Abstract BaSr2(PO4)2: 4 %Eu3+, 4 %A (A = Li+, Na+, K+) phosphors were prepared by high-temperature solid-phase method. The crystal structure, photoluminescence properties, thermal stability, chromaticity coordinates, and fluorescence lifetime of the samples were investigated. The excitation and emission spectra of the samples are broadbands and the maximum peak of the emission spectrum is located at 619 nm. Among three charge compensators, the luminescence intensity is optimal for Li+ co-doping case, and the quenching temperature of the typical sample is about 500 K. the fluorescence lifetime τ $leftlangle tau rightrangle $ is 1469.6 ns, and the chromaticity coordinates exhibit a strong red emission. The present phosphor has a potential application for white light-emitting diodes (LEDs) under the near-ultra violet (n-UV) light excitation.
BaSr2(PO4) 2:4 %Eu3+, 4 %A (A = Li+, Na+, K+) phosphors were prepared by high-temperature solid-phase method. The crystal structure, photoluminescence properties, thermal stability, chromaticity coordinates, and fluorescence lifetime of the samples were investigated. The excitation and emission spectra of the samples are broadbands and the maximum peak of the emission spectrum is located at 619 nm. Among three charge compensators, the luminescence intensity is optimal for Li+ co-doping case, and the quenching temperature of the typical sample is about 500 K. the fluorescence lifetime τ $leftlangle tau rightrangle $ is 1469.6 ns, and the chromaticity coordinates exhibit a strong red emission. The present phosphor has a potential application for white light-emitting diodes (LEDs) under the near-ultra violet (n-UV) light excitation.
{"title":"Red-emitting phosphors of BaSr2(PO4)2: 4 %Eu3+, 4 %A (A = Li+, Na+, K+) for white LEDs","authors":"Cong Liu, Junshen Xing, Zheng Liu, Wenlin Feng","doi":"10.1515/zna-2023-0102","DOIUrl":"https://doi.org/10.1515/zna-2023-0102","url":null,"abstract":"Abstract BaSr2(PO4)2: 4 %Eu3+, 4 %A (A = Li+, Na+, K+) phosphors were prepared by high-temperature solid-phase method. The crystal structure, photoluminescence properties, thermal stability, chromaticity coordinates, and fluorescence lifetime of the samples were investigated. The excitation and emission spectra of the samples are broadbands and the maximum peak of the emission spectrum is located at 619 nm. Among three charge compensators, the luminescence intensity is optimal for Li+ co-doping case, and the quenching temperature of the typical sample is about 500 K. the fluorescence lifetime τ $leftlangle tau rightrangle $ is 1469.6 ns, and the chromaticity coordinates exhibit a strong red emission. The present phosphor has a potential application for white light-emitting diodes (LEDs) under the near-ultra violet (n-UV) light excitation.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"64 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79366530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Kengne, J. T. Mbé, Janvier Fotsing, A. Mezatio, Francine July Ntsafack Manekeng, R. Tchitnga
Abstract In the literature, hyperjerk systems raised up meaningful interest due to their simple and elegant structure as well as their complex dynamical features. In this work, we propose a novel 4D autonomous hyperjerk system which the particularity resides on the type of its nonlinearity namely the Van der Pol nonlinearity. The dynamics of this hyperjerk system is assessed thanks to the well-known nonlinear dynamic tools such as time series, bifurcation diagrams, Lyapunov exponent spectrum, two-parameter phase diagram, and phase portraits. As important result, it is established that the system presents a particular phenomenon of hysteretic dynamics that leads to the coexistence of attractors. Next, through the calculation of the Hamiltonian energy, we show that this latter depends on all the variables of the novel hyperjerk system. Furthermore, basing on an adaptive backstepping method whose target is a function of the states of the error system, a new controller is designed to carry out from t = 30, complete chaotic synchronization of the identical novel hyperjerk chaotic systems. Likewise, PSpice (9.2 full version) based simulations are presented in detail to confirm the feasibility of the theoretical model. One of the key points of this work is the designing in PSpice environment of this new adaptive backstepping controller to validate both theoretical and numerical synchronization results. Finally, our experimental measurements in the laboratory are in good agreement with the numerical and analog results.
