scientific Instruments 93, no. 11 (November 1, 2022): 113541. http://dx.doi.org/10.1063/5.0111685.

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In this work, coherent microwave scattering in the Thomson regime was demonstrated for small-scale plasmas enclosed within a glass tube and validated using a well-known hairpin resonator probe technique. The experiments were conducted in a DC discharge tube with a diameter of 1.5 cm and a length of 7 cm. Thomson microwave scattering (TMS) diagnostics yielded electron number densities of about 5.9 × 1010 cm−3, 2.8 × 1010 cm−3, and 1.8 × 1010 cm−3 for air pressures in the discharge tube of 0.2, 0.5, and 2.5 Torr, respectively. Measurements using the TMS technique were consistent across the tested microwave frequencies of 3–3.9 GHz within the margin of error associated with non-idealities of the IQ mixer utilized in the circuit. The corresponding densities measured with the hairpin resonator probe were 4.8 × 1010, 3.8 × 1010, and 2.6 × 1010 cm−3. Discrepancies between the two techniques were within 30% and can be attributed to inaccuracies in the sheath thickness estimation required for correct interpretation of the hairpin resonator probe results.

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Galea, Christopher A., Mikhail N. Shneider, Mark Gragston, and Zhili Zhang. "Coherent microwave scattering from xenon resonance-enhanced multiphoton ionization-initiated plasma in air." Journal of Applied Physics 127, no. 5 (February 7, 2020): 053301. http://dx.doi.org/10.1063/1.5135316.

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Каныгина, О. Н., В. Л. Бердинский, М. М. Филяк, А. Г. Четверикова, В. Н. Макаров, and М. В. Овечкин. "Фазовые превращения в оксидах железа под действием микроволнового излучения." Журнал технической физики 90, no. 8 (2020): 1311. http://dx.doi.org/10.21883/jtf.2020.08.49541.308-19.

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It is shown that microwave radiation induces structure changes and, consequently, magnetic phase transitions in iron oxide alpha-Fe2O3. We subjected finely dispersed partially amorphized particles of iron oxide Fe2O3 to 10-minute-long microwave field treatment in a humid air environment. This resulted in a reduction of the hematite crystalline phase by 40%. At the same time the total fraction of crystalline components increased due to the creation of a new ferromagnetic modification which is maghemite alpha-Fe2O3. The original antiferromagnetic samples and the finial ferrimagnetic batches were powders composed of spherical particles with similar values of the area of a coherent X-ray scattering area (40-60 nm).

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Casella, D., A. Mugnai, P. Sanò, and M. Formenton. "Microwave single-scattering properties of randomly oriented soft-ice hydrometeors." Advances in Geosciences 17 (November 14, 2008): 79–85. http://dx.doi.org/10.5194/adgeo-17-79-2008.

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Abstract. Large ice hydrometeors are usually present in intense convective clouds and may significantly affect the upwelling radiances that are measured by satellite-borne microwave radiometers – especially, at millimeter-wavelength frequencies. Thus, interpretation of these measurements (e.g., for precipitation retrieval) requires knowledge of the single scattering properties of ice particles. On the other hand, shape and internal structure of these particles (especially, the larger ones) is very complex and variable, and therefore it is necessary to resort to simplifying assumptions in order to compute their single-scattering parameters. In this study, we use the discrete dipole approximation (DDA) to compute the absorption and scattering efficiencies and the asymmetry factor of two kinds of quasi-spherical and non-homogeneous soft-ice particles in the frequency range 50–183 GHz. Particles of the first kind are modeled as quasi-spherical ice particles having randomly distributed spherical air inclusions. Particles of the second kind are modeled as random aggregates of ice spheres having random radii. In both cases, particle densities and dimensions are coherent with the snow hydrometeor category that is utilized by the University of Wisconsin – Non-hydrostatic Modeling System (UW-NMS) cloud-mesoscale model. Then, we compare our single-scattering results for randomly-oriented soft-ice hydrometeors with corresponding ones that make use of: a) effective-medium equivalent spheres, b) solid-ice equivalent spheres, and c) randomly-oriented aggregates of ice cylinders. Finally, we extend to our particles the scattering formulas that have been developed by other authors for randomly-oriented aggregates of ice cylinders.

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Munoz-Martin, Joan Francesc, Raul Onrubia, Daniel Pascual, Hyuk Park, Adriano Camps, Christoph Rüdiger, Jeffrey Walker, and Alessandra Monerris. "Untangling the Incoherent and Coherent Scattering Components in GNSS-R and Novel Applications." Remote Sensing 12, no. 7 (April 9, 2020): 1208. http://dx.doi.org/10.3390/rs12071208.

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As opposed to monostatic radars where incoherent backscattering dominates, in bistatic radars, such as Global Navigation Satellite Systems Reflectometry (GNSS-R), the forward scattered signals exhibit both an incoherent and a coherent component. Current models assume that either one or the other are dominant, and the calibration and geophysical parameter retrieval (e.g., wind speed, soil moisture, etc.) are developed accordingly. Even the presence of the coherent component of a GNSS reflected signal itself has been a matter of discussion in the last years. In this work, a method developed to separate the leakage of the direct signal in the reflected one is applied to a data set of GNSS-R signals collected over the ocean by the Microwave Interferometer Reflectometer (MIR) instrument, an airborne dual-band (L1/E1 and L5/E5a), multi-constellation (GPS and Galileo) GNSS-R instrument with two 19-elements antenna arrays with 4 beam-steered each. The presented results demonstrate the feasibility of the proposed technique to untangle the coherent and incoherent components from the total power waveform in GNSS reflected signals. This technique allows the processing of these components separately, which increases the calibration accuracy (as today both are mixed and processed together), allowing higher resolution applications since the spatial resolution of the coherent component is determined by the size of the first Fresnel zone (300–500 meters from a LEO satellite), and not by the size of the glistening zone (25 km from a LEO satellite). The identification of the coherent component enhances also the location of the specular reflection point by determining the peak maximum from this coherent component rather than the point of maximum derivative of the incoherent one, which is normally noisy and it is blurred by all the glistening zone contributions.

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15

Long Liu, Kun Li, Yun Shao, Nicolas Pinel, Zhi Yang, Huaze Gong, and Longfei Wang. "Extension of the Monte Carlo Coherent Microwave Scattering Model to Full Stage of Rice." IEEE Geoscience and Remote Sensing Letters 12, no. 5 (May 2015): 988–92. http://dx.doi.org/10.1109/lgrs.2014.2371914.

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16

Veldman, Lukas M., Laëtitia Farinacci, Rasa Rejali, Rik Broekhoven, Jérémie Gobeil, David Coffey, Markus Ternes, and Alexander F. Otte. "Free coherent evolution of a coupled atomic spin system initialized by electron scattering." Science 372, no. 6545 (May 27, 2021): 964–68. http://dx.doi.org/10.1126/science.abg8223.

