高能推进剂燃烧效率研究和实测比冲预估

采用燃烧残渣中活性铝含量分析、真空爆热和发动机试验等方法，研究了高能推进剂中主要组分对推进剂燃烧效率的影响。研究结果表明：增塑剂的种类和含量是影响效率的主要因素，AP的含量及固体组分的粒度级配也有明显影响；BSF－φ315发动机试车结果证明高能推进剂的的实测比冲效率大于0．94。采用软件计算发动机的实测比中，可预估高能推进剂配方在不同压强及燃速条件下标准试验发动机（BSF－φ165和BSF－φ315）试车的实测比冲值。     

整体级发动机用叠氮含硼推进剂研究

为适应整体级发动机强制偏流喷管的需要,研究了(BAMO/THF)/HMX/AP/B叠氮含硼推进剂的工艺性能、力学性能和燃烧性能。结果表明:对营口产硼粉进行包覆、团聚处理,解决了硼粉与推进剂其它组分相容性差和推进剂工艺性能差的问题;使用经处理的硼粉、较高相对分子质量的叠氮粘合剂BAMO/THF(50/50)和高效键合剂,能有效提高含硼推进剂的力学性能,达到:常温最大抗拉强度σm≥0 7MPa,高、中、低温的最大伸长率εm≥40%;推进剂具有较低的燃速压强指数(<0 40)和较宽的燃速可调范围,118发动机演示试验后喷管收敛段和喉部结构保持完好,无凝相产物沉积,且优于HTPB含铝推进剂的结果。叠氮含硼推进剂适合整体级发动机强制偏流喷管的使用。     

Velocity correlation functions of charged particles derived from the Fokker–Planck equation

An important ingredient in theories for diffusion of charged particles across a mean magnetic field are velocity correlation functions along and across that field. In the current article we present an analytical study of these functions by investigating the two-dimensional Fokker–Planck equation. We show that for an isotropic pitch-angle Fokker–Planck coefficient, the parallel velocity correlation function is an exponential function in agreement with the standard model used previously. For other forms of the pitch-angle diffusion coefficient, however, we find non-exponential forms. Also a new, velocity correlation function based, approach for deriving the so-called Earl-relation is presented. This new derivation is more systematic and simpler than previous derivations. We also discuss higher-order velocity correlations and the applicability of the quasi-normal hypothesis in particle diffusion theory. Furthermore, we compute velocity correlation functions across the mean field and develop an alternative theory for perpendicular diffusion.     

HEDM－CMDB推进剂燃烧性能的理论预测

利用建立不久的双基系平台推进燃烧模型，对几种ＨＥＤＭ加入平台推进剂后的燃烧性能进行了理论计算。结果表明：在所计算的几种ＨＥＤＭ中，ＨＮＨＡＡ最有利于提高燃速；ＣＬ－２０最有利于降低燃速压力指数；ＣＬ－２０作为平台推进剂的高能填料综合性能最好。     

核壳结构纳米铝粉热学行为

为了研究不同表面包覆物对纳米铝粉热学行为的影响,采用激光-感应复合加热法制备了三种不同表面包覆的核/壳结构纳米铝粉(氧化铝钝化、碳包覆及增塑剂DOS包覆)。采用高分辨透射电镜(HRTEM)对制备的纳米粉末结构进行表征,并采用差示扫描量热及热重分析(DSC-TG)对不同物质包覆纳米铝粉的热学性能进行研究。结果表明,这些纳米粒子均呈现出明显的核壳结构,且包覆层厚度约3.5nm。这三种不同表面包覆纳米铝粉在400℃至铝熔点(660℃)之间均发生了氧化,但非氧化物包覆纳米铝粉(碳包覆与增塑剂DOS包覆)的氧化开始温度及峰温比氧化铝钝化纳米铝粉提前了约30℃左右,而且氧化放热热焓和氧化质量增重均高于氧化铝钝化纳米铝粉,表明这两种非氧化物表面包覆对纳米铝粉的热学行为有积极的影响。最后对不同物质包覆纳米铝粉的破壳氧化机制进行了探讨。     

The elemental composition in energetic particle events at high heliospheric latitudes

The relative abundances of low energy ions (0.6–2.0 MeV/n) in solar energetic particle (SEP) and corotating interaction region (CIR) events have been measured by the EPAC experiment aboard Ulysses since launch in October 1990 until the present time. We give an overview of the abundances of heavy ions (He, C, Ne, Fe) relative to oxygen during energetic particle events lasting longer than 5 days during the in- and out-of-ecliptic phase of the mission. While the period Oct. 1990 to Aug. 1992 was dominated by high solar activity the Ulysses out of ecliptic passage at solar latitudes up to 45° went parallel to the declining phase of solar activity. Thus a very clear structure of corotating interaction regions was observed. While the in-ecliptic composition is in general agreement with measurements made near the Earth, the development of the CIR-composition shows two phases: From Aug. 1992 to May 1993 the C/O-ratio is 0.55–0.70, afterwards it increases to 0.8–0.9. This increase is correlated to the disappearance of the current sheet at 30° solar latitude reported by Smithet al. (1993).     