在文献中，超跳系统以其简单优美的结构和复杂的动力学特性引起了人们的广泛关注。在这项工作中，我们提出了一种新的四维自主超跳系统，其特殊性在于其非线性类型，即Van der Pol非线性。利用时间序列、分岔图、李雅普诺夫指数谱、双参数相图和相图等众所周知的非线性动力学工具对该超跳系统的动力学进行了评估。作为重要的结果，我们确定了系统呈现一种特殊的滞回动力学现象，导致吸引子共存。其次，通过计算哈密顿能量，我们证明后者依赖于新超跳系统的所有变量。在此基础上，基于目标为误差系统状态函数的自适应反演方法，设计了一种新的控制器，用于从t = 30开始对相同的新型超跳混沌系统进行完全混沌同步。同样，基于PSpice(9.2完整版)的详细仿真验证了理论模型的可行性。本工作的重点之一是在PSpice环境下设计这种新的自适应反步控制器，以验证理论和数值同步结果。最后，我们在实验室的实验测量结果与数值和模拟结果吻合得很好。
{"title":"Dynamics and synchronization of a novel 4D-hyperjerk autonomous chaotic system with a Van der Pol nonlinearity","authors":"R. Kengne, J. T. Mbé, Janvier Fotsing, A. Mezatio, Francine July Ntsafack Manekeng, R. Tchitnga","doi":"10.1515/zna-2023-0063","DOIUrl":"https://doi.org/10.1515/zna-2023-0063","url":null,"abstract":"Abstract In the literature, hyperjerk systems raised up meaningful interest due to their simple and elegant structure as well as their complex dynamical features. In this work, we propose a novel 4D autonomous hyperjerk system which the particularity resides on the type of its nonlinearity namely the Van der Pol nonlinearity. The dynamics of this hyperjerk system is assessed thanks to the well-known nonlinear dynamic tools such as time series, bifurcation diagrams, Lyapunov exponent spectrum, two-parameter phase diagram, and phase portraits. As important result, it is established that the system presents a particular phenomenon of hysteretic dynamics that leads to the coexistence of attractors. Next, through the calculation of the Hamiltonian energy, we show that this latter depends on all the variables of the novel hyperjerk system. Furthermore, basing on an adaptive backstepping method whose target is a function of the states of the error system, a new controller is designed to carry out from t = 30, complete chaotic synchronization of the identical novel hyperjerk chaotic systems. Likewise, PSpice (9.2 full version) based simulations are presented in detail to confirm the feasibility of the theoretical model. One of the key points of this work is the designing in PSpice environment of this new adaptive backstepping controller to validate both theoretical and numerical synchronization results. Finally, our experimental measurements in the laboratory are in good agreement with the numerical and analog results.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84817361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nagandla Prasad, P. Pardhasaradhi, B. Madhav, Rama Krishna Nanchara Rao Manepalli
Abstract In this research article, a novel MBBA nematic liquid crystal (NLC) based circular trident-shaped antenna is proposed for both C-band and X-band microwave applications. The proposed antenna contains a trident-shaped radiating patch, which is made of copper material, and glass material is utilized as a dielectric substrate for the proposed novel MBBA-based trident shaped antenna. The dielectric substrate contains two glass plates with a thickness of 1 mm each and is separated by an air gap of 0.003 mm to fill MBBA nematic liquid crystal. So, the overall size of the proposed antenna will become 15 × 20 × 2.003 mm3. The dielectric constant of each glass plate is chosen as 5.438. However, the antenna operates at a single frequency band, when MBBA material is not present between the glass plates and produces two distinct resonant frequencies when the air gap between the glass plates is filled with MBBA NLC. Antenna radiation parameters such as gain, radiation efficiency, reflection coefficient, and radiation patterns are compared for both simulation and measurement.