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Full insight into the dynamics of a coupled quantum system depends on the ability to follow the effect of a local excitation in real-time. Here, we trace the free coherent evolution of a pair of coupled atomic spins by means of scanning tunneling microscopy. Rather than using microwave pulses, we use a direct-current pump-probe scheme to detect the local magnetization after a current-induced excitation performed on one of the spins. By making use of magnetic interaction with the probe tip, we are able to tune the relative precession of the spins. We show that only if their Larmor frequencies match, the two spins can entangle, causing angular momentum to be swapped back and forth. These results provide insight into the locality of electron spin scattering and set the stage for controlled migration of a quantum state through an extended spin lattice.

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17

Schweizer, Matthias R., Alexander J. E. Kreil, Georg von Freymann, Burkard Hillebrands, and Alexander A. Serga. "Confinement of Bose–Einstein magnon condensates in adjustable complex magnetization landscapes." Journal of Applied Physics 132, no. 18 (November 14, 2022): 183908. http://dx.doi.org/10.1063/5.0123233.

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Coherent wave states such as Bose–Einstein condensates (BECs), which spontaneously form in an overpopulated magnon gas even at room temperature, have considerable potential for wave-based computing and information processing at microwave frequencies. The ability to control the transport properties of magnon BECs plays an essential role in their practical use. Here, we demonstrate the spatiotemporal control of the BEC density distribution through the excitation of magnon supercurrents in an inhomogeneously magnetized yttrium iron garnet film. The BEC is created by microwave parametric pumping and probed by Brillouin light scattering spectroscopy. The desired magnetization profile is prepared by heating the film with optical patterns projected onto its surface using a phase-based wavefront modulation technique. Specifically, we observe a pronounced spatially localized magnon accumulation caused by magnon supercurrents flowing toward each other originating in two heated regions. This accumulation effect increases the BEC lifetime due to the constant influx of condensed magnons into the confinement region. The shown approach to manipulate coherent waves provides an opportunity to extend the lifetime of freely evolving magnon BECs, create dynamic magnon textures, and study the interaction of magnon condensates formed in different regions of the sample.

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Mihalceanu, L., D. A. Bozhko, V. I. Vasyuchka, A. A. Serga, B. Hillebrands, A. Pomyalov, V. S. L'vov, and V. S. Tyberkevych. "Magnon Bose–Einstein Condensate and Supercurrents Over a Wide Temperature Range." Ukrainian Journal of Physics 64, no. 10 (November 1, 2019): 927. http://dx.doi.org/10.15407/ujpe64.10.927.

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Magnon Bose–Einstein Condensates (BECs) and supercurrents are coherent quantum phenomena, which appear on a macroscopic scale in parametrically populated solid state spin systems. One of the most fascinating and attractive features of these processes is the possibility of magnon condensation and supercurrent excitation even at room temperature. At the same time, valuable information about a magnon BEC state, such as its lifetime, its formation threshold, and coherence, is provided by experiments at various temperatures. Here, we use Brillouin Light Scattering (BLS) spectroscopy for the investigation of the magnon BEC dynamics in a single-crystal film of yttrium iron garnet in a wide temperature range from 30 K to 380K. By comparing the BLS results with previous microwave measurements, we revealed the direct relation between the damping of the condensed and the parametrically injected magnons. The enhanced supercurrent dynamics was detected at 180 K near the minimum of BEC damping.

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Obrusník, A., P. Synek, S. Hübner, J. J. A. M. van der Mullen, L. Zajíčková, and S. Nijdam. "Coherent and incoherent Thomson scattering on an argon/hydrogen microwave plasma torch with transient behaviour." Plasma Sources Science and Technology 25, no. 5 (September 9, 2016): 055018. http://dx.doi.org/10.1088/0963-0252/25/5/055018.

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20

Zhang, Zhili, and Mikhail N. Shneider. "Measurement of plasma decay processes in mixture of sodium and argon by coherent microwave scattering." Physics of Plasmas 17, no. 3 (March 2010): 033108. http://dx.doi.org/10.1063/1.3356053.

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21

Aryshev, A., A. Araki, M. Fukuda, P. Karataev, G. Naumenko, A. Potylitsyn, K. Sakaue, L. Sukhikh, J. Urakawa, and D. Verigin. "Development of microwave and soft X-ray sources based on coherent radiation and Thomson scattering." Journal of Physics: Conference Series 236 (June 1, 2010): 012009. http://dx.doi.org/10.1088/1742-6596/236/1/012009.

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Funke, K., T. Lauxtermann, D. Wilmer, and S. M. Bennington. "Creation and Recombination of Frenkel Defects in AgBr." Zeitschrift für Naturforschung A 50, no. 6 (June 1, 1995): 509–20. http://dx.doi.org/10.1515/zna-1995-0601.

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Abstract Complete ionic conductivity spectra as well as quasielastic and inelastic neutron scattering spectra have been taken of solid silver bromide at various temperatures. High-amplitude vibrational movements, essentially of the silver ions, contribute to both kinds of spectra. In particular, a conductivity maximum, located at about 500 GHz, reflects oscillations of individual silver ions along directions. -The microwave and millimetre-wave conductivities are dominated by a thermally activated Debye-type relaxation process. The effect is consistently explained by the frequent hopping of silver ions from regular octahedral lattice sites into tetrahedral interstitial sites and back again, i.e., by the frequent creation and recombination of Frenkel pairs. -The effect is also responsible for the existence of thermally activated quasielastic components in the neutron scattering spectra. The width of the coherent quasielastic scattering shows that the forward-backward hopping of a silver ion is accompanied by fast correlated movements of ions in its immediate neighbourhood.

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Proksch, M., C. Mätzler, A. Wiesmann, J. Lemmetyinen, M. Schwank, H. Löwe, and M. Schneebeli. "MEMLS3&a: Microwave Emission Model of Layered Snowpacks adapted to include backscattering." Geoscientific Model Development Discussions 8, no. 3 (March 6, 2015): 2605–52. http://dx.doi.org/10.5194/gmdd-8-2605-2015.

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Abstract. The Microwave Emission Model of Layered Snowpacks (MEMLS) was originally developed for microwave emissions of snowpacks in the frequency range 5–100 GHz. It is based on six-flux theory to describe radiative transfer in snow including absorption, multiple volume scattering, radiation trapping due to internal reflection and a combination of coherent and incoherent superposition of reflections between horizontal layer interfaces. Here we introduce MEMLS3&a, an extension of MEMLS, which includes a backscatter model for active microwave remote sensing of snow. The reflectivity is decomposed into diffuse and specular components. Slight undulations of the snow surface are taken into account. The treatment of like and cross polarization is accomplished by an empirical splitting parameter q. MEMLS3&a (as well as MEMLS) is set up in a way that snow input parameters can be derived by objective measurement methods which avoids fitting procedures of the scattering efficiency of snow, required by several other models. For the validation of the model we have used a combination of active and passive measurements from the NoSREx campaign in Sodankylä, Finland. We find a reasonable agreement between the measurements and simulations, subject to uncertainties in hitherto unmeasured input parameters of the backscatter model. The model is written in MATLAB and the code is publicly available for download through the following website: http://www.iapmw.unibe.ch/research/projects/snowtools/memls.html.

