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Plasmasphere And Upper Ionosphere Contributions And Corrections During The Assimilation Of Gps Slant Tec, D. C. Thompson, L. Scherliess, Jan Josef Sojka, Robert W. Schunk

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Total electron content (TEC) measurements from ground stations to Global Positioning System (GPS) satellites provide a rich source of information about the Earth's ionosphere. These data comprise a significant part of the typical data set used by various data ingestion and assimilation models of the ionosphere. For example, the Utah State University (USU) Global Assimilation of Ionospheric Measurements (GAIM) data assimilation model uses slant TEC, along with various other types of data, to obtain a global reconstruction of the ionosphere. There are presently two different USU GAIM models: the Gauss‐Markov Kalman Filter (GAIM‐GM), which is operational at the NASA Community …

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A Frequency Agile, Distributed Sensor System To Address Space Weather Effects Upon Ionospherically Dependent Systems, D. D. Rice, J. V. Eccles, Jan Josef Sojka, J. W. Raitt, J. Brady, R. D. Hunsucker

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The outstanding problem faced by operational systems that utilize the ionosphere is that ionospheric weather variability is comparable to the ionospheric climate variability. However, the number of simultaneous measurements is orders of magnitude too few to resolve the weather scales that are impacting systems. We describe a prototype distributed array of affordable passive radio beacon monitors combined with a central data repository and a data-model analysis system called the Frequency-Agile Distributed Sensor System (FADSS). By monitoring signals from terrestrial VLF/HF radio beacons the FADSS tracks changes in the D, E, or F regions and makes appropriate modifications to the ionospheric …

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Observations Of Ionospheric Heating During The Passage Of Solar Coronal Hole Fast Streams, Jan Josef Sojka, R. L. Mcpherron, A. P. Van Eyken, M. J. Nicolis, C. J. Heinselman, J. D. Kelley

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Using ionospheric temperature measurements made continuously by the Poker Flat Incoherent Scatter Radar (PFISR) and EISCAT Svalbard Radar (ESR) during the International Polar Year (IPY), we provide evidence for directly driven ionospheric heating associated with the solar wind corotating interaction region (CIR). Both ESR and PFISR operated almost continuously during the IPY, which began on 1 March 2007. During this period 55 CIR events occurred and when ISR observations were available during these events ionospheric heating was observed. This study is the first comprehensive observation of ionospheric heating by CIRs demonstrated through case study comparisons and statistically over the 1-year …

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Detecting A Stochastic Gravitational-Wave Background: The Overlap Reduction Function, Lee Samuel Finn, Shane L. Larson, Joseph D. Romano

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Detection of a gravitational-wave stochastic background via ground or space-based gravitational-wave detectors requires the cross correlation of the response of two or more independent detectors. The cross correlation involves a frequency-dependent factor—the so-called overlap reduction function or Hellings-Downs curve—that depends on the relative geometry of each detector pair, i.e., the detector separations and the relative orientation of their antenna patterns (beams). An incorrect formulation of this geometrical factor has appeared in the literature, leading to incorrect conclusions regarding the sensitivity of proposed detectors to a stochastic gravitational-wave background. To rectify these errors and as a reference for future work we …

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Bubble Behavior In Nucleate Boiling Experiment Aboard The Space Shuttle, Justin P. Koeln, Jeffrey C. Boulware, Heng Ban

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Boiling dynamics in microgravity need to be better understood before heat transfer systems based on boiling mechanism can be developed for space applications. This paper presents the results of a nucleate boiling experiment aboard Space Shuttle Endeavor (STS- 108). The experiment utilized nickel-chromium resistance wire to boil water in microgravity, and the data was recorded with a CCD camera and six thermistors. This data was analyzed to determine the behavior of bubble formation, detachment from the heating wire, and travel in the water with effects of drag on bubble movement. Bubbles were observed to be ejected from the wire, travel …

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Core-Level Shifts At The Pt/W(110) Monolayer Bimetallic Interface, D. Mark Riffe, N. D. Shinn, B. Kim, K. J. Kim, T. H. Kang

