bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermoelastic strains and tilts revisited
Authors: Harrison J. C. , Herbst Klaus
Published: February 2008

Coupling between the thermal boundary layer and surface topography is an important source of thermoelastic tilts and strains. Simple formulas are given to compute these effects on uniform slopes. In contradiction to inferences derived from analyses for a semi‐infinite half space, these effects can be considerably reduced by burying instruments at practical depths.
The plasma line revisited as an aeronomical diagnostic: Suprathermal electrons, solar EUV, electron‐gas thermal balance
Authors: Carlson Herbert C. , Wickwar Vincent B. , Mantas George P.
Published: February 2008

Spectra of plasma wave intensities (kTp) in the ionosphere over Arecibo are calculated and compared with those from observations of the plasma line intensity. This approach involving directly observed quantities avoids the uncertainties that have plagued past comparisons with photoelectron theory. In addition, careful comparisons in physically relevant segments of the spectra show that any significant increase in the magnitude of the solar EUV flux would lead to a contradiction of the observed plasma wave intensities. Further, the comparisons indicate that resolution of the thermal electron‐gas heat balance problem must be sought through better heat transfer rates (e.g., heating and cooling rates, etc.), rather than in the solar EUV. This approach utilizes more fully the potential of the plasma line experiment as a diagnostic tool for aeronomical studies, (e.g., photoelectrons, auroral secondaries, ionosphere‐modification experiments, etc.).
Gravity changes and the Palmdale Uplift
Authors: Rundle John B.
Published: February 2008

In this paper I examine the published uplift and gravity data on the Palmdale bulge in light of two possible mechanisms for the uplift, dilatancy and thrust faulting. A method for computing the gravity anomalies is formulated which eliminates the pole in the integrand. The method is of general utility and can be applied to any problem which requires numerical integration of a potential equation. The gravity integrals are evaluated numerically and the results are plotted. On the basis of both the gravity and uplift computations, I conclude that the Palmdale uplift is more consistent with thrust faulting than it is with dilatancy.
A search for nitric oxide gamma band emission in an aurora
Authors: Beiting E. J. , Feldman P. D.
Published: February 2008

A strong emission feature at 2150 Å has been observed by a rocket‐borne spectrophotometer in an IBC II+ aurora. This feature, commonly identified with the NO γ(1,0) band, is comparable in intensity to the nearby N 2 Vegard‐Kaplan bands. Comparison of the observed spectra with a theoretically produced synthetic spectrum allows all but this feature to be assigned to N 2 transitions. No bands of the v′=0 or 2 progressions or any other bands from v′=1 appear, casting serious doubt on the identification of this feature as the NO γ(1,0) band.
Low altitude acceleration of ionospheric ions
Authors: Whalen B. A. , Bernstein W. , Daly P. W.
Published: February 2008

Energetic ion and electron observations were made from a high altitude sounding rocket launched into the expansive phase of an auroral substorm near local midnight. In the 400‐500 km altitude range, on both the up‐ and down‐leg, intense (∼108 cm−2 sec−1 sr−1 keV−1) beams of 90‐500 eV ions were observed at 90° pitch angles. At higher altitudes the beam appeared at larger pitch angles, the variation of these pitch angles with height being consistent with adiabatic expansion of a population injected at 90° at lower altitudes. The width of the beam was within the angular response (∼10°) of the ion sensor at all energies and altitudes. These ions, energized up to 500 eV, were observed throughout the flight, enhancements occurring at the edges of auroral precipitation regions and, for the largest event, in coincidence with intense field‐aligned electron precipitation. Acceleration by ion cyclotron waves produced via a current‐driven or beam‐plasma instability is suggested as a possible source mechanism.
Radial diffusion equation for collision‐affected plasma
Authors: Nishida Atsuhiro
Published: February 2008

The equation for radial diffusion in a planetary magnetosphere is developed for the case in which the mean collision time is longer than the bounce time but shorter than the characteristic time scale of diffusion. An intuitive, mean‐free‐time method is used on the assumption that the coherence time of the perturbation electric field is longer than the mean collision time. The equation can be applied to ambient plasma in the Jovian magnetosphere.
A note on the complications of the Compton‐Getting effect for low energy charged particle measurements in interplanetary space
Authors: Keppler E.
Published: February 2008

The response of thin window semiconductor detectors to various energetic ions is discussed. Different ions produce response at a given energy loss at different energies per nucleon. The Compton‐Getting effect causes further shifts to lower and higher energy ranges dependent upon direction, hence a particular differential channel may count particles coming from quite different energy ranges in the solar wind frame. The implications of these effects are discussed.
On the contribution of water products from Galilean satellites to the Jovian magnetosphere
Authors: Lanzerotti L. J. , Brown W. L. , Poate J. M. , Augustyniak W. M.
Published: February 2008

We demonstrate, by using the recent experimental results on the “sputtering” rates of water ice by energetic protons, that significant fluxes of heavy atoms can be eroded from Europa, Ganymede, and Callisto. These atoms may play an important role in contributing to an atmosphere around Ganymede. If they can escape from the satellites and be ionized, they can be important contributors to the heavy ions that may dominate the plasma centrifugal distortion of the Jovian magnetosphere.
On the apparent source depth of planetary magnetic fields
Authors: Elphic R. C. , Russell C. T.
Published: February 2008

