Composition of Interstellar Neutrals and the Origin of Anomalous Cosmic Rays

Knowledge of the elemental composition of the interstellar gas is of fundamental importance for understanding galactic chemical evolution. In addition to spectroscopic determinations of certain element abundance ratios, measurements of the composition of interstellar pickup ions and Anomalous Cosmic Rays (ACRs) have provided the principal means to obtain this critical information. Recent advances in our understanding of particle acceleration processes in the heliosphere and measurements by the Voyagers of the energy spectra and composition of energetic particles in the heliosheath provide us with another means of determining the abundance of the neutral components of the local interstellar gas. Here we compare the composition at the termination shock of six elements obtained from measurements of (a) pickup ions at ～5 AU, (b) ACRs in the heliosphere at ～70 AU, and (c) energetic particles as well as (d) ACRs in the heliosheath at ～100 AU. We find consistency among these four sets of derived neutral abundances. The average interstellar neutral densities at the termination shock for H, N, O, Ne and Ar are found to be 0.055±0.021 cm^?3, (1.44±0.45)×10^?5 cm^?3, (6.46±1.89)×10^?5 cm^?3, (8.5±3.3)×10^?6 cm^?3, and (1.08±0.49)×10^?7 cm^?3, respectively, assuming the He density is 0.0148±0.002 cm^?3.     

The Dynamic Heliosphere: Outstanding Issues

Properties of the heliospheric interface, a complex product of an interaction between charged and neutral particles and magnetic fields in the heliosphere and surrounding Circumheliospheric Medium, are far from being fully understood. Recent Voyager spacecraft encounters with the termination shock and their observations in the heliosheath revealed multiple energetic particle populations and noticeable spatial asymmetries not accounted for by the classic theories. Some of the challenges still facing space physicists include the origin of anomalous cosmic rays, particle acceleration downstream of the termination shock, the role of interstellar magnetic fields in producing the global asymmetry of the interface, the influence of charge exchange and interstellar neutral atoms on heliospheric plasma flows, and the signatures of solar magnetic cycle in the heliosheath. These and other outstanding issues are reviewed in this joint report of working groups 4 and 6.     

IBEX Education and Public Outreach

The IBEX mission includes a comprehensive Education and Public Outreach (E/PO) program that develops programs and products in exciting themes from astronomy and space physics. With the active involvement of the Principal Investigator and several science team partners, it is overseen and implemented by the Adler Planetarium & Astronomy Museum. The program includes an internationally distributed planetarium show with accompanying informal education materials that are also accessible to individuals with special needs; a national Space Science Core Curriculum for grades 6–8 in collaboration with other NASA missions; a professional development program for teachers; and workshops that engage Hispanic and Native American students. Materials are made available for download or for order via the IBEX website: http://www.ibex.swri.edu/. Our program is developed, implemented and monitored for effectiveness by organizations with proven capabilities and experience in their respective areas of E/PO. This paper describes these program elements in detail and includes the rationale and design process for this E/PO program.     

Doppler Compensation & Single Pulse Imaging using Adaptive Pulse Compression

The effects of target Doppler are addressed in relation to adaptive receive processing for radar pulse compression. To correct for Doppler-induced filter mismatch over a single pulse, the Doppler-compensated adaptive pulse compression (DC-APC) algorithm is presented whereby the respective Doppler shifts for large target returns are jointly estimated with the illuminated range profile and subsequently incorporated into the original APC adaptive receive filter formulation. As a result, the Doppler-mismatch-induced range sidelobes can be suppressed thereby regaining a significant portion of the sensitivity improvement that is possible when applying adaptive pulse compression (APC) without the existence of significant Doppler mismatch. In contrast, instead of compensating for Doppler mismatch, the single pulse imaging (SPI) algorithm generalizes the APC formulation for a bank of Doppler-shifted matched filters thereby producing a sidelobe-suppressed range-Doppler image from the return signal of a single radar pulse which is applicable for targets with substantial variation in Doppler. Both techniques are based on the recently proposed APC algorithm and its generalization, the multistatic adaptive pulse compression (MAPC) algorithm, which have been shown to be effective for the suppression of pulse compression range sidelobes thus dramatically increasing the sensitivity of pulse compression radar.     

