December 2006 solar extreme events and their influence on the near-Earth space environment: “Universitetskiy-Tatiana” satellite observations

The Russian microsatellite “Universitetskiy-Tatiana” was launched on Jan. 20, 2005 and was both a scientific and educational mission. Its two main aims were declared as: (1) monitoring of the energetic particles dynamics in the near-Earth space environment after solar events and during quiet times, (2) educational activities based on experimental data obtained from the spacecraft. In this paper observations acquired during Dec. 5–16, 2006, known as “Solar Extreme Events 2006”, were analyzed. The “Universitetskiy-Tatiana” microsatellite orbit permits one to measure both solar energetic particle dynamics, variations of the boundary of solar particle penetration, as well as relativistic and sub-relativistic electrons of the Earth’s outer radiation belt during and after magnetic storms. Both relativistic electrons of the Earth’s outer radiation and solar energetic particles are an important source of radiation damage in near-Earth space. Therefore, the presented experimental results demonstrate the successful application of a small educational spacecraft both for scientific and educational programs.     

Ozone variability related to several SEP events occurring during solar cycle no. 23

Data from geostationary operational environmental satellite (GOES) series were used to identify intense solar energetic particle (SEP) events occurred during the solar activity cycle no. 23. We retrieved O₃, NO, NO₂, HNO₃, OH, HCl and OHCl profiles coming from different satellite sensors (solar occultation and limb emission) and we looked for the mesospheric/stratospheric response to SEPs at high terrestrial latitudes. The chemistry of the minor atmospheric components is analysed to evaluate the associated odd nitrogen (NO_x) and odd hydrogen (HO_x) production, able to cause short (h) and medium (days) term ozone variations. We investigated the effects of SEPs on the polar atmosphere in three different seasons, i.e., January 2005, April 2002 and July 2000. The inter-hemispheric variability of the ozone, induced by the SEP series of January 2005, has been compared with the effects connected both to larger and quite similar events. We found that during SEP events: (i) solar illumination is the key factor driving SEP-induced effects on the chemistry of the polar atmosphere; (ii) even events with limited particle flux in the range 15–40 MeV are able to change the abundance of the minor constituents in the mesosphere and upper stratosphere.     

2010年4月地球同步轨道相对论电子增强事件分析

为研究2010年4月地球同步轨道相对论电子通量异常增强事件的原因, 选取了2004-2010年之间高速太阳风下7个类似事件进行对比分析. 探讨了多种可能导致此次异常事件的太阳风和地磁条件. 结果表明, 较弱的磁暴使得相对论电子高通量区域更接近同步轨道, 此外, 哨声波加速很可能在2010年4月地球同步轨道相对论电子通量异常增强事件中起到重要作用. 磁暴强度与种子电子的注入深度密切相关, 表现为Dst指数曲线的形态与能量为30～100keV的电子高通量区域的下边缘高度吻合. 能量为30～100keV电子的注入深度影响了能量大于300keV的电子出现的磁层区域. 此事件中, 由于磁暴相对较弱, 种子电子向内磁层注入的深度较浅, 更靠近同步轨道区域, 这使得相对论电子大量出现的区域也靠近同步轨道, 最终导致同步轨道相对论电子通量异常增强. 另外, 2010年4月地球同步轨道相对论电子通量异常增强事件中, 高强度的亚暴提供了充足的种子电子并加强了波粒相互作用, 这也是相对论电子增强的必要条件.      

Particle Acceleration at Interplanetary Shocks

This paper briefly reviews proton acceleration at interplanetary shocks. This is key to describing the acceleration of heavy ions at interplanetary shocks because wave excitation—and hence particle scattering—at oblique shocks is controlled by the protons and not the heavy ions. Heavy ions behave as test particles, and their acceleration characteristics are controlled by the properties of proton-excited turbulence. As a result, the resonance condition for heavy ions introduces distinctly different signatures in abundance, spectra, and intensity profiles, depending on ion mass and charge. Self-consistent models of heavy-ion acceleration and the resulting fractionation are discussed. This includes discussion of the injection problem and the acceleration characteristics of quasi-parallel and quasi-perpendicular shocks.     

