Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Ionosphere (22)
- General Relativity and Quantum Cosmology (19)
- High Energy Physics - Theory (16)
- Gravity waves (14)
- Electron (13)
-
- Spacecraft (13)
- Airglow (12)
- High-latitude (12)
- Theoretical study (12)
- F region (11)
- Mesosphere (11)
- Mathematical Physics (10)
- Gravitational waves (9)
- Observations (9)
- Lidar (8)
- Polar cap arcs (8)
- Charging (7)
- Spacecraft Charging (7)
- ALOHA-93 (6)
- Convection (6)
- Gauge theory (6)
- Graphite (6)
- Insulators (6)
- LISA (6)
- Resistivity (6)
- Sodium (6)
- Spectroscopy (6)
- Conductivity (5)
- Electron emission (5)
- Gravity wave (5)
- Publication Year
Articles 1 - 30 of 652
Full-Text Articles in Physical Sciences and Mathematics
Inertial Motion On The Earth's Spheroidal Surface, Boyd F. Edwards, Cade Pankey, John M. Edwards
Inertial Motion On The Earth's Spheroidal Surface, Boyd F. Edwards, Cade Pankey, John M. Edwards
All Physics Faculty Publications
As seen by an observer in the rotating frame, the earth’s small spheroidal deformations neutralize the centrifugal force, leaving only the smaller Coriolis force to govern the “inertial” motion of objects that move on its surface, assumed smooth and frictionless. Previous studies of inertial motion employ weakly spheroidal equations of motion that ignore the influence of the centrifugal force and yet treat the earth as a sphere. The latitude dependence of these equations renders them strongly nonlinear. We derive and justify these equations and use them to identify, classify, name, describe, and illustrate all possible classes of inertial motion, including …
What Is A Photon? Foundations Of Quantum Field Theory, Charles G. Torre
What Is A Photon? Foundations Of Quantum Field Theory, Charles G. Torre
All Physics Faculty Publications
This is a brief, informal, and relatively low-level course on the foundations of quantum field theory. The prerequisites are undergraduate courses in quantum mechanics and electromagnetism.
Normal-Mode Oscillations For The Circular And Dipolar States Of A Filled Hexagonal Magnetic Dipole Cluster, Peter T. Haugen, Andrew D. P. Smith, Boyd F. Edwards
Normal-Mode Oscillations For The Circular And Dipolar States Of A Filled Hexagonal Magnetic Dipole Cluster, Peter T. Haugen, Andrew D. P. Smith, Boyd F. Edwards
All Physics Faculty Publications
We analyze the rotational dynamics of six magnetic dipoles of identical strength at the vertices of a regular hexagon with a variable-strength dipole in the center. The seven dipoles spin freely about fixed axes that are perpendicular to the plane of the hexagon, with their dipole moments directed parallel to the plane. Equilibrium dipole orientations are calculated as a function of the relative strength of the central dipole. Small-amplitude perturbations about these equilibrium states are calculated in the absence of friction and are compared with analytical results in the limit of zero and infinite central dipole strength. Normal modes and …
Hysteretic Transition Between States Of A Filled Hexagonal Magnetic Dipole Cluster, Andrew D. P. Smith, Peter T. Haugen, Boyd F. Edwards
Hysteretic Transition Between States Of A Filled Hexagonal Magnetic Dipole Cluster, Andrew D. P. Smith, Peter T. Haugen, Boyd F. Edwards
All Physics Faculty Publications
By minimizing the magnetostatic potential energy and by finding zeros in the sum of the squares of the torques, we find the equilibrium states of six dipoles of identical strength at the vertices of a regular hexagon and a variable-strength dipole at the center. The seven dipoles spin freely about fixed axes that are perpendicular to the plane of the hexagon, with their dipole moments directed parallel to the plane. When the central dipole is weak compared with the perimeter dipoles, a ‘‘circular’’ state applies in which the perimeter dipole moments circle around the central dipole, which points toward a …
Geodetic Model For Teaching Motion On The Earth's Spheroidal Surface, Boyd F. Edwards, John M. Edwards
Geodetic Model For Teaching Motion On The Earth's Spheroidal Surface, Boyd F. Edwards, John M. Edwards
All Physics Faculty Publications
