基于RAMS V6.0的非感应起电机制评估和雷暴初期电荷结构模拟

数值模式是研究雷暴内起电和电荷结构的重要工具. 本文将Takahashi (1978) 和Saunders (1991) 两种主流非感应起电机制加入最新版本的中尺度模式RAMS(Version 6.0), 建立了一个区域大气-电耦合中尺度雷暴云模式, 据此对发生于北京的一次雷暴过程首次放电前的电荷结构和水成物粒子起电情况进行了较成功的模拟. 结果表明, Takahashi (1978) 和Saunders (1991)方案模拟的雷暴电荷结构在电场达到击穿阈值时均呈现三极性特征, 但Takahashi和Saunders方案模拟的雷暴电荷结构演变过程有一定的差异, Takahashi方案的电荷结构从起电到放电都是三极性特征, Saunders方案的电荷结构从反偶极性演变为三极性. 此外, 两种方案的模拟结果均表明雨滴是雷暴云低层的正电荷载体, 聚合物和霰是高层的主要电荷载体, 霰的电荷中心分布形态与雷暴云的总电荷分布形态相似.     

雷暴云内电场力对起电和电荷结构的反馈作用

利用美国国家强风暴实验室(NSSL)发展的耦合了详细起电机制和放电过程的中尺度电耦合数值模式WRF(weather research forecasting)-Elec,在NSSL云微物理双参数化方案中增加了电场力对霰、雹粒子降落末速度的影响,完善了WRF-Elec模式的物理过程,建立了双向耦合WRF-Elec模式.利用改进后的WRF-Elec模式,通过敏感性数值实验,定量分析了雷暴云内电场力对起电和电荷结构的反馈作用.结果发现:雷暴云发展旺盛阶段,由于电场力作用,霰、雹粒子质量加权平均降落末速度的瞬时变化极值可以超过4 m/s,但这种情况仅出现在雷暴云内局部区域,并且维持时间较短;电场力对直径小且数浓度较低的霰和雹粒子影响较大,但这种影响不是由单一物理量决定,而是由电场强度和霰、雹粒子的电荷密度、极性以及粒子的直径与数浓度共同决定;电场力通过对霰、雹粒子降落末速度的调整,增强了雷暴云内感应、非感应起电率,且前者远大于后者,云内局部产生-0.6—1.2 n C/m~3总电荷密度的变化,从而使电荷结构重新分布,局部垂直电场强度增强5 k V/m,总闪电数增加,与此同时,雷暴云内降水粒子的微观增长过程也发生改变.总体上,电场力对雷暴云起电过程的作用为正反馈,电场力对雷暴云电荷结构的反馈作用不可忽略.     

环球大气电路—一个充满奥秘的迷

本文将介绍环球大气电路，首先介绍了大气中的离子，晴天大气电场，晴天大气电流等概念，进而引入电荷再生机制，－雷暴概念，并介绍了维持大气电荷平衡的几种主要电流机制最后给出全球大气电过程的球形电容器模型。     

环球大气电路—— 一个充满奥秘的迷

本文将介绍环球大气电路．首先介绍大气中的离子，晴天大气电场，晴天大气电流等概念．进而引入电荷再生机制——雷暴概念．并介绍维持大气电荷平衡的几种主要电流机制．最后给出全球大气电过程的球形电容器模型．     

混合电解质溶液中考虑介电饱和度的表面电位评估原理

基于非线性泊松-玻尔兹曼方程，推导了混合电解质溶液中考虑介电饱和度的表面电位的解析表达式. 近似解析解和精确数值解计算出的表面电位在很大范围的电荷密度和离子强度条件下均具有很好的一致性. 当表面电荷密度大于0.30 C/m^{2 时，介电饱和度对表面电位的影响变得尤为重要；当表面电荷密度小于0.30 C/m2时，可忽略介电饱和度的影响，即基于经典泊松-玻尔兹曼方程可获得有效的表面电位解析模型. 因此，0.3 C/m2可作为是否考虑介电饱和度的颗粒临界表面电荷密度值. 在低表面电荷密度时，考虑介质饱和度的表面电位解析模型可自然回归到经典泊松-玻尔兹曼理论的结果，得到的表面电位可以正确地预测一价和二价反离子之间的吸附选择性.}     

