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Optical Design of EcEI Diagnostic System for HT-T Tokamak

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Plasma Science and Technology 2004年第1期6卷 2166-2171页

作者：王俊闻一之俞昌旋万宝年 n.c.luhmann WangJian XiaZ.G. DepartmentofModernPhysics UniversityofScienceandTechnologyofChinaHefei230027China InstituteofPlasmaPhysics theChineseAcademyofSciencesHefei230031China DepartmentofAppliedScience UniversityofCaliforniaDavisCalifornia95616USA

Electron cyclotron emission imaging system in the frequency range of 95 GHz -125 GHz is going to be constructed for a two-dimensional diagnosis of the electron temperature profiles and fluctuations on the HT-7 Tokamak. The optical design for the EcEI diagnostic system is completed. Because of the superconducting technology used in HT-7, the vacuum chamber is rather thick (630 mm), the height of the horizontal windows is limited (maximum 450 mm), which constrains greatly the EcE imaging Gaussian beam that passing through the windows. We here comes to make a design compromise between the number of the beams that can pass through the windows and the spatial resolution (around 1.1 cm). We also find that due to the field curvature of the optical system, the gaussian beams of edge channels are always overlapped. To flatten the field curvature, it is needed to insert a concave made of a material with a low refractive index (compared with the one used in the convex). But the suitable material has not been available so far, therefore the deterioration of the resolution in some channels (e.g. the edge channels) is acceptable.

关键词： electron cyclotron emission imaging optical design electron temperature and its fluctuations

One-Dimensional Vertical Electron cyclotron Emission Imaging Diagnostic for HT-7 Tokamak

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Plasma Science and Technology 2006年第1期8卷 76-79页

作者：王俊徐小圆闻一之俞昌旋万宝年 n.c.luhmann 王剑夏振刚 cAS Key Laboratory of Plasma Physics Department of Modern PhysicsUniversity of Science and Technology of ChinaHefei 230027China Institute of Plasma Physics Chinese Academy of SciencesHefei 230031China Department of Applied Science University of CaliforniaDavis California 95616USA

At the first stage of the electron cyclotron emission imaging （EcEI） diagnostic project on HT-7, a 16-channel vertical-resolved EcEI diagnostic has been developed and installed on HT-7 tokamak to measure electron cyclotron emission with a temporal resolution of 0.5 usec. The system works at a fixed frequency of 97.5 GHz. The sample volumes of the system are aligned vertically with a vertical channel spacing of 11 mm, and can be shifted across the plasma cross-section by varying the toroidal magnetic field. The high spatial resolution of the system is achieved by utilizing a low-cost linear mixer/receiver array and an optical imaging system. The focus location may be shifted horizontally when translating one of the optical imaging elements. The details of the system design and laboratory testing of the EcEI optics are presented together with the preliminary experimental results.

关键词： electron cyclotron emission imaging optical and electronic setting electron temperature and its fluctuations

Electron temperature fluctuation in the HT-7 tokamak plasma observed by electron cyclotron emission imaging

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chinese Physics B 2009年第3期18卷 1153-1160页

作者：徐小圆王俊余弈闻一之俞昌旋刘万东万宝年高翔 n.c.luhmann c.W.Domier 王剑夏正刚申作玮 chinese Academy of Sciences(cAS) Key Laboratory of Plasma Physics Department of Modern PhysicsUniversity of Science and Technology of China Institute of Plasma Physics Chinese Academy of Sciences Department of Applied Science University of California

The fluctuation of the electron temperature has been measured by using the electron cyclotron emission imaging in the Hefei Tokamak-7 （HT-7） plasma. The electron temperature fluctuation with a broadband spectrum shows that it propagates in the electron diamagnetic drift direction, and the mean poloidal wave-number kθ is calculated to be about 1.58cm^-1, or k^-θρs ≈ 0.34. It indicates that the fluctuation should come from the electron drift wave turbulence. The linear global scaling of the electron temperature fluctuation with the gradient of electron temperature is consistent with the mixing length scale qualitatively. Evolution of spectrum of the fluctuation during the sawtooth oscillation phases is investigated, and the fluctuation is found to increase with the gradient of electron temperature increasing during most phases of the sawtooth oscillation. The results indicate that the electron temperature gradient is probably the driver of the fluctuation enhancement. The steady heat flux driven by electron temperature fluctuation is estimated and compared with the results from power balance estimation.

