bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploring Solar Wind Origins and Connecting Plasma Flows from the Parker Solar Probe to 1 au: Nonspherical Source Surface and Alfvénic Fluctuations
Authors: Panasenco Olga , Velli Marco , D’Amicis Raffaella , Shi Chen , Réville Victor , Bale Stuart D. , Badman Samuel T. , Kasper Justin , Korreck Kelly , Bonnell J. W. , Wit Thierry Dudok de , Goetz Keith , Harvey Peter R. , MacDowall Robert J. , Malaspina David M. , Pulupa Marc , Case Anthony W. , Larson Davin , Livi Roberto , Stevens Michael , Whittlesey Phyllis 
Published: February 2020

Abstract
The magnetic field measurements of the FIELDS instrument on the Parker Solar Probe (PSP) have shown intensities, throughout its first solar encounter, that require a very low source surface (SS) height (

) to be reconciled with magnetic field measurements at the Sun via potential field extrapolation (PFSS). However, during PSP’s second encounter, the situation went back to a more classic SS height (

). Here we use high-resolution observations of the photospheric magnetic field (Solar Dynamics Observatory/Helioseismic and Magnetic Imager) to calculate neutral lines and boundaries of the open field regions for SS heights from 1.2 to 2.5 R
⊙ using an evolving PFSS model and the measured solar wind speed to trace the source of the wind observed by PSP to the low corona and photosphere. We adjust R
SS to get the best match for the field polarity over the period 2018 October–November and 2019 March–April, finding that the best fit for the observed magnetic field polarity inversions requires a nonspherical SS. The geometry of the coronal hole boundaries for different R
SS is tested using the PSP perihelion passes, 3D PFSS models, and LASCO/C2 observations. We investigate the sources of stronger-than-average magnetic fields and times of Alfvénic fast and slow wind. Only some of the strongly Alfvénic slow wind streams seen by PSP survive and are observed at 1 au: the origins and peculiar topology of the background in which they propagate is discussed.
Anticorrelation between the Bulk Speed and the Electron Temperature in the Pristine Solar Wind: First Results from the Parker Solar Probe and Comparison with Helios
Authors: Maksimovic M. , Bale S. D. , Berčič L. , Bonnell J. W. , Case A. W. , Wit T. Dudok de , Goetz K. , Halekas J. S. , Harvey P. R. , Issautier K. , Kasper J. C. , Korreck K. E. , Jagarlamudi V. Krishna , Lahmiti N. , Larson D. E. , Lecacheux A. , Livi R. , MacDowall R. J. , Malaspina D. M. , Martinović M. M. , Meyer-Vernet N. , Moncuquet M. , Pulupa M. , Salem C. , Stevens M. L. , Štverák Š. , Velli M. , Whittlesey P. L. 
Published: February 2020

Abstract
We discuss the solar wind electron temperatures T

e
as measured in the nascent solar wind by Parker Solar Probe during its first perihelion pass. The measurements have been obtained by fitting the high-frequency part of quasi-thermal noise spectra recorded by the Radio Frequency Spectrometer. In addition we compare these measurements with those obtained by the electrostatic analyzer discussed in Halekas et al. These first electron observations show an anticorrelation between T

e
and the wind bulk speed V: this anticorrelation is most likely the remnant of the well-known mapping observed at 1 au and beyond between the fast wind and its coronal hole sources, where electrons are observed to be cooler than in the quiet corona. We also revisit Helios electron temperature measurements and show, for the first time, that an in situ (

) anticorrelation is well observed at 0.3 au but disappears as the wind expands, evolves, and mixes with different electron temperature gradients for different wind speeds.
Detailed Imaging of Coronal Rays with the Parker Solar Probe
Authors: Poirier Nicolas , Kouloumvakos Athanasios , Rouillard Alexis P. , Pinto Rui F. , Vourlidas Angelos , Stenborg Guillermo , Valette Emeline , Howard Russell A. , Hess Phillip , Thernisien Arnaud , Rich Nathan , Griton Lea , Indurain Mikel , Raouafi Nour-Edine , Lavarra Michael , Réville Victor 
Published: February 2020