飞行器外挂投放数值模拟

采用非结构重叠网格Euler方程的CFD方法数值模拟了外挂投放。该方法在重叠网格"挖洞"时,以"离壁面距离"为挖洞判据;在建立重叠区域插值关系时,对Neighbor to Neighbor(N2N)和Alternating Digital Tree(ADT)两种方法的效率进行了比较。采用机翼/挂架/带舵外挂物模型开展了验证计算。在此基础上,完成了某飞行器外挂投放的初步计算。     

基于气动参数之间关系的桥梁断面气动导纳识别

气动导纳的准确估计对大跨桥梁抖振分析具有重要意义.目前在识别方法、试验技术等方面均有诸多进展,但尚未建立识别全部气动导纳函数的方法.针对这一问题,基于气动导数与气动导纳之间的关系,结合根据紊流风场中的抖振响应同时识别桥梁结构气动导数和气动导纳这一思路,首先采用随机子空间法识别得到紊流风场中桥梁结构的气动导数,然后利用气动导数与气动导纳之间的近似关系获取与竖向脉动风分量对应的气动导纳函数,最后根据抖振力谱和脉动风速谱来确定与水平向脉动风分量对应的气动导纳函数.实例研究表明,本文方法对流线型断面气动导纳的识别是可行的.     

电工实验室的建设与实践

实验教学环节在高等学校有着重要的地位和作用.因此,必须开展实验室的建设工作,充分发挥其在实践性教学和科学研究中的作用.介绍了电工实验教学改革的内容,以及实验室内涵的建设.实验室开放不仅能充分利用学校实验室资源,提高教学水平,而且有助于培养具有创新能力的高素质人才.     

Vibrations of circular sandwich plates connected with an elastic foundation

The results of analyzing axisymmetric forced vibrations of an elastic circular sandwich plate connected with an elastic foundation under different surface loads are presented. The hypotheses of a broken normal are accepted to describe the kinematics of a package that is nonsymmetrical over the thickness. The analytical solutions of a problem for plates with a light filler are obtained and numerical analysis is carried out.     

TUGSAT-1/BRITE-Austria—The first Austrian nanosatellite

A nanosatellite to investigate the brightness oscillations of massive luminous stars by differential photometry is currently developed by a Canadian/Austrian team within the BRITE (Bright Target Explorer) project. The first Austrian satellite funded by the Austrian Space Program, called TUGSAT-1/BRITE-Austria, builds on the space heritage of the most successful Canadian CanX-2 and MOST missions. The satellite makes use of recent advances in miniaturized attitude determination and control systems. Precision three-axis stabilization by small reaction wheels and a star tracker provides the necessary accuracy for the photometer telescope to the arcminute level. This will provide to the astronomers photometric data of the most massive stars with unprecedented precision; data which cannot be obtained from the ground due to limitations imposed by the terrestrial atmosphere.The paper describes the spacecraft characteristics and the ground infrastructure being established in support of the BRITE mission which will consist of a constellation of up to four nearly identical satellites allowing to carry out long-term observation of stars (magnitude +3.5) not only with respect to brightness variations, but also in different spectrum ranges.     

Venus Express—Science observations experience at Venus

The Venus Express mission is the European Space Agency's (ESA) first spacecraft at Venus. It was launched in November 2005 by a Soyuz–Fregat launcher and arrived at Venus in April 2006. The mission covers a broad range of scientific goals including physics, chemistry, dynamics and structure of the atmosphere as well as atmospheric interaction with the surface and several aspects of the surface itself. Furthermore, it investigates the plasma environment and interaction of the solar wind with the atmosphere and escape processes.One month after the arrival at Venus the Venus Express spacecraft started routine science operations. Since then Venus Express has been observing Venus every day for more than one year continuously making new discoveries.In order to ensure that all the science objectives are fulfilled the Venus Express Science Operations Centre (VSOC) has the task of coordinating and implementing the science operations for the mission. During the first year of Venus observations the VSOC and the experiment teams gained a lot of experience in how to make best use of the observation conditions and payload capabilities. While operating the spacecraft in orbit we also acquired more knowledge on the technical constraints and more insight in the science observations and their results.As the nominal mission is coming to an end, the extended mission will start from October 2007. The Extended Science Mission Plan was developed taking into account the lessons learned. At the same time new observations were added along with specific fine-tuned observations in order to complete the science objectives of the mission.This paper will describe how the previous observations influence the current requirements for the observations around Venus today and how they influence the observations in the mission extension. Also it will give an overview of the Extended Science Mission Plan and its challenges for the future observations.