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Effect of interplanetary magnetic field B_(x)on the polar electrojets as observed by CHAMP and Swarm satellites
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作者 Hui Wang ChengZhi Wang YunFang Zhong 《Earth and Planetary Physics》 EI CAS CSCD 2024年第2期382-390,共9页
Based on 16 years of magnetic field observations from CHAMP and Swarm satellites,this study investigates the influence of the Interplanetary Magnetic Field(IMF)Bx component on the location and peak current density of ... Based on 16 years of magnetic field observations from CHAMP and Swarm satellites,this study investigates the influence of the Interplanetary Magnetic Field(IMF)Bx component on the location and peak current density of the polar electrojets(PEJs).We find that the IMF Bx displays obvious local time,seasonal,and hemispherical effects on the PEJs,as follows:(1)Compared to other local times,its influence is weakest at dawn and dusk.(2)In the midnight sectors of both hemispheres,the IMF Bx tends to amplify the westward PEJ when it is<0 in the Northern Hemisphere and when it is>0 in the Southern Hemisphere;this effect is relatively stronger in the local winter hemisphere.(3)At noontime,the IMF Bx intensifies the eastward current when it is<0 in the Northern Hemisphere;in the Southern Hemisphere when it is>0,it reduces the westward current;this effect is notably more prominent in the local summer hemisphere.(4)Moreover,the noontime eastward current shifts towards higher latitudes,while the midnight westward current migrates towards lower latitudes when IMF Bx is<0 in the Northern Hemisphere and when it is>0 in the Southern Hemisphere. 展开更多
关键词 polar electrojet interplanetary magnetic field Bx local time asymmetry hemispheric difference
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Accelerations in the Local Magnetic Field on the Adriatic Tectonic Microplate 被引量:1
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作者 Rudi Čop Jean L. Rasson Andrej Bilc 《Open Journal of Earthquake Research》 2021年第3期95-104,共10页
The high level of noise is a special feature of the geomagnetic field on the territory of Slovenia. The tension of the Adriatic tectonic microplate, on which Slovenia entirely lies, was recognized as one of its source... The high level of noise is a special feature of the geomagnetic field on the territory of Slovenia. The tension of the Adriatic tectonic microplate, on which Slovenia entirely lies, was recognized as one of its sources. The interior of the Earth is also the source of geomagnetic jerks. They are impulses in the secular variation calculated on the basis of monthly or annual mean values of variation of the geomagnetic field. The paper presents an analysis of accelerations in a local magnetic field calculated on the bases of daily mean values of the magnetic field measured at PIA geomagnetic Observatory (Piran, Slovenia) in 2020. These accelerations indicate geomagnetic impulses at the regional level over days or weeks. Then these results are compared with the registered seismic activity in the West Balkans. 展开更多
关键词 Geomagnetic Observatory Geomagnetic Jerks accelerations in the local magnetic fields Seismic Activity
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“Doubling” of local photon emissions when two simultaneous, spatially-separated, chemiluminescent reactions share the same magnetic field configurations 被引量:9
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作者 Blake T. Dotta Michael A. Persinger 《Journal of Biophysical Chemistry》 2012年第1期72-80,共9页
The aim of the present experiments was to discern if the “entanglement”-like photon emissions from pairs of cell cultures or human brains separated by significant distances but sharing the same circling magnetic fie... The aim of the present experiments was to discern if the “entanglement”-like photon emissions from pairs of cell cultures or human brains separated by significant distances but sharing the same circling magnetic field could be demonstrated with a classic chemiluminescent reaction produced by hydrogen peroxide and hypochlorite. Simultaneous injection of the same amount of peroxide into a local dish (above a photomultiplier tube) and a dish 10 m away in a closed chamber produced a “doubling” of the durations of the photon spikes only when the two reactions were placed in the center of separate spaces around each of which magnetic fields were generated as accelerating group velocities containing decreasing phase modulations followed by decelerating group velocities embedded with increasing phase modulations. The duration of this “entanglement” was about 8 min. These results suggest that separate distances behave as if they were “the same space” if they are exposed to the same precise temporal configuration of magnetic fields with specific angular velocities. 展开更多