NC/GAP-TPE共混聚合物的制备和性能研究

采用扩链后共混再熟化的方法,制备了1组不同组成的硝化棉(NC)/含能热塑性弹性体(GAP-TPE)共混聚合物.采用红外光谱(FTIR)和X射线衍射(XRD)表征NC/GAP-TPE共混物的结构,扫描电镜(SEM)观察共混物的断面,动态热机械分析(DMA)测定共混物的玻璃化转变,运用拉伸实验研究不同配比NC/GAP-TP...     

含能粘合剂研究的新进展

新型含能粘合剂的研发对提高固体火箭推进剂的能量及性能有着重要的作用。本文根据国内外近年来在新型含能粘合剂研究方面取得的新进展,按照聚合物侧链所含取代基的不同,分别介绍了叠氮基聚醚粘合剂、硝酸酯粘合剂及其他几种含能粘合剂,对这些粘合剂的应用及性能进行了综合比较与讨论,最后展望了含能粘合剂技术的发展趋势,认为GAP、PGN等粘合剂将是21世纪初高能推进剂、低特征信号推进剂使用的主要品种。     

Solitary and periodic waves in magneto–rotating plasmas: Effect of the Kappa–Cairns distributed electrons

The nonlinear propagation of ion–acoustic (IA) waves in a magneto–rotating plasma is studied by considering the Kappa-Cairns electron distribution. Employing the perturbation scheme, Korteweg–de Vries equation is derived. It is seen that both positive and negative potential solitons can be supported in the present plasma model. The numerical results reveal that the Kappa-Cairns distributed electrons modify features of the electrostatic waves significantly. The effects of non–thermal parameters, plasma rotation frequency, ion temperature, and the wave propagation angle on electrostatic solitary wave structures are also discussed here. It is found that the plasma parameters considerably influence the propagation of IA waves in rotating plasmas. Furthermore, using the bifurcation theory of planar dynamical systems to the K-dV equation, we have presented the existence of solitary and periodic traveling waves. Our study may be helpful to understand the behavior of ion–acoustic wave in the rotating plasma.     

Advances in modeling gradual solar energetic particle events

Solar energetic particles pose one of the most serious hazards to space probes, satellites and astronauts. The most intense and largest solar energetic particle events are closely associated with fast coronal mass ejections able to drive interplanetary shock waves as they propagate through interplanetary space. The simulation of these particle events requires knowledge of how particles and shocks propagate through the interplanetary medium, and how shocks accelerate and inject particles into interplanetary space. Several models have appeared in the literature that attempt to model these energetic particle events. Each model presents its own simplifying assumptions in order to tackle the series of complex phenomena occurring during the development of such events. The accuracy of these models depends upon the approximations used to describe the physical processes involved in the events. We review the current models used to describe gradual solar energetic particle events, their advances and shortcomings, and their possible applications to space weather forecasting.     

Solar Energetic Particle Charge States: An Overview

The ionic charge distributions of solar energetic particles (SEP) as observed in interplanetary space provide fundamental information about the origin of these particles, and the acceleration and propagation processes at the Sun and in interplanetary space. In this paper we review the measurements of ionic charge states of energetic particles in interplanetary space and discuss their implication for our understanding of SEP sources, and acceleration and propagation processes.     

Diagnosis of coronal magnetic field and nonthermal electrons from Nobeyama observations of a simple flare

Coronal magnetic field and nonthermal electrons are very important parameters for understanding of the global heliophysical processes. A flare on November 1, 2004 is selected for self-consistent calculations of coronal magnetic field parallel and perpendicular to the line-of-sight, and density of nonthermal electrons from Nobeyama observations. Both of the diagnosis methods and results are discussed in this paper.