Two simple assumptions regarding the ratios of the strengths of the field contributions of the multipole moments of the terrestrial magnetic field at its effective source depth are used to examine the consistency between the apparent source depths for the magnetic fields of Mercury and Jupiter and our present understanding of their interior structure. Both fields are consistent with our present understanding. However, the comparison would be facilitated by further measurements of the magnetic fields at both planets, especially at Mercury.
Sedimentation rates of deepsea cores determined by fission/alpha track counting
Authors: Fisher David E.
Published: February 2008

A method is presented for determining deepsea sedimentation rates based on total alpha activity as measured by counting alpha tracks in cellulose nitrate. Correction for contributions from the U and Th families are made by counting fission tracks in lexan. Data obtained are in good agreement with previous measurements.
Marine manganese concretion growth rates: Non‐radiometric considerations
Authors: Greenslate J.
Published: February 2008

Non‐radiometric data are inconsistent with fast growth rates for marine manganese concretions. A simple box model calculation can place an upper limit on growth rates that is consistent with the majority of radiometric interpretations. The vast majority of these concretions cannot presently be growing faster than a few millimeters per 106 years.
Solar UV variability and its effect on stratospheric thermal structure and trace constituents
Authors: Callis L. B. , Nealy J. E.
Published: February 2008

Observational evidence suggests the presence of solar UV variability in the spectral range 0.175 ≤ λ ≤ 0.310µ during the 11 year solar cycle. The present paper reports the results of a study using a steady‐state 1‐D radiative‐convective‐photochemical model conducted to determine the response of stratospheric temperatures and O3, O(¹D), O(³P), and N2O constituent distributions to UV variability. Results show that concentrations of constituents and the thermal structure may be altered significantly for the altitude interval between 20 and 55 km.
Partial reflection and scattering of VHF radar signals from the clear atmosphere
Authors: Röttger J. , Liu C. H.
Published: February 2008

Estimates are made for received power due to partial reflection and turbulence scattering of VHF radar echoes from the clear atmosphere. We show that, under rather general conditions, partial reflections from stratified layers in the atmosphere can contribute significantly to the received echo power and therefore should be taken into account in data interpretation. Possible experimental techniques to investigate the partial reflection are discussed. Some results from tropospheric observations will be presented indicating high echo power from thin layers having a long correlation time.
Using Dynamo Theory to predict the sunspot number during Solar Cycle 21
Authors: Schatten Kenneth H. , Scherrer Philip H. , Svalgaard Leif , Wilcox John M.
Published: February 2008

On physical grounds it is suggested that the sun's polar field strength near a solar minimum is closely related to the following cycle's solar activity. Four methods of estimating the sun's polar magnetic field strength near solar minimum are employed to provide an estimate of cycle 21's yearly mean sunspot number at solar maximum of 140 ± 20. We think of this estimate as a first order attempt to predict the cycle's activity using one parameter of physical importance based upon dynamo theory.
The Lunar Mare Basalt suite
Authors: Papike J. J. , Vaniman D. T.
Published: February 2008

Recent studies have greatly expanded our knowledge of lunar mare basalts. Since 1976 there has been a revision of the Apollo 12 low‐Ti mare basalt suite and the discovery of a new very low‐Ti (VLT: < 1% TiO2) basalt suite at Apollo 17 and in the new Soviet samples from Mare Crisium (LUNA 24). Current studies suggest that the VLT basalts may be in some way related to the enigmatic “green glasses” which are found in the soils from every lunar landing site. Telescopic studies of spectral reflectance and crater systematics show that basalts of varying Ti content were extruded throughout the history of mare volcanism. These new discoveries indicate that mare basalts can no longer be classified into the two simple groups of older, high‐Ti basalts and younger, low‐Ti basalts.
A method for finite plate reconstructions, with applications to Pacific‐Nazca Plate evolution
Authors: Pilger Rex H.
Published: February 2008

As an alternative to trial‐and‐error methods, a least‐squares technique for derivation of finite plate reconstructions has been developed. The method involves minimization of the summed distances squared separating data sets on corresponding former plate margin segments as a function of the reconstruction (rotation) parameters. Each data value consists of the distance between a point on one former plate margin (as defined by magnetic anomalies and fracture zones, for example) and the chord formed by the nearest two points on the corresponding, rotated former plate margin. The individual distance values are calculated in sets, corresponding to individual anomaly or fracture zone segments, to reduce the likelihood of convergence to a local minimum. This technique is illustrated by derivation of plate reconstructions for anomalies 7 through 13 and 16 in the east central Pacific Ocean, based on published identifications.
More anomalies from the Allende Meteorite: Samarium
Authors: McCulloch M. T. , Wasserburg G. J.
Published: February 2008

The isotopic composition of Sm has been measured in the Allende inclusions Cl and EK1‐4‐1. These inclusions were previously shown to have isotopic anomalies for the elements O, Mg, Ca, Ba and Nd. Sample Cl has a normal Sm isotopic composition except for the “p‐process” isotope 144Sm, which has an excess of 15±5 parts in 104. Sample EK1‐4‐1 was found to have Sm with a highly aberrant composition, indicating excess at all unshielded isotopes and an excess at 144Sm. These data confirm the previous evidence for an addition of “r‐process” isotopes to this material and also indicate an addition to the “p‐process” isotope 144Sm. From the observations on Cl it is inferred that the “p‐process” addition is decoupled from the “r‐process” addition.
The development of residual stress in cooling rock bodies
Authors: Savage William Z.
Published: February 2008