关键词 PHOTON Emission ENTANGLEMENT Angularly Accelerating magnetic fields Hydrogen Per-oxide/Hypochlorite Reaction
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THE EFFECT OF MAGNETIC FIELDS ON LOW FREQUENCY OSCILLATING NATURAL CONVECTION WITH PRESSURE GRADIENT 被引量:1
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作者 G.C.Sharma Madhu Jain Mahesh Chandra 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2003年第3期274-283,共10页
The oscillating natural convection in the presence of transverse magnetic field with time depending pressure gradient is studied. The analysis of the problem is carried out by assuming that the fluid is flowing in a... The oscillating natural convection in the presence of transverse magnetic field with time depending pressure gradient is studied. The analysis of the problem is carried out by assuming that the fluid is flowing in a parallel plate configuration. The emphasis is on low frequency oscillating convective flows induced by g-jitter associated with micro gravity because of their importance to the space processing materials. A general solution for an oscillating flow in the presence of transverse magnetic field is carried out. Some special cases of the oscillating flow and its response to an applied magnetic field are performed. It was observed that the behavior of oscillating free convective flows depends on frequency, amplitude of the driving buoyancy forces, temperature gradient,magnetic field and the electric conditions of the channel walls. In the absence of magnetic field, buoyancy force plays a predominant role in driving the oscillatory flow pattern, and velocity magnitude is also affected by temperature gradients. To suppress the oscillating flow external magnetic field can be used. It is also found that the reduction of the velocity is inversely proportional to the square of the applied magnetic field with conducting wall but directly proportional to the inverse of the magnetic field with insulating wall. Detailed calculations and computational results are also carried out to depict the real situation. 展开更多
关键词 CONVECTION g- jitter acceleration buoyancy force magnetic field pressure gradient
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Numerical simulation of the plasma acceleration process in a magnetically enhanced micro-cathode vacuum arc thruster 被引量:6
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作者 Jinyue GENG Yongcai CHEN +2 位作者 Surong SUN Wendong HUANG Haixing WANG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2020年第9期95-105,共11页
A particle-in-cell simulation is conducted to investigate the plasma acceleration process in a micro-cathode vacuum arc thruster.A coaxial electrode structure thruster with an applied magnetic field configuration is u... A particle-in-cell simulation is conducted to investigate the plasma acceleration process in a micro-cathode vacuum arc thruster.A coaxial electrode structure thruster with an applied magnetic field configuration is used to investigate the effects of the distribution of the magnetic field on the acceleration process and the mechanism of electrons and ions.The modeling results show that due to the small Larmor radius of electrons,they are magnetized and bound by the magnetic field lines to form a narrow electron channel.Heavy ions with a large Larmor radius take a long time to keep up with the electron movement.The presence of a magnetic field strengthens the charge separation phenomenon.The electric field caused by the charge separation is mainly responsible for the ion acceleration downstream of the computation.The impact of variations in the distribution of the magnetic field on the acceleration of the plasma is also investigated in this study,and it is found that the position of the magnetic coil relative to the thruster exit has an important impact on the acceleration of ions.In order to increase the axial velocity of heavy ions,the design should be considered to reduce the confinement of the magnetic field on the electrons in the downstream divergent part of the applied magnetic field. 展开更多
关键词 micro-cathode vacuum arc thruster magnetic field ion acceleration
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The Self-Consistent Nonlinear Theory of Charged Particle Beam Acceleration by Slowed Circularly Polarized Electromagnetic Waves 被引量:1
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作者 孔令宝 王虹宇 +1 位作者 侯志灵 金海波 《Plasma Science and Technology》 SCIE EI CAS CSCD 2013年第12期1174-1177,共4页