{"title":"Trident-shaped monopole antenna with p-methoxy-benzylidene-p-n-butyl aniline (MBBA) nematic liquid crystal (NLC) for C- and X-band applications","authors":"Nagandla Prasad, P. Pardhasaradhi, B. Madhav, Rama Krishna Nanchara Rao Manepalli","doi":"10.1515/zna-2023-0069","DOIUrl":"https://doi.org/10.1515/zna-2023-0069","url":null,"abstract":"Abstract In this research article, a novel MBBA nematic liquid crystal (NLC) based circular trident-shaped antenna is proposed for both C-band and X-band microwave applications. The proposed antenna contains a trident-shaped radiating patch, which is made of copper material, and glass material is utilized as a dielectric substrate for the proposed novel MBBA-based trident shaped antenna. The dielectric substrate contains two glass plates with a thickness of 1 mm each and is separated by an air gap of 0.003 mm to fill MBBA nematic liquid crystal. So, the overall size of the proposed antenna will become 15 × 20 × 2.003 mm3. The dielectric constant of each glass plate is chosen as 5.438. However, the antenna operates at a single frequency band, when MBBA material is not present between the glass plates and produces two distinct resonant frequencies when the air gap between the glass plates is filled with MBBA NLC. Antenna radiation parameters such as gain, radiation efficiency, reflection coefficient, and radiation patterns are compared for both simulation and measurement.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79028581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This work demonstrates the study of the optimal system of solutions for shock wave propagation in a non-ideal self-gravitating gas in rotating medium with magnetic field (axial or azimuthal) for the adiabatic flow in cylindrical geometry by applying the group invariance technique. Using the group invariance technique, we have obtained the one-dimensional (1-D) optimal system of sub-algebra for the basic governing equations. The infinitesimal group optimal classes are obtained and the similarity solution in four possible cases (two cases for perfect gas and two cases for non-ideal gas) with exponential law shock path are discussed. The numerical solution by using the Runge Kutta 4th order method is obtained and the distribution of physical variables are shown via graph. The impact of the rotational parameter, non-idealness parameter, shock Cowling number, similarity exponent and gravitational parameter on the strength of the shock and flow variables are investigated. With an increase in the shock Cowling number, non-idealness and rotational parameters, the shock strength decreases, i.e., they have decaying impact on shock wave; whereas the shock strength increases with gravitational parameter and similarity exponent. Also, the strength of the shock is reduced by considering the magnetic field to be axial instead of azimuthal.
{"title":"Optimal system of solution using group invariance technique for shock wave in a non-ideal self-gravitating gas in rotating medium in presence of magnetic field","authors":"G. Nath, Abhaysingh A. Maurya","doi":"10.1515/zna-2023-0026","DOIUrl":"https://doi.org/10.1515/zna-2023-0026","url":null,"abstract":"Abstract This work demonstrates the study of the optimal system of solutions for shock wave propagation in a non-ideal self-gravitating gas in rotating medium with magnetic field (axial or azimuthal) for the adiabatic flow in cylindrical geometry by applying the group invariance technique. Using the group invariance technique, we have obtained the one-dimensional (1-D) optimal system of sub-algebra for the basic governing equations. The infinitesimal group optimal classes are obtained and the similarity solution in four possible cases (two cases for perfect gas and two cases for non-ideal gas) with exponential law shock path are discussed. The numerical solution by using the Runge Kutta 4th order method is obtained and the distribution of physical variables are shown via graph. The impact of the rotational parameter, non-idealness parameter, shock Cowling number, similarity exponent and gravitational parameter on the strength of the shock and flow variables are investigated. With an increase in the shock Cowling number, non-idealness and rotational parameters, the shock strength decreases, i.e., they have decaying impact on shock wave; whereas the shock strength increases with gravitational parameter and similarity exponent. Also, the strength of the shock is reduced by considering the magnetic field to be axial instead of azimuthal.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"156 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76797769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Patidar, Hemlata Joshi, Sonali Patidar, R. Pensia, Shaheen Mansuri
Abstract The influence of quantum plasma on Jeans instability is investigated in the presence of magnetic fields, and the dispersion relation obtained in both parallel and perpendicular directions has shown the stabilizing effect on the growth rate of Jeans instability with a moderate temperature high-density regime. The influence of the magnetic field on the Jeans criteria is illustrated through the graphical representation. The inclusion of magnetic fields with quantum effect on the motion of a charged particle involves the essential properties of acceleration and the transport of highly ionized particles is important in connection with a well-known application of the confinement of magnetized plasma. In this paper, we analytically discuss the effect of magnetic field on white dwarfs. The mass-radius relation of highly magnetized white dwarfs is different from their non-magnetic equivalent and leads to a modified super-Chandrashekhar mass limit.