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We have measured W and Pt 4f7/2 core-level photoemission spectra from interfaces formed by ultrathin Pt layers on W(110), completing our core-level measurements of W(110)-based bimetallic interfaces involving the group-10 metals Ni, Pd, and Pt. With increasing Pt coverage the sequence of W spectra can be described using three interfacial core-level peaks with binding-energy (BE) shifts (compared to the bulk) of −0.220 ± 0.015, −0.060 ± 0.015, and +0.110 ± 0.010 eV. We assign these features to 1D, 2D pseudomorphic (ps), and 2D closed-packed (cp) Pt phases, respectively. For ~1 ps ML the Pt 4f7/2 BE is 71.40 ± 0.02 …

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Critical Level Interaction Of A Gravity Wave With Background Winds Driven By A Large-Scale Wave Perturbation, M. K. Ejiri, Michael J. Taylor, T. Nakamura, S. J. Franke

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As part of the Maui-Mesosphere and Lower Thermosphere program, data from the Utah State University Mesospheric Temperature Mapper (MTM) and the University of Illinois Meteor Wind Radar (MWR) have been used to investigate wave-driven dynamical interactions in the upper mesosphere at low latitudes. On 29 June 2003, short-period (20 min) gravity waves (GWs) were imaged in the MTM in the near-infrared OH and O2 airglow emissions for most of the night from 0700 to 1500 UT. The GWs were observed to disappear rapidly in the O2 data (peak altitude: 94 km) around 1400 UT but remained evident in the lower …

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The Spread F Experiment (Spreadfex): Overview And Summary Of The Spread F Experiment (Spreadfex), D. C. Fritts, M. A. Abdu, B. R. Batista, I. S. Batista, P. P. Batista, R. Buriti, B. R. Clemesha, T. Dautermann, E. De Paula, B. J. Fechine, B. G. Fejer, D. Gobbi, J. Haase, F. Kamalabadi, B. Luughman, P. P. Lima, H. L. Liu, A. F. Medeiros, P. D. Pautet, D. M. Riggin, F. São Sabbas, J. H.A. Sobral, P. Stamus, H. Takahashi, Michael J. Taylor, S. L. Vadas, C. Wrasse

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The Spread F Experiment, or SpreadFEx, was performed from September to November 2005 to define the potential role of neutral atmosphere dynamics, primarily gravity waves propagating upward from the lower atmosphere, in seeding equatorial spread F (ESF) and plasma bubbles extending to higher altitudes. A description of the SpreadFEx campaign motivations, goals, instrumentation, and structure, and an overview of the results presented in this special issue, are provided by Fritts et al. (2008a). The various analyses of neutral atmosphere and ionosphere dynamics and structure described in this special issue provide enticing evidence of gravity waves arising from deep convection in …

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Overview And Summary Of The Spread F Experiment (Spreadfex), D. C. Fritts, M. A. Abdu, B. R. Batista, I. S. Batista, P. P. Batista, R. Buritii, B. R. Clemesha, J. Comberiate, T. Dautermann, E. De Paula, B. J. Fechine, B. G. Fejer, D. Gobbi, J. Haase, F. Kalamabadi, B. Laughman, P. P. Lima, H. L. Liu, A. Medeiros, Pierre-Dominique Pautet, F. Sao Sabbas, J. H.A. Sobral, P. Stamus, H. Takahashi, Michael J. Taylor, S. L. Vadas, C. Wrasse

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We provide here an overview of, and a summary of results arising from, an extensive experimental campaign (the Spread F Experiment, or SpreadFEx) performed from September to November 2005, with primary measurements in Brazil. The motivation was to define the potential role of neutral atmosphere dynamics, specifically gravity wave motions propagating upward from the lower atmosphere, in seeding Rayleigh-Taylor instability (RTI) and plasma bubbles extending to higher altitudes. Campaign measurements focused on the Brazilian sector and included ground-based optical, radar, digisonde, and GPS measurements at a number of fixed and temporary sites. Related data on convection and plasma bubble structures …

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Characterization Of Electrical Materials Properties Related To Spacecraft Charging, John R. Dennison

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No abstract provided.