The relativistic interaction of charged particle beams with a circularly polarized electromagnetic wave propagating along a uniform guiding magnetic field in the tunneling of a dielectric medium is analyzed. The accel... The relativistic interaction of charged particle beams with a circularly polarized electromagnetic wave propagating along a uniform guiding magnetic field in the tunneling of a dielectric medium is analyzed. The acceleration mechanism and a self-consistent nonlinear theory are presented for the interaction of relativistic charged particle beams with electromagnetic waves. Numerical results show that the beam particle can be efficiently accelerated in the interaction process. 展开更多
关键词 charged particle acceleration slowed circular electromagnetic wave self-consistent nonlinear equation guiding magnetic field
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Heat transfer intensification in hydromagnetic and radiative 3D unsteady flow regimes: A comparative theoretical investigation for aluminum and γ-aluminum oxides nanoparticles 被引量:2
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作者 Naveed AHMED ADNAN +3 位作者 Umar KHAN Syed Zulfiqar Ali ZAIDI Imran FAISAL Syed Tauseef MOHYUD-DIN 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第5期1233-1249,共17页
This article investigates the colloidal study for water and ethylene glycol based nanofluids.The effects of Lorentz forces and thermal radiation are considered.The process of non-dimensionalities of governing equation... This article investigates the colloidal study for water and ethylene glycol based nanofluids.The effects of Lorentz forces and thermal radiation are considered.The process of non-dimensionalities of governing equations is carried out successfully by means of similarity variables.Then,the resultant nonlinear nature of flow model is treated numerically via Runge-Kutta scheme.The characteristics of various pertinent flow parameters on the velocity,temperature,streamlines and isotherms are discussed graphically.It is inspected that the Lorentz forces favors the rotational velocity and rotational parameter opposes it.Intensification in the nanofluids temperature is observed for volumetric fraction and thermal radiation parameter and dominating trend is noted for γ-aluminum nanofluid.Furthermore,for higher rotational parameter,reverse flow is investigated.To provoke the validity of the present work,comparison between current and literature results is presented which shows an excellent agreement.It is examined that rotation favors the velocity of the fluid and more radiative fluid enhances the fluid temperature.Moreover,it is inspected that upturns in volumetric fraction improves the thermal and electrical conductivities. 展开更多
关键词 conventional fluids aluminum and γ-aluminum oxides magnetic field thermal radiation Runge-Kutta scheme shear stress local rate of heat transfer
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Ensembling Neural Networks for User’s Indoor Localization Using Magnetic Field Data from Smartphones 被引量:1
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作者 Imran Ashraf Soojung Hur +1 位作者 Yousaf Bin Zikria Yongwan Park 《Computers, Materials & Continua》 SCIE EI 2021年第8期2597-2620,共24页
Predominantly the localization accuracy of the magnetic field-based localization approaches is severed by two limiting factors:Smartphone heterogeneity and smaller data lengths.The use of multifarioussmartphones cripp... Predominantly the localization accuracy of the magnetic field-based localization approaches is severed by two limiting factors:Smartphone heterogeneity and smaller data lengths.The use of multifarioussmartphones cripples the performance of such approaches owing to the variability of the magnetic field data.In the same vein,smaller lengths of magnetic field data decrease the localization accuracy substantially.The current study proposes the use of multiple neural networks like deep neural network(DNN),long short term memory network(LSTM),and gated recurrent unit network(GRN)to perform indoor localization based on the embedded magnetic sensor of the smartphone.A voting scheme is introduced that takes predictions from neural networks into consideration to estimate the current location of the user.Contrary to conventional magnetic field-based localization approaches that rely on the magnetic field data intensity,this study utilizes the normalized magnetic field data for this purpose.Training of neural networks is carried out using Galaxy S8 data while the testing is performed with three devices,i.e.,LG G7,Galaxy S8,and LG Q6.Experiments are performed during different times of the day to analyze the impact of time variability.Results indicate that the proposed approach minimizes the impact of smartphone variability and elevates the localization accuracy.Performance comparison with three approaches reveals that the proposed approach outperforms them in mean,50%,and 75%error even using a lesser amount of magnetic field data than those of other approaches. 展开更多
关键词 indoor localization magnetic field data long short term memory network data normalization gated recurrent unit network deep learning
