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Physical Processes Commons™

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2017

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Articles 1 - 12 of 12

Full-Text Articles in Physical Processes

Energy From Active Galactic Nuclei And The Effects On Host Spiral Galaxies, Amanda Schilling Dec 2017

Energy From Active Galactic Nuclei And The Effects On Host Spiral Galaxies, Amanda Schilling

Graduate Theses and Dissertations

I have investigated the energy output of active galactic nuclei (AGN) in order to understand how these objects evolve and the impact they may have on host galaxies. First, I looked at a sample of 96 AGN at redshifts $z \sim 2, 3,$ and $4$ which have imaging and thus luminosity measurements in the $griz$ and $JHK$ observed wavebands. For these galaxies, I have co-epochal data across those bands which accounted for variability in AGN luminosity. I used the luminosity measurements in the five bands to construct spectral energy distributions (SED) in the emitted optical-UV bands for each AGN. I …

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Ion-Scale Wave Properties And Enhanced Ion Heating Across The Low-Latitude Boundary Layer During Kelvin-Helmholtz Instability, T. W. Moore, K. Nykyri, A. P. Dimmock Nov 2017

Ion-Scale Wave Properties And Enhanced Ion Heating Across The Low-Latitude Boundary Layer During Kelvin-Helmholtz Instability, T. W. Moore, K. Nykyri, A. P. Dimmock

Publications

In the Earth's magnetosphere, the magnetotail plasma sheet ions are much hotter than in the shocked solar wind. On the dawn sector, the cold-component ions are more abundant and hotter by 30–40% when compared to the dusk sector. Recent statistical studies of the flank magnetopause and magnetosheath have shown that the level of temperature asymmetry of the magnetosheath is unable to account for this, so additional physical mechanisms must be at play, either at the magnetopause or plasma sheet that contributes to this asymmetry. In this study, we perform a statistical analysis on the ion-scale wave properties in the three …

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Physoon - Radiation Detection In Various High Altitude Environments, Christopher Helmerich Oct 2017

Physoon - Radiation Detection In Various High Altitude Environments, Christopher Helmerich

2017 Academic High Altitude Conference

Physoon is a high altitude ballooning payload designed and built by members of the Space Hardware Club for the purpose of comparing cosmic and terrestrial radiation from a variety of environmental conditions, including clear days, night times, solar events (eclipses, solar flares, coronal mass ejections), and thunderstorms. Over three design iterations, Physoon has flown eleven times with various combinations of Geiger counters sensors: a low energy Alpha-Beta-Gamma detector, an unshielded high-energy Beta-Gamma detector, and a shielded high-energy Beta-Gamma detector. One of these iterations successfully recovered data from high altitude during totality of the Great American Solar Eclipse. Another iteration was …

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On The Dawn-Dusk Asymmetry Of The Kelvin-Helmholtz Instability Between 2007 And 2013, Z. W. Henry, K. Nykyri, T. W. Moore, A. P. Dimmock, X. Ma Oct 2017

On The Dawn-Dusk Asymmetry Of The Kelvin-Helmholtz Instability Between 2007 And 2013, Z. W. Henry, K. Nykyri, T. W. Moore, A. P. Dimmock, X. Ma

Publications

Using data from Time History of Events and Macroscale Interactions during Substorms (THEMIS), a statistical study was performed to determine whether a dawn-dusk asymmetry exists in the occurrence rates of the Kelvin-Helmholtz (KH) instability during Parker-Spiral (PS) and Ortho-Parker-Spiral (OPS) orientations of the interplanetary magnetic field (IMF). It is determined from the data that there is a strong preference toward the dawn side during PS orientation, and although a preference to the dusk side during OPS is suggested, this requires further study for an unambiguous confirmation. The uncertainty in the OPS result is due to a low number of events …

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Martian Cave Air-Movement Via Helmholtz Resonance, Kaj E. Williams, Timothy N. Titus, Chris H. Okubo, Glen E. Cushing Oct 2017

Martian Cave Air-Movement Via Helmholtz Resonance, Kaj E. Williams, Timothy N. Titus, Chris H. Okubo, Glen E. Cushing

International Journal of Speleology

Infrasonic resonance has previously been measured in terrestrial caves by other researchers, where Helmholtz resonance has been suggested as the plausible mechanism resulting in periodic wind reversals within cave entrances. We extend this reasoning to possible Martian caves, where we examine the characteristics of four atypical pit craters (APCs) on Tharsis, suggested as candidate cave entrance locations. The results show that, for several possible cave air movement periods, we are able to infer the approximate cave volumes. The utility of inferring cave volumes for planetary cave exploration is discussed.

