Dear Colleagues, The International Scientific Committee and the Local Organizing Committee are pleased to invite you to participate in the XXX International Conference on Phenomena in Ionized Gases (ICPIG), which will be held in Belfast, Northern Ireland, on August 28th September 2nd 2011 . The XXX ICPIG will cover a wide range of fundamental and applied aspects of ionized gases. This conference emphasises interdisciplinary research and fosters exchange between different communities. All interested participants are kindly invited to present the latest results of their scientific work in one of the ICPIG subject areas. The first announcement is attached and more details can be found on the regularly updated website: http://www.qub.ac.uk/sites/icpig2011/ We wish you enjoyable Christmas holidays and a happy new year, Timo Gans on behalf of the LOC. ----------------------------------------------------------------------------------- 30. International Conference on Phenomena in Ionized Gases ICPIG Belfast 2011 Queen's University Belfast, Northern Ireland, UK 28. August - 2. September 2011 http://www.qub.ac.uk/icpig2011 icpig2011@qub.ac.uk Local Organising Committee Chair: Timo Gans Queen's University Belfast, Northern Ireland, UK International Scientific Committee Chair: Ursel Fantz Max-Planck-Institut fuer Plasmaphysik, Garching, Germany Secretary: Nicholas Braithwaite The Open University, Milton Keynes, UK Topics A. Fundamentals 1) Elementary processes and fundamental data Reaction paths, plasma chemistry, cross sections, swarm studies and data 2) Thermodynamics and transport phenomena Distribution functions, kinetic theory, transport models, dissipation, heating mechanisms 3) Plasma wall interactions, electrode and surface effects Secondary emission, wall erosion, surface reactions, edge plasmas in fusion devices 4) Collective and Nonlinear Phenomena Boundary sheaths, flows, waves, shocks, instabilities, self-organization, chaos, plasma-beam interaction, magnetized plasmas. B. Modelling, Simulation, and Diagnostics 5) Modeling and simulation techniques Analytical techniques, numerical methods, codes, visualization tools 6) Plasma diagnostic methods Optical, electrical, particle and laser-assisted diagnostics. Other plasma diagnostics methods C. Plasma Sources and Discharge Regimes 7) Astrophysical, geophysical and other natural plasmas Cosmic plasmas, interstellar nebula, magnetospheres, ionospheres, lightning, sprites 8) Low pressure plasmas DC glows, magnetrons, pseudo-sparks, edge-physics of fusion devices 9) High frequency discharges Radio-frequency and microwave driven discharges 10) Non-equilibrium plasmas and microplasmas at high pressures Breakdown, streamers, sparks, coronas, surface discharges, dielectric barrier discharges, high pressure glows, microplasmas 11) Thermal plasmas Arcs, thermo-ionic arcs, thermal plasma torches 12) Complex and dusty plasmas, ion-ion plasmas Particle dynamics, plasma crystals, structure formation, negative ion dominated plasmas D. Applications 13) Plasma processing of surfaces and particles Plasma etching and deposition, surface activation, thin film technology, generation, coating and deposition of nano-particles 14) High pressure and thermal plasma processing Torches, plasma synthesis, combustion, plasma spraying, pollution control 15) Plasma lamps and radiation sources Low and high pressure lamps, flat-panel plasma displays, X-ray sources, medical imaging, resistive plate detectors, gaseous photomultipliers. 