Abstract
The Wide-field Imager for Solar PRobe (WISPR) obtained the first high-resolution images of coronal rays at heights below 15 R
⊙ when the Parker Solar Probe (PSP) was located inside 0.25 au during the first encounter. We exploit these remarkable images to reveal the structure of coronal rays at scales that are not easily discernible in images taken from near 1 au. To analyze and interpret WISPR observations, which evolve rapidly both radially and longitudinally, we construct a latitude versus time map using the full WISPR data set from the first encounter. From the exploitation of this map and also from sequential WISPR images. we show the presence of multiple substructures inside streamers and pseudostreamers. WISPR unveils the fine-scale structure of the densest part of streamer rays that we identify as the solar origin of the heliospheric plasma sheet typically measured in situ in the solar wind. We exploit 3D magnetohydrodynamic models, and we construct synthetic white-light images to study the origin of the coronal structures observed by WISPR. Overall, including the effect of the spacecraft relative motion toward the individual coronal structures, we can interpret several observed features by WISPR. Moreover, we relate some coronal rays to folds in the heliospheric current sheet that are unresolved from 1 au. Other rays appear to form as a result of the inherently inhomogeneous distribution of open magnetic flux tubes.
CME-associated Energetic Ions at 0.23 au: Consideration of the Auroral Pressure Cooker Mechanism Operating in the Low Corona as a Possible Energization Process
Authors: Mitchell D. G. , Giacalone J. , Allen R. C. , Hill M. E. , McNutt R. L. , McComas D. J. , Szalay J. R. , Schwadron N. A. , Rouillard A. P. , Bale S. B. , Chaston C. C. , Pulupa M. P. , Whittlesey P. L. , Kasper J. C. , MacDowall R. J. , Christian E. R. , Wiedenbeck M. E. , Matthaeus W. H. 
Published: February 2020

Abstract
We draw a comparison between a solar energetic particle event associated with the release of a slow coronal mass ejection close to the Sun, and the energetic particle population produced in high current density field-aligned current structures associated with auroral phenomena in planetary magnetospheres. We suggest that this process is common in CME development and lift off in the corona, and may account for the electron populations that generate Type III radio bursts, as well as for the prompt energetic ion and electron populations typically observed in interplanetary space.
Properties of Suprathermal-through-energetic He Ions Associated with Stream Interaction Regions Observed over the Parker Solar Probe’s First Two Orbits
Authors: Desai M. I. , Mitchell D. G. , Szalay J. R. , Roelof E. C. , Giacalone J. , Hill M. E. , McComas D. J. , Christian E. R. , Schwadron N. A. , McNutt Jr. R. L. , Wiedenbeck M. E. , Joyce C. , Cohen C. M. S. , Ebert R. W. , Dayeh M. A. , Allen R. C. , Davis A. J. , Krimigis S. M. , Leske R. A. , Matthaeus W. H. , Malandraki O. , Mewaldt R. A. , Labrador A. , Stone E. C. , Bale S. D. , Pulupa M. , MacDowall R. J. , Kasper J. C. 
Published: February 2020

Abstract
The Integrated Science Investigation of the Sun (IS⊙IS) suite on board NASA’s Parker Solar Probe (PSP) observed six distinct enhancements in the intensities of suprathermal-through-energetic (∼0.03–3 MeV nucleon−1) He ions associated with corotating or stream interaction regions (CIR or SIR) during its first two orbits. Our results from a survey of the time histories of the He intensities, spectral slopes, and anisotropies and the event-averaged energy spectra during these events show the following: (1) In the two strongest enhancements, seen at 0.35 and 0.85 au, the higher-energy ions arrive and maximize later than those at lower energies. In the event seen at 0.35 au, the He ions arrive when PSP was away from the SIR trailing edge and entered the rarefaction region in the high-speed stream. (2) The He intensities either are isotropic or show sunward anisotropies in the spacecraft frame. (3) In all events, the energy spectra between ∼0.2 and 1 MeV nucleon−1 are power laws of the form ∝E
−2. In the two strongest events, the energy spectra are well represented by flat power laws between ∼0.03 and 0.4 MeV nucleon−1 modulated by exponential rollovers between ∼0.4 and 3 MeV nucleon−1. We conclude that the SIR-associated He ions originate from sources or shocks beyond PSP’s location rather than from acceleration processes occurring at nearby portions of local compression regions. Our results also suggest that rarefaction regions that typically follow the SIRs facilitate easier particle transport throughout the inner heliosphere such that low-energy ions do not undergo significant energy loss due to adiabatic deceleration, contrary to predictions of existing models.
Parker Solar Probe Observations of a Dust Trail in the Orbit of (3200) Phaethon
Authors: Battams Karl , Knight Matthew M. , Kelley Michael S. P. , Gallagher Brendan M. , Howard Russell A. , Stenborg Guillermo 
Published: February 2020