关键词： electron temperature fluctuation electron cyclotron emission imaging Tokamak

nanoPhysics of Electron Dynamics near Surfaces in High Power Microwave Devices and Systems

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NanoPhysics of Electron Dynamics near Surfaces in High Power...

MOnOLITHIc InTEGRATIOn OF VARAcTOR DIODES On III-V cOMPOUnD SEMIcOnDUcTORS FOR WATT-LEVEL FREQUEncY MULTIPLIcATIOn AT MILLIMETER-WAVE WAVELEnGTHS

The 5th International Vacuum Electron Sources conference(IVESc2004)

作者： n.c.luhmann G..caryotakis J.P.Heritage R.Umstadd Department of Applied Science University of California Electrical and computer Engineering University of California Department of Physics Naval Postgraduate School

Recently,a consortium comprising the above indicated universities have been awarded a five year Multidisciplinary University Research Initiative （MURI） program aimed at providing a fundamental understanding of RF breakdown phenomena and developing novel, high current density cathodes. The start date is June 1,2004 and this talk will focus on both the initial activities and long term directions. The above goals will be accomplished by addressing two underlying issues: "pulse shortening" caused by RF breakdown and the lack of suitable, robust high current density cathodes. RF breakdown is a phenomenon that is poorly understood with respect to both the "nano-physics" of its inception as well the techniques to minimize its effects. Understanding it and preventing it require coordinated experimental and simulation programs. The cathodes required for so-called high power microwave （HPM） sources must provide in excess of 100 A/cm2 and conventional thermionic cathode technology falls short of that current density by about a factor of 5.

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MONOLITHIC INTEGRATION OF VARACTOR DIODES ON III-V COMPOUND ...

Translating Pathological Brain Activity Primers in Parkinson’s Disease Research

The Second International conference on Solid State and Integrated circuit Technology

作者： R.J.Hwu L.P.Sadwick n.c.luhmann M.Sokolich D.B.Rutledge University of california Los AngelesDepartment of Electrical Engineering Hughes Aircraft company TorranceCa 90509 california Institute of Technology PasadenaCa 91125

The major thrust of the current work is the development of monolithic planar diode-grid arrays for watt-level frequency multiplication at millimeter *** approach employs spatial power combining of device outputs together with monolithic integrated circuit techniques and results in potentially low-cost fabrication and small-size *** Schottky diode grids have been previously fabricated in a proof-of-principle test of the spatial powercombining concept.A doubling efficiency of 9.5%and output power of 0.5 W were achieved at 66 ***,a monolithic planar frequency multiplier array of GaAs Barrier-Intrinsic-n diodes has been fabricated. Tripling and quintupling to 100 GHz and 165 GHz,respectively,are predicted to yield watt-level output *** tripling studies combined with theoretical predictions are in good agreement with these predictions.A device simulation model has been developed and combined with large-signal nonlinear circuit analysis to guide the design of the device structure and *** experimental measurement of Dc and low-frequency electrical properties from several different structures agrees very well with the device modelling *** optimized device structure and operating conditions will be presented and discussed in detail.

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Research 2024年第1期2023卷 735-752页

作者： Daniela Mirzac Svenja L.Kreis Heiko J.luhmann Gabriel Gonzalez-Escamilla Sergiu Groppa Movement Disorders and neurostimulation Department of NeurologyFocus Program Translational NeuroscienceRhine Main Neuroscience NetworkUniversity Medical Center of the Johannes Gutenberg University Mainz55131 MainzGermany Institute of Physiology University Medical Center of the Johannes Gutenberg University Mainz55131 MainzGermany

Translational experimental approaches that help us better trace Parkinson’s disease(PD)pathophysiological mechanisms leading to new therapeutic targets are urgently *** this article,we review recent experimental and clinical studies addressing abnormal neuronal activity and pathological network oscillations,as well as their underlying mechanisms and *** aim is to enhance our knowledge about the progression of Parkinson's disease pathology and the timing of its symptom’s ***,we present mechanistic insights relevant for the generation of aberrant oscillatory activity within the cortico-basal ganglia *** summarize recent achievements extrapolated from available PD animal models,discuss their advantages and limitations,debate on their differential applicability,and suggest approaches for transferring knowledge on disease pathology into future research and clinical applications.

