Ponderomotive Forces in Cosmos

This review is devoted to ponderomotive forces and their importance for the acceleration of charged particles by electromagnetic waves in space plasmas. Ponderomotive forces constitute time-averaged nonlinear forces acting on a media in the presence of oscillating electromagnetic fields. Ponderomotive forces represent a useful analytical tool to describe plasma acceleration. Oscillating electromagnetic fields are also related with dissipative processes, such as heating of particles. Dissipative processes are, however, left outside these discussions. The focus will be entirely on the (conservative) ponderomotive forces acting in space plasmas. The review consists of seven sections. In Section 1, we explain the rational for using the auxiliary ponderomotive forces instead of the fundamental Lorentz force for the study of particle motions in oscillating fields. In Section 2, we present the Abraham, Miller, Lundin–Hultqvist and Barlow ponderomotive forces, and the Bolotovsky–Serov ponderomotive drift. The hydrodynamic, quasi-hydrodynamic, and ‘`test-particle’' approaches are used for the study of ponderomotive wave-particle interaction. The problems of self-consistency and regularization are discussed in Section 3. The model of static balance of forces (Section 4) exemplifies the interplay between thermal, gravitational and ponderomotive forces, but it also introduces a set of useful definitions, dimensionless parameters, etc. We analyze the Alfvén and ion cyclotron waves in static limit with emphasis on the specific distinction between traveling and standing waves. Particular attention has been given to the impact of traveling Alfvén waves on the steady state anabatic wind that blows over the polar regions (Section~5). We demonstrate the existence of a wave-induced cold anabatic wind. We also show that, at a critical point, the ponderomotive acceleration of the wind is a factor of 3 greater than the thermal acceleration. Section 6 demonstrates various manifestations of ponderomotive forces in the Earth's magnetosphere, for instance the ionospheric plasma acceleration and outflow. The polar wind and the auroral density cavities are considered in relation to results from the Freja and Viking satellites. The high-altitude energization and escape of ions is discussed. The ponderomotive anharmonicity of standing Alfvén waves is analyzed from ground based ULF wave measurements. The complexity of the many challenging problems related with plasma processes near the magnetospheric boundaries is discussed in the light of recent Cluster observations. At the end of Section 6, we consider the application of ponderomotive forces to the diversity of phenomena on the Sun, in the interstellar environment, on newborn stars, pulsars and active galaxies. We emphasize the role of forcing of magnetized plasmas in general and ponderomotive forcing in particular, presenting some simple conceivable scenarios for massive outflow and jets from astrophysical objects.     

Calculation of the effect of opacity in the solar spectral lines of carbon ions

In this paper, using the intensity ratio of carbon ions emission lines, we determined the optical depths at the line center of the CI at about 165.7 nm, CII at about 133.5 nm, CIII at about 117.5 nm and CIV at about 154.9 nm emission lines by escape factor treatment. For CI and CII emission lines, we discuss the intensity ratio of two lines arising from the common upper levels; while for CIII and CIV emission lines, we discuss the intensity ratio of two lines arising from the common lower levels. By introducing the measured abundance of carbon and the results of ionization balance calculations, we make an estimate of the line-of-sight physical thickness of the regions of carbon ions. This discussion will provide some results in the discussion of opacity on the solar ultraviolet (UV) or extreme-ultraviolet (EUV) spectrum.     

80C31微处理器单粒子效应敏感性地面试验研究

文章针对不同厂家的80C31微处理器,利用重离子、锎源模拟源进行单粒子效应地面试验研究。详细介绍了80C31微处理器单粒子效应试验原理、试验方法、试验系统的软硬件组成以及试验取得的结论。通过试验研究获得了80C31微处理器单粒子翻转和单粒子锁定特征参数。研究结果可为被测器件在卫星型号的使用提供技术参考依据。     

直升机重装空投状态下的动态特性

为了研究直升机在重装空投过程中货物的运动对直升机姿态角的影响,首先建立了直升机CH-53D的动力学模型,并通过模型仿真结果和直升机飞行实验数据的对比验证了的直升机动力学模型的合理性。然后在直升机动力学模型的基础上,采用分离法建立了直升机重装空投两个阶段的动力学模型,并进行了直升机在悬停和前飞两种空投状态下的配平仿真。结果表明:相较于悬停状态空投,前飞状态空投具有更好姿态保持能力,主要表现在前飞状态下空投只会对直升机的纵向姿态角产生影响,而在悬停状态下空投对直升机的纵横向姿态角都会产生较大的影响。      