Two elastic models for the development of residual stresses due to cooling in rock bodies are presented. The first describes the "locking in" of stresses on grain‐to‐grain (microstructural) scale and the second describes the locking in of stresses on a macrostructural scale. Application of the microstructural model to uniform cooling of solid granite from 300°C to 0°C leads to a self‐equilibrating stress field and an average volumetric residual strain of −7050×10−6. Application of the macrostfuctural model to the cooling from 300°C to 0°C of an idealized granite pluton surrounded by metasedimentary country rock leads to residual radial and hoop stresses of −232×105 Pa in the granite and residual radial and hoop stresses of −232 and 116×105 Pa in the metasediment at its contact with the granite.
Measurements of relative diffusion at small scales
Authors: Miksad Richard W. , Zimmermann Keith A.
Published: February 2008

An oscillating grid water tank is used to collect data on the dispersive spreading of a cluster of floating particles in a horizontally homogeneous turbulent field. It is shown that the rate of relative diffusion increases with increasing distance between neighboring particles until the distance exceeds the scale of the energy containing eddies generated in the tank. A diffusion diagram is used to compare the laboratory results with collections of oceanic diffusion data. The results indicate Richardson's 4/3 power law of oceanic relative diffusion can be modeled in the laboratory.
The ultraviolet aurora: The spectrum between 2100 Å and 2300 Å
Authors: Sharp William E.
Published: February 2008

Rocket‐borne spectroscopic observations of the ultraviolet aurora between 2100 Å and 2300 Å reveal bands from the N2 Lyman‐Birge‐Hopfield and Vegard‐Kaplan systems. A strong feature at 2144 Å is identified as the quintet doublet of NII. This emission feature is shown from altitude profiles to have little if any quenching.
Explosive tearing mode reconnection in the magnetospheric tail
Authors: Galeev A. A. , Coroniti F. V. , Ashour‐Abdalla M.
Published: February 2008

A speculative model for the nonlinear phase of the collisionless tearing instability is developed for the case of a single long wavelength tearing mode. Using an energy principle formalism, we find that the nonlinear growth rate is linearly proportional to the mode amplitude. Hence in the nonlinear phase, the tearing mode grows explosively in time, and saturates when the width of the magnetic islands become comparable to the thickness of the current sheet. For typical plasma sheet parameters, the explosive phase lasts 5 ‐ 10 minutes, and develops cross‐tail emf's of several 100 KV.
Origin of air masses producing acid precipitation at Ithaca, New York: A preliminary report
Authors: Miller John M. , Galloway James N. , Likens Gene E.
Published: February 2008

Precipitation chemistry data collected on an event basis at Ithaca, New York, were interpreted using the ARL trajectory model and meteorological maps. Forty‐five events were separated according to trajectory directions and were categorized by using four compass sectors around the collection site. It was shown that the acid precipitation (pH < 5.6) came predominantly from the SW sector, where the largest anthropogenic sources of acid‐forming gases exist. The NW sector also showed high acidity. The method described in this paper will prove useful in the future for identifying general sources of acid precipitation as increased amounts of fossil fuel are burned.
Topside sounder observations of equatorial bubbles
Authors: Dyson Peter L. , Benson Robert F.
Published: February 2008

Large scale regions of depleted equatorial ionospheric plasma, called equatorial bubbles, are investigated using topside sounder data. The sounder’s unique remote measuring capability enables the magnetic field‐aligned nature of the bubbles to be investigated. A search of all available Alouette 2 and ISIS 1 ionograms during nighttime perigee passes near the magnetic equator has revealed a variety of echo signatures associated with bubbles. In addition to a sudden drop in electron density, these signatures usually include in situ spread F and ducted traces. The ducted traces have been used to determine the electron density distribution and to infer changes in ion composition along the magnetic field line within the duct associated with the bubble. In some cases it can be determined that the bubble is asymmetric with respect to the magnetic equator. Even though such features require 3 dimensional models for their explanation, the great field‐aligned extent of the bubbles (relative to their cross section) suggests that current theories, which ignore variations along the magnetic field, are still applicable.
Changes in crustal resistivity near Palmdale, California
Authors: Searls Craig , Poehls Kenneth A. , Jackson David D. , Wescott Eugene M.
Published: February 2008

The largest change in apparent resistivity observed across a 3.3 km galvanic resistivity array during the first year of operation was 6%. This 6% decrease is strongly correlated with several months of continuous rain. Fluctuations in apparent resistivity appear to be larger after than before the rain. This is believed to be the result of a newly formed surface layer of high conductivity. No correlation is observed between local seismicity and resistivity.
Discrete events at Viking‐2 Mars site, northern summer
Authors: Goepel James , Nicholson Bruce , Ryan J. A.
Published: February 2008

The Viking‐2 Mars Lander landed at 48°N 226°W, northern summer. During the summer period the wind vector exhibited a repetitive clockwise turning with a period of one Sol (Mars day). Occasionally, however, the rotation ceased and wind became principally northeasterly. These "events" were always multiples of a Sol in duration, and all began around local midnight. The exact reason for this behavior is not clear, but it is suggested that small variations in the strength of the global circulation may be responsible.
Energetic plasma ions within the Earth's magnetosheath
Authors: Asbridge J. R. , Bame S. J. , Gosling J. T. , Paschmann G. , Sckopke N.
Published: February 2008

