College of Sciences and Mathematics: Recent submissions
Now showing items 81-100 of 393
Magma-facilitated transpressional strain partitioning within the Sawtooth metamorphic complex, Idaho: A zone accommodating Cretaceous orogen-parallel translation in the Idaho batholith
(2022-10-29)
Structural data from metasedimentary rocks and geochronologic data from intrusive rocks in the Idaho batholith provide evidence for the relationship between deformation and magmatism in the northern U.S. Cordillera. The ...
The U.S. educational effort in unsaturated zone hydrology
(2022-10-29)
The region of the earth below the land surface and above the water-saturated zone plays a major role in determining the behavior of hydrologic systems. To help educators and other interested individuals evaluate and continue ...
Pickup proton instabilities and scattering in the distant solar wind and the outer heliosheath: Hybrid simulations
(2022-10-27)
The growth of magnetic field fluctuations driven by the injection of pickup ions perpendicular to a background magnetic field in a homogeneous, collisionless plasma is studied using one-dimensional hybrid simulations. ...
Kinetic Alfven waves in three-dimensional magnetic reconnection
(2022-10-27)
Alfvenic waves are believed to be fundamentally important in magnetic reconnection. Kinetic dynamics of particles can break the Alfven speed limit in the evolution and propagation of perturbations during reconnection. In ...
Hall effect control of magnetotail dawn-dusk asymmetry: A three-dimensional global hybrid simulation
(2022-10-27)
Magnetotail reconnection and related phenomena (e.g., flux ropes, dipolarizing flux bundles, flow bursts, and particle injections) occur more frequently on the duskside than on the dawnside. Because this asymmetry can ...
Comparison of CIMI Simulations and TWINS Observations on June 28 and 29, 2013
(2022-10-27)
A moderate geomagnetic storm (Sym/H similar to-100 nT) during June 28 and 29, 2013 was studied using Comprehensive Inner Magnetosphere-Ionosphere (CIMI) simulations and results were compared with Two wide-angle Imaging ...
Magnetosheath Reconnection Before Magnetopause Reconnection Driven by Interplanetary Tangential Discontinuity: A Three-Dimensional Global Hybrid Simulation With Oblique Interplanetary Magnetic Field
(2022-10-27)
Terrestrial dayside dynamics associated with a southward turning, oblique interplanetary magnetic field (IMF) carried by an interplanetary tangential discontinuity (TD) is investigated by performing a three-dimensional ...
Scalings for the Alfven-cyclotron instability: Linear dispersion theory and hybrid particle-in-cell simulations
(2022-10-27)
The Alfven-cyclotron instability is driven by an ion temperature anisotropy such that T-perpendicular to/T-|| >1 where and || denote directions perpendicular and parallel to a uniform background magnetic field B-o, ...
Statistically Determining the Spatial Extent of Relativistic Electron Precipitation Events Using 2-s Polar-Orbiting Satellite Data
(2022-10-27)
Relativistic electron precipitation (REP) from the outer radiation belt into Earth's atmosphere poses risks for satellites and affects Earth's climate, producing ozone-destroying compounds. Characterizing the spatial extent ...
Global observations of ring current dynamics during corotating interaction region-driven geomagnetic storms in 2008
(2022-10-27)
We examine the evolution of the ring current during the main and early recovery phases of three geomagnetic storms driven by corotating interaction regions. The equatorial energy density profiles of 5-30 keV ions are ...
TWINS Observations of the Dynamics of Ring Currents Ion Spectra on March 17 and October 7, 2015
(2022-10-27)
Direct comparisons between RBSP (Van Allen Probes or Radiation Belt Storm Probes) and TWINS (Two Wide-angle Imaging Neutral-atom Spectrometers) for the main phase of two storms, March 17 and October 7, 2015, showed agreement ...
Dynamics of ring current ions as obtained from IMAGE HENA and MENA ENA images
(2022-10-27)
Ion distributions from three storms in the year 2000 have been obtained from HENA and MENA ENA images at 27-39 keV and 5-12 keV, respectively. The observed motion of the ring current is compared with calculations of expected ...
Solitary potential structures associated with ion and electron beams near 1 R-E altitude
(2022-10-27)
Small-scale solitary electric potential structures are commonly observed on auroral field lines with the Polar Electric Field Instrument (EFI). This study focuses on observations of solitary structures in the southern ...
Impact Gardening as a Constraint on the Age, Source, and Evolution of Ice on Mercury and the Moon
(2022-10-26)
We update an analytic impact gardening model (Costello et al., 2018, https://doi.org/10.1016/j.icarus.2018.05.023) to calculate the depth gardened by impactors on the Moon and Mercury and assess the implications of our ...
Natural arsenic contamination of Holocene alluvial aquifers by linked tectonic, weathering, and microbial processes
(2022-10-26)
Linked tectonic, geochemical, and biologic processes lead to natural arsenic contamination of groundwater in Holocene alluvial aquifers, which are the main threat to human health around the world. These groundwaters are ...
Evolution of CIR storm on 22 July 2009
(2022-10-25)
Global images of ion intensities are deconvolved from TWINS ENA images during the main and recovery phase of a CIR storm on 22 July 2009. The global spatial ion images taken at different times, along with solar wind data, ...
Simulation of pressure pulses in the bow shock and magnetosheath driven by variations in interplanetary magnetic field direction
(2022-10-25)
Two-dimensional (2-D) hybrid simulations are carried out to study the effects of the variation in the interplanetary magnetic field (IMF) direction on the bow shock, magnetosheath, and magnetosphere. A curvilinear coordinate ...
An 40Ar/39Ar thermochronology of the Ofoten-Troms region: Implications for terrane amalgamation and extensional collapse of the northern Scandinavian Caledonides
(2022-10-25)
Fifteen Ar-40/Ar-39 cooling ages are reported for metamorphic hornblende and muscovite from far traveled terranes constituting the Ofoten nappe stack of northern Norway. Eight cooling ages on hornblende range from 425 to ...
Reactive transport of trace elements and isotopes in the Eutaw coastal plain aquifer, Alabama
(2022-10-25)
We integrate groundwater geochemistry, mineralogy, and numerical modeling techniques to study the reactive transport of heavy metals and isotopes in the Eutaw coastal plain aquifer, Alabama. Geochemical data show that the ...
EUV emissions from solar wind charge exchange in the Earth's magnetosheath: Three-dimensional global hybrid simulation
(2022-10-25)
In this paper, a three-dimensional (3-D) global hybrid simulation code and a 3-D geocoronal hydrogen model are used to systematically study the extreme ultraviolet (EUV) emissions at 30.4nm produced by solar wind charge ...