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Tsang, Leung, Tien-Hao Liao, Ruoxing Gao, Haokui Xu, Weihui Gu, and Jiyue Zhu. "Theory of Microwave Remote Sensing of Vegetation Effects, SoOp and Rough Soil Surface Backscattering." Remote Sensing 14, no. 15 (July 29, 2022): 3640. http://dx.doi.org/10.3390/rs14153640.

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In this paper, we provide updates on our recent work on the theory of microwave remote sensing for applications in remote sensing of soil moisture and snow water equivalent (SWE). The three topics are the following. (i) For the effects of forests and vegetation, we developed the hybrid method of NMM3D full-wave simulations over the vegetation field and forest canopies. In the hybrid method, we combined the use of commercial off-the-shelf software and wave multiple scattering theory (W-MST). The results showed much larger transmission than classical radiative transfer theory. (ii) In signals of opportunity at L-band and P-band, which are radar bistatic scattering in the vicinity of the specular direction, we developed the Analytical Kirchhoff solution (AKS) and Numerical Kirchhoff approach (NKA) in the calculations of coherent waves and incoherent waves. We also took into account of the effects of topographical elevations and slopes which have strong influences. (iii) In rough surface radar backscattering, we used the volume integral equation approach for NMM3D full-wave simulations for soil surfaces with kh up to 15. The simulations were calculated for the X-band and Ku-band and the results showed saturation effects. The simulation results can be applied to microwave remote sensing of SWE at these two frequencies.

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Proksch, M., C. Mätzler, A. Wiesmann, J. Lemmetyinen, M. Schwank, H. Löwe, and M. Schneebeli. "MEMLS3&a: Microwave Emission Model of Layered Snowpacks adapted to include backscattering." Geoscientific Model Development 8, no. 8 (August 24, 2015): 2611–26. http://dx.doi.org/10.5194/gmd-8-2611-2015.

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Abstract. The Microwave Emission Model of Layered Snowpacks (MEMLS) was originally developed for microwave emissions of snowpacks in the frequency range 5–100 GHz. It is based on six-flux theory to describe radiative transfer in snow including absorption, multiple volume scattering, radiation trapping due to internal reflection and a combination of coherent and incoherent superposition of reflections between horizontal layer interfaces. Here we introduce MEMLS3&a, an extension of MEMLS, which includes a backscatter model for active microwave remote sensing of snow. The reflectivity is decomposed into diffuse and specular components. Slight undulations of the snow surface are taken into account. The treatment of like- and cross-polarization is accomplished by an empirical splitting parameter q. MEMLS3&a (as well as MEMLS) is set up in a way that snow input parameters can be derived by objective measurement methods which avoid fitting procedures of the scattering efficiency of snow, required by several other models. For the validation of the model we have used a combination of active and passive measurements from the NoSREx (Nordic Snow Radar Experiment) campaign in Sodankylä, Finland. We find a reasonable agreement between the measurements and simulations, subject to uncertainties in hitherto unmeasured input parameters of the backscatter model. The model is written in Matlab and the code is publicly available for download through the following website: http://www.iapmw.unibe.ch/research/projects/snowtools/memls.html.

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Stefko, Marcel, Silvan Leinss, Othmar Frey, and Irena Hajnsek. "Coherent backscatter enhancement in bistatic Ku- and X-band radar observations of dry snow." Cryosphere 16, no. 7 (July 19, 2022): 2859–79. http://dx.doi.org/10.5194/tc-16-2859-2022.

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Abstract. The coherent backscatter opposition effect (CBOE) enhances the backscatter intensity of electromagnetic waves by up to a factor of 2 in a very narrow cone around the direct return direction when multiple scattering occurs in a weakly absorbing, disordered medium. So far, this effect has not been investigated in terrestrial snow in the microwave spectrum. It has also received little attention in scattering models. We present the first characterization of the CBOE in dry snow using ground-based and spaceborne bistatic radar systems. For a seasonal snowpack in the Ku-band (17.2 GHz), we found backscatter enhancement of 50 %–60 % (+1.8–2.0 dB) at a zero bistatic angle and a peak half-width at half-maximum (HWHM) of 0.25∘. In the X-band (9.65 GHz), we found backscatter enhancement of at least 35 % (+1.3 dB) and an estimated HWHM of 0.12∘ in the accumulation areas of glaciers in the Jungfrau–Aletsch region, Switzerland. Sampling of the peak shape at different bistatic angles allows estimating the scattering and absorption mean free paths, ΛT and ΛA. In the VV polarization, we obtained ΛT=0.4±0.1 m and ΛA=19±12 m at the Ku-band and ΛT=2.1±0.4 m and ΛA=21.8±2.7 m at the X-band, assuming an optically thick medium. The HH polarization yielded similar results. The observed backscatter enhancement is thus significant enough to require consideration in backscatter models describing monostatic and bistatic radar experiments. Enhanced backscattering beyond the Earth, on the surface of solar system bodies, has been interpreted as being caused by the presence of water ice. In agreement with this interpretation, our results confirm the presence of the CBOE at X- and Ku-band frequencies in terrestrial snow.

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Ji, Jin Zu, and Jing Li. "Mono Pulse Confocal Microwave Imaging in Breast Cancer Detection." Advanced Materials Research 748 (August 2013): 525–30. http://dx.doi.org/10.4028/www.scientific.net/amr.748.525.

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Mono pulse algorithm for confocal microwave imaging (CMI) for breast cancer detection is presented in this paper. All the antennas are used as receiver but only one is also used as transmitter. The transmitted signal is emitted for only once, thus the gross electromagnetic wave energy to the breast is reduced and the diagnosis time can be saved. Two confocal microwave imaging algorithms are presented in this paper: delay-sum-max and delay-production-sum. Both algorithms use the same delayed backscattered signals as the convectional CMI. The difference is how to use the delayed signals to form the image of the scattering intensity. Delay-sum-max method adds the signal together to generate the different value in confocal point via coherent and incoherent addition. Delay-production-sum algorithm products the delayed signal so as to make the assigned value in the confocal point outside the tumor is nearly zero. The image results can be compliment for more confirm diagnosis. Finite-difference time-domain (FDTD) method is used for simulation on 3 models of different tumor arrangements. The results show both methods are effective in detecting single-tumor, while there are some limitations in dealing with multi-tumor.

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Zhao, Hong, Yijian Zeng, Jun Wen, Xin Wang, Zuoliang Wang, Xianhong Meng, and Zhongbo Su. "An Air-to-Soil Transition Model for Discrete Scattering-Emission Modelling at L-Band." Journal of Remote Sensing 2021 (March 26, 2021): 1–20. http://dx.doi.org/10.34133/2021/3962350.