Observations in the dawn magnetosheath with the LASL/MPI fast plasma experiment on ISEE 1 and 2 reveal the existence of two distinct states of plasma flow within the sheath: 1) a "quiet" state; and 2) a "disturbed" state. Energetic ions in the range of 3‐40 keV are the distinguishing feature of the disturbed state. Long period (∼ 1 minute) fluctuations in plasma density, temperature, flow speed, and flow direction occur simultaneously with the appearance of these high energy particles. The most likely explanation of these observaons is that the energetic ions are produced in the vicinity of the bow shock under certain (unspecified) interplanetary conditions, and the fluctuations in plasma flow are produced locally by the interaction of the energetic ions with the ambient plasma.
Evidence for solar wind origin of energetic heavy ions in the Earth's radiation belt
Authors: Hovestadt D. , Gloeckler G. , Fan C. Y. , Fisk L. A. , Ipavich F. M. , Klecker B. , O’Gallagher J. J. , Scholer M.
Published: February 2008

Analysis of data from our energetic ion composition experiment on ISEE‐1 has revealed the presence of substantial fluxes of carbon, oxygen, and heavier ions above 400 keV/nucleon at L values between ∼ 2.5 and 4 Re. The measured C/O ratio varies systematically from 1.3 at 450 keV/nucleon to 4.1 at 1.3 MeV/nucleon, and no iron is observed above 200 keV/nucleon. These results provide strong evidence for a solar wind origin for energetic ions in the outer radiation belt. The absence of iron and the increase of the carbon to oxygen ratio with energy suggest that the condition for the validity of the first adiabatic invariant may have a strong influence on the trapping of these particles.
Pore fluids and seismic attenuation in rocks
Authors: Winkler Kenneth , Nur Amos
Published: February 2008

Seismic attenuation and velocities were measured in resonating bars of Massilon sandstone at various degrees of saturation. Whereas shear energy loss simply increases with degree of saturation, bulk compressional energy loss increases to ∼95% saturation and then rapidly decreases as total saturation is achieved. This behavior is analogous to the behavior of shear and compressional velocities, but the effect on attenuation is larger by an order of magnitude. Our observations are in excellent agreement with the predictions of several models of energy loss involving partial or total saturation. Pore fluid attenuation mechanisms are expected to be dominant at least in the shallow crust.
About the influence of electron temperature and relative ionic composition on ion depletion in the wake of the AE‐C satellite
Authors: Samir Uri , Brace L. H. , Brinton H. C.
Published: February 2008

Data from the cylindrical electrostatic probe and from the Bennett ion mass spectrometer on board the AE‐C satellite were examined in order to determine the influence of electron temperature (Te) and ion composition on the amount of ion depletion in the wake of an ionospheric satellite. We observe that both electron temperature and ionic composition significantly influence the amount of ion depletion in the near wake zone, as measured by the ion current collected by the cylindrical probe mounted about 32 cm from the surface of the satellite. The ion current in the wake in an O+ dominated plasma decreases with respect to ambient by about two orders of magnitude at Te ≈ 1000°K and by a factor of about 30 at Te ≈ 3000°K. For a plasma where the O+ density equals the H+ density, the ion current decreases by a factor of 6 in the wake at Te = 1000°K and by a factor of 2.3 at 3000°K.
SO2 oxidation via the hydroxyl radical: Atmospheric fate of HSOx radicals
Authors: Davis D. D. , Ravishankara A. R. , Fischer S.
Published: February 2008

Reported in this study are the results from a gas kinetics — aerosol laboratory study involving the OH induced oxidation of SO2. At tropospheric and lower stratospheric pressures, reaction (1) is neither a third order process nor is it a simple bimolecular reaction. The effective bimolecular k value at one atmosphere (N2) pressure has been estimated by these authors to be 9 × 10−13cm³/molec/s. Based on estimated k values and concentrations for several trace gases, it is suggested here that the resulting HSO3 radical from reaction (1) under atmospheric conditions would react predominantly with O2 in both the lower stratosphere and the troposphere. It is further suggested that the product HSO5 radical would undergo hydration in both atmospheric regions.
A meteor ablation‐cluster ion atmospheric sodium theory
Authors: Richter E. S. , Sechrist C. F.
Published: February 2008

Neutral and ionic forms of sodium form narrow, well‐defined layers which peak in the 90‐95 km altitude region at midlatitudes. A new theory for the sodium layer is presented, which is found to be in good agreement with existing atmospheric observations as well as available laboratory measurements of rate constants. The layer is believed to result naturally from a meteor ablation source over a chemical sink with vertical transport of Na+ playing an important role in the layer shape and variation. While the neutral chemistry is believed to consist of chemical equilibrium between Na and NaO, the ion chemistry departs from earlier studies and considers a cluster ion scheme. It is possible that higher‐order cluster ions of sodium play a role in the formation of aerosols, through attachment or ion‐induced nucleation processes.
Strong electron pitch angle diffusion observed at geostationary orbit
Authors: Baker D. N. , Stauning P. , Hones E. W. , Higbie P. R. , Belian R. D.
Published: February 2008

