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Full-Text Articles in Physical Sciences and Mathematics

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 …


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 …


Velocity-Dependent Inverse Cubic Force And Solar System Gravity Tests, Quentin G. Bailey, Daniel Havert Sep 2017

Velocity-Dependent Inverse Cubic Force And Solar System Gravity Tests, Quentin G. Bailey, Daniel Havert

Publications

Higher mass dimension terms in an effective field theory framework for tests of spacetime symmetries are studied. Using a post-Newtonian expansion method, we derive the spacetime metric and the equations of motion for a binary system. This reveals an effective inverse cubic force correction to post-Newtonian general relativity that depends on the velocity of the bodies in the system. The results are studied in the context of laboratory and space-based tests including the effects on solar-system ephemeris, laser ranging observations, and gravimeter tests. This work reveals the coefficient combinations for mass dimension 5 operators controlling CPT violation for gravity that …


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 …


Creating An Experimental Learning And Research Driven Spacesuit Lab For Erau, Ryan L. Kobrick, Erik Seedhouse Jul 2017

Creating An Experimental Learning And Research Driven Spacesuit Lab For Erau, Ryan L. Kobrick, Erik Seedhouse

Publications

This paper evaluates key functional data parameters that must be considered for suborbital spaceflight participants wearing pressurized suits for intravehicular activity (IVA). Data parameters of an analog spacesuit worn in an analog flight environment were obtained from 40 civilian participants using the Suborbital Space Flight Simulator (SSFS) at Embry-Riddle Aeronautical University (ERAU) while donning Final Frontier Design’s (FFD) fully pressurized third-generation spacesuit as part of their training for Project PoSSUM (the Polar Suborbital Science in the Upper Mesosphere Project). The physiological data collected included: blood pressure, electrocardiograms, heart rate, grip strength, and skin temperature. These parameters were measured using a …


Book Review: Shoot The Moon: A Complete Guide To Lunar Imaging, T. D. Oswalt Jun 2017

Book Review: Shoot The Moon: A Complete Guide To Lunar Imaging, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Shoot the Moon: a Complete Guide to Lunar Imaging by Dupont-Bloch, Nicolas. Cambridge, 2016, 323 p index, 9781107548442 $39.95, 9781316657867 $32.00.


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 …


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 …


Book Review: From The Realm Of The Nebulae To Populations Of Galaxies: Dialogues On A Century Of Research, Astrophysics And Space Science Library, 435, T. D. Oswalt Apr 2017

Book Review: From The Realm Of The Nebulae To Populations Of Galaxies: Dialogues On A Century Of Research, Astrophysics And Space Science Library, 435, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of From the Realm of the Nebulae to Populations of Galaxies : Dialogues on a Century of Research, Astrophysics and Space Science Library, 435. by Mauro D'Onofrio, Roberto Rampazzo, and Simone Zaggia Springer, 2016 785p bibl index afp, 9783319310046 $279.00, 9783319310060 $219.00