Abstract
We present the identification and preliminary analysis of a dust trail following the orbit of (3200) Phaethon as seen in white-light images recorded by the Wide-field Imager for Parker Solar Probe (WISPR) instrument on the NASA Parker Solar Probe (PSP) mission. During PSP's first solar encounter in 2018 November, a dust trail following Phaethon’s orbit was visible for several days and crossing two fields of view. Preliminary analyses indicate this trail to have a visual magnitude of 15.8 ± 0.3 per pixel and a surface brightness of 25.0 mag arcsec−2 as seen by PSP/WISPR from a distance of ∼0.2 au from the trail. We estimate the total mass of the stream to be ∼(0.4–1.3) × 1012 kg, which is consistent with, though slightly underestimates, the assumed mass of the Geminid stream, but is far larger than the current dust production that Phaethon could support. Our results imply that we are observing a natural clustering of at least some portion of the Geminid meteor stream through its perihelion, as opposed to dust produced more recently from perihelion activity of Phaethon.
An Overview of the Abundance, Relative Mobility, Bioavailability, and Human Toxicity of Metals
Authors: Smith Kathleen S. , Huyck Holly L.O. 
Published: February 2020

Abstract
A major reason for considering the environmental geochemistry of mineral deposits is the environmental impact from such deposits on human, animal, and plant life. Some human activities may perturb or alter natural cycles of metals in the environment leading to accumulation of many potentially toxic metals in the food chain. To adequately assess the impact of human activities on metals in the environment, one must approach the issue from both a geological/geochemical/physical viewpoint and a biological/ biochemical/toxicological perspective.
This chapter provides a geochemical and a biological context for chapters in this volume that discuss specifics of environmental geochemistry of mineral deposits. We alternate between the geological/geochemical/physical and biological/biochemical/toxico- logical aspects of selected metals. Because the emphasis of this volume is the environmental geochemistry of mineral deposits, we present examples that relate to metals or mineral deposits rather than provide a review of the literature. We also place emphasis on geological, geochemical, and chemical factors that affect metal bioavailability and toxicity to highlight connections between the earth and biological sciences. Radioactive materials are beyond the scope of this chapter.
The Environmental Geology of Mineral Deposits
Authors: Plumlee G.S. 
Published: February 2020

Abstract
Mineral deposits are concentrations of metallic or other mineral commodities in the Earth's crust that result from a variety of complex geologic processes. The natural weathering and erosion of a mineral deposit at the Earth's surface disperses its constituents into the waters, soils, and sediments of its surrounding environment. There, the constituents may be taken up by plants and (or) organisms. The concentrations and chemical, mineralogical, or biological forms of metals and other constituents from a mineral deposit prior to mining in soils, waters, sediments, plants, and organisms are defined here to be the natural environmental signatures of the deposit.
Modern mining and mineral processing activities employ a wide variety of methods to prevent or minimize adverse environmental impacts (Ripley et al., 1996; Plumlee and Logsdon, 1999; references therein). However, if not carried out with appropriate mitigation and prevention practices (as was common in most historical operations), or as a result of accidental releases, mining and mineral processing can disperse potentially deleterious metals, other deposit constituents, and mineral processing chemicals or byproducts into the environment. Mining-related environmental signatures are defined here as the concentrations and chemical, mineralogical, or biological forms of these metals and chemicals prior to mitigation or remediation in mining and milling wastes, mine waters, mineral processing solutions and byproducts, and smelter emissions and byproducts.
Some Fundamentals of Aqueous Geochemistry
Authors: Nordstrom D. Kirk 
Published: February 2020