Comparison of auroral zone riometer data with high‐resolution energetic electron data at the geosynchronous orbit confirms previous observations that significant electron (E ≳ 30 keV) precipitation begins remarkably near the flux level predicted in the Kennel‐Petschek theory. The present new observations, however, also provide adequate pitch angle information to study the detailed evolution of energetic electron anisotropies from the weak pitch angle diffusion limit to the strong diffusion limit predicted in the theory of wave‐particle interactions. Since all substorm‐accelerated electrons which are injected after fluxes have reached the strong diffusion limit are rapidly scattered and lost from the magnetosphere, the present measurements provide a new experimental electron upper flux limit of 5 × 107 electrons (cm²‐sec‐sr)−1 at L = 6.6.
Paleomagnetism of varved sediments from western New England: Variability of the paleomagnetic recorder
Authors: Verosub Kenneth L.
Published: February 2008

Comparison of the paleomagnetic directions recorded by varved sediments in western New England has provided a means of determining the inherent variability of the paleomagnetic recorder of depositional detrital remanent magnetism. Although a given varve has a stable, well‐defined direction of magnetization, successive sampling horizons at the same site as well as the same sampling horizon at different sites may show variations of as much as 8° in inclination and 15° in declination. This variability is attributed not to the secular variation of the geomagnetic field but rather to the physical factors which can influence the magnetic direction recorded by a sediment. Since the time scale for changes in these factors is comparable to the time scale for changes of the geomagnetic field, it may not always be possible to distinguish the true variation of the geomagnetic field from the variability of the paleomagnetic recorder. In certain circumstances correlation of sedimentary sequences on the basis of apparent secular variation will thus be impossible.
On the connection of interplanetary shock wave parameters and energetic storm particle events
Authors: Gombosi T. , Kecskeméty K. , Pintér S.
Published: February 2008

A series of energetic storm particle (ESP) events is investigated on the basis of observations of energetic solar protons by IMPs IV and V between 1967 and 1972. The total number and energy of particles associated with 20 ESP events are analyzed in connection with several plasma parameters at the shock surface; i.e., magnetic and thermal pressure, magnetic field and plasma mass flux. Correlation is established between the total energy of ESPs in the energy range of 1‐80 MeV and the jump in the total pressure. It is pointed out that the amount of shock energy converted to the acceleration of ESP particles is not negligible and could, in principle, contribute to the deceleration of the shock wave.
Plasma diffusion into the wake of Venus
Authors: Gombosi T. , Cravens T. E. , Nagy A. F. , Brace L. H. , Owens A. J.
Published: February 2008

A model of the diffusion of ionosheath plasma into the wake region of Venus is presented. It is shown that particle diffusion, which is assumed to be a consequence of the fluctuating magnetic field observed in the wake of Venus by Pioneer Venus and Veneras 9 and 10, can explain the plasma observations made in the wake by Veneras 9 and 10. The pressure due to these diffusing particles when balanced against the ionospheric pressure yield ionopause heights less than 1000 km for zenith angles less than about 135°. The model also predicts significant fluxes of low energy electrons and ions for zenith angles less than 135°, which are capable of producing the observed nightside ionosphere.
Change in the solar constant between 1968 and 1978
Authors: Kosters John J. , Murcray David G.
Published: February 2008

Solar irradiance measurement made from a balloon on January 27, 1978, indicates a change of +0.4% over similar measurements made in 1968. This change is greater than the experimental uncertainty of the measurement and is felt to be the result of change in the solar constant.
The role of energetic particle precipitation in Jovian magnetospherics: 1. Secondary electrons from the ionosphere of Jupiter
Authors: Swartz Wesley E. , Williams Gregory J. , McDonough Thomas R.
Published: February 2008

Escape of photoelectrons from the Jovian ionosphere produces only a meager source of thermal plasma for the inflated centrifugally unstable magnetosphere and is unable to account for the 100 eV thermal plasma temperatures of the magnetosphere. Since the Jovian magnetosphere is well populated with highly energetic electrons, the creation of secondaries and the energy degradation of the primaries precipitating into the lower ionosphere provide additional sources of magnetospheric thermal plasma as well as of the energy for further elevating the plasma temperatures in the top side ionosphere. The efficiencies with which escaping electrons are created by precipitating electrons with energies up to several MeV are computed using energetic electron transport and thermalization codes. The more energetic incident fluxes are far less efficient in creating escaping electrons than the lower energy fluxes with only 0.001% of the secondaries escaping for a 1 MeV source versus 3% for a 1 keV source. Incident fluxes of the order of 10 to 100 per sq cm per sec per eV between 100 eV and 100 keV are required to produce 50 eV escape fluxes comparable to those generated by solar EUV.
Relativistic electron precipitation
Authors: Parks G. K. , Gurgiolo C. , West R.
Published: February 2008

Intense atmospheric bremsstrahlung X‐rays of energies ≳ 120 keV were detected by a balloon borne X‐ray experiment on September 30, 1976, flown from Fairbanks, Alaska. The X‐ray energy spectra have been obtained and compared to the primary electron energy spectra responsible for the X‐rays. Using the Monte Carlo results, which predict the X‐ray fluxes at various atmospheric depths, we deduce that the electron energy spectra responsible for the X‐rays have e‐folding energies around 200 keV (average energy ≳ 300 keV) if it is assumed that the primary electron energy spectra incident on top of the atmosphere is exponential in form. The event reported here falls in the category of relativistic electron precipitation event.
Acceleration of upper stratospheric radiative damping: Observational evidence
Authors: Ghazi A. , Ramanathan V. , Dickinson R. E.
Published: February 2008