16) Medical, biological, environmental and aeronautical applications Plasma sterilization, bio compatible coatings, diffusion barriers, plasma actuators and igniters 17) Plasma power and pulsed power technology, particle sources MHD and other plasma generators, circuit breakers, plasma switches, high power electron beams, Hall thrusters, Z Pinch, Theta pinch, and Plasma Focus apparatus
The 10th APCPST (Asia Pacific Conference on Plasma Science and Technology) and 23th SPSM (Symposium on Plasma Science for Materials) will be jointly held for July 4 - 8, 2010 at Jeju island in Korea . The conference details can be found in the attached 1 st circular or on the web homepage ( http://www.apcpst2010.org ). Important deadline: Abstract submission by March 28, 2010 The submitted regular manuscripts will be published in a SCI-rated journal, Thin Solid Films (Elsevier Science) as a special issue after peer review Topics 1. Basic plasma physics generation - Atmospheric/thermal/low-temperature plasma - Plasma sources, simulation and modeling, plasma diagnostics, plasma sources - Plasma chemistry, plasma-surface interactions 2. Material synthesis etching by plasma - Surface modification etching by plasma - Synthesis of thin films nano-structured materials - Large-scale plasma processing 3. Various applications of plasmas - Plasma process for semiconductor, display, and energy conversion devices - Plasma process for transparent, flexible, or stretchable electronic devices - Plasma for fusion energy - Plasma for bio medical application - Other applications We hope you could join the conference as we feel your participation will provide a strong contribution to the program. Yours Sincerely, Chi Kyu Choi, Conference Chair
It is our great pleasure to inform you that the 15th International Congress on Plasma Physics (ICPP 2010) will be held in Santiago, capital of Chile, during August 8-13, 2010, in combination with the 13th Latin American Workshop on Plasma Physics (LAWPP 2010). We invited all of you to be part of this great scientific event. For more information, visit www.icpp-lawpp-2010.cl Leopoldo Soto (chairman) and Local Organizing Committee Topics Fundamentals of Plasma Physics Fusion Plasmas Plasmas in Astrophysics and Space Physics Plasma Applications and Technologies Complex Plasmas High Energy Density Plasmas Quantum Plasmas Laser-Plasma Interaction ITER Project NIF Project Schedule： Early registration March 15th June 15th Abstract submission March 15th April 3th Desk registration (School) August 1st (Sunday) School on Plasma Physics August 2nd August 6th Desk registration (ICPP-LAWPP-2010) August 8th (Sunday) ICPP LAWPP 2010 August 9th August 13th