Relativistic solar protons in the ground level event of 23 February 1956: New study

In this study we applied again to the outstanding solar particle event of 23 February 1956, the largest one in the entire history of observations of solar cosmic rays. Due to significant improvement of the analysis/modeling techniques and new understanding of physical processes in the solar atmosphere and interplanetary space, a possibility arises to interpret the old data in the light of modern concept of multiple particle acceleration at/near the Sun. In our new analysis the data of available then neutron monitors and muon telescopes are used. The technique of the analysis includes: (a) calculation of asymptotic cones of ground-based detectors; (b) modeling of cosmic ray detector responses at variable parameters of the flux of solar relativistic protons; (c) determination of primary solar proton parameters outside magnetosphere by comparison of computed responses with observations. Certain evidence was obtained that the flux of relativistic solar protons consisted of two distinct components: prompt and delayed ones. The prompt component with exponential energy spectrum caused a giant impulse-like increase at a number of European cosmic ray stations. The delayed component had a power-law spectrum and was a cause of gradual increase at cosmic ray stations in the North American region. A numerical simulation of the proton acceleration in the vicinity of the magnetic reconnection region brings to the proton spectrum with exponential dependence on energy. This agrees with observational data for the prompt component. It is also shown that the huge increase in ∼5000% on neutron monitors was due to the prompt component only with the exponential proton spectrum. The power-law spectrum of comparable intensity gave considerably smaller effect.     

太阳高能粒子观测特征经向分布统计

基于多卫星联合观测数据,筛选了2006年12月至2017年10月期间122个太阳高能粒子（SEP）事件及其伴随的日冕物质抛射（CME）,分析了SEP事件属性随相对经度的变化、与CME属性之间相关性的经向分布以及与Fe/O比值的关联.研究结果显示：低Fe/O类事件的峰值通量I_p通常更高,伴随CME更大,但通量上升速度较慢,且其D_u（持续时间）和I_p与CME速度呈现更强的相关性;SEP特征时间T_O（CME爆发至SEP事件爆发）与T_R（SEP事件爆发至半峰值）随相对经度增加而增大,D_u与I_p随相对经度增加而减小,通量上升斜率K在±90°范围内自东向西递减;SEP事件属性与伴随CME属性的相关性随相对经度的改变有明显变化,在磁连接好的位置,T_O与CME速度等属性呈现负相关,T_R与CME速度等属性呈现正相关,D_u,I_p与CME速度之间的相关性更强.研究结果进一步表明,SEP事件观测属性既与CME参数相关,同时又具有很强的经度依赖性,在磁连接越好的位置卫星观测到的SEP事件强度越高,SEP观测参数受CME的影响越大,这对大型SEP事件的预报很有意义.此外,高Fe/O类SEP事件与CME相关性的减弱暗示了耀斑加速、种子粒子源等因素的影响.     

Energetic neutral atom (ENA) and charged particle periodicities in Saturn’s magnetosphere

The Magnetospheric Imaging Instrument (MIMI) on the Cassini spacecraft has observed energetic neutral atoms (ENA) and charged particles at Saturn from mid-2004 to the present. The particles often but not always reveal striking periodic behavior that seems to depend on the type of particle and spacecraft location. When subjected to a Lomb periodogram analysis, energetic electrons (>150 keV) exhibited strong frequency peaks near 10.80 h (the nominal or “base” period of Saturn kilometric radiation) during 2006–2008, but essentially no periodicity during 2005. The electron periodograms also show pronounced “double” frequency peaks in 2007 and 2008. Energetic protons (3–26 keV) show strong peaks near the same period for 2005–2007, but none for 2008. Oxygen ions at the same energies display strong peaks for 2005 and 2006, but not for 2007 and 2008. By projecting the ENA images onto Saturn’s equatorial plane or onto a plane perpendicular to the equatorial plane and then summing the data in the appropriate dimension, “strip” images can be constructed from which a time history can be derived. These time histories of ENA emissions are also subjected to a Lomb periodogram analyses. The energetic hydrogen neutrals (20–50 keV) exhibited periodic behavior only during 2007, while energetic oxygen neutrals (64–144 keV) displayed a strong SKR-like period in 2005 and 2006 but not for 2007 or 2008. Some of this behavior may be due to changing spacecraft aspect relative to the ENA emissions, and some of it may be real. This periodic behavior may be consistent with a rotating anomaly that “flashes” brightly in the midnight-to-dawn sector once per 10.8 h, with the flash parameters depending on particle species and energy.     

Research Advances of Solar Corona and Interplanetary Physics in China: 2012–2014

Solar transients and their related interplanetary counterparts have severe effects on the space environments of the Earth. Therefore, the research of solar corona and interplanetary physics has become the focus of study for both solar and space scientists. Considerable progress has been achieved in these aspects by the solar and space physics community of China during 2012–2014, which will be given in this report. The brief report summarizes the research advances of solar corona and interplanetary physics into the following parts: solar wind origin and turbulence, coronal waves and seismology, solar eruptions, solar energetic particle and galactic cosmic ray, magnetic reconnection,Magnetohydrodynamic(MHD) models and their applications, waves and structures in solar wind,propagation of ICMEs/shocks and their arrival time predictions. These research achievements have been achieved by Chinese solar and space scientists independently or via international collaborations.