Satellite observations of southern hemisphere stratospheric ozone and temperature near the stratopause during October 1970 show these fields to have undergone large longitudinal variations, negatively correlated with each other. Radiative transfer model calculations of the corresponding variations in ozone solar heating rates, show that the observed negative correlation between temperature and ozone nearly doubles the rate of radiative damping of temperature perturbations in the upper stratosphere from that due to infrared radiation alone.
The flow of salt glaciers
Authors: Wenkert Daniel D.
Published: February 2008

The flow of salt glaciers is investigated. On the basis of data extracted from published sources, order of magnitude estimates (and probable upper and lower limits) for the stress and strain rate in a salt glacier in Iran are determined. The estimate of strain rate is much larger (by a factor of ∼108) than strain rates predicted by previously investigated flow mechanisms for halite (i.e., Nabarro‐Herring creep and dislocation climb) at the stress estimated. The observed stress and strain rate can better be explained as creep due to the diffusion of ions through an interstitial salt‐water solution.
Diffuse Jovian aurora influenced by plasma injection from Io
Authors: Thorne Richard Mansergh , Tsurutani Bruce Tadashi
Published: February 2008

Cyclotron resonant instability of Jovian energetic electrons is dramatically enhanced as a consequence of the lower resonant electron energy (Eres ⧜ B²/8πN) within the equatorial high density plasma torus surrounding the orbit of Io. This mechanism accounts adequately for the continuous broad band whistler mode waves observed within the Io torus on Voyager I. The higher energy resonant electrons (∼ 100 keV to 1 MeV) can be scattered by the observed low frequency waves (≲ 1 kHz) at a rate as high as 10 percent of the limit attainable under strong pitch‐angle diffusion; the corresponding energetic electron lifetimes are comparable to a day. This is much shorter than any realistic estimates for radial diffusion transport near Io. Thus an efficient local acceleration process is required to continually replenish the precipitating relativistic electrons. Concomitant energy deposition into the Jovian atmosphere is estimated to be ∼5 to 15 ergs cm−2 sec−1 over a broad invariant latitude range mapping from the Io plasma torus (65° ≲ Δ ≲ 75°). This intense precipitation should both provide a dominant source of middle atmospheric ionization and excite a continuous band of diffuse auroral emission. In the absence of significant extinction, H Lyα intensity is estimated to be 30 to 100 kR in approximate agreement with the Voyager Extreme Ultraviolet observations. Total power dissipation over the diffuse auroral zone should be at least 1013 watts. Because the cyclotron resonant scattering process is strongly influenced by the ambient equatorial thermal plasma density we suggest that the diffuse Jovian aurora should be influenced by the variable volcanic activity on Io which is thought to be an important source of plasma.
Physical properties of the aerosol at the South Pole
Authors: Hogan Austin W. , Barnard Stephen , Bortiniak J.
Published: February 2008

The size distribution of aerosol arriving at the South Pole was measured several times during four days of relatively homogeneous meteorological transport conditions. This aerosol had a maximum number concentration in the 10−6cm < r < 8×10−6cm radius rangeand a maximum volume concentration in the 2×10−5 − 2×10−4cm radius rangea total number concentration of 106/cm³ and a total volume concentration of 10−6cm³/m³which would correspond to a mean mass concentration of about 1‐2 µgm/m³. Almost all particles of r ⪖ 1.5×10−5cm were hygroscopicwith refractive index near 1.54. No particles of r ≥ 6×10−4cm were found in 75m³ of airand an average of 44/cm³ carried charges.

This aerosol represents the background aerosol which occurs at the end point of a long series of meteorological precipitation processes; aerosols suffering a similar chain of processes while being transported vertically in the troposphere may also approach the same end point.
Detection of Jovian whistler mode chorus; Implications for the Io torus aurora
Authors: Coroniti F. V. , Scarf F. L. , Kennel C. F. , Kurth W. S. , Gurnett D. A.
Published: February 2008

Near the Io torus outer boundary (L ≃ 8), the Voyager 1 plasma wave instrument detected high frequency (f) waves near one‐half the electron cyclotron frequency fc. High resolution waveform measurements demonstrate that these f ≃ fc/2 signals are banded whistler mode chorus at f ≲ fc/2 and half‐cyclotron frequency emissions with f slightly above fc/2. The high resolution spectral information, and the theory of whistler mode waves, permit us to estimate the density (≃2.5 cm−3), energy (few keV), and omnidirectional energy flux (10² ergs/cm²‐sec) of the electrons resonant with the chorus. Chorus precipitates about 6 ergs/cm²‐sec of few keV electron energy to the Jovian ionosphere at L = 8. Electrostatic emissions, probably electron cyclotron half‐harmonic modes, have also been detected near the magnetic equator in the Io torus region. At L = 8, the multimode pitch‐angle diffusion associated with the detected waves should produce a precipitation flux about a factor two below the 50 ergs/cm²‐sec required to generate the observed auroral emissions; however, the flux could well be larger deeper within the torus.
Electrostatic waves in the Jovian magnetosphere
Authors: Kurth W. S. , Barbosa D. D. , Gurnett D. A. , Scarf F. L.
Published: February 2008