中子并非任何场合都是电中性

自由中子的电荷是由中子束通过电场测出的.实验测得电荷上限为10-20e,电偶极矩小于 6 ×10-25e·cm.然而,人们用高能电子散射测出中子有电流环,用低能中子对束缚无自旋原子的电子散射测出中子有微小电荷分离[1].从高能电子散射中子的数据分析得出中子的电荷结构:中心是一个半径为 0.2 fm带正电荷0.35。的核,0.8fm内带负电荷0.5e,在1.4fm内带有正电荷 0.15e(通常把 0.8fm和 1.4fm内的电荷分别称作矢量云和张量云)[2].夸克模型提出:中子是由带电的ddu夸克组成;中子的核心为夸克,其外层为π介子及其他介子.中子有电荷分布和每层带有不同的电荷…     

混合电解质溶液中考虑介电饱和度的表面电位评估原理（英文）

基于非线性泊松-玻尔兹曼方程,推导了混合电解质溶液中考虑介电饱和度的表面电位的解析表达式.近似解析解和精确数值解计算出的表面电位在很大范围的电荷密度和离子强度条件下均具有很好的一致性.当表面电荷密度大于0.30 C/m~2时,介电饱和度对表面电位的影响变得尤为重要;当表面电荷密度小于0.30 C/m~2时,可忽略介电饱和度的影响,即基于经典泊松-玻尔兹曼方程可获得有效的表面电位解析模型.因此,0.3 C/m~2可作为是否考虑介电饱和度的颗粒临界表面电荷密度值.在低表面电荷密度时,考虑介质饱和度的表面电位解析模型可自然回归到经典泊松-玻尔兹曼理论的结果,得到的表面电位可以正确地预测一价和二价反离子之间的吸附选择性.     

通过序列化实验建构物理模型的设计——以“静电”为例

模型是对现象或实物特征的一种结构性和系统化的抽象，物理模型包括了物理概念、原理、公式、图示等.通过做实验、观察现象、归纳推理等过程，可以将实验现象特征抽象为物理模型，序列化的建模实验可以建构出序列性、系统化的知识.以“静电”部分的模型建构为例，设计序列化的实验，建构出正负电荷、摩擦起电、传导起电、感应起电及电荷守恒定律模型，并通过一系列应用型问题促进学生自主建模或应用模型.     

静电雾化过程中雾滴空间电荷密度的实验测试

采用金属网笼法对静电雾化中雾滴群的空间电荷密度进行了实验测试，结果表明该方法可以大致了解雾化空间中雾滴群的局部带电情况。实验数据进一步表明，荷电雾滴的带电特性在不同空间位置处有极大的差异性，雾化轴心处的雾滴电荷密度最高，雾滴电荷密度沿径向方向逐渐减小。当施加电压增大时，不同空间位置处的雾滴电荷密度均有所提高，但电荷密度...     

雷暴电场对宇宙射线次级粒子μ 子的影响研究

西藏羊八井宇宙射线观测站的中子监测器主要探测宇宙射线次级粒子中能量在500 MeV—20 GeV的核子成分和少量的负μ子成分. 本文分析了2008—2010年观测站附近发生的62次雷暴期间中子监测器和大气平均电场仪的同步观测资料, 发现27次雷暴期间中子监测器计数率发生明显变化, 显著性S>5σ, 其中13次变化显著, 显著性S>10σ . 显著性S>10σ的13次个例信号变化百分比与地面电场场强幅值之间存在大体一致的变化趋势, 而显著性在5σ <S<10σ之间的14次个例信号变化百分比与地面电场场强幅值之间不存在相似的变化趋势. 较强雷暴当顶时中子监测器计数率变化一般不明显, 而中子监测器计数率变化明显的个例则多发生于雷暴云不当顶, 但探测器仍处于雷暴云下部正电荷层的控制范围之内时, 或者当顶雷暴处于形成或消散阶段. Dorman等把雷暴期间中子监测器计数率的变化归因于雷暴云内电场对宇宙射线次级粒子μ子的作用, 并建立了雷暴期间中子监测器计数率变化与雷暴地面电场相关联的理论. 本文分析发现雷暴期间羊八井中子监测器计数率变化与地面电场场强之间相关性较小或者没有相关性, 不支持Dorman的理论.     

