Vertical profiles of halocarbons in the stratosphere

Stratospheric air samples collected between 10 and 35 km altitude my means of a cryogenic sampler were analyzed by gaschromatography. Thus vertical profiles of source gases for halogen radicals were derived, such as CCl₄, CCl₃F, CCl₂F₂, CClF₃, CF₄, C₂F₃Cl₃, C₂F₄Cl₂, C₂F₅Cl, C₂F₆, CH₃Cl, CH₃CCl₃, CHF₂Cl, CH₃Br, CBrF₃, and CBrCl₂F. Systematic discrepancies between measured and modelled halocarbon profiles point to deficiencies of present one- and two-dimensional models. Measurements of fully halogenated hydrocarbons provide a tool for systematically studying these deficiencies and thus improving the models.     

Stimulation of plasma waves in the magnetosphere using satellite JIKIKEN (EXOS-B)

The stimulated plasma wave experiment (SPW) has been successfully carried out in the plasmasphere and the magnetosphere along the JIKIKEN (EXOS-B) satellite orbit where the plasma parameters indicate wide variety of the combination of the electron number density, ranging from 1/cc to 10⁴/cc, and the electron cyclotron frequency, ranging from 6 kHz to 200 kHz.The upper hybrid resonances F_UHR usually persists for long periods up to 125 msec and the electron cyclotron resonances nF_H are stimulated at frequencies with the very high harmonic number n; sometimes, the nF_H resonance takes place for n=47.All the features of the resonances including F_On reflect the characteristics of the magnetospheric plasma that contains the energetic and non-Maxwellian components of the particles. The measurement of the plasma resonance contributes to the detection of the local electron density and the magnetic field intensity. The mode of the propagating radio waves is also determined being compared with the observed local plasma resonance frequency F_p.     

Saturn's E ring

The E ring is a loose collection of debris orbiting Saturn well outside the classical ring system. Compared to the classical ring system, the E ring is extraordinarily tenuous but occupies an enormous volume. The optical depth has a pronounced maximum near the orbit of Enceladus, which is therefore widely assumed to be the source of ring material. Optical properties of the ring suggest a collection of micron-sized spheroids whose composition is generally supposed to be water ice in accordance with the assumed Enceladus source.Apart from its unusual physical properties, the very existence of the E ring as a permanent feature of the Saturn system is problematical. The particles of the ring are susceptible to erosion by ion sputtering and outward transport by ion drag. Lifetimes against either of these processes in the presence of observed ion populations are estimated to be no more than a few thousand years, and it is not clear that Enceladus can replenish the ring particles continuously on such a time scale. It has thus been suggested that the E ring is a transient feature of the Saturn system, resulting from an episodic disturbance of Enceladus (e.g., a sizeable meteoroid impact or tectonic event) in the recent past. In any case, the E ring presently provides a convenient natural probe of magnetospheric transport processes because it presents a marginally significant cross section for the absorption of magnetospherically-trapped particles traversing its volume.     

Ralicon anodes fabricated by electron beam lithography for image photon counting detectors

The Anger wedge and strip anode event location system developed for microchannel plate image photon detectors at the Space Sciences Laboratory of the University of California, Berkeley, has been extended in the present work by the use of electron beam lithography (EBL). Computer-aided design methods have been used to develop several types of RALICON ($\text{R}$eadout $\text{A}$nodes of $\text{Lit}$hographic $\text{Con}$struction) for use in photon counting microchannel plate imaging detectors. These anodes are suitable for linear, two dimensional or radial position measurements and they incorporate novel design features made possible by the EBL fabrication technique which significantly extend their application relative to published wedge-strip anode designs.     

Expressions in Closed Form for the Angular Accuracy of a Scanning Radar

Closed-form expressions are given for the standard deviation of the error in estimating angle (usually azimuth) in a scanning radar. The formulas apply to Swerling's lower bound and to the error using a pulse-to-pulse two-pole filter. They apply to non-fluctuating and Swerling II targets and hold for all signal-to-noise ratios. Comparison with graphical results in the literature shows that the average deviation obtained using the formulas is less than 4 percent.     

Genetic response of bacterial spores to very heavy ions.

Using spores of two Bacillus subtilis strains differing in repair capacity, we have studied repair and mutation induction in the spores after irradiation with very heavy ions up to uranium with specific particle energies up to 18.6 MeV/u. The results indicate that repair and mutation induction after heavy ion irradiation are closely related to each other and that both phenomena strongly depend on the atomic number and specific energy of the ions. The effects are discussed in comparison with results obtained after X-irradiation.     

Comparative neutral composition instrumentation and new results

Composition and gas density measurement at all altitudes in the atmospheres of earth and other planets are made by mass spectrometers. Because of the impartiality and large dynamic range they are particularly favored for exploratory missions. Measurements of trace constituents, inert gases and height profiles, especially below clouds, are objectives where mass spectrometry is most useful. Significant advances have been made in recent years in development of light weight automated instruments. Experiments conducted in rarified atmospheres have been more successful or results were less controversial than in attempts to analyze high pressure atmospheres. Gas sampling and conditioning techniques are highly specific because of measurement environments and engineering constraints on the mission, and are usually the most critical elements in the experiment. Chemical sample enrichment and scrubbing for noble gas enhancement are additional sample conditioning techniques now employed. Dynamic range of more than 10⁸ is achievable. Reliable measurements of complex organic or chemically active trace constituents with mixing ratios of less than 10^?9 still require significant instrument development particularly where weight, power and sampling time are severely restricted. Adaptation of familiar and proven laboratory techniques for flight instruments is usually not straightforward and practical.     

Software Maintenance Criteria for Small Microprocessor-Based Systems

Criteria is provided for designing and implementing small microprocessor-based programs with the objective of enhancing their maintainability properties. Since microprocessor-based programs typically have relatively short schedules and low budgets. it is necessary to adapt maintainability enhancing practices for these projects in such a manner that their impact in these critical areas is not excessive. Since many of the practices which can be used to enhance maintainability actually coincide with those which improve productivity during software development, application of those practices should incur little or no added cost or duration to a microprocessor-based program. This paper suggests practical steps which can be applied to the software design and implementation activities, to the software documentation, and to the development environment which will enhance the maintainability of the resultant computer programs.     

Analysis of gravity-wave induced instabilities and turbulence viscosity parameters from optical emissions

The effects of gravity waves on OH and 5577 0I emissions have been used to investigate (1) the possible production of “secondary” waves or “ripples” by a “primary” wave; (2) the possible application of such observed optical emissions for computing atmospheric parameters such as turbulence viscosity in the mesospheric regions.     

Wide angle X-ray optics for use in astronomy

Recently there was a suggestion in the literature to apply the principle of the lobster-eye to X-ray astronomy imaging (J.R.P. Angel, Ap. J. 233, 364, 1979). Our own suggestion for a wide angle X-ray telescope made earlier (W.K.H. Schmidt, Nucl. Instr. Meth.127, 285, 1975) is very similar to the above one. It consists of one or two sets of plane mirrors used in a grazing incidence configuration. The advantages of this type of X-ray optics over other systems for particular astronomical observations will be discussed.