Observations by the plasma wave receivers on Voyagers 1 and 2 show that a wide variety of electrostatic waves are present within the Jovian magnetosphere and that the Jovian electrostatic waves are for the most part very similar to those observed in the terrestrial magnetosphere. Bands of emission near the upper hybrid resonance frequency in the dayside outer magnetosphere are detected between higher harmonics of the electron gyrofrequency. Inside of about 23 RJ, electron cyclotron harmonic emissions appear to be durable features of the inner Jovian magnetosphere and are extremely well confined to the Jovian magnetic equator. The cyclotron emissions extend from just above the local electron gyrofrequency to the upper hybrid resonance frequency.
Dobson spectrophotometer systematic total ozone measurement error
Authors: Komhyr W. D.
Published: February 2008

Ozone measurements made with different kinds of instruments in clean air during the past few years indicate that total ozone amounts measured with Dobson spectrophotometers on AD wavelengths may be too high by about 5%. An examination of the consistency of ozone data determined from A, B, C, and D wavelength ozone absorption coefficients adopted for use at the beginning of the International Geophysical Year (1957‐1959) suggests that the problem stems from either a significant error in the determination of the effective ozone absorption coefficient at the short (305.5 nm) wavelength of the A wavelength pair, the value of the effective wavelength itself, or from the presence in the atmosphere of an anomalous absorber other than ozone. Since Dobson spectrophotometers serve as reference standard instruments for measurements of total ozone, it is imperative that the source of the systematic error be identified, and its magnitude assessed.
Preliminary estimates of the resolution capability of the Seasat radar altimeter
Authors: Brammer R. F. , Sailor R. V.
Published: February 2008

This paper reports preliminary results on the capability of the SEASAT radar altimeter to resolve short wavelength geoid features. Spectral coherence calculated for pairs of repeat tracks provides an estimate of the shortest repeatable (geoid) wavelength that can be resolved in the data. Coherence is high for wavelengths longer than 70 km but is insignificant for wavelengths shorter than about 30 km. For SEASAT, oceanographic effects may be more significant than the instrument noise in limiting geoidal resolution. A parametric error model for SEASAT data based on repeat track analysis is also presented. This model will be useful for filtering or smoothing SEASAT data.
Pioneer Venus observations of the Venus dayglow spectrum 1250‐1430 A
Authors: Durrance Samuel T. , Barth Charles A. , Stewart A. Ian F.
Published: February 2008

The spectrum of the dayglow of Venus between 1250 and 1430 A has been measured by the Pioneer Venus Orbiter Ultraviolet Spectrometer. Four bands of the (14,v″) progression in the fourth positive system of carbon monoxide are identified and their excitation mechanism is shown to be fluorescent scattering of the solar Lyman alpha line. The (14,3) and (14,4) bands at 1317 and 1354 A are blended with the atomic oxygen 1304 and 1356 A lines. The (14,5) band at 1392 A is a prominent unblended spectral feature in the Venus dayglow. This identification provides an additional remote sensing technique to determine the density distribution of carbon monoxide in the upper atmosphere of Venus.
The vertical distribution of tropospheric ammonia
Authors: Levine Joel S. , Augustsson Tommy R. , Hoell James M.
Published: February 2008

A one‐dimensional tropospheric photochemical model is used to simulate measured profiles of NH3 obtained with the Infrared Heterodyne Radiometer. The relative roles of homogeneous loss, heterogeneous loss, and vertical eddy transport are discussed in terms of selecting parameters which best fit the measurements. The best fit was obtained for a vertical eddy diffusion coefficient of 2 × 105 cm−2 sec−1 or greater (corresponding to a characteristic vertical transport time in excess of about 35 days), and a characteristic heterogeneous loss time in excess of 10 days. The characteristic homogeneous chemical loss time was found to be about 40 days at the surface and decreased to about l80 days at 10 km, and not very sensitive to model chemical perturbations. Increased ground level concentrations of NH3 to about 10 ppb, compared to background surface concentrations of about 1 ppb, were measured several weeks after application of ammonium nitrate fertilizer. This suggests that the volatilization of ammonium nitrate fertilizer is rapid, and an important source of NH3. Because of the characteristic times for the loss mechanisms, synoptic time scale phenomena may play an important role in determining the tropospheric distribution of NH3 concentrations.
Nitric acid and aerosol nitrate measurements in the equatorial Pacific Region
Authors: Huebert B. J.
Published: February 2008

Surface nitric acid and particulate nitrate measurements were made in the equatorial Pacific region using impregnated filter techniques. The average HNO3 mixing ratio of 38 pptv is nearly ten times the average noonday NO mixing ratio measured simultaneously by McFarland, et al. The highest HNO3 values, 61 and 68 pptv, were measured when rain‐showers were taking place in the vicinity of the sampler. Particulate NO3− concentrations ranged from 68 to 254 pptm.
Incoherent scatter observations of mesospheric dynamics at Arecibo
Authors: Ganguly Suman
Published: February 2008

Incoherent scatter spectral observations at Arecibo have been extended down to 59 km. For the first time vertical velocities in the mesosphere have been observed using this technique. The velocities unambiguously reveal a wavelike structure growing with height and varying in time. Above around 75 km, the vertical wavelength is around 16 km and the time period about 4 hours ± 20 minutes. Vertical velocities near 90 km were as large as 1 ms−1 and the apparent vertical energy flux was reasonably constant above 75 km. Below 75 km the energy flux was substantially lower, suggesting a mechanism where the gravity waves acquire significant energy from the diurnal tidal component trapped below the mesopause.