Abstract
Aqueous geochemistry is the application of chemistry to reactions between rock and natural water. Analytical chemistry, inorganic and organic chemistry, and physical chemistry are used to understand and interpret the dominant processes that effect a redistribution of the elements in man's environment. Examples of these processes are the dissolution and precipitation of minerals, adsorption and desorption of ions, oxidation-reduction or redox reactions, gas uptake or production, transformations involving organic matter, complexation and chelation, evaporation, ion exchange, and anthropogenic changes. In the field of aqueous geochemistry these processes are known to occur in a variety of environments including rain, fog, snow, soils, bedrock weathering, streams, rivers, lakes, estuaries, ground waters, subsurface brines, diagenetic environments, the formation and weathering of mineral deposits, and the global movement of elements and compounds. Aqueous geochemistry is synonymous with low-temperature geochemistry, where the approximate temperature and pressure limits of 0-100°C and 1-500 bars commonly apply. The term environmental geochemistry is often used to emphasize the environmental aspects of geochemistry. Another common term, hydrogeochemistry, is usually applied to the aqueous geochemistry of ground waters. These four terms all refer to the same basic subject matter.
In physics and chemistry, great advances are made through theoretical research, experimental research, or optimally through a blend of both. In aqueous geochemistry, a third aspect plays an essential role: field observations. By applying the best that theoretical chemistry and physics can offer to the interpretation of field observations aided by reliable experimental and analytical determinations, the aqueous geochemist is at the crossroads of theory, experiment and the natural environment. Geological phenomena are of a much greater complexity than the carefully controlled systems investigated in physics and chemistry, so that the geochemist has had to expand his knowledge creatively beyond the traditional boundaries of the physical sciences. The challenge of this type of scientific research is not generally appreciated (Alvarez, 1990). There are far more unknown and uncontrolled variables in natural systems than in the typical physicochemical investigation carried out in the laboratory. The hydrological, microbiological, macrobi- ological, and meteorological sciences are all necessary in addition to geology and chemistry.
Geochemical Processes Controlling Uranium Mobility in Mine Drainages
Authors: Wanty R.B. , Miller W.R. , Briggs P.H. , McHugh J.B. 
Published: February 2020

Abstract
Comprehensive models of ore genesis incorporate metal sources, transport and concentration mechanisms, and preservation mechanisms. Analogous concepts apply to the problem of metal migration from mines, mine wastes, and mine tailings, including: the concentrations, mineralogical occurrence, and availability of metals in mineral deposits, host rocks, mine wastes, and tailings (the source); the mechanisms for metal mobilization and transport during weathering; the mechanisms for metal fixation and the permanence of the fixation. Similarly, undisturbed mineral deposits or alteration zones that are exposed at the Earth's surface may be natural sources from which metals can be solubilized during weathering.
Uranium (U), a naturally-occurring radioactive element, may be present in mineral deposits in sufficient concentrations that in itself constitutes ore. It may also be present in ores of other metals at concentrations that exceed average crustal abundances. Any uranium that is not completely removed from these ores in the mining and milling process may be available for mobilization into ground or surface waters via the weathering and oxidation of solid tailings or mine waste piles. This chapter discusses the relative importance of various geochemical processes that control uranium mobility via weathering in both mined and unmined mineralized environments. The data presented in this paper focus on mined areas because the great extent of historic mining in the field areas examined for this study preclude extensive consideration of undisturbed areas.
Geochemistry of the Processes that Attenuate Acid Mine Drainage in Wetlands
Authors: Walton-Day Katherine 
Published: February 2020

Abstract
Because conventional treatment of acid-mine drainage (AMD) involves installation and maintenance of water treatment plants, regulators and mine operators have sought lower cost and lower maintenance technologies. One ecological engineering technology that has received increasing research attention is the use of natural and constructed wetlands for remediation of some of the water-quality problems associated with AMD. As surface water flows through a wetland, several processes can occur to decrease the elevated concentrations of sulfate, trace metals, arsenic, and hydrogen ions that characterize AMD. These processes range from precipitation of mineral phases to the active uptake of solutes by vegetation. The relative importance of these processes between different wetlands depends on the hydrologic and geochemical characteristics of the wetlands.
This paper describes the geochemistry of the processes that contribute to AMD attenuation in wetlands and presents some of the case studies that have identified these processes. The attenuation of AMD in wetlands has been studied in natural and in man- made (constructed) wetlands. In this paper, case studies of both are presented. A discussion of some of the general characteristics of wetlands is followed by more detailed discussions of the processes and geochemistry that contribute to the treatment of AMD in wetlands, relevant case studies, and a brief discussion of constructed wetland design. The physical, chemical, and hydrologic characteristics of a wetland that affect its potential for supporting specific types of reactions are also emphasized.
The Environmental Geochemistry of Cyanide
Authors: Smith A.C.S. , Mudder T.I. 
Published: February 2020