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Local non-similarity solution to impact of chemical reaction on MHD mixed convection heat and mass transfer flow over porous wedge in the presence of suction /injection
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作者 P.LOGANATHAN P.PUVI-ARASU R.KANDASAMY 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2010年第12期1517-1526,共10页
Combined heat and mass transfer on free, forced, and mixed convection flow along a porous wedge with magnetic effect in the presence of chemical reaction is investigated. The flow field characteristics are analyzed by... Combined heat and mass transfer on free, forced, and mixed convection flow along a porous wedge with magnetic effect in the presence of chemical reaction is investigated. The flow field characteristics are analyzed by the Runge-Kutta-Gill scheme with the shooting method as well as the local non-similarity method up to the third level of truncation, which are used to reduce the governing partial differential equations into nine ordinary differential equations. The governing boundary layer equations are converted to a dimensionless form by Falkner-Skan transformations. Because of the effect of suction/injection on the wall of the wedge with buoyancy force and variable wall temperature, the flow field is locally non-similar. Numerical calculations up to the third order level of truncation are carried out as a special case for different values of dimensionless parameters. Effects of the magnetic field strength in the presence of chemical reaction with variable wall temperature and concentration on the dimensionless velocity, temperature and concentration profiles are shown graphically. 展开更多
关键词 local non-similarity suction/injection buoyancy force magnetic field wallof wedge
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Cosmic Ether, Possessing Electric-Tension and Magnetic-Resistance, Is the Unified Field for Physics 被引量:1
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作者 Chandrasekhar Roychoudhuri 《Journal of Modern Physics》 2021年第5期671-699,共29页
The paper presents the case that physics is already and effectively unified by the energetic tension field, ether. We identify this integrating power of ether first, by re-defining the action generating parameters of ... The paper presents the case that physics is already and effectively unified by the energetic tension field, ether. We identify this integrating power of ether first, by re-defining the action generating parameters of this energetic tension field as the electric-tension, <img src="Edit_1233fa02-9a1c-416a-8153-196733a12887.png" alt="" />, and the magnetic-resistance, <em>μ</em><sub>0</sub>, while re-deriving the Maxwell’s wave equation in analogy with the mechanically stretched string, where the <img src="Edit_07813a1b-d94f-4e68-a3ed-b3023cd3fb5f.png" alt="" />. Then, replacing <img src="Edit_7d06fa1e-760d-4b80-a503-db81378a3512.png" alt="" /> by <img src="Edit_58f15ef0-2e86-42ae-a899-d0b4741f12d0.png" alt="" /> and <em>m</em><sub>0</sub> by <img src="Edit_f8cb7020-1a27-404a-b146-5c1357e1c5b5.png" alt="" />, one can find that almost all working physics theories are being energized by<img src="Edit_f860fcdd-1dc1-40bf-aaf1-e07b0e4a7524.png" alt="" />and <em>μ</em><sub>0</sub>. To complete the unification, we can now postulate that the particles are also freely propagating EM waves, but they are spatially localized as in-phase, close-looped (IP-CL) vortex-like propagation modes of ether. Because of their IP-CL mode structure, they have space-finite spatial structures and remain spatially stationary in the absence of any spatially influencing potential gradients (forces) in their vicinity. Particles’ <em>harmonic phase</em> driven interactions between quantum particles give birth to the <em>appearance</em> of wave-particle duality. There is no need for the confusing and unnecessary de Broglie’s Pilot Wave. The inertia to spatial motion of IP-CL modes automatically accommodates Newton’s laws of motion. The cosmic universality of Maxwellian wave velocity, and particles as IP-CL modes, jointly accommodate the two key postulates of special relativity without the need for unphysical four-dimensionality. The observable universe is represented only by its diverse oscillatory excited states. The stable and stationary Cosmic Ether keeps holding 100% of its energy all the time. We have proposed a one-way light pulse propagation experiment to directly validate the existence of ether, rather than approaching Michelson’s way of measuring the ether drag. We have identified a good number of examples of working theoretical expressions in terms of <img src="Edit_fd739625-efbd-4edd-9e1e-ba4ab5b7c07f.png" alt="" />and<em> μ</em><sub>0</sub> and presented our critical views in physics thinking, belonging to Classical, Relativity, Quantum and Cosmology Physics. 展开更多