{"title":"The effect of magnetized quantum plasma on Jeans instability","authors":"A. Patidar, Hemlata Joshi, Sonali Patidar, R. Pensia, Shaheen Mansuri","doi":"10.1515/zna-2023-0084","DOIUrl":"https://doi.org/10.1515/zna-2023-0084","url":null,"abstract":"Abstract The influence of quantum plasma on Jeans instability is investigated in the presence of magnetic fields, and the dispersion relation obtained in both parallel and perpendicular directions has shown the stabilizing effect on the growth rate of Jeans instability with a moderate temperature high-density regime. The influence of the magnetic field on the Jeans criteria is illustrated through the graphical representation. The inclusion of magnetic fields with quantum effect on the motion of a charged particle involves the essential properties of acceleration and the transport of highly ionized particles is important in connection with a well-known application of the confinement of magnetized plasma. In this paper, we analytically discuss the effect of magnetic field on white dwarfs. The mass-radius relation of highly magnetized white dwarfs is different from their non-magnetic equivalent and leads to a modified super-Chandrashekhar mass limit.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"50 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74065933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Segovia-Chaves, Santiago Santos Beltrán, H. Vinck-Posada
Abstract This study uses the transfer matrix method to calculate the transmittance spectrum of a one-dimensional photonic crystal (1D-PC). Herein, the crystal is composed of alternating layers of barium titanate ferroelectric and yttrium oxide dielectric. The spatial periodicity of the 1D-PC is broken by a cavity surrounded by thin layers of a critical high-temperature superconductor, which can be used to detect refractive index changes of plasma cells infiltrated into the cavity. The results reflect the existence of a maximum transmittance peak in the telecom region known as a localized mode within the photonic band gap. This study reveals that the localized mode shifts toward longer wavelengths as the operating temperature of the superconductor increases. Additionally, we calculate the sensitivity and quality factor of the localized mode, thereby finding that these quantities increase as the incidence angle increases. The proposed model works in cryogenic temperature environments and may be integrated into biosensor designs.
{"title":"Design of blood plasma concentrations sensor based on a one-dimensional photonic crystal","authors":"F. Segovia-Chaves, Santiago Santos Beltrán, H. Vinck-Posada","doi":"10.1515/zna-2023-0106","DOIUrl":"https://doi.org/10.1515/zna-2023-0106","url":null,"abstract":"Abstract This study uses the transfer matrix method to calculate the transmittance spectrum of a one-dimensional photonic crystal (1D-PC). Herein, the crystal is composed of alternating layers of barium titanate ferroelectric and yttrium oxide dielectric. The spatial periodicity of the 1D-PC is broken by a cavity surrounded by thin layers of a critical high-temperature superconductor, which can be used to detect refractive index changes of plasma cells infiltrated into the cavity. The results reflect the existence of a maximum transmittance peak in the telecom region known as a localized mode within the photonic band gap. This study reveals that the localized mode shifts toward longer wavelengths as the operating temperature of the superconductor increases. Additionally, we calculate the sensitivity and quality factor of the localized mode, thereby finding that these quantities increase as the incidence angle increases. The proposed model works in cryogenic temperature environments and may be integrated into biosensor designs.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79903432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In the work reported in this paper, we have analyzed generalized Chaplygin gas (GCG) and modified generalized Chaplygin gas (MGCG) in an interacting scenario. The equation of state parameter has been analyzed in both the cases and the stability of the models has been discerned through squared speed of sound. Stability against gravitational perturbations has been observed for both GCG and MGCG interacting with pressureless dark matter. Also, the generalized second law (GSL) of thermodynamics has been tested for different enveloping horizons and validity of GSL has been observed throughout. Furthermore, f(T) gravity has been reconstructed with GCG and MGCG and phantom behaviour has been observed through reconstructed EoS parameters. The squared speed of sound has been derived for f(T) gravity and stability of the model has been established through its positivity.