We explore the forces that shape our spheroidal Earth and the forces that govern the motion of a puck that slides without friction on its surface. The Earth's stable spheroidal shape (apart from small-scale surface features) is determined by balancing the gravitational forces that hold it together against the centrifugal forces that try to tear it apart. The motion of a puck on its surface differs profoundly from motion on a sphere because the Earth's spheroidal deformations neutralize the centrifugal and gravitational forces on the puck, leaving only the Coriolis force to govern the motion. Yet the Earth's spheroidal deformations …
Forces And Conservation Laws For Motion On Our Spheroidal Earth, Boyd F. Edwards, John M. Edwards
Forces And Conservation Laws For Motion On Our Spheroidal Earth, Boyd F. Edwards, John M. Edwards
All Physics Faculty Publications
We explore the forces and conservation laws that govern the motion of a hockey puck that slides without friction on a smooth, rotating, self-gravitating spheroid. The earth's oblate spheroidal shape (apart from small-scale surface features) is determined by balancing the gravitational forces that hold it together against the centrifugal forces that try to tear it apart. The earth achieves this shape when the apparent gravitational force on the puck, defined as the vector sum of the gravitational and centrifugal forces, is perpendicular to the earth's surface at every point on the surface. Thus, the earth's spheroidal deformations neutralize the centrifugal …
Temperature Tides Across The Mid-Latitude Summer Turbopause Measured By A Sodium Lidar And Mighti/Icon, Tao Yuan, M. H. Stevens, C. R. Englert, T. J. Immel
Temperature Tides Across The Mid-Latitude Summer Turbopause Measured By A Sodium Lidar And Mighti/Icon, Tao Yuan, M. H. Stevens, C. R. Englert, T. J. Immel
All Physics Faculty Publications
Local full diurnal coverage of temperature variations across the turbopause (∼90–115 km altitude) is achieved by combining the nocturnal observations of a Sodium (Na) Doppler lidar on the Utah State University (USU) campus (41.7°N, 248.2°E) and NASA Michelson interferometer for global high-resolution thermospheric imaging (MIGHTI)/Ionospheric connection explorer (ICON) daytime observations made in the same vicinity. In this study, utilizing this hybrid data set during summer 2020 between June 12th and July 15th, we retrieve the temperature signatures of diurnal and semidiurnal tides in this region. The tidal amplitudes of both components have similar vertical variation with increasing altitude: less than …
Benchmarking Nimrod Continuum Kinetic Formulations Through The Steady-State Poloidal Flow, Joseph R. Jepson, Chris C. Hegna, Eric D. Held, J. Andrew Spencer, B. C. Lyons
Benchmarking Nimrod Continuum Kinetic Formulations Through The Steady-State Poloidal Flow, Joseph R. Jepson, Chris C. Hegna, Eric D. Held, J. Andrew Spencer, B. C. Lyons
All Physics Faculty Publications
In this work, continuum kinetic formulations are employed as a mechanism to include closure physics in an extended magnetohydrodynamics model. Two continuum kinetic approaches have been implemented in the plasma fluid code NIMROD [Sovinec et al., “Nonlinear magnetohydrodynamics with high-order finite elements,” J. Comput. Phys. 195, 355 (2004)] including a Chapman–Enskog-like (CEL) formulation and a more conventional δf approach. Ion kinetic closure schemes are employed to describe the neoclassical flow properties in axisymmetric toroidal geometry. In particular, predictions for steady-state values of poloidal flow profiles in tokamak geometry are provided using both the δf formulation and two different solution …
Potential, Field, And Interactions Of Multipole Spheres: Coated Spherical Magnets, Jeong-Young Ji, Boyd F. Edwards, J. Andrew Spencer, Eric D. Held
Potential, Field, And Interactions Of Multipole Spheres: Coated Spherical Magnets, Jeong-Young Ji, Boyd F. Edwards, J. Andrew Spencer, Eric D. Held
All Physics Faculty Publications
We show that the energy, force, and torque between two spherically symmetric multipole density distributions are identical to those between two point multipoles, and apply this point-sphere equivalence to coated spherical dipole magnets. We also show that the potential and field of such a distribution are equivalent to those due to point multipoles located at the center of the distribution. We expand the inverse-distance potential in terms of harmonic (Hermite irreducible) tensors, whose properties enable us to express the potential energy, force, and torque for two arbitrary source distributions in a series of point-multipole interactions. This work generalizes recent work …