关键词 Cosmic Ether Ether as the Unifying Field Ether Energetic Tension Field (1/ε0)-Electric Tension of Ether μ0-magnetic Resistance of Ether Particles as localized EM Oscillating Modes of Ether
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基于改良Pan-Tompkins算法的心磁R波定位方法
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作者 王睿奇 封燮 +1 位作者 张斌珍 汤苏晋 《舰船电子工程》 2024年第7期29-34,共6页
针对传统的心电图检查对心脏区域结构不敏感性以及心磁检测中多周期R峰难以定位的问题,该文提出一种改进的Pan-Tompkins算法,旨在精确定位R波并分析心磁信号。通过对心磁信号和心电信号进行预处理,并运用Savitz⁃ky-Golay滤波器和LOF算... 针对传统的心电图检查对心脏区域结构不敏感性以及心磁检测中多周期R峰难以定位的问题,该文提出一种改进的Pan-Tompkins算法,旨在精确定位R波并分析心磁信号。通过对心磁信号和心电信号进行预处理,并运用Savitz⁃ky-Golay滤波器和LOF算法处理信号及检测异常点,该方法可高精度识别R波位置。利用有限元模型逆问题求解方法,推测心脏内电流密度分布,进而获取磁场图和伪电流密度矢量图。在30个样本共计7348个心动周期中,改进的Pan-Tomp⁃kins算法成功识别7321个R波,准确率高达99.63%。该方法可应用于MCG的R波识别和心磁病理分析,对于研究心脏电活动的时空演化规律和机制具有重要意义。 展开更多
关键词 心脏磁场 R峰定位 异常点检测 超导量子干涉 二维电流密度分布
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A novel localization method for noninvasive monitoring capsule 被引量:3
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作者 何文辉 Yan Guozheng Jiang Pingping Cuo Xudong 《High Technology Letters》 EI CAS 2006年第3期255-259,共5页
Noninvasive monitoring capsule for gastrointestinal tract can De swauowed by patient.It is of great importance for the physician to monitor the precise position of capsule in gastrointestinal tract. The authors invest... Noninvasive monitoring capsule for gastrointestinal tract can De swauowed by patient.It is of great importance for the physician to monitor the precise position of capsule in gastrointestinal tract. The authors investigated a novel method for it. Using three coils with DC current to excite magnetic field and one triaxial magnetoresistive sensor to measure the excited magnetic vectors, they tried to solve the problem. The authors provided the localization principle of the method and analyzed it by an experiment, too. The method may be applied in practice in the future though it is still immature now. 展开更多
关键词 gastrointestinal tract COIL magnetic field localIZATION
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Influence of a Magnetic Guide Field on Injection in Wakefield Acceleration 被引量:1
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作者 Alain Bourdier Sébastien Rassou +1 位作者 Guillaume Girard Mathieu Drouin 《Journal of Modern Physics》 2012年第9期1018-1020,共3页
The influence of an external static field applied in the direction parallel to the direction of propagation of a high intensity driving laser pulse on the electron trapping in laser wakefield acceleration is explored.
关键词 Laser WAKEFIELD ACCELERATION magnetic Field ELECTRON inJECTION SELF-TRAPPinG
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3D Finite Element Analysis of the Stray Loss in Power Transformer Structure Parts
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作者 Yan Li Longnv Li +1 位作者 Yongteng Jing Bo Zhang 《Energy and Power Engineering》 2013年第4期1089-1092,共4页
In order to analyze the leakage magnetic field and stray loss in power transformer, leakage magnetic field and stray loss in structure parts of a power transformer are calculated by three-dimensional (3-D) non-linear ... In order to analyze the leakage magnetic field and stray loss in power transformer, leakage magnetic field and stray loss in structure parts of a power transformer are calculated by three-dimensional (3-D) non-linear time harmonic finite element method (FEM). The results show that stray loss and loss density in structure parts are large and which may lead to local overheating and affect performance of the transformer. The magnetic shields are used to reduce the stray loss and loss density of power transformer. Effects of these shields on stray loss and loss density of structure parts are discussed. The results show that stray loss and local overheating can be reduced and eliminated effectively by adding magnetic shields. It provides some references for the analysis of stray loss and optimization design in transformer. 展开更多
关键词 FinITE Element Method Stray Loss LEAKAGE magnetic Field local OVERHEATinG magnetic SHIELDS
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Thermal Radiation Effect on the MHD Turbulent Compressible Boundary Layer Flow with Adverse Pressure Gradient, Heat Transfer and Local Suction
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作者 Michalis Xenos 《Open Journal of Fluid Dynamics》 2017年第1期1-14,共14页