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Topsoil structures and inhomogeneous distribution of moisture in the soil volume will induce dielectric discontinuities from air to bulk soil, which in turn may induce multiple and volume scattering and affect the microwave surface emission. In situ ELBARA-III L-band radiometer observations of brightness temperature TBp (p =H or V polarization) at the Maqu site on the Eastern Tibetan Plateau are exploited to understand the effect of surface roughness on coherent and incoherent emission processes. Assisted with in situ soil moisture (SM) and temperature profile measurements, this study develops an air-to-soil transition (ATS) model that incorporates the dielectric roughness (i.e., resulted from fine-scale topsoil structures and the soil volume) characterized by SM and geometric roughness effects, and demonstrates the necessity of the ATS model for modelling L-band TBp. The Wilheit (1978) coherent and Lv et al. (2014) incoherent models are compared for determining the dielectric constant of bulk soil in the ATS zone and for calculating soil effective temperature Teff. The Tor Vergata discrete scattering model (TVG) integrated with the advanced integral equation model (AIEM) is used as the baseline model configuration for simulating L-band TBp. Whereafter, the ATS model is integrated with the foregoing model for assessing its performance. Results show the ATS-based models reduce the underestimation of TBp (≈20-50 K) by the baseline simulations. Being dynamic in nature, the proposed dielectric roughness parameterization in the ATS model significantly improves the ability in interpreting TBp dynamics, which is important for improving SM retrieval at the global scale.

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Ellithy, K., A. Gastli, S. Al-Alawi, A. Al-Hinai, and Z. Al-Abri. "Voltage Stability Analysis of Muscat Power System During Summer Weather Conditions." Sultan Qaboos University Journal for Science [SQUJS] 5 (December 1, 2000): 35. http://dx.doi.org/10.24200/squjs.vol5iss0pp35-45.

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A systematic and general formulation of a Propagation Simulation Program (PSP) is developed for the coherent field of microwave and millimeter wave carrier signals traversing intermediate layered precipitation media taking into account the random behavior of particle size, orientation, shape and concentration distributions. Based on a rigorous solution of the volumetric multiple-scattering integral equations, the formalism offers the capability of treating the potential transmission impairments on satellite-earth links and radar remote sensing generated by composite atmospheric layers of precipitation in conjunction with the finite polarization isolation of dual-polarized transmitting and receiving antennas. A multi-layered formulation is employed which encompasses an ensemble of discrete particles comprising an arbitrary mixture of ice crystals, melting snow and raindrops that may exist simultaneously along satellite-earth communication paths.

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Al-Rizzo, H. M., H. T. Al-Hafid, and J. M. Tranquilla. "Electromagnetic Modeling of the Propagation Characteristics of Satellite Communications Through Composite Precipitation Layers, Part1: Mathematical Formulation." Sultan Qaboos University Journal for Science [SQUJS] 5 (December 1, 2000): 47. http://dx.doi.org/10.24200/squjs.vol5iss0pp47-54.

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A systematic and general formulation of a Propagation Simulation Program (PSP) is developed for the coherent field of microwave and millimeter wave carrier signals traversing intermediate layered precipitation media, taking into account the random behavior of particle size, orientation, shape and concentration distributions. Based on a rigorous solution of the volumetric multiple-scattering integral equations, the formalism offers the capability of treating the potential transmission impairments on satellite-earth links and radar remote sensing generated by composite atmospheric layers of precipitation in conjunction with the finite polarization isolation of dual-polarized transmitting and receiving antennas. A multi-layered formulation is employed which encompasses an ensemble of discrete particles comprising an arbitrary mixture of ice crystals, melting snow and raindrops that may exist simultaneously along satellite-earth communication paths.

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Nagaoka, Ryutaro, and Karl L. F. Bane. "Collective effects in a diffraction-limited storage ring." Journal of Synchrotron Radiation 21, no. 5 (August 27, 2014): 937–60. http://dx.doi.org/10.1107/s1600577514015215.

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This paper gives an overview of collective effects that are likely to appear and possibly limit the performance in a diffraction-limited storage ring (DLSR) that stores a high-intensity ultra-low-emittance beam. Beam instabilities and other intensity-dependent effects that may significantly impact the machine performance are covered. The latter include beam-induced machine heating, Touschek scattering, intra-beam scattering, as well as incoherent tune shifts. The general trend that the efforts to achieve ultra-low emittance result in increasing the machine coupling impedance and the beam sensitivity to instability is reviewed. The nature of coupling impedance in a DLSR is described, followed by a series of potentially dangerous beam instabilities driven by the former, such as resistive-wall, TMCI (transverse mode coupling instability), head–tail and microwave instabilities. In addition, beam-ion and CSR (coherent synchrotron radiation) instabilities are also treated. Means to fight against collective effects such as lengthening of the bunch with passive harmonic cavities and bunch-by-bunch transverse feedback are introduced. Numerical codes developed and used to evaluate the machine coupling impedance, as well as to simulate beam instability using the former as inputs are described.

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Kwoh, D. S. W., B. M. Lake, and H. Rungaldier. "Microwave scattering from internal wave modulated surface waves: A shipboard real aperture coherent radar study in the Georgia Strait Experiment." Journal of Geophysical Research 93, no. C10 (1988): 12235. http://dx.doi.org/10.1029/jc093ic10p12235.

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Pott, A., T. Doerk, J. Uhlenbusch, J. Ehlbeck, J. Höschele, and J. Steinwandel. "Polarization-sensitive coherent anti-Stokes Raman scattering applied to the detection of NO in a microwave discharge for reduction of NO." Journal of Physics D: Applied Physics 31, no. 19 (October 7, 1998): 2485–98. http://dx.doi.org/10.1088/0022-3727/31/19/020.

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Wang, Xingxing, Adam Patel, and Alexey Shashurin. "Initial transient stage of pin-to-pin nanosecond repetitively pulsed discharges in air." Journal of Applied Physics 132, no. 1 (July 7, 2022): 013301. http://dx.doi.org/10.1063/5.0093794.

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In this work, evolution of parameters of nanosecond repetitively pulsed (NRP) discharges in pin-to-pin configuration in air was studied during the transient stage of initial 20 discharge pulses. Gas and plasma parameters in the discharge gap were measured using coherent microwave scattering, optical emission spectroscopy, and laser Rayleigh scattering for NRP discharges at repetition frequencies of 1, 10, and 100 kHz. Memory effects (when perturbations induced by the previous discharge pulse would not decay fully until the subsequent pulse) were detected for the repetition frequencies of 10 and 100 kHz. For 10 kHz NRP discharge, the discharge parameters experienced significant change after the first pulse and continued to substantially fluctuate between subsequent pulses due to rapid evolution of gas density and temperature during the 100 μs inter-pulse time caused by intense redistribution of the flow field in the gap on that time scale. For 100 kHz NRP discharge, the discharge pulse parameters reached a new steady-state at about five pulses after initiation. This new steady-state was associated with well-reproducible parameters between the discharge pulses and substantial reduction in breakdown voltage, discharge pulse energy, and electron number density in comparison to the first discharge pulse. For repetition frequencies 1–100 kHz considered in this work, the memory effects can be likely attributed to the reduction in gas number density and increase in the gas temperature that cannot fully recover to ambient conditions before subsequent discharge pulses.

