Advances in Astrophysics最新文献_第3页

Quantum Electron-acoustic Envelope Solitons and Their Modulational Instability in a Degenerate Quantum Plasma 简并量子等离子体中的量子电子-声学包络孤子及其调制不稳定性

Advances in Astrophysics Pub Date : 2018-08-01 DOI: 10.22606/ADAP.2018.33006

Foisal B. T. Siddiki, Abdullah Al Mamun, M. Amin

{"title":"Quantum Electron-acoustic Envelope Solitons and Their Modulational Instability in a Degenerate Quantum Plasma","authors":"Foisal B. T. Siddiki, Abdullah Al Mamun, M. Amin","doi":"10.22606/ADAP.2018.33006","DOIUrl":"https://doi.org/10.22606/ADAP.2018.33006","url":null,"abstract":"The basic features of linear and nonlinear quantum electron-acoustic (QEA) waves in a degenerate quantum plasma (containing non-relativistically degenerate electrons, superthermal or κ-distributed electrons, and stationary ions) are theoretically investigated. The nonlinear Schödinger (NLS) equation is derived by employing the reductive perturbation method. The stationary solitonic solution of the NLS equation is obtained, and examined analytically as well as numerically to identify the basic features of the QEA envelope solitons. It has been found that the effects of the degeneracy and exchange/Bohm potentials of cold electrons, and superthermality of hot electrons significantly modify the basic properties of linear and nonlinear QEA waves. It is observed that the QEA waves are modulationally unstable for k < kc, where kc is the maximum (critical) value of the QEA wave number k below which the QEA waves are modulationally unstable), and that for k < kc the solution of the NLS equation gives rise to the bright envelope solitons, which are found to be localized in both spatial (ξ) and time (τ) axes. It is also observed that as the spectral index κ is increased, the critical value of the wave number (amplitude of the QEA envelope bright solitons) decreases (increases). The implications of our results should be useful in understanding the localized electrostatic perturbation in solid density plasma produced by irradiating metals by intense laser, semiconductor devices, microelectronics, etc.","PeriodicalId":131060,"journal":{"name":"Advances in Astrophysics","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117181981","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}

引用次数: 0

The Electromagnetic Energy-Momentum Tensor in Expanding Universes 膨胀宇宙中的电磁能量-动量张量

Advances in Astrophysics Pub Date : 2018-08-01 DOI: 10.22606/ADAP.2018.33007

H. Fahr, M. Heyl

{"title":"The Electromagnetic Energy-Momentum Tensor in Expanding Universes","authors":"H. Fahr, M. Heyl","doi":"10.22606/ADAP.2018.33007","DOIUrl":"https://doi.org/10.22606/ADAP.2018.33007","url":null,"abstract":"In two previous papers the authors have investigated the characteristics of freely propagating cosmic photons in expanding homogenous flat universes from particle and wave points of view, respectively. The result was that the energy density of these freely propagating photons scales with 1/S3 instead with the generally accepted and redshift-related 1/S4, with S being the cosmic scale factor. This is a surprising result at first glance but finally very understandable if energy conservation has to be required also for cosmic photons without creating a conflict with observations. In this paper we treat freely propagating cosmic photons with a totally different approach, namely with the electromagnetic energy-momentum tensor (from now on abbreviated with EMT). The implementation of the EMT, when correctly interpreted for freely propagating photons, into Einstein’s field equations then automatically leads to the same 1/S3-scaling law for the energy density of cosmic photons, herewith confirming the results found earlier for the particle and wave view. We conclude that the observed cosmological redshift of photons (energy density ∝ 1/S4) is compatible with the law of energy conservation, i.e energy density ∝ 1/S3 if interpreted on a new physical basis.","PeriodicalId":131060,"journal":{"name":"Advances in Astrophysics","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133867947","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}

引用次数: 1

Application of the Non-Local Physics in the Theory of the Matter Movement in Black Holes 非局域物理在黑洞物质运动理论中的应用

Advances in Astrophysics Pub Date : 2018-08-01 DOI: 10.22606/adap.2018.33001

B. Alexeev

引用次数: 0

Low-energy Quantum Gravity and Cosmology without Dark Energy 没有暗能量的低能量子引力和宇宙学

Advances in Astrophysics Pub Date : 2018-05-01 DOI: 10.22606/ADAP.2019.41001

Michael A. Ivanov

引用次数: 6

Self-gravitating Envelope Solitons in a Degenerate Quantum Plasma System 简并量子等离子体系统中的自引力包络孤子

Advances in Astrophysics Pub Date : 2018-03-04 DOI: 10.22606/adap.2018.34005

N. Ahmed, N. A. Chowdhury, A. Mannan, A. Mamun