Spacetime Groups, Ian M. Anderson, Charles G. Torre
Spacetime Groups, Ian M. Anderson, Charles G. Torre
All Physics Faculty Publications
A spacetime group is a connected 4-dimensional Lie group G endowed with a left invariant Lorentz metric h and such that the connected component of the isometry group of h is G itself. The Newman-Penrose formalism is used to give an algebraic classification of spacetime groups, that is, we determine a complete list of inequivalent spacetime Lie algebras, which are pairs, (g, n), with g being a 4-dimensional Lie algebra and n being a Lorentzian inner product on g. A full analysis of the equivalence problem for spacetime Lie algebras is given which leads to a completely …
Evidence For Horizontal Blocking And Reflection Of A Small‐Scale Gravity Wave In The Mesosphere, Neal R. Criddle, Pierre-Dominique Pautet, Tao Yuan, C. Heale, J. Snively, Yucheng Zhao, Michael J. Taylor
Evidence For Horizontal Blocking And Reflection Of A Small‐Scale Gravity Wave In The Mesosphere, Neal R. Criddle, Pierre-Dominique Pautet, Tao Yuan, C. Heale, J. Snively, Yucheng Zhao, Michael J. Taylor
All Physics Faculty Publications
The variations of the horizontal phase velocity of an internal gravity wave, generated by wave “blocking” or “reflection” due to an inhomogeneous wind field, have been predicted theoretically and numerically investigated but had yet to be captured experimentally. In this paper, through a collaborative observation campaign using a sodium (Na) Temperature/Wind lidar and a collocated Advanced Mesospheric Temperature Mapper (AMTM) at Utah State University (USU), we report the first potential evidence of such a unique gravity wave process. The study shows that a small‐scale wave, captured by the AMTM, with initial observed horizontal phase velocity of 37 ± 5 m/s …
Strategies For Determining Electron Yield Material Parameters For Spacecraft Charge Modeling, Phil Lundgreen, John R. Dennison
Strategies For Determining Electron Yield Material Parameters For Spacecraft Charge Modeling, Phil Lundgreen, John R. Dennison
All Physics Faculty Publications
Accurate modeling of spacecraft charging is essential to mitigate well‐known and all‐too‐common deleterious and costly effects on spacecraft resulting from charging induced by interactions with the space plasma environment. This paper addresses how limited availability of electron emission and transport properties of spacecraft materials—in particular, secondary electron yields—and the wide ranges measured for such properties pose a critical issue for modeling spacecraft charging. It describes a materials charging database for electron emission properties under development, which facilitates more accurate spacecraft charge modeling when used in concert with the strategies outlined herein. These data and techniques provide tools for more accurate …
The Development And Validation Of A 'Flux-Corrected Transport' Based Solution Methodology For The Plasmasphere Refilling Problem Following Geomagnetic Storms, Kausik Chatterjee, Robert W. Schunk
The Development And Validation Of A 'Flux-Corrected Transport' Based Solution Methodology For The Plasmasphere Refilling Problem Following Geomagnetic Storms, Kausik Chatterjee, Robert W. Schunk
All Physics Faculty Publications
The refilling of the plasmasphere following geomagnetic storms remains one of the longstanding and interesting problems in ionosphere-magnetosphere coupling research. The objective of this paper is the formulation and development of a one-dimensional (1D) refilling model using the flux-corrected transport method, a numerical method that is extremely well-suited to handling problems with shocks and discontinuities. In this paper, the developed methodology has been validated against exact, analytical benchmarks, and extremely good agreement has been obtained between these analytical benchmarks and numerical results. The ultimate objective of this research is the development of a three-dimensional (3D) multi-ion model for ionosphere-magnetosphere coupling …
Periodic Bouncing Modes For Two Uniformly Magnetized Spheres. I. Trajectories, Boyd F. Edwards, Bo A. Johnson, John M. Edwards
Periodic Bouncing Modes For Two Uniformly Magnetized Spheres. I. Trajectories, Boyd F. Edwards, Bo A. Johnson, John M. Edwards
All Physics Faculty Publications