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The Capabilities Of The Geostationary Operational Environmental Satellite-16 (Goes-16), Brandon M. Kane Oct 2017

The Capabilities Of The Geostationary Operational Environmental Satellite-16 (Goes-16), Brandon M. Kane

Student Works

This report investigates the capability of the new Geostationary Operational Environmental Satellite-16 (GOES-16) satellite to display 16 channels of the electromagnetic spectrum, to produce images at a higher resolution at increased intervals, and to detect and display lightning. This report also discusses the main instrumentation aboard the new geostationary satellite and how it aids in creating accurate data collection, which in turn, produces quicker weather forecasts and warnings. The 16 different channels produced by the Advanced Baseline Imager aboard the new satellite are analyzed in detail as to the functions and wavelengths on which the channels operate. The image resolution …

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Influence Of Velocity Fluctuations On The Kelvin-Helmholtz Instability And Its Associated Mass Transport, Katariina Nykyri, Xuanye Ma, Andrew Dimmock, Claire Foullon, Antonius Otto, Adnane Osmane Sep 2017

Influence Of Velocity Fluctuations On The Kelvin-Helmholtz Instability And Its Associated Mass Transport, Katariina Nykyri, Xuanye Ma, Andrew Dimmock, Claire Foullon, Antonius Otto, Adnane Osmane

Publications

Kelvin-Helmholtz instability (KHI) and associated magnetic reconnection and diffusion processes provide plasma transport from solar wind into the magnetosphere. The efficiency of this transport depends on the magnetosheath and magnetospheric plasma and field properties at the vicinity of the magnetopause. Our recent statistical study using data from the Time History of Events and Macroscale Interactions during Substorms spacecraft indicates that the amplitude of the magnetosheath velocity fluctuations perpendicular to the magnetopause can be substantial. We have performed a series of local macroscale 2.5-dimensional magnetohydrodynamic simulations of the KHI during strongly northward interplanetary magnetic field and with the initial plasma parameters …

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Temperature Variations In The Dayside Magnetosheath And Their Dependence On Ion-Scale Magnetic Structures: Themis Statistics And Measurements By Mms, A. P. Dimmock, A. Osmane, T. I. Pulkkinen, K. Nykyri, E. Kilpua Jun 2017

Temperature Variations In The Dayside Magnetosheath And Their Dependence On Ion-Scale Magnetic Structures: Themis Statistics And Measurements By Mms, A. P. Dimmock, A. Osmane, T. I. Pulkkinen, K. Nykyri, E. Kilpua

Publications

The magnetosheath contains an array of waves, instabilities, and nonlinear magnetic structures which modify global plasma properties by means of various wave-particle interactions. The present work demonstrates that ion-scale magnetic field structures (∼0.2–0.5 Hz) observed in the dayside magnetosheath are statistically correlated to ion temperature changes on orders 10–20% of the background value. In addition, our statistical analysis implies that larger temperature changes are in equipartition to larger amplitude magnetic structures. This effect was more pronounced behind the quasi-parallel bow shock and during faster solar wind speeds. The study of two separate intervals suggests that this effect can result from …

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Shape Modeling And Boulder Napping Of Asteroid 1992 Uy4., Nicholas D Duong May 2017