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Smith, Peter F. "Status of Experiments for Direct Detection of Galactic Dark Matter Particles." Symposium - International Astronomical Union 201 (2005): 312–21. http://dx.doi.org/10.1017/s0074180900216409.

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There is increasing evidence that the majority of dark matter is non-baryonic. Principal candidates are weakly interacting massive particles (WIMPS), axions, and neutrinos. There has been increasing effort on sensitive WIMP searches, motivated in particular by supersymmetry theory, which predicts a stable neutral particle in the mass range 10-1000 GeV. Interactions of these with normal matter would produce low energy nuclear recoils which could be observed by underground detectors capable of discriminating these from background. Current experimental progress is summarised, together with plans for more sensitive experiments. These include gaseous detectors with directional sensitivity, offering the prospect of a ‘dark matter telescope’ which would provide information on the dark matter velocity distribution. Axions could be detected by conversion to microwave photons, and experimental sensitivity is approaching the theoretically-required levels. Relic neutrinos could also form a component of the dark matter if any has a cosmologically significant mass, and the latter could be checked with a new detector able to detect the higher neutrino flavours from a Galactic supernova burst. More distant future possibilities are outlined for direct detection of relic neutrinos by coherent scattering.

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Hirose, Masafumi, Riko Oki, Shuji Shimizu, Misako Kachi, and Tomohiko Higashiuwatoko. "Finescale Diurnal Rainfall Statistics Refined from Eight Years of TRMM PR Data." Journal of Applied Meteorology and Climatology 47, no. 2 (February 1, 2008): 544–61. http://dx.doi.org/10.1175/2007jamc1559.1.

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Abstract The adequacy of hourly rainfall sampling was examined in terms of the detection of diurnal variations using 8 yr (1998–2005) of data observed by the precipitation radar on the Tropical Rainfall Measuring Mission (TRMM) satellite. It was found that the monthly and hourly rain samples for each 0.2° grid point over the 8-yr period are composed of multiple precipitation systems. In this study, a “3-h-significant diurnal peak” was defined as the time of maximum rainfall with consecutive positive anomalies for more than 3 h. The fraction of the analyzed area with a 3-h-significant diurnal peak increased annually and accounted for 43% of the total global tropics at 0.2° resolution over the 8-yr period. The diurnal signature over Tibet and the Amazon showed a high degree of spatial uniformity (at >10° scale). The degree of similarity and locations of the regional diurnal characteristics are described in terms of seasonal variations and at multiple resolutions based on spatial uniformity. For example, uniform early-afternoon peaks generally appear over the coastal land and areas of high relief, whereas a seasonally invariant early-afternoon peak over the low-lying Amazon basin is recognized as a regional characteristic. In areas of coastal ocean, early-morning peaks appear in certain regions such as the area surrounding the so-called Maritime Continent and the area off the west coast of Mexico. These peaks are distinct from the global characteristics of late-morning rainfall maxima recorded over most coastal oceans and early-morning peaks recorded over open ocean. The results are also compared with those derived from TRMM Microwave Imager (TMI) data. In addition to obtaining a coherent signal, regional differences in the timing of maximum rainfall over the Tibetan Plateau were addressed; this discrepancy is attributed to limitations of the scattering algorithm used for TMI data in terms of detecting shallow convection and screening cold surfaces.

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Erkelens, J. S., V. K. C. Venema, H. W. J. Russchenberg, and L. P. Ligthart. "Coherent Scattering of Microwaves by Particles: Evidence from Clouds and Smoke." Journal of the Atmospheric Sciences 58, no. 9 (May 2001): 1091–102. http://dx.doi.org/10.1175/1520-0469(2001)058<1091:csombp>2.0.co;2.

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Dzyapko, O., V. E. Demidov, G. A. Melkov, and S. O. Demokritov. "Bose–Einstein condensation of spin wave quanta at room temperature." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 369, no. 1951 (September 28, 2011): 3575–87. http://dx.doi.org/10.1098/rsta.2011.0128.

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Spin waves are delocalized excitations of magnetic media that mainly determine their magnetic dynamics and thermodynamics at temperatures far below the critical one. The quantum-mechanical counterparts of spin waves are magnons, which can be considered as a gas of weakly interacting bosonic quasi-particles. Here, we discuss the room-temperature kinetics and thermodynamics of the magnon gas in yttrium iron garnet films driven by parametric microwave pumping. We show that for high enough pumping powers, the thermalization of the driven gas results in a quasi-equilibrium state described by Bose–Einstein statistics with a non-zero chemical potential. Further increases of the pumping power cause a Bose–Einstein condensation documented by an observation of the magnon accumulation at the lowest energy level. Using the sensitivity of the Brillouin light scattering spectroscopy to the degree of coherence of the scattering magnons, we confirm the spontaneous emergence of coherence of the magnons accumulated at the bottom of the spectrum, occurring if their density exceeds a critical value.

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Gupta, Mukesh, Randall K. Scharien, and David G. Barber. "Microwave Emission and Scattering from Ocean Surface Waves in the Southern Beaufort Sea." International Journal of Oceanography 2014 (March 10, 2014): 1–12. http://dx.doi.org/10.1155/2014/872342.

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Estimates of the relationships between geophysical variables and microwave backscatter/emission are important for the evaluation of atmosphere-ocean interaction, as well as energy, and mass transfer across this interface. We evaluate ship-based passive microwave brightness temperatures Tb at 37 and 89 GHz and active polarimetric backscatter at 5.5 GHz (C-band), as these relate to buoy-derived ocean wave parameters for distinct wave regimes in the southern Beaufort Sea. Microwave emission and backscatter are shown to be sensitive to the ocean surface physical roughness as defined by the significant wave height Hm0, compared to wind speed. The Tb shows significant correlation with Hm0, with the strongest correlation for the H-polarization channel at 37 and 89 GHz. Active co-γco and cross-γcross polarization ratios at 40° incidence angle are associated with Hm0, with the γco increase proportional to Hm0. The polarimetric coherence parameter ρVVHH at 20° also shows an inverse relationship with Hm0 because of an expected decorrelation of complex returns with greater surface roughness.

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Kapilevich, Boris, and Boris Litvak. "NOISE VERSUS COHERENCY IN MM-WAVE AND MICROWAVE SCATTERING FROM NONHOMOGENEOUS MATERIALS." Progress In Electromagnetics Research B 28 (2011): 35–54. http://dx.doi.org/10.2528/pierb10111502.