{"title":"Some versions of Chaplygin gas model in modified gravity framework and validity of generalized second law of thermodynamics","authors":"Sanjeeda Sultana, E. Güdekli, S. Chattopadhyay","doi":"10.1515/zna-2023-0085","DOIUrl":"https://doi.org/10.1515/zna-2023-0085","url":null,"abstract":"Abstract In the work reported in this paper, we have analyzed generalized Chaplygin gas (GCG) and modified generalized Chaplygin gas (MGCG) in an interacting scenario. The equation of state parameter has been analyzed in both the cases and the stability of the models has been discerned through squared speed of sound. Stability against gravitational perturbations has been observed for both GCG and MGCG interacting with pressureless dark matter. Also, the generalized second law (GSL) of thermodynamics has been tested for different enveloping horizons and validity of GSL has been observed throughout. Furthermore, f(T) gravity has been reconstructed with GCG and MGCG and phantom behaviour has been observed through reconstructed EoS parameters. The squared speed of sound has been derived for f(T) gravity and stability of the model has been established through its positivity.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86205834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract ZnO nanoparticles doped with Co at different concentration (Zn1−xCo x O) were synthesized by sol–gel auto combustion method and are characterized by using various characterization tools. Structural study using X-ray diffraction technique (XRD) analysis showed the crystalline nature with hexagonal wurtzite geometry and the composition analysis using energy dispersive X-ray spectroscopy (EDX) confirmed the incorporation of Co in the ZnO lattice in the case of doped nanoparticles. Scanning electron-microscopy (SEM) and transmission electron microscopy (TEM) analysis showed the prepared nanoparticles as spherical, loosely agglomerated and having dimension of nanoscale. UV–vis DRS studies indicated a red shift in optical band gap with Co doping. PL spectra exhibits emission in the UV and visible region and the analysis revealed information about the presence of various types of defects in the ZnO lattice. An increase in the excitation wavelength gives intense emission in the high wavelength region for doped nanoparticles confirming the presence of divalent and monovalent oxygen as main defects. The Zn0.93Co0.07O nanoparticles records CIE coordinates lying in the white region of CIE color space at 350 nm with CCT of 5561.4 K suggesting their suitability in fabrication of white light emitting diodes.