The combined effect of magnetic field, thermal radiation and local suction on the steady turbulent compressible boundary layer flow with adverse pressure gradient is numerically studied. The magnetic field is constant... The combined effect of magnetic field, thermal radiation and local suction on the steady turbulent compressible boundary layer flow with adverse pressure gradient is numerically studied. The magnetic field is constant and applied transversely to the direction of the flow. The fluid is subjected to a localized suction and is considered as a radiative optically thin gray fluid. The Reynolds Averaged Boundary Layer (RABL) equations with appropriate boundary conditions are transformed using the compressible Falkner Skan transformation. The nonlinear and coupled system of partial differential equations (PDEs) is solved using the Keller box method. For the eddy-kinematic viscosity the Baldwin Lomax turbulent model and for the turbulent Prandtl number the extended Kays Crawford model are used. The numerical results show that the flow field can be controlled by the combined effect of the applied magnetic field, thermal radiation, and localized suction, moving the separation point, xs , downstream towards the plate’s end, and increasing total drag, D . The combined effect of thermal radiation and magnetic field has a cooling effect on the fluid at the wall vicinity. The combined effect has a greater influence in the case of high free-stream temperature. 展开更多
关键词 Computational Fluid Mechanics magnetic Field theRMAL Radiation local SUCTION TURBULENT Flow COMPRESSIBLE Boundary Layer
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MagneFi: Multiuser, Multi-Building and Multi-Floor Geomagnetic Field Dataset for Indoor Positioning
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作者 Imran Ashraf Muhammad Usman Ali +2 位作者 Soojung Hur Gunzung Kim Yongwan Park 《Computers, Materials & Continua》 SCIE EI 2022年第10期1747-1768,共22页
Indoor positioning and localization have emerged as a potential research area during the last few years owing to the wide proliferation of smartphones and the inception of location-attached services for the consumer i... Indoor positioning and localization have emerged as a potential research area during the last few years owing to the wide proliferation of smartphones and the inception of location-attached services for the consumer industry.Due to the importance of precise location information,several positioning technologies are adopted such as Wi-Fi,ultrawideband,infrared,radio frequency identification,Bluetooth beacons,pedestrian dead reckoning,and magnetic field,etc.Although Wi-Fi and magnetic field-based positioning are more attractive concerning the deployment of Wi-Fi access points and ubiquity of magnetic field data,the latter is preferred as it does not require any additional infrastructure as other approaches do.Despite the advantages of magnetic field positioning,comparing the performance of positioning and localization algorithms is very difficult due to the lack of good public datasets that cover various aspects of the magnetic field data.Available datasets do not provide the data to analyze the impact of device heterogeneity,user heights,and time-specific magnetic field mutation.Moreover,multi-floor and multibuilding data are available for the evaluation of state-of-the-art approaches.To overcome the above-mentioned issues,this study presents multi-user,multidevice,multi-building magnetic field data which is collected over a longer period.The dataset contains the data from five different smartphones including Samsung Galaxy S8,S9,A8,LG G6,and LG G7 for three geographically separated buildings.Three users including one female and two males collected the data for various path geometry and data collection scenarios.Moreover,the data contains the magnetic field samples collected on stairs to test multifloor localization.Besides the magnetic field data,the data from inertial measurement unit sensors like the accelerometer,motion sensors,and barometer is provided as well. 展开更多
关键词 magnetic field dataset magnetic-field based positioning smartphone sensors benchmark analysis indoor positioning and localization
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Influence of a Magnetic Guide Field on Self-Injection in Wakefield Acceleration
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作者 Alain Bourdier Guillaume Girard +2 位作者 Sébastien Rassou Xavier Davoine Mathieu Drouin 《Journal of Modern Physics》 2012年第12期1983-1990,共8页
The influence of an external static field applied in the direction of propagation of a high intensity driving laser pulse on the electron trapping in laser wakefield acceleration is explored. It is shown that, in the ... The influence of an external static field applied in the direction of propagation of a high intensity driving laser pulse on the electron trapping in laser wakefield acceleration is explored. It is shown that, in the case of self-injection, the electric charge accelerated can be enhanced in some physical situations. 展开更多
关键词 Laser WAKEFIELD ACCELERATION magnetic Guide Field Electron inJECTION SELF-TRAPPinG