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FANG, LI-ZHI, ZHENG HUANG, and XIANG-PING WU. "STOCHASTIC FLUCTUATIONS IN THE PRIMEVAL PLASMA OF THE UNIVERSE." International Journal of Modern Physics D 05, no. 05 (October 1996): 495–506. http://dx.doi.org/10.1142/s0218271896000308.

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Before recombination of the universe the cosmic “fluid” consisting of primeval plasma and radiation cannot be perfect, but necessarily possesses nonvanishing dissipations. The subhorizon evolution of density perturbations in the radiation-plasma system must be described by stochastic kinetic theories. Both the dissipation and stochastic fluctuation in the coupled radiation-plasma system are caused by the incoherent electron-photon scattering. Using the Boltzmann equation with a Langevin-like term describing the stochastic force, we investigate the influence of this incoherent scattering on the evolution of acoustic oscillations in the radiation-plasma system. The stochastic fluctuation per collision time on average is small. Nevertheless, it cumulatively leads to a significant Brownian drifting of the phase of the acoustic oscillations. The coherence of the oscillations cannot be maintained during their evolution by the recombination. As a consequence, the linear-theory-predicted fine structures in the angular power spectrum of the anisotropies of cosmic microwave radiation, such as the Doppler peaks, are most likely erased by the stochastic fluctuations.

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Park, Sang-Eun, and Wooil M. Moon. "Theoretical evaluation of microwave vegetation scattering through an eigen-analysis of the coherency matrix." Canadian Journal of Remote Sensing 31, no. 1 (January 2005): 103–11. http://dx.doi.org/10.5589/m04-061.

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Carella, Giulia, Mathieu Vrac, Hélène Brogniez, Pascal Yiou, and Hélène Chepfer. "Statistical downscaling of water vapour satellite measurements from profiles of tropical ice clouds." Earth System Science Data 12, no. 1 (January 3, 2020): 1–20. http://dx.doi.org/10.5194/essd-12-1-2020.

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Abstract. Multi-scale interactions between the main players of the atmospheric water cycle are poorly understood, even in the present-day climate, and represent one of the main sources of uncertainty among future climate projections. Here, we present a method to downscale observations of relative humidity available from the Sondeur Atmosphérique du Profil d'Humidité Intertropical par Radiométrie (SAPHIR) passive microwave sounder at a nominal horizontal resolution of 10 km to the finer resolution of 90 m using scattering ratio profiles from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) lidar. With the scattering ratio profiles as covariates, an iterative approach applied to a non-parametric regression model based on a quantile random forest is used. This allows us to effectively incorporate into the predicted relative humidity structure the high-resolution variability from cloud profiles. The finer-scale water vapour structure is hereby deduced from the indirect physical correlation between relative humidity and the lidar observations. Results are presented for tropical ice clouds over the ocean: based on the coefficient of determination (with respect to the observed relative humidity) and the continuous rank probability skill score (with respect to the climatology), we conclude that we are able to successfully predict, at the resolution of cloud measurements, the relative humidity along the whole troposphere, yet ensure the best possible coherence with the values observed by SAPHIR. By providing a method to generate pseudo-observations of relative humidity (at high spatial resolution) from simultaneous co-located cloud profiles, this work will help revisit some of the current key barriers in atmospheric science. A sample dataset of simultaneous co-located scattering ratio profiles of tropical ice clouds and observations of relative humidity downscaled at the resolution of cloud measurements is available at https://doi.org/10.14768/20181022001.1 (Carella et al., 2019).

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Goryachko, Alexander Ivanovich, Sergey Nikolaevich Ivanin, and Vladimir Yurievich Buzko. "Synthesis, Microstructural and Electromagnetic Characteristics of Cobalt-Zinc Ferrite." Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases 22, no. 4 (December 15, 2020): 446–52. http://dx.doi.org/10.17308/kcmf.2020.22/3115.