Autowave Regimes of Thundercloud Electrification

We consider the evolution of the electric field and charge in a one-dimensional electrohydrodynamic (EHD) distributed-parameter system which serves as a simple model of a thundercloud. A diffusion equation for the electric field is proposed which, under reasonable assumptions on the nonlinear dependence of the dissipation current on the electric field (caused by the corona effect around aerosol particles in strong fields), has autowave solutions describing the dynamics of spatially separated electric-charge regions in the thundercloud. The nonlinear set of equations describing the electric-field dynamics in an ensemble of colliding aerosol particles and light ions is reduced to a rather simple basic model which admits solutions in the form of traveling fronts and traveling pulses. We find the asymptotic values of the velocity and thickness of the space-charge front, which are determined by the diffusion and the separation and conductivity currents. Using these values, we estimate the electrostatic-energy growth rate in a thunderstorm cell at the stage of its intensive electrification. A possibility is shown of the formation of a traveling pulse of field and conductivity in such an EHD system with allowance for inductive and noninductive mechanisms of aerosol-particle charging.     

滴水感应起电仪的实验及其改进研究

滴水自激感应起电仪,即开尔文滴水感应起电仪,是利用水滴流动与玻璃管摩擦起电,并静电感应循环累积电荷而产生越来越高的电位差的静电起电装置。本文通过对装置的系统划分,研究各部分对最终起电现象的影响,主要在漏电测试、电荷累积测量和仪器装置材料更换等方面来改进仪器装置。经过实验改进后,开尔文滴水感应起电仪的起电效果明显,现象稳定。     

Contemporary review on nature of sonoluminescence and sonochemical reactions

The major cases for a local electrification of bubbles in a cavitation field were considered: with the fragmentation of cavitation bubbles and also with only deformation of them. The problem of the uncompensated charge on the surface of the deformed cavitation bubble is solved in general view. The radial deformations approximated by the paraboloid of rotation and axial deformations by one cavity hyperboloid of rotation. The maximum electric strength is accounted. In the terms of electrical theory of the local electrification of cavitation bubbles the explanation of some physical and physico-chemical effects in the cavitation fields is proposed. The theory of local electrification now is single theory which correlates majority of experimental facts for multibubble cavitation fields. The theory of single bubble sonoluminescence was worked out.     

Theory of local electrification of cavitation bubbles: new approaches

The theory of local electrification of cavitation bubbles has been generalised. The major cases for a local electrification of bubbles in a cavitation field were considered; i.e., fragmentation and deformation of cavitation bubbles. The splitting of cavitation bubbles was considered taking into account surface tension, bubble perturbation, Stokes force and electrostatic forces between like charges on the wall of the collapsing neck of the fragment bubble. The problem of the uncompensated charge on the surface of the deformed cavitation bubble is solved. For this purpose radial deformations are considered in terms of the paraboloid of rotation and axial deformation approximated by one cavity hyperboloid of rotation. The maximum electric strength is accounted for. An explanation for some physical and physico-chemical effects in cavitation fields is proposed in terms of the electrical theory of the local electrification of cavitation bubbles.     