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Influence of a Static Magnetic Field on Beam Emittance in Laser Wakefield Acceleration
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作者 Mathieu Drouin Alain Bourdier +1 位作者 Quentin Harry Sébastien Rassou 《Journal of Modern Physics》 2012年第12期1991-1997,共7页
The enhancement of trapping and the optimization of beam quality are two key issues of Laser Wakefield Acceleration (LWFA). The effect of a homogenous constant magnetic field B0, parallel to the direction of propagati... The enhancement of trapping and the optimization of beam quality are two key issues of Laser Wakefield Acceleration (LWFA). The effect of a homogenous constant magnetic field B0, parallel to the direction of propagation of the pump pulse, is studied in the blowout regime via 2Dx3Dv Particle-In-Cell simulations. Electrons are injected into the wake using a counter-propagating low amplitude laser. Transverse currents are generated at the rim of the bubble, which results in the amplification of the B0 field at the rear of the bubble. Therefore the dynamics of the beam is modified, the main effect is the reduction of the transverse emittance when B0 is raised. Depending on beam loading effects the low energy tail, observed in the non-magnetized case, can be suppressed when B0 is applied, which provides a mono-energetic beam. 展开更多
关键词 Laser WAKEFIELD ACCELERATION magnetic Field BEAM EMITTANCE BEAM LOADinG
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Theory of Electromagnetism and Gravity —Modeling Earth as a Rotating Solenoid Coil
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作者 Greg Poole 《Journal of High Energy Physics, Gravitation and Cosmology》 2017年第4期663-692,共30页
Presented in this manuscript are conventional electrical engineering tools to model the earth as a rotating electrical machine. Calculations using known parameters of the earth and measured field data has resulted in ... Presented in this manuscript are conventional electrical engineering tools to model the earth as a rotating electrical machine. Calculations using known parameters of the earth and measured field data has resulted in new understanding of the earth’s electrical system and gyroscopic rotation. The material makeup of the inner earth is better understood based on derived permeability and permittivity constants. The planet has been modeled as simple coils and then as a parallel impedance circuit which has led to fundamental insight into planetary speed control and RLC combination for Schumann Resonance of 7.83 Hz. Torque and Voltage Constants and the inverse Speed Constant are calculated using three methods and all compare favorably with Newton’s Gravitational Constant. A helical resonator is referenced and Schumann’s Resonant ideal frequency is calculated and compared with others idealism. A new theory of gravity based on particle velocity selector at the poles is postulated. Two equations are presented as the needed links between Faraday’s electromagnetism and Newtonian physics. Acceleration and Deceleration of earth is explained as a centripetal governor. A new equation for planetary attraction and the attraction of atomic matter is theorized. Rotation of the earth’s electrical coil is explained in terms of the Richardson effect. Electric power transfer from the sun to the planets is proposed via Flux Transfer Events. The impact of this evolving science of electromagnetic modeling of planets will be magnified as the theory is proven, and found to be useful for future generations of engineers and scientists who seek to discover our world and other planets. 展开更多
关键词 Ampere Biot-Savart CENTRIPETAL Acceleration CENTRIPETAL GOVERNOR Dynamo EARTH Einstein-de Haas Effect Electric Field Electromagnetism Flux Transfer Events GOVERNOR Control GRAVITY Gravitational CONSTANT Helical Resonator Lenz Law Lorentz Lightning magnetic Field Motor CONSTANT Parallel Impedance Planet SPEED Control Schumann Resonance Richardson Effect Solenoid SPEED CONSTANT Solar Power System Torque CONSTANT Velocity Selector Voltage CONSTANT
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SHINE超导波荡器磁场点测量霍尔探头位置标定
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作者 吴泽州 张继东 +1 位作者 陈金雅 周巧根 《核技术》 CAS CSCD 北大核心 2023年第9期9-16,共8页
正在建设的上海硬X射线自由电子激光装置(Shanghai HIgh repetitioN rate XFEL and Extreme light facility,SHINE)将利用40台周期长度为16 mm、磁长度为4 m、净气隙高度为4 mm的真空内超导波荡器,以产生垂直线极化的自由电子激光。霍... 正在建设的上海硬X射线自由电子激光装置(Shanghai HIgh repetitioN rate XFEL and Extreme light facility,SHINE)将利用40台周期长度为16 mm、磁长度为4 m、净气隙高度为4 mm的真空内超导波荡器,以产生垂直线极化的自由电子激光。霍尔探头磁场测量是目前测量波荡器场图最可靠的测量方法之一,而霍尔探头灵敏中心的定位精度是影响磁场测量精度的主要因素之一。本文介绍了这些超导波荡器的磁场点测量系统,以及霍尔探头灵敏中心的高精度位置标定。通过翻转安装有霍尔探头与角锥棱镜的磁测滑车,可分别标定霍尔探头灵敏中心以及角锥棱镜顶点和磁测滑车翻转轴的横向间距,从而获得霍尔探头灵敏中心彼此之间的横向距离,以及霍尔探头灵敏中心与角锥棱镜顶点之间的横向距离。该方法的标定精度好于±10μm,能满足该超导波荡器磁场测量的要求。 展开更多
关键词 超导波荡器 磁场点测量 三维激光定位
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