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This investigation has focused on development of key technology elements for low energy neutral atom imaging. More specifically, we have investigated the conversion of low energy neutral atoms to negatively charged ions upon reflection from specially prepared surfaces. This 'surface conversion' technique appears to offer a unique capability of detecting, and thus imaging, neutral atoms at energies of 0.01 - 1 keV with high enough efficiencies to make practical its application to low energy neutral atom imaging in space. Such imaging offers the opportunity to obtain the first instantaneous global maps of macroscopic plasma features and their temporal variation. Through previous in situ plasma measurements, we have a statistical picture of large scale morphology and local measurements of dynamic processes. However, with in situ techniques it is impossible to characterize or understand many of the global plasma transport and energization processes. A series of global plasma images would greatly advance our understanding of these processes and would provide the context for interpreting previous and future in situ measurements. Fast neutral atoms, created from ions that are neutralized in collisions with exospheric neutrals, offer the means for remotely imaging plasma populations. Energy and mass analysis of these neutrals provides critical information about the source plasma distribution. The flux of neutral atoms available for imaging depends upon a convolution of the ambient plasma distribution with the charge exchange cross section for the background neutral population. Some of the highest signals are at relatively low energies (well below 1 keV). This energy range also includes some of the most important plasma populations to be imaged, for example the base of the cleft ion fountain. Quinn, J. M. Unspecified Center NAS8-39950...
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Recently proposed low energy neutral atom (LENA) imaging techniques use a collisional process to convert the low energy neutrals into ions before detection. At low energies, collisional processes limit the angular resolution and conversion efficiencies of these devices. However, if the intense ultraviolet light background can be suppressed, direct LENA detection is possible. We present results from a series of experiments designed to develop a novel filtering structure based on free-standing transmission gratings. If the grating period is sufficiently small, free standing transmission gratings can be employed to substantially polarize ultraviolet (UV) light in the wavelength range 300 Å to 1500 Å. If a second grating is placed behind the first grating with its axis of polarization oriented at a right angle to the first's, a substantial attenuation of UV radiation is achievable. ne neutrals will pass through the remaining open area of two gratings and be detected without UV background complications. We have obtained nominal 2000 Å period (1000 Å bars with 1000 Å slits) free standing, gold transmission gratings and measured their UV and atomic transmission characteristics. The geometric factor of a LENA imager based on this technology is comparable to that of other proposed LENA imagers. In addition, this of imager does not distort the neutral trajectories, allowing for high angular resolution.
Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 103. Space plasma measurements are conducted in a hostile, remote environment. The art and science of measurements gathered in space depend therefore on unique instrument designs and fabrication methods to an extent perhaps unprecedented in experimental physics. In-situ measurement of space plasmas constitutes an expensive, unforgiving, and highly visible form of scientific endeavor.
Astronomy has been associated with the detection of electromagnetic waves or photons from within and beyond the solar system, ranging from Radio to Gamma-ray Astronomy. Particle Astrophysics, including Neutrino and Dark-Matter Astrophysics today, started with the discovery of cosmic rays in 1911. The Space Age expanded particle observations to in-situ studies of lower energy electrons and ions with a variety of charge states in space plasmas traversed by spacecraft. Remote observation of space plasmas became possible only after the discovery of energetic neutral atoms (ENAs) in space in 1950.This book is a primer for those who wish to learn more about the origins of ENAs, related detection techniques, and how ENA images and spectra can be used to study space plasmas beyond the reach of spacecraft. It tells a comprehensive story from the first encounters with ENAs in the Earth's magnetosphere to Neutral-Atom Astronomy of the edge of the heliosphere and the interstellar medium. This story includes how ion mass spectrographs evolved into ENA imagers, overcoming the technical challenges, how to extract information from ENA data, and a variety of diagnostic applications on the magnetosphere, interplanetary space, other solar-system objects, the heliospheric boundary, the local interstellar medium, and a glimpse into the future of Neutral-Atom Astronomy.The authors hope to inform and inspire readers to further enrich this field of study.
IMAGE (Imager for Magnetopause-to-Aurora Global Exploration) is the first NASA MIDEX mission and the first mission dedicated to imaging the Earth's magnetosphere. This volume offers detailed descriptions of the IMAGE instrumentation and of the image inversion techniques used to interpret the data. Also included are chapters on the IMAGE science objectives, the spacecraft design and capabilities, science and mission operations, and the processing and distribution of IMAGE's nonproprietary data products.
The Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) is a NASA Explorer mission that is the first space mission dedicated to imaging of the Earth's magnetosphere. IMAGE was launched from Vandenberg AFB into an elliptical polar orbit by a Delta II launch vehicle on March 25, 2000. The two-year prime sci entific mission of IMAGE began on May 25, 2000 after instrument commissioning was successfully completed. IMAGE has now been approved for operation until October 1,2005, and an additional two-year extension is now being considered by NASA. The papers in this volume represent many of the scientific results obtained dur ing the IMAGE prime mission and include some of the early correlative research with ground-based measurements, measurements from other spacecraft such as Cluster II, and relevant theory and modeling programs. All of the reported work is related to the overall IMAGE science objective: How does the magnetosphere respond globally to the changing conditions in the solar wind? IMAGE addresses this question with multi-spectral imaging of most of the important plasma pop ulations of the inner magnetosphere, combined with radio sounding of gradients of total plasma content. The new experimental techniques fall into the following areas: neutral atom imaging (NAI) over an energy range from 10 eV to 500 keY for detection of ionospheric outflow, the plasma sheet, and the ring current; far ultraviolet (FUV) imaging at 121-190 nm for detection of precipitating protons and the global aurora; extreme ultraviolet (EUV) imaging at 30.
Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.
Überblick über den aktuellen Wissensstand und künftige Forschungsrichtungen in der Magnetosphärenphysik In den sechs Jahrzehnten seit der Einführung des Begriffs ?Magnetosphäre? sind über den magnetisierten Raum, der jeden Körper in unserem Sonnensystem umgibt, viele Theorien entstanden und viele Erkenntnisse gewonnen worden. Jede Magnetosphäre ist einzigartig und verhält sich doch entsprechend den universellen physikalischen Vorgängen. Der Band ?Magnetospheres in the Solar System? enthält Beiträge von Experten für Experimentalphysik, theoretische Physik und numerische Modellierung, die einen Überblick über verschiedene Magnetosphären vermitteln, von der winzigen Magnetosphäre des Merkur bis zu den gewaltigen planetarischen Magnetosphären von Jupiter und Saturn. Das Werk bietet insbesondere: * Einen kompakten Überblick über die Geschichte der Magnetosphäre, ihre Grundsätze und Gleichungen * Eine Zusammenfassung der grundlegenden Prozesse in der Magnetospährenphysik * Instrumente und Techniken zur Untersuchung von Prozessen in der Magnetosphäre * Eine besondere Schwerpunktsetzung auf die Magnetosphäre der Erde und ihre Dynamik * Eine Darstellung der planetaren Magnetfelder und Magnetosphären im gesamten Sonnensystem * Eine Definition der künftigen Forschungsrichtungen in der Magnetosphärenphysik Die Amerikanische Geophysikalische Vereinigung fördert die wissenschaftliche Erforschung der Erde und des Weltraums zum Wohle der Menschheit. In ihren Publikationen werden wissenschaftliche Erkenntnisse veröffentlicht, die Forschern, Studenten und Fachkräften zur Verfügung stehen.