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Engineering Tool For Temperature, Electric Field And Dose Rate Dependence Of High Resistivity Spacecraft Materials, John R. Dennison, Alec Sim, Jerilyn Brunson, Steven Hart, Jodie Gillespie, Justin Dekany, Charles Sim, Dan Arnfield

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An engineering tool has been developed to predict the equilibrium conductivity of common spacecraft insulating materials as a function of electric field, temperature, and adsorbed dose rate based on parameterized, analytic functions derived from physics-based theories. The USU Resistivity Calculator Engineering Tool calculates the total conductivity as the sum of three independent conductivity mechanisms: a thermally activated hopping conductivity, a variable range hopping conductivity, and a radiation induced conductivity using a total of nine independent fitting parameters determined from fits to an extensive data set taken by the Utah State University Materials Physics Group. It also provides a fit for …

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Relevance Of Ground-Based Electron-Induced Electrostatic Discharge Measurements To Space Plasma Environments, Jennifer A. Roth, Ryan Hoffmann, John R. Dennison, Jonathon R. Tippetts

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Electron-induced electrostatic discharge (ESD) can lead to severe spacecraft anomalies. It is crucial to the success of space missions that the likelihood of ESD occurrence is understood and mitigated. To aid in predicting ESD occurrence, a model for electric fields above and below the charge layer inside an electronirradiated dielectric material was developed. An instrumentation system was also designed to induce and detect ESD events. Because ESD events with a wide range of maximum current values can occur over a range of time intervals, multiple simultaneous detection methods were employed as charge was accumulated on a sample surface; these included …

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Thin Wire Nucleate Boiling Of Water In Sustained Microgravity, Justin P. Koeln, Heng Ban, John R. Dennison

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The advancement of small satellite technology relies on the development of effective thermal management systems that can be made smaller, safer, and more robust. This paper presents the results and analysis of a nucleate boiling experiment in sustained microgravity aboard the Space Shuttle Endeavor (STS-108). Bubble growth and departure were observed from a single and a braid of three 0.16 mm diameter and 80 mm long nickel-chromium resistive wires. Analysis showed that the braided wire provides a unique surface configuration to enhance the onset of boiling. The braid of wires was also observed to produce several bubble explosions; this is …

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Full-Text Articles in Physics

Plasmasphere And Upper Ionosphere Contributions And Corrections During The Assimilation Of Gps Slant Tec, D. C. Thompson, L. Scherliess, Jan Josef Sojka, Robert W. Schunk

All Physics Faculty Publications

A Frequency Agile, Distributed Sensor System To Address Space Weather Effects Upon Ionospherically Dependent Systems, D. D. Rice, J. V. Eccles, Jan Josef Sojka, J. W. Raitt, J. Brady, R. D. Hunsucker

All Physics Faculty Publications

Observations Of Ionospheric Heating During The Passage Of Solar Coronal Hole Fast Streams, Jan Josef Sojka, R. L. Mcpherron, A. P. Van Eyken, M. J. Nicolis, C. J. Heinselman, J. D. Kelley

All Physics Faculty Publications

Detecting A Stochastic Gravitational-Wave Background: The Overlap Reduction Function, Lee Samuel Finn, Shane L. Larson, Joseph D. Romano

All Physics Faculty Publications

Bubble Behavior In Nucleate Boiling Experiment Aboard The Space Shuttle, Justin P. Koeln, Jeffrey C. Boulware, Heng Ban

All Physics Faculty Publications

Core-Level Shifts At The Pt/W(110) Monolayer Bimetallic Interface, D. Mark Riffe, N. D. Shinn, B. Kim, K. J. Kim, T. H. Kang

All Physics Faculty Publications

Critical Level Interaction Of A Gravity Wave With Background Winds Driven By A Large-Scale Wave Perturbation, M. K. Ejiri, Michael J. Taylor, T. Nakamura, S. J. Franke

All Physics Faculty Publications

All Physics Faculty Publications

All Physics Faculty Publications

Characterization Of Electrical Materials Properties Related To Spacecraft Charging, John R. Dennison

All Physics Faculty Publications

Engineering Tool For Temperature, Electric Field And Dose Rate Dependence Of High Resistivity Spacecraft Materials, John R. Dennison, Alec Sim, Jerilyn Brunson, Steven Hart, Jodie Gillespie, Justin Dekany, Charles Sim, Dan Arnfield

All Physics Faculty Publications

Relevance Of Ground-Based Electron-Induced Electrostatic Discharge Measurements To Space Plasma Environments, Jennifer A. Roth, Ryan Hoffmann, John R. Dennison, Jonathon R. Tippetts

All Physics Faculty Publications

Thin Wire Nucleate Boiling Of Water In Sustained Microgravity, Justin P. Koeln, Heng Ban, John R. Dennison

All Physics Faculty Publications