Abstract
“His ways precedeth his coming. We speaketh his name in fear and trembling (Anon, circa 451 AD).” Obscure perhaps, but these words of the Roman centurion about his foe Attila the Hun, immediately prior to the defeat of Attila at the Battle of Chalons-sur- Marne in 451 AD, reflect a similar perception within the community of the nature of cyanide. The status of cyanide as a social and environmental pariah is not founded in the technical literature but is emotionally driven, consequent perhaps from the historic use of cyanide by the agencies of law enforcement in the United States and in other jurisdictions to carry out capital punishment.
However, a technically based evaluation of the nature and behavior of cyanide in the environment leads to a more sympathetic view of the potential impact of this widely used industrial and mining chemical. In this chapter, we review the environmental geochemistry of cyanide in mining applications. We will first consider the extraction process chemistry for precious metal ores, a chemical process in which cyanide is a vital ingredient. We will then describe fundamental aspects of cyanide chemistry, and translate this chemistry to geochemical reactions and processes. The application of these processes and reactions forms the root of how cyanide migration and attenuation in the natural environment can be evaluated.
Effects of Heavy Metals on the Aquatic Biota
Authors: Kelly M.G. 
Published: February 2020

Abstract
This review focuses on the effects of heavy metals on the aquatic (primarily freshwater) biota. During the 1970s and 1980s there was intense research interest in the biological effects of heavy metals. While this has provided a firm foundation for the interpretation of toxic effects associated with metalliferous mining in particular, many other aspects of mining, with potentially adverse effects on the biota, have received less attention. In particular, physical factors, such as those associated with high suspended solid loads, for example, are studied comparatively rarely, although for many deposits of insoluble metals (e.g., gold, tin) such factors may be more significant than toxicity (LaPerriere et al., 1985; Van Nieuwenhuyse and LaPerriere, 1986; Briones, 1987). Moreover, discovery of a valuable mineral may lead to large increases in population. The town of Jos in Nigeria, for example, owes its existence to the tin mines in the region and the main water quality problem in the Delimi river downstream of the town is due to sewage pollution rather than to mining (Kelly and Ali, 1993). Further environmental impacts can include clearing land for agriculture to feed the growing population (Livett et al., 1979). It would be wrong to consider the potential impact of a new development without considering these aspects as well.
Geologic Controls on the Composition of Natural Waters and Mine Waters Draining Diverse Mineral-Deposit Types
Authors: Plumlee G.S. , Smith K.S. , Montour M.R. , Ficklin W.H. , Mosier E.L. 
Published: February 2020

Abstract
Sulfide-bearing mineral deposits formed in reduced conditions out of contact with an oxygenated atmosphere. When sulfides in the deposits are exposed by natural erosion or by mining to atmospheric oxygen and water, weathering of the sulfides can produce natural or mining-related acid-rock drainage. The prediction of water quality that results from mining and mineral processing activities has therefore become a high priority in the permitting of mining activities worldwide, in order to prevent the formation of or mitigate the environmental effects of deleterious drainage waters. In addition, estimating the compositions of natural waters that drained mineral deposits prior to mining is crucial to establish appropriate baseline environmental standards at mine sites.
There are a variety of techniques currently in use to predict the acidity or metal content of mine-drainage waters, most common of which are static and kinetic testing procedures. In static procedures such as acid-base accounting (White et al., 1997, 1999), the contents of acid-generating sulfide minerals from ores and wastes from a proposed mine are measured and balanced against the measured contents of acid-consuming minerals such as carbonates; based on this balance, the materials are determined to be acid generating or non-acid-generating. In kinetic tests such as column or humidity-cell tests (ASTM, 1996), samples of ores and wastes are allowed to react over a period of time under laboratory conditions with oxidized waters or moist air, and the pH and metal contents of the resulting leachates are then measured.