The estimated adiabatic density and temperature changes near 90 km, estimated using simple idealized theories, were around 11%. The observed changes in spectral width were also found to be in harmony with estimated density and temperature changes to within 25%.
Aftershock sequence of the January 1st, 1980, earthquake and present‐day tectonics in the Azores
Authors: Hirn A. , Haessler H. , Trong P. Hoang , Wittlinger G. , Victor L. A. Mendes
Published: February 2008

The composite focal solution of a 7‐days aftershock sequence to the M 7.2 Azorean earthquake shows a quadrantal repartition of first motions similar to those of all former major earthquakes on this western part of the Azores‐Gibraltar line. However for the first time is the choice of the fault‐plane constrained, the spatial repartition of aftershocks indicating the slip direction to be N 150°E, with sinistral shear. Interpretations of all former shocks had chosen the conjugate nodal plane as fault‐plane, dextral shear along this direction seeming coherent with the difference in average spreading rates North and South of the Azores and approximate direction of the Europe‐Africa plate boundary. The direction of rupture documented here coincides with the volcano‐tectonic directions dated as recent by Féraud et al. (1980). This supports a model in which the island volcanism would be tectonically controlled by the direction of rupture of earthquakes.
Nonlinear evolution of diffuse auroral F region ionospheric irregularities
Authors: Keskinen M. J. , Ossakow S. L. , McDonald B. E.
Published: February 2008

Numerical simulations of the nonlinear evolution of the current convective instability in the diffuse aurora have been performed for conditions typical of the nighttime high latitude F region. Our results show nearly field aligned plasma irregularities developing in regions of well‐defined northward gradients of total electron content (TEC) and field‐aligned diffuse auroral particle precipitation. In addition, we find equatorward movement of plasma enhancements and northward (poleward) movement of plasma depletions (holes). Furthermore, one‐dimensional spatial power spectra of the irregularities in both the north‐south and east‐west directions are well described by inverse power laws.
Dynamic recrystallization of olivine single crystals during high‐temperature creep
Authors: Karato Shun‐ichiro , Toriumi Mitsuhiro , Fujii Toshitsugu
Published: February 2008

High‐temperature creep experiments were made on olivine single crystals under compressional stress to large strains. At strains larger than about 40 to 60%, dynamic recrystllization occurs and cellular wall dislocation structure is formed. Recrystallized grain size dg(µm) and cell wall spacing ds(µm) are dependent upon applied stress σ(MPa) as: and
Thermal iron ions in high speed solar wind streams: Detection by the IMP 7/8 energetic particle experiments
Authors: Mitchell D. G. , Roelof E. C.
Published: February 2008

The first measurements of the abundance of iron ions in high speed (> 600 km s−1) solar wind streams have been made with the NOAA/JHU Energetic Particles Experiments (EPE) on IMP 7/8. The identification of iron ions is quantitatively established using 4 years of observations and heavy ion accelerator calibrations of detectors similar to those flown on the spacecraft. Preliminary estimates of the Fe/H ratio are within a factor of 2 of the adopted coronal abundance (5 × 10−5), and there is some evidence that Fe/H may remain approximately constant within a given stream. In the peaks of fast streams (700 < V < 800 km s−1), about 50 iron ion counts are obtained every 20 s, offering the possibility of studying the Fe/H ratio with ∼ 1 m time resolution in high speed streams throughout the decline of Solar Cycle 20 and the rise of Solar Cycle 21.
Pressure induced metallization of SrO and BaO: Theoretical estimate of transition pressures
Authors: Bukowinski M. S. T. , Hauser J.
Published: February 2008

Measured X‐ray charge densities of the alkali‐earth oxides, and theoretical calculations of the electronic structure of MgO and CaO, suggest that the metal's valence states play a very significant role in simple oxide's response to pressure. Of particular interest is the effect of compression on d‐orbitals or bands, which are responsible for observed metallizations in a number of rare earth chalcogenides, and are predicted to lead to metallization of CaO. The rare earth chalcogenides data suggest that, for a series of compounds in which the anion or cation does not change, metallization pressures are positively correlated with the ratio of anion to cation atomic numbers. New calculations of the electronic structure of SrO and BaO produce results that are in agreement with that trend and further confirm the dominant role of d‐bands. It is predicted that SrO should become metallic at approximately 3 Mb while the corresponding pressure for BaO is 800‐1200 kb, thus allowing for an experimental test with diamond cell techniques.
Formic and acetic acids in the atmosphere of the southwest U.S.A.
Authors: Dawson G. A. , Farmer J. Carl , Moyers Jarvis L.
Published: February 2008

Gaseous formate and acetate have been detected at ground level both within and near Tucson, Arizona, and at relatively remote sites. Concentrations downwind of the city were several parts per billion. At the more remote sites, concentrations were usually less than 1 ppb. In view of the reactivity of these compounds, their contribution to tropospheric photochemistry, specifically OH loss and O3 production, could be significant.