R0110重型燃气轮机燃烧室三维数值模拟

采用SIMPLE算法,应用带有旋流修正的k-ε双方程湍流模型及有限速率／涡耗散化学反应模型,对R011O重型燃气轮机逆流环管型燃烧室单个火焰筒进行了三维数值模拟计算。将计算出的燃烧室出口温度场的分布、品质及火焰筒壁温与试验结果进行了对比分析。燃烧室进口流量、温度、压力等气动参数均与试验时保持一致,火焰筒各部分空气流量也均按火焰筒空气流量分配试验结果给定。计算和对比分析的结果表明,计算得到的燃烧室出口温度场的分布、品质及火焰筒壁温分布与试验结果比较接近。     

驻涡燃烧室主流对凹腔涡流动的影响

利用粒子图像测速仪(PIV)对矩形模型驻涡燃烧室冷态流场进行了测试,分析了驻涡燃烧室主流速度及结构变化对凹腔内涡流动的影响.实验结果表明,主流速度对凹腔内涡的大小、形状、涡心位置影响不大,旋涡强度及凹腔回流量随速度增大而增大.主流无稳定器时凹腔内涡心基本居中;主流加入稳定器后,凹腔中心剖面涡较大,涡心偏向后方,稳定器剖面涡较小,涡心偏向前方.实验结果为开展热态研究打下基础.      

电荷交换离子对栅极系统束流影响的数值研究

采用二维网格质点法(PIC)计算离子在离子发动机栅极系统中的运动, 通过在模型中添加离子和中性粒子电荷交换的Monte Carlo碰撞模块, 得到了电荷交换离子在栅极周围的分布及电荷交换离子的运动规律.计算结果表明:考虑电荷交换离子后, 屏栅极电流较不考虑电荷交换离子情况时增大了1.42%, 所受影响不大, 加速栅极电流由0增大到主束流电流的1.41%.模拟结果表明:加速栅极下游较远处产生的电荷交换离子, 是造成加速栅极下游面腐蚀及加速栅极电流的主要原因.      

驻涡燃烧室掺混孔对流量分配及燃烧性能的影响

数值模拟了三种不同掺混孔面积对二元模型驻涡燃烧室试验器流量分配的影响,并在进口马赫数约为0.3、进口温度约为540 K工况条件下,分别对其进行了试验研究,对比分析了它们的总压损失、贫熄边界和燃烧效率.研究表明:掺混孔面积对流量分配影响较大,在本试验条件下,掺混孔面积较大的驻涡燃烧室试验器的燃烧性能优于其余两种.      

联焰板长度对驻涡燃烧室凹腔流动特性影响的数值模拟

开展了联焰板长度对驻涡燃烧室凹腔冷态流场特性影响的数值研究,结果表明：联焰板的流向长度存在两个临界值：Lc1=1 mm 和Lc2=9 mm,当联焰板的流向长度小于等于临界长度Lc1时,主流会卷入凹腔中,凹腔中无法形成双涡结构;当联焰板的流向长度大于临界长度Lc1小于等于Lc2时,凹腔中可以形成双涡结构,但仍有部分主流会卷入凹腔中;当联焰板流向长度大于Lc2时,凹腔中可以形成双涡结构, 主流几乎不会卷入凹腔中。     

重离子在生物组织中的阻止本领

根据中能重离子与靶物质相互作用的特点,将参数化的阻止本领计算方法进行了改进和推广,给出了计算重离子在人体组织及生物等效介质中阻止本领的方法。作为带电离子适形放疗的基础,计算了中能碳离子在肌肉、骨胳、脂肪、水及其他生物等效介质中的阻止本领,Bragg峰、射程等参量,并对计算方法的可靠性及在临床肿瘤治疗剂量控制方面的应用进行了分析。参数化的计算方法能满足实际应用的要求。