{"title":"Excitation wavelength altered PL study of Co doped ZnO nanoparticles suitable for white LED application","authors":"N. Lavanya, N. Deepak","doi":"10.1515/zna-2023-0008","DOIUrl":"https://doi.org/10.1515/zna-2023-0008","url":null,"abstract":"Abstract ZnO nanoparticles doped with Co at different concentration (Zn1−xCo x O) were synthesized by sol–gel auto combustion method and are characterized by using various characterization tools. Structural study using X-ray diffraction technique (XRD) analysis showed the crystalline nature with hexagonal wurtzite geometry and the composition analysis using energy dispersive X-ray spectroscopy (EDX) confirmed the incorporation of Co in the ZnO lattice in the case of doped nanoparticles. Scanning electron-microscopy (SEM) and transmission electron microscopy (TEM) analysis showed the prepared nanoparticles as spherical, loosely agglomerated and having dimension of nanoscale. UV–vis DRS studies indicated a red shift in optical band gap with Co doping. PL spectra exhibits emission in the UV and visible region and the analysis revealed information about the presence of various types of defects in the ZnO lattice. An increase in the excitation wavelength gives intense emission in the high wavelength region for doped nanoparticles confirming the presence of divalent and monovalent oxygen as main defects. The Zn0.93Co0.07O nanoparticles records CIE coordinates lying in the white region of CIE color space at 350 nm with CCT of 5561.4 K suggesting their suitability in fabrication of white light emitting diodes.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73281904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Generation and amplification of magnetic fields is a subject of interest to both laboratory and astrophysical plasmas. The counter-streaming instability or Weibel instability is a mechanism responsible for self-generating magnetic fields in plasmas. In this paper, we investigate that the non-stationary ponderomotive force of a large amplitude electromagnetic wave (EMWs) propagating through dense two stream quantum electron ion plasma, may lead to the generation of d.c. magnetic fields. It is shown that degeneracy parameters, specifically the exchange correlation potential and Fermi pressure can reduce/control the self-induced magnetic field. Next the linear propagation of EMWs through plasma under consideration has also been considered in the presence of exchange correlation potential along with other quantum effects. Linear dispersion relation, the instability conditions and growth rate have been derived. It is found that the degeneracy parameters stabilize the propagation of instability and lead to reduction of the exponentially growing magnetic field. Threshold scale length of EMWs is also obtained for the stable propagation. The present result may be account helpful to understand the seed magnetic fields in dense plasmas.
{"title":"Specific features of electromagnetic waves in degenerate two stream electron-ion plasma: self-induced magnetic field","authors":"C. Rozina, M. Pervaiz, Z. Iqbal, Nourina Nadeem","doi":"10.1515/zna-2023-0009","DOIUrl":"https://doi.org/10.1515/zna-2023-0009","url":null,"abstract":"Abstract Generation and amplification of magnetic fields is a subject of interest to both laboratory and astrophysical plasmas. The counter-streaming instability or Weibel instability is a mechanism responsible for self-generating magnetic fields in plasmas. In this paper, we investigate that the non-stationary ponderomotive force of a large amplitude electromagnetic wave (EMWs) propagating through dense two stream quantum electron ion plasma, may lead to the generation of d.c. magnetic fields. It is shown that degeneracy parameters, specifically the exchange correlation potential and Fermi pressure can reduce/control the self-induced magnetic field. Next the linear propagation of EMWs through plasma under consideration has also been considered in the presence of exchange correlation potential along with other quantum effects. Linear dispersion relation, the instability conditions and growth rate have been derived. It is found that the degeneracy parameters stabilize the propagation of instability and lead to reduction of the exponentially growing magnetic field. Threshold scale length of EMWs is also obtained for the stable propagation. The present result may be account helpful to understand the seed magnetic fields in dense plasmas.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77954660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In this paper we consider the porous medium flow through a corrugated channel where the viscosity of the fluid can significantly change with the pressure. Assuming the exponential dependence of the viscosity and drag coefficient on the pressure, we propose the higher-order approximation of the solution to the nonlinear boundary-value problem governing the flow. To accomplish that, we combine the concept of the transformed pressure with asymptotic techniques.
{"title":"Modelling of the porous medium flow with pressure-dependent viscosity and drag coefficient","authors":"E. Marušić‐Paloka, Igor Pažanin","doi":"10.1515/zna-2023-0109","DOIUrl":"https://doi.org/10.1515/zna-2023-0109","url":null,"abstract":"Abstract In this paper we consider the porous medium flow through a corrugated channel where the viscosity of the fluid can significantly change with the pressure. Assuming the exponential dependence of the viscosity and drag coefficient on the pressure, we propose the higher-order approximation of the solution to the nonlinear boundary-value problem governing the flow. To accomplish that, we combine the concept of the transformed pressure with asymptotic techniques.","PeriodicalId":23871,"journal":{"name":"Zeitschrift für Naturforschung A","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87687363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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