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In this study, cobalt-zinc ferrite (Co0.5Zn0.5Fe2O4) was obtained by the glycine-nitrate method followed by annealing in a high-temperature furnace at a temperature of 1300 °С. The qualitative composition and its microstructural characteristics were determined using energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, and scanning electron microscopy.The analysis of the micrographs demonstrated that the cobalt-zinc ferrite micropowder obtained after thermal annealing has an average particle size of 1.7±1 μm. The analysis of XRD data showed that the annealed cobalt-zinc ferrite micropowder has a cubic crystal structure with a lattice parameter of a = 8.415 Å. Using the Scherrer and Williamson-Hall equations we calculated the average sizes of the coherent scattering regions, which were commensurate with the size of crystallites: according to the Scherrer equation D = 28.26 nm and according to the Williamson-Hall equation D = 33.59 nm and the microstress value e = 5.62×10–4 in the ferrite structure.Using a vector network analyser, the electromagnetic properties of a composite material based on synthesized cobalt-zinc ferrite were determined. The frequency dependences of the magnetic and dielectric permeability values from the measured S-parameters of the composite material (50% ferrite filler by weight and 50% paraffin) were determined using the Nicolson-Ross-Weir method and were in the range of 0.015–7 GHz. The analysis of the graphs of the dependence of the magnetic permeability on the frequency of electromagnetic radiation revealed a resonance frequency of fr ≈ 2.3 GHz. The discoveredmagnetic resonance in the UHF range allows the obtained material to be considered as being promising for use as an effective absorber of electromagnetic radiation in the range of 2–2.5 GHz. References 1. Thakur P., Chahar D., Taneja S., Bhalla N. andThakur A. A review on MnZn ferrites: Synthesis,characterization and applications. CeramicsInternational. 2020;46(10): 15740–15763. DOI: https://doi.org/10.1016/j.ceramint.2020.03.2872. Pullar R. C. Hexagonal ferrites: A review of thesynthesis, properties and applications of hexaferriteceramics. Progress in Materials Science. 2012;57(7):1191–1334. DOI: https://doi.org/10.1016/j.pmatsci.2012.04.0013. Kharisov B. I., Dias H. V. R., Kharissova O. V.Mini-review: Ferrite nanoparticles in the catalysis.Arabian Journal of Chemistry. 2019;12(7): 1234–1246.DOI: https://doi.org/10.1016/j.arabjc.2014.10.0494. Stergiou C. Microstructure and electromagneticproperties of Ni-Zn-Co ferrite up to 20 GHz. Advancesin Materials Science and Engineering. 2016;2016: 1–7.DOI: https://doi.org/10.1155/2016/19347835. Economos G. Magnetic ceramics: I, Generalmethods of magnetic ferrite preparation. Journal of theAmerican Ceramic Society. 1955;38(7): 241–244. DOI:https://doi.org/10.1111/j.1151-2916.1955.tb14938.x6. Yurkov G. Y., Shashkeev K. A., Kondrashov S. V.,Popkov O. V., Shcherbakova G. I., Zhigalov D. V.,Pankratov D. A., Ovchenkov E. A., Koksharov Y. A.Synthesis and magnetic properties of cobalt ferritenanoparticles in polycarbosilane ceramic matrix.Journal of Alloys and Compounds. 2016;686: 421–430.DOI: https://doi.org/10.1016/j.jallcom.2016.06.0257. Karakaş Z. K., Boncukçuoğlu R., Karakaş İ. H.The effects of fuel type in synthesis of NiFe2O4nanoparticles by microwave assisted combustionmethod. Journal of Physics: Conference Series. 2016;707: 012046. DOI: https://doi.org/10.1088/1742-6596/707/1/0120468. Shirsath S. E., Jadhav S. S., Mane M. L., Li S.Handbook of sol-gel science and technology. Springer,Cham.; 2016. p. 1–41. DOI: https://doi.org/10.1007/978-3-319-19454-7_125-19. Vyzulin S. A., Kalikintseva D. A., MiroshnichenkoE. L., Buz’ko V. Y., Goryachko A. I. Microwaveabsorption properties of nickel–zinc ferritessynthesized by different means. Bulletin of the RussianAcademy of Sciences: Physics. 2018;82(8): 943–945.DOI: https://doi.org/10.3103/s106287381808043910. Janasi S. R., Emura M., Landgraf F. J. G.,Rodrigues D. The effects of synthesis variables on themagnetic properties of coprecipitated barium ferritepowders. Journal of Magnetism and Magnetic Materials.2002;238(2-3): 168–172. DOI: https://doi.org/10.1016/s0304-8853(01)00857-511. Ahmed Y. M. Z. Synthesis of manganese ferritefrom non-standard raw materials using ceramictechnique. Ceramics International. 2010;36(3): 969–977. DOI: https://doi.org/10.1016/j.ceramint.2009.11.02012. Mahadule R. K., Arjunwadkar P. R., MahaboleM. P. Synthesis and characterization ofCaxSryBa1–x–yFe12–zLazO19 by standard ceramic method.International Journal of Metals. 2013;2013: 1–7. DOI:https://doi.org/10.1155/2013/19897013. Tarța V. F., Chicinaş I., Marinca T. F.,Neamţu B. V., Popa F., Prica C. V. Synthesis of thenanocrystalline/nnosized NiFe2O4 powder by ceramicmethod and mechanical milling. Solid State Phenomena.2012;188: 27–30. DOI: https://doi.org/10.4028/www.scientific.net/ssp.188.2714. Pradhan A. K., Saha S., Nath T. K. AC and DCelectrical conductivity, dielectric and magneticproperties of Co0.65Zn0.35Fe2−xMoxO4 (x = 0.0, 0.1 and 0.2)ferrites. Applied Physics A. 2017;123(11): 715. DOI:https://doi.org/10.1007/s00339-017-1329-z15. Low Z. H., Ismail I., Tan K. S. Sinteringprocessing of complex magnetic ceramic oxides: Acomparison between sintering of bottom-up approachsynthesis and mechanochemical process of top-downapproach synthesis. Sintering Technology - Method andApplication. Malin Liu (ed.). 2018: 25–43. DOI: https://doi.org/10.5772/intechopen.7865416. Costa A. C. F. M., Morelli M. R., KiminamiR. H. G. A. Combustion synthesis: Effect of urea onthe reaction and characteristics of Ni–Zn ferritepowders. Journal of Materials Synthesis and Processing.2001; 9(6): 347–352. DOI: https://doi.org/10.1023/A:101635662340117. Maleknejad Z., Gheisari K., Raouf A. H.Structure, microstructure, magnetic, electromagnetic,and dielectric properties of nanostructured Mn–Znferrite synthesized by microwave-induced urea–nitrate process. Journal of Superconductivity and NovelMagnetism. 2016;29(10): 2523–2534. DOI: https://doi.org/10.1007/s10948-016-3572-518. Jalaiah K., Chandra Mouli K., Vijaya Babu K.,Krishnaiah R.V. The structural, DC resistivity andmagnetic properties of Mg and Zr Co-substitutedNi0.5Zn0.5Fe2O4. Journal of Science: Advanced Materialsand Devices. 2018;4(2): 310–318 DOI: https://doi.org/10.1016/j.jsamd.2018.12.00419. Yue Z., Zhou J., Li L., Zhang H., Gui Z. Synthesisof nanocrystalline NiCuZn ferrite powders by sol–gelauto-combustion method. Journal of Magnetism andMagnetic Materials. 2000;208(1-2): 55–60. DOI:https://doi.org/10.1016/s0304-8853(99)00566-120. Chick L. A., Pederson L. R., Maupin G. D.,Bates J. L., Thomas L. E., Exarhos G. J. Glycine-nitratecombustion synthesis of oxide ceramic powders.Materials Letters. 1990;10(1-2): 6–12. DOI: https://doi.org/10.1016/0167-577x(90)90003-521. Salunkhe A. B., Khot V. M., Phadatare M. R.,Pawar S. H. Combustion synthesis of cobalt ferritenanoparticles—Influence of fuel to oxidizer ratio.Journal of Alloys and Compounds. 2012;514: 91–96.DOI: https://doi.org/10.1016/j.jallcom.2011.10.09422. Martinson K. D., Cherepkova I. A., Sokolov V. V.Formation of cobalt ferrite nanoparticles via glycine-nitrate combustion and their magnetic properties.Glass Physics and Chemistry. 2018;44(1): 21–25.DOI: https://doi.org/10.1134/s108765961801009123. Kuzmin V. A., Zagrai I. A. A comprehensivestudy of combustion products generated from pulverizedpeat combustion in the furnace of BKZ-210-140Fsteam boiler. Journal of Physics: Conference Series.2017;891: 012226. DOI: https://doi.org/10.1088/1742-6596/891/1/01222624. Maleki A., Hosseini N., Taherizadeh A. Synthesisand characterization of cobalt ferrite nanoparticlesprepared by the glycine-nitrate process. Ceramics International.2018;44(7): 8576–8581. DOI: https://doi.org/10.1016/j.ceramint.2018.02.06325. Waje S. B., Hashim M., Wan Yusoff W. D., AbbasZ. Sintering temperature dependence of roomtemperature magnetic and dielectric properties ofCo0.5Zn0.5Fe2O4 prepared using mechanically alloyednanoparticles. Journal of Magnetism and MagneticMaterials. 2010;322(6): 686–691. DOI: https://doi.org/10.1016/j.jmmm.2009.10.04126. Nicolson A. M., Ross G. F. Measurement of theintrinsic properties of materials by time-domain techniques.IEEE Transactions on Instrumentation andMeasurement. 1970;19(4): 377–382. DOI: https://doi.org/10.1109/tim.1970.431393227. Rothwell E. J., Frasch J. L., Ellison S. M., ChahalP., Ouedraogo R.O. Analysis of the Nicolson-Ross-Weir method for characterizing the electromagneticproperties of engineered materials. ProgressIn Electromagnetics Research. 2016;157: 31–47. DOI:https://doi.org/10.2528/pier1607170628. Vicente A. N., Dip G. M., Junqueira C. The stepby step development of NRW method. ProceedingsArticle in: 2011 SBMO/IEEE MTT-S International Microwaveand Optoelectronics Conference (IMOC 2011).29 Oct. –1 Nov. 2011. 738–742. DOI: https://doi.org/10.1109/imoc.2011.616931829. Ivanin S. N., Buz’ko V. Yu., Goryachko A. I.,Panyushkin V. T. Electromagnetic characteristics ofheteroligand complexes of gadolinium stearate. RussianJournal of Physical Chemistry A. 2020;94(8):1623–1627. DOI: https://doi.org/10.1134/S003602442008013030. Liu Y.-W., Zhang J., Gu L.-S., Wang L.-X.,Zhang Q.-T. Preparation and electromagnetic propertiesof nanosized Co0.5Zn0.5Fe2O4 ferrite. Rare Metals. 2016.DOI: https://doi.org/10.1007/s12598-015-0670-7

