Distributed weather radar using X-band active arrays

Dense networks of short-range radars capable of mapping storms and detecting atmospheric and airborne hazards are described. Comprised of physically small, low-power antennas, these networks defeat the Earth curvature blockage that limits today's long-range radar networks and enable high resolution views that extend from the lower-troposphere to the tops of storms. The networks are comprised of 1-meter antennas that transmit 10's of W peak power and are capable of high-speed electronic beam-steering. A system architecture is described that maximizes the value accrued to users of radar data through utility functions that specify dynamic, optimal allocation of resources in response to the needs of multiple end-users and associated information retrieval algorithms.     

Coherent matter wave inertial sensors for precision measurements in space

We analyze the advantages of using ultra-cold coherent sources of atoms for matter-wave interferometry in space. We present a proof-of-principle experiment that is based on an analysis of the results previously published in Richard et al. (2003) from which we extract the ratio h/m for ⁸⁷Rb. This measurement shows that a limitation in accuracy arises due to atomic interactions within the Bose–Einstein condensate. Finally we discuss the promising role of coherent-matter-wave sensors, in particular inertial sensors, in future fundamental physics missions in space.     

The National Space Biomedical Research Institute's education and public outreach program: Working toward a global 21st century space exploration society

Space Exploration educators worldwide are confronting challenges and embracing opportunities to prepare students for the global 21st century workforce. The National Space Biomedical Research Institute (NSBRI), established in 1997 through a NASA competition, is a 12-university consortium dedicated to space life science research and education. NSBRI's Education and Public Outreach Program (EPOP) is advancing the Institute's mission by responding to global educational challenges through activities that: provide teacher professional development; develop curricula that teach students to communicate with their peers across the globe; provide women and minority US populations with greater access to, and awareness of science careers; and promote international science education partnerships.A recent National Research Council (NRC) Space Studies Board Report, America's Future in Space: Aligning the Civil Program with National Needs, acknowledges that “a capable workforce for the 21st century is a key strategic objective for the US space program… (and that) US problems requiring best efforts to understand and resolve…are global in nature and must be addressed through mutual worldwide action”. [1] This sentiment has gained new momentum through a recent National Aeronautics and Space Administration (NASA) report, which recommends that the life of the International Space Station be extended beyond the planned 2016 termination. [2] The two principles of globalization and ISS utility have elevated NSBRI EPOP efforts to design and disseminate science, technology, engineering and mathematics (STEM) educational materials that prepare students for full participation in a globalized, high technology society; promote and provide teacher professional development; create research opportunities for women and underserved populations; and build international educational partnerships.This paper describes select EPOP projects and makes the case for using innovative, emerging information technologies to transfer space exploration knowledge to students, engage educators from across the globe in discourse about science curricula, and foster multimedia collaborations that inform citizens about the benefits of space exploration for life on Earth. Special references are made to educational activities conducted at professional meetings in Austria, Canada, France, China, Greece, Italy, Russia, Scotland and Spain.     

A review of chatter vibration research in milling

Chatter is a self-excited vibration of parts in machining systems. It is widely present across a range of cutting processes, and has an impact upon both efficiency and quality in production processing. A great deal of research has been dedicated to the development of technologies that are able to predict and detect chatter. The purpose of these technologies is to facilitate the avoidance of chatter during cutting processes, which leads to better surface precision, higher productivity, and longer tool life. This paper summarizes the current state of the art in research regarding the problems of how to arrive at stable chatter prediction, chatter identification, and chatter control/suppression, with a focus on milling processes. Particular focus is placed on the theoretical relationship between cutting chatter and process damping, tool runout, and gyroscopic effect, as well as the importance of this for chatter prediction. The paper concludes with some reflections regarding possible directions for future research in this field.     

Fine structure of the interplanetary shock front according to measurements of the ion flux of the solar wind with high time resolution

According to the data of the BMSW/SPEKTR-R instrument, which measured the density and velocity of solar wind plasma with a record time resolution, up to ~3 ×10^–2 s, the structure of the front of interplanetary shocks has been investigated. The results of these first investigations were compared with the results of studying the structure of the bow shocks obtained in previous years. A comparison has shown that the quasi-stationary (averaged over the rapid oscillations) distribution of plasma behind the interplanetary shock front was significantly more inhomogeneous than that behind the bow-shock front, i.e., in the magnetosheath. It has also been shown that, to determine the size of internal structures of the fronts of quasi-perpendicular (θ_BN > 45°) shocks, one could use the magnetic field magnitude, the proton density, and the proton flux of the solar wind on almost equal terms. A comparison of low Mach (М _А < 2), low beta (β₁ < 1) fronts of interplanetary and bow shocks has shown that the dispersion of oblique magnetosonic waves plays an essential role in their formation.     

Origin, Injection, and Acceleration of CIR Particles: Observations Report of Working Group 6

This report emphasizes new observational aspects of CIR ions revealed by advanced instruments launched on the Ulysses, WIND, SOHO, and ACE spacecraft, and by the unique vantage point of Ulysses which carried out the first survey of Corotating Interaction Region (CIR) properties over a very wide range of heliolatitudes. With this more complete observational picture established, this review is the basis to consider the status of theoretical models on origin, injection, and acceleration of CIR particles reported by Scholer, Mann et al. (1999) in this volume. This revised version was published online in August 2006 with corrections to the Cover Date.     

The relationship between field-aligned currents and the auroral electrojets: A review

The recent development of several new observational techniques as well as of advanced computer simulation codes has contributed significantly to our understanding of dynamics of the three-dimensional current system during magnetospheric substorms. This paper attempts to review the main results of the last decade of research in such diverse fields as electric fields and currents in the high-latitude ionosphere and field-aligned currents and their relationship to the large-scale distribution of auroras and auroral precipitation. It also contains discussions on some efforts in synthesizing the vast amount of the observations to construct an empirical model which connects the ionospheric currents with field-aligned currents. While our understanding has been greatly improved during the last decade, there is much that is as yet unsettled. For example, we have reached only a first approximation model of the three-dimensional current system which is not inconsistent with integrated, ground-based and space observations of electric and magnetic fields. We have just begun to unfold the cause of the field-aligned currents both in the magnetosphere and ionosphere. Dynamical behaviour of the magnetosphere-ionosphere coupling relating to substorm variability can be an important topic during the coming years.On leave of absence from Kyoto Sangyo University, Kyoto 603, Japan.     

Microinstabilities associated with a high Mach number,perpendicular bow shock

The instabilities associated with a high Mach number perpendicular shock are reexamined in light of recent enhanced understanding of the Earth's bow shock. The insights provided by both the ISEE observations and hybrid simulations are reviewed and subsequently incorporated into the instability analyses. The discussion of the instabilities is divided according to their location in the shock layer. In the regions in front of and at the shock transition the cross-field instabilities are subdivided into low frequency modes (e.g. ion-ion streaming, kinetic cross-field streaming, drift lower hybrid instabilities) and high frequency modes (electron cyclotron drift, ion sound and electron whistler instabilities). Further downstream various ion ring-like and anisotropy driven instabilities are considered. In each case the instability analysis is reviewed and recent developments are emphasized. Implications of these results concerning the wave signatures and plasma heating and acceleration are also discussed.