解读等离子体天线 刘红 魏佳羽 近日科学网上发布了一则关于等离子天线的报道 （ http://www.sciencenet.cn/htmlnews/2007112281030111194869.html?id=194869 ），此消息来源于美国物理学会等离子体物理分会的年会 : http://meetings.aps.org/Meeting/DPP07/Event/69787 上的报告 , 《 Plasma Antenna Shielding 》 . A method and calculation have been developed to protect space based antennas using plasma Frequency selective surfaces radom. The antennas we are trying to protect are currently metal but could be plasma. The scattering process of the electromagnetic waves has been investigated in a plasma antenna tube; this process is of self-important value from the point of view of studying wave propagation and absorption. When electromagnetic waves propagate in media with random inhomogeneities, there appear waves with frequencies and wave vectors which are different from the frequency and wave vector of the fundamental wave. Here, the so-called scattering process occurs. If the medium is spatially homogeneous but parameters defining its electromagnetic properties experience fluctuations, then scattering must occur on these fluctuations, the latter being random inhomogeneities. Induced charges and currents leading to radiating new scattered waves emerge in a medium under the influence of the fundamental wave, thereby initiating the appearance of scattered waves. However, within the linear approximation induced charges and currents in the homogeneous medium represent only the modification of wave propagation characteristics in a medium, as compared to vacuum, i.e., modification of the complex refractive index. The results may be generalized for physical understanding of the scattering process in plasma. 文中提到这种新型天线非常适合军事用途，并且将在移动电话网络中大显身手。同时比较金属天线的一些“缺点”：低频天线体积很大；高频天线虽然体积很小，但其在发射高频信号时却很容易暴露它们的位置；金属天线容易受到干扰和抑制，指出这种新型天线巧妙的克服了这些问题。我们将结合等离子体的性质针对上述特点给出一些解释 , 既然谈到等离子体，那么总要先说清楚究竟什么是等离子体？众所周知我们身边的物质绝大多数处于固态，液态，气态这三种状态，但无论是固体，液体还是气体它们都是由中性的原子组成 , 而原子又可以进一步分解为原子核和核外电子，核外电子在通常情况下会被束缚在原子核周围 , 但是如果核外电子获得了较高的能量，它们将会逃离原子核的束缚，（我们称该过程为电离），从而成为自由电子，当有足够多的电子从束缚电子电离成自由电子之后，就会出现大量电子和原子核相互作用的集体行为 , 成为整体电中性 , 而局域带电的特殊态 , 我们称处于该种状态的物质为等离子体态 , 由于等离子体态在地球的自然界中不能存在 , 一旦出现带电体 , 马上就会被中和掉 , 所以 , 在初、高中课本中没有出现这个态 , 但它的确是物质存在的第四态。 等离子体态大多存在于宇宙空间 , 地球上只有实验室里或极端天气情况下才会有等离子体的存在 , 太阳里没有固态、液态、气态物质的存在 , 因为那里的高温不允许中性物质存在 , 只有氢等离子体、氦等离子体等等。等离子体的特殊组成形成了它的特殊性质 , 最显著的行为之一就是等离子体的震荡 , 这是一个集体行为 , 处于正电的原子核和负电的电子若应若离 , 永不停息地震荡 , 而震荡所带来的等离子体频率是我们非常感兴趣，看看这个等离子体天线的装置图 : 照片来源 : http://www.groupsrv.com/science/post-2454354.html 这里的等离子体显然要被束缚在那根弯曲的管子 ( 玻璃管或者陶管 ) 里 , 要弄清楚等离子体天线发光的原理，首先让我们来看一下日光灯管的发光原理，在日光灯管两端加上强电压时，灯管两端的微细白热灯丝便会放出电子 , 电子从一端移至另一端，形成非中性等离子体。这些等离子体中的电子每秒能产生上百次的闪光（韧制辐射），发出肉眼看不见的紫外光 , 灯管中的水银，由于高温而蒸发成气体，由于灯光壁温度较低，他们会覆在灯管的内侧壁，这种带电的蒸气能将紫外线转换成为可见光 因此灯管发光。而在等离子体天线中等离子体的形成可能也类似于日光灯管中等离子体的形成（但具体技术手段可能是商业甚至国防秘密） , 所不同的是等离子体不仅发出紫外线，而且还要对外加电磁场做出响应 , 由等离子的基本性质可知，当等离子的振荡频率和电磁场的频率一致时，等离子体会在临界密度处有共振，使信号得以放大。而等离子体的振荡频率取决于等离子体的密度 , 它与电子的电荷和质量有关。我们知道，能够产生的等离子体往往不可能是均匀分布的，有一定的密度梯度和密度范围 , 如果知道最大的密度，我们就可以知道相应的等离子体振荡频率，因而也就知道了等离子体所能响应的最大电磁波频率。低于此频率的电磁波，由于等离子体中有相应的密度区域存在，因而也能做出响应；但如果电磁波频率超过了此范围，等离子体中没有这么高的密度，因而不能做出响应。 等离子体天线的工作原理大致可以总结如下，等离子体天线，一般来说由内部填充了一定气体的玻璃管或者陶管所组成，通过将其内部的气体电离从而使天线处于工作状态，在电离过程中可以对调控气体的密度，控制电磁场对其结构进行动态重构，使其适应不同的传输频率，方向，增益，传输带宽等，因此一个等离子天线可以承担几个不同的金属天线的功能，使得组建天线阵列所需的天线数量大大减少，其体积和重量也一并减少。相对于金属天线，等离子天线可以不需要很大的体积就可以进行低频信号的传输（注：传统金属天线需要尺寸与所传输或接受信号的波长相当，这里我们猜测等离子体天线进行低频信号传输的时候应该是利用等离子体自身的电磁震荡进行传输，否则按照传统天线理论，天线的尺寸应该只与所需传输信号的波长相关。）同样由于等离子的性质，等离子天线将只会对低于或等于等离子体本身震荡频率的电磁波进行响应，高于该频率的电磁波，将可以自由穿过等离子体天线，并不会对等离子天线产生影响，从而大大降低了等离子天线之间的干扰。 综合上述性质，一方面等离子天线在不工作的时候只是一些填充了气体的玻璃管或者陶管，使其不会被对方的雷达所发现。伴随着天线数量的减少，也极大地消除了天线之间彼此的干扰，并且较难被对方的雷达发现，所以等离子天线十分适合与军事用途。另一方面对于组建同样天线阵列，等离子天线需要的天线数量较少，从而是天线阵列的体积和重量大大降低，容易被应用在移动设备之上。 《中国科技信息》2008年第2期第269页.
标签: 等离子体