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Patel, Adam R., Apoorv Ranjan, Xingxing Wang, Mikhail N. Slipchenko, Mikhail N. Shneider, and Alexey Shashurin. "Thomson and collisional regimes of in-phase coherent microwave scattering off gaseous microplasmas." Scientific Reports 11, no. 1 (December 2021). http://dx.doi.org/10.1038/s41598-021-02500-y.

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AbstractThe total number of electrons in a classical microplasma can be non-intrusively measured through elastic in-phase coherent microwave scattering (CMS). Here, we establish a theoretical basis for the CMS diagnostic technique with an emphasis on Thomson and collisional scattering in short, thin unmagnetized plasma media. Experimental validation of the diagnostic is subsequently performed via linearly polarized, variable frequency (10.5–12 GHz) microwave scattering off laser induced 1–760 Torr air-based microplasmas (287.5 nm O2 resonant photoionization by ~ 5 ns, < 3 mJ pulses) with diverse ionization and collisional features. Namely, conducted studies include a verification of short-dipole-like radiation behavior, plasma volume imaging via ICCD photography, and measurements of relative phases, total scattering cross-sections, and total number of electrons $$N_{e}$$ N e in the generated plasma filaments following absolute calibration using a dielectric scattering sample. Findings of the paper suggest an ideality of CMS in the Thomson “free-electron” regime—where a detailed knowledge of plasma and collisional properties (which are often difficult to accurately characterize due to the potential influence of inhomogeneities, local temperatures and densities, present species, and so on) is unnecessary to extract $$N_{e}$$ N e from the scattered signal. The Thomson scattering regime of microwaves is further experimentally verified via measurements of the relative phase between the incident electric field and electron displacement.

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Patel, Adam R., Xingxing Wang, Erik L. Braun, Apoorv Ranjan, Mikhail Slipchenko, Sergey Macheret, Mikhail Shneider, and Alexey Shashurin. "Electron momentum-transfer collision frequency measurements in small plasma objects via Coherent Microwave Scattering." Plasma Sources Science and Technology, November 18, 2022. http://dx.doi.org/10.1088/1361-6595/aca430.

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Abstract We present the possibility of using coherent microwave scattering (CMS) for temporally resolved measurements of the electron momentum-transfer collision frequency in small plasma objects. Specifically, the electron collision frequency is inferred via phase information from microwave scattering off microplasmas operating in the mixed collisional-Thomson scattering regime. We further suggest the combination of phase and amplitude measurements to derive total electron count and temperature in small plasmas. An experimental validation of this concept is performed by 10.5 GHz CMS off laser-induced, variable-pressure oxygen and air plasmas.

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Kaﬀash, Mojtaba Taghipour, Dinesh Wagle, Anish Rai, Thomas Meyer, John Q. Xiao, and M. Benjamin Jungfleisch. "Direct probing of strong magnon-photon coupling in a planar geometry." Quantum Science and Technology, September 22, 2022. http://dx.doi.org/10.1088/2058-9565/ac9428.

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Abstract We demonstrate direct probing of strong magnon-photon coupling using Brillouin light scattering spectroscopy in a planar geometry. The magnonic hybrid system comprises a split-ring resonator loaded with epitaxial yttrium iron garnet thin films of 200 nm and 2.46 μm thickness. The Brillouin light scattering measurements are combined with microwave spectroscopy measurements where both biasing magnetic field and microwave excitation frequency are varied. The cooperativity for the 200 nm-thick YIG films is 1.1, and larger cooperativity of 29.1 is found for the 2.46 μm-thick YIG film. We show that Brillouin light scattering is advantageous for probing the magnonic character of magnon-photon polaritons, while microwave absorption is more sensitive to the photonic character of the hybrid excitation. A miniaturized, planar device design is imperative for the potential integration of magnonic hybrid systems in future coherent information technologies, and our results are a first stepping stone in this regard. Furthermore, successfully detecting the magnonic hybrid excitation by Brillouin light scattering is an essential step for the up-conversion of quantum signals from the optical to the microwave regime in hybrid quantum systems.

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Suwunnarat, Suwun, Yaqian Tang, Mattis Reisner, Fabrice Mortessagne, Ulrich Kuhl, and Tsampikos Kottos. "Non-linear coherent perfect absorption in the proximity of exceptional points." Communications Physics 5, no. 1 (January 10, 2022). http://dx.doi.org/10.1038/s42005-021-00782-2.

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AbstractCoherent perfect absorption is one of the possibilities to get high absorption but typically suffers from being a resonant phenomena, i.e., efficient absorption only in a local frequency range. Additionally, if applied in high power applications, the understanding of the interplay of non-linearities and coherent perfect absorption is crucial. Here we show experimentally and theoretically the formation of non-linear coherent perfect absorption in the proximity of exceptional point degeneracies of the zeros of the scattering function. Using a microwave platform, consisting of a lossy nonlinear resonator coupled to two interrogating antennas, we show that a coherent incident excitation can trigger a self-induced perfect absorption once its intensity exceeds a critical value. Note, that a (near) perfect absorption persists for a broad-band frequency range around the nonlinear coherent perfect absorption condition. Its origin is traced to a quartic behavior that the absorbance spectrum acquires in the proximity of the exceptional points of the nonlinear scattering operator.

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Zhang, Zhili, Mikhail N. Shneider, and Richard B. Miles. "Coherent Microwave Rayleigh Scattering from Resonance-Enhanced Multiphoton Ionization in Argon." Physical Review Letters 98, no. 26 (June 29, 2007). http://dx.doi.org/10.1103/physrevlett.98.265005.

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Grimsditch, M., F. Y. Fradin, Y. Ji, A. Hoffmann, R. E. Camley, V. Metlushko, and V. Novosad. "Coherent Inelastic Light Scattering from a Microwave-Excited Array of Magnetic Particles." Physical Review Letters 96, no. 4 (January 31, 2006). http://dx.doi.org/10.1103/physrevlett.96.047401.

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Journal articles on the topic 'Coherent Microwave Scattering'

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