关键词： clinical knowledge insight

啁啾逆自由电子激光——高梯度真空激光加速器

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强激光技术进展 2000年第2期10卷 43-48,F003,F004,42页

作者： F．V．Hartemann E．c．Landahl A．L．TrohaJr J．R．VanMeter H．A．Baldis R．R．Freeman n．c．luhmann Jr．L．Song A．K．Kerman D．U．L．Yu 范品忠劳仑斯·里弗莫尔国家实验室激光科学应用中心戴维思加州大学应用科学系麻省理工学院理论物理中心与物理系加州DULY研究公司不详

在驱动激光强度接近相对论范围和脉冲持续时间只有几个光周期的情况下，对逆自由电子激光(IFEL)相互作用作了理论研究和数值计算。作为很有前途的真空激光加速过程，已演示了逆自由电子激光原理；这里证明了利用超短超高强度驱动激光脉... 详细信息

在驱动激光强度接近相对论范围和脉冲持续时间只有几个光周期的情况下，对逆自由电子激光(IFEL)相互作用作了理论研究和数值计算。作为很有前途的真空激光加速过程，已演示了逆自由电子激光原理；这里证明了利用超短超高强度驱动激光脉冲，大大增加逆自由电子激光作用带宽和加速梯度，因而产生大的能量增益。利用啁啾脉冲和负色散聚焦光学系统允许人们利用激光光学带宽的优点，产生具有最大梯度的彩色线聚焦。这些新颖思想的结合形成了紧凑的真空激光加速器，能以高梯度(Gev／m)和低能散加速皮秒电子束簇。

关键词：啁啾逆自由电子激光真空激光加速器高梯度负色散聚焦光学系统彩色线聚焦

Early Phases of Star Formation: Testing chemical Tools

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Research in Astronomy and Astrophysics 2024年第1期24卷 96-118页

作者： n.c.Martinez S.Paron cOnIcET-Universidad de Buenos Aires.Instituto de Astronomía y Física del Espacio Ciudad Universitaria(C1428EGA)Ciudad Autónoma de Buenos AiresArgentina

Star-forming processes strongly influence the ISM ***,many high-quality databases are available at millimeter *** them,it is possible to carry out studies that review and deepen previous *** these studies involve large samples of sources,it is preferred to use direct tools to study the molecular *** the aim of testing these tools such as the use of the Hcn/Hnc ratio as a thermometer,and the use of H^(13)cO^(+),Hc_(3)n,n_(2)H^(+) and c_(2)H as "chemical clocks," we present a molecular line study toward 55 sources representing massive young stellar objects at different evolutionary stages:infrared dark clouds(IRDcs),highmass protostellar objects(HMPOs),hot molecular cores(HMcs) and ultracompact H II *** found that the use of the Hcn/Hnc ratio as a universal thermometer in the ISM should be taken with care because the Hcn optical depth is a big issue that can affect the ***,this tool should be utilized only after a careful analysis of the Hcn spectrum,checking that no line,neither the main nor the hyperfine ones,presents absorption *** point out that the analysis of the emission of H^(13)cO^(+),Hc_(3)n,n_(2)H^(+) and c_(2)H could be useful to trace and distinguish regions among IRDcs,HMPOs and *** molecular line widths of these four species increase from the IRDc to the HMc stage,which can be a consequence of the gas dynamics related to the starforming processes taking place in the molecular *** results not only contribute with more statistics,acting as a probe of such chemical tools,useful to obtain information in large samples of sources,but also complement previous works through the analysis of other types of sources.

关键词： stars:formation ISM:molecules ISM:clouds

Imprints of a gravitational wave through the weak field deflection of photons

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chinese Physics c 2024年第8期48卷 240-245页

作者： Reggie c.Pantig Ali Övgün Physics Department Mapúa University658 Muralla St.IntramurosManila 1002Philippines Physics Department Eastern Mediterranean UniversityFamagusta99628 North Cyprusvia Mersin 10Turkiye

In this study,we investigate the novel phenomenon of gravitational lensing experienced by gravitational waves traveling past a Schwarzschild black hole perturbed by a specific,first-order,polar gravitational *** apply the Gauss-Bonnet theorem,finding a topological contribution to the deflection of light rays passing near the black *** demonstrate that the deflection angle can be determined by analyzing a region entirely outside the path of the light ray,leading to a calculation based solely on the parameters of the perturbing wave(Legendre polynomial order,l;frequency,σ).This approach offers a unique perspective on gravitational lensing and expands our understanding of black hole interactions with gravitational waves.

关键词： supermassive black holes gravitational waves chaos weak deflection angle Gauss-Bonnet theorem