On the instability of ionospheric plasma originated by charge separations in the troposphere. The «UFO» phenomenon mechanism

Summary The troposphere is the seat of powerful processes which originate separation of electric charges. Thunder clouds give rise to a huge vertical separation of charges. But also known is a different electrification mechanism activated by wind, which allows for horizontal separation of charges. In favourable conditions, when charges are displaced at long distances, image charges appear in the ionspheric plasma and an upward electric field is originated which makes the ionosphere boundary unstable. If this occurs, recombination of displaced charges involves ionosphere conductivity and gives rise to a downward electron stream ejected from the bottom of the ionosphere. It may produce a peculiar airglow phenomenon, which consists of the emission of light in a narrow region lying at stratospheric or mesospheric altitudes. This outcome of the electrification process just mentioned shows a close connection with a special class of ?UFO? sightings, that is, those referred to by J. Hynek as ?nocturnal light? and which consist of bright specks of light moving in the night sky.     

雷云电场作用下长地线表面正极性辉光电晕放电的仿真研究

在雷云电场的缓慢作用下, 一种无流注的正极性辉光电晕在接地物体表面起始, 向周围空间注入大量正极性空间电荷, 从而改变雷电先导对雷击目的物的选择. 本文对雷云电场作用下起始于长地线表面的正极性辉光电晕放电进行了仿真研究; 考虑了正极性离子与其他离子的附着与碰撞作用, 建立了一种精确的二维正极性辉光电晕模型; 并通过在实验室内开展高压电晕放电试验, 测量了不同背景电场下的电晕电流; 与本文所建模型的仿真结果进行对比, 对模型的正确性进行了验证. 基于上述模型, 对正极性辉光电晕在雷云感应作用下的起始发展过程与电晕特性进行了仿真模拟, 得到了该电晕的电晕电流、正离子密度分布规律以及正离子迁移规律. 发现在雷云电场作用下, 电晕放电产生的正离子在迁移初期于垂直于地线的平面内基本呈圆对称状均匀分布, 但随着离子逐渐远离地线其分布不再均匀, 呈拉长的椭圆形分布, 多数离子最终分布于地线上方区域并逐渐向雷云方向迁移; 由于正离子在地线上方迁移区聚集形成的正空间电荷背景对行进电子束具有衰减和消耗作用, 抑制了电子崩的形成, 并降低了电子崩转化为流注的概率, 阻止了新的电子崩对流注的不断注入, 同时正空间电荷背景使气体的碰撞面增大, 增加了与电子的复合概率, 引起大量电子的消耗, 最终抑制了电子崩的形成与流注的发展, 地线表面的上行先导得到抑制.     

Contact electrification phenomena on phosphor particle surfaces

Contact electrification phenomena are reviewed to understand phosphor powder behavior. The origin of contact electrification is described in terms of the acid–base concept for solid surfaces. Electric charges produced by contact electrification affect phosphor properties. Various examples related to contact electrification are shown: particle surface modification, dispersion in liquids, adhesion strength to a substrate, electrostatic coating, interaction between a phosphor and mercury in a fluorescent lamp, and electron emission ability in a fluorescent lamp.     

Electrostatics in wind-blown sand

Wind-blown sand, or "saltation," is an important geological process, and the primary source of atmospheric mineral dust aerosols. Significant discrepancies exist between classical saltation theory and measurements. We show here that these discrepancies can be resolved by the inclusion of sand electrification in a physically based saltation model. Indeed, we find that electric forces enhance the concentration of saltating particles and cause them to travel closer to the surface, in agreement with measurements. Our results thus indicate that sand electrification plays an important role in saltation.     

Amplification and nonlinear modification of runaway breakdown

The astonishing natural phenomenon of narrow bipolar pulses (NBP) is an isolated discharges in thunderstorms at tropopause heights (10–20 km) that generates enormously powerful radio emission but lasts only a few microseconds. The theory of this phenomenon based on runaway breakdown is elaborated. At such high heights extensive atmospheric shower (EAS) become well developed only if the energetic cosmic ray particle momentum is directed close to the horizon. For these conditions the runaway breakdown–extensive atmospheric shower (RB–EAS) discharge amplified strongly what lead to the effective diminishing of thundercloud electric field and results in nonlinear saturation of the discharge current. A reasonable agreement of the theory with NBP observations is demonstrated.