Shape Modeling And Boulder Napping Of Asteroid 1992 Uy4., Nicholas D Duong

College of Arts & Sciences Senior Theses

In August 2005, the near-Earth Asteroid 1992 UY4 made a close flyby, coming within 0.04 au of our planet. Between the dates of 1-10 August 2005, it was observed via delay-Doppler radar imaging by the Arecibo Observatory (2380 MHz, 13 cm) and the DSS-14 antenna at the Goldstone Deep Space Communications Complex (8560 MHz, 3.5 cm). The images achieve a resolution as fine as 7.5 m/pixel and reveal a lumpy and modestly asymmetric object. The images also revealed the presence of numerous large boulders/blocks on the surface of 1992 UY4. By using the modeling software SHAPE, which is standard in …

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Imf Dependence Of Energetic Oxygen And Hydrogen Ion Distributions In The Near-Earth Magnetosphere, H. Luo, E. A. Kronberg, K. Nykyri, K. J. Trattner, P. W. Daly, G. X. Chen, A. M. Du, Y. S. Ge May 2017

Imf Dependence Of Energetic Oxygen And Hydrogen Ion Distributions In The Near-Earth Magnetosphere, H. Luo, E. A. Kronberg, K. Nykyri, K. J. Trattner, P. W. Daly, G. X. Chen, A. M. Du, Y. S. Ge

Publications

Energetic ion distributions in the near-Earth plasma sheet can provide important information for understanding the entry of ions into the magnetosphere and their transportation, acceleration, and losses in the near-Earth region. In this study, 11 years of energetic proton and oxygen observations (> ~274 keV) from Cluster/Research with Adaptive Particle Imaging Detectors were used to statistically study the energetic ion distributions in the near-Earth region. The dawn-dusk asymmetries of the distributions in three different regions (dayside magnetosphere, near-Earth nightside plasma sheet, and tail plasma sheet) are examined in Northern and Southern Hemispheres. The results show that the energetic ion distributions …

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Fast-Moving Diffuse Auroral Patches: A New Aspect Of Daytime Pc3 Auroral Pulsations, Tetsuo Motoba, Yusuke Ebihara, Akira Kadokura, Mark J. Engebretson, Marc R. Lessard, Allan T. Weatherwax, Andrew J. Gerrard Feb 2017

Fast-Moving Diffuse Auroral Patches: A New Aspect Of Daytime Pc3 Auroral Pulsations, Tetsuo Motoba, Yusuke Ebihara, Akira Kadokura, Mark J. Engebretson, Marc R. Lessard, Allan T. Weatherwax, Andrew J. Gerrard

Physics Faculty Publications

Auroral pulsations are a convenient diagnostic of wave-particle interactions in the magnetosphere. A case study of a daytime Pc3 (22–100 mHz) auroral pulsation event, measured with a ~2 Hz sampling all-sky camera at South Pole Station (74.4°S magnetic latitude) on 17 May 2012, is presented. The daytime Pc3 auroral pulsations were most active in a closed field line region where the aurora was dominated by diffuse green-line emissions and within ±2 h of magnetic local noon. Usually, but not always, the corresponding periodic variations were recorded with a colocated search coil magnetometer. Of particular interest is the two-dimensional auroral signature, …

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Using Student Characteristics, Student Spatial-Content Knowledge, And Teacher Spatial-Content Knowledge To Predict Student Spatial-Content Knowledge Of Lunar Phases, Kyle A. Curry Jan 2017

Using Student Characteristics, Student Spatial-Content Knowledge, And Teacher Spatial-Content Knowledge To Predict Student Spatial-Content Knowledge Of Lunar Phases, Kyle A. Curry

Theses and Dissertations--Science, Technology, Engineering, and Mathematics (STEM) Education

Student demographic characteristics of gender and race/ethnicity, students’ spatial-content knowledge as measured by pre-instructional performance on the Lunar Phases Concept Inventory (LPCI) (Lindell & Olsen), and post-instructional performance on the Purdue Visualization of Rotations Test (PSVT) (Bodner & Guay, 1997), and teachers’ spatial-content knowledge as measured by the two assessments were considered to predict students’ overall understanding of lunar phases as measured by post-instructional results on the LPCI. A mixed modeling approach was used in a hierarchal manner to evaluate the student learning outcomes. Results showed that student gender was not a significant predictor of post-instructional student performance, but students …

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