We consider a uniformly magnetized sphere that moves without friction in a plane in response to the field of a second, identical, fixed sphere, making elastic hard-sphere collisions with this sphere. We seek periodic solutions to the associated nonlinear equations of motion. We find closed-form mathematical solutions for small-amplitude modes and use these to characterize and validate our large-amplitude modes, which we find numerically. Our Runge-Kutta integration approach allows us to find 1243 distinct periodic modes with the free sphere located initially at its stable equilibrium position. Each of these modes bifurcates from the finite-amplitude radial bouncing mode with infinitesimal-amplitude …
Periodic Bouncing Modes For Two Uniformly Magnetized Spheres. Ii. Scaling, Boyd F. Edwards, Bo A. Johnson, John M. Edwards
Periodic Bouncing Modes For Two Uniformly Magnetized Spheres. Ii. Scaling, Boyd F. Edwards, Bo A. Johnson, John M. Edwards
All Physics Faculty Publications
A uniformly magnetized sphere moves without friction in a plane in response to the field of a second, identical, fixed sphere and makes elastic hard-sphere collisions with this sphere. Numerical simulations of the threshold energies and periods of periodic finite-amplitude nonlinear bouncing modes agree with small-amplitude closed-form mathematical results, which are used to identify scaling parameters that govern the entire amplitude range, including power-law scaling at large amplitudes. Scaling parameters are combinations of the bouncing number, the rocking number, the phase, and numerical factors. Discontinuities in the scaling functions are found when viewing the threshold energy and period as separate …
A Semi-Kinetic Model Of Plasmasphere Refilling Following Geomagnetic Storms And Comparison With Hydrodynamic Results, Kausik Chatterjee, Robert W. Schunk
A Semi-Kinetic Model Of Plasmasphere Refilling Following Geomagnetic Storms And Comparison With Hydrodynamic Results, Kausik Chatterjee, Robert W. Schunk
All Physics Faculty Publications
The objective of this paper is the development of a kinetic model for plasmasphere refilling following geomagnetic storms. The kinetic model is based on the ‘particle-in-cell’ method, a method based on the simulation of particle motion and thus well-suited to high altitude, low-density regimes, where the plasma transport equations are not valid. The model was validated with exact, analytical benchmarks, which are provided in this paper. The refilling results obtained from the kinetic model were then compared with results from a recently developed hydrodynamic solution methodology based on the ‘flux-corrected transport’ (FCT) method, and the limitations of hydrodynamic modeling for …
Model‐Based Properties Of The Dayside Open/Closed Boundary: Is There A Ut‐Dependent Variation?, David A. Smith, Jan Josef Sojka
Model‐Based Properties Of The Dayside Open/Closed Boundary: Is There A Ut‐Dependent Variation?, David A. Smith, Jan Josef Sojka
All Physics Faculty Publications
The open‐closed boundary (OCB) defines a region of significant transformation in Earth's protective magnetic shield. Principle among these changes is the transition of magnetic field lines from having two foot points, one in each hemisphere, to one foot point at Earth, the other mapping to the solar wind. Charged particles in the solar wind are able to follow these open field lines into Earth's upper atmosphere. The OCB also defines the polar cap boundary. Being able to identify and track the OCB allows study of several components of the geomagnetic system. Among them are the electrodynamics of the geomagnetic field …
Halving Iso(7) Supergravity, Adolfo Guarino, Javier Tarrío, Oscar J. Varela
Halving Iso(7) Supergravity, Adolfo Guarino, Javier Tarrío, Oscar J. Varela
All Physics Faculty Publications
Half-maximal, N = 4, sectors of D = 4 N = 8 supergravity with a dyonic ISO(7) gauging are investigated. We focus on a half-maximal sector including three vector multiplets, that arises as a certain SO(3)R-invariant sector of the full theory. We discuss the embedding of this sector into the largest half-maximal sector of the N = 8 supergravity retaining six vector multiplets. We also provide its canonical N = 4 formulation and show that, from this perspective, our model leads in its own right to a new explicit gauging of N = 4 supergravity. Finally, expressions for …
Melissa: System Description And Spectral Features Of Pre- And Post-Midnight F-Region Echoes, Fabiano S. Rodrigues, Weijia Zhan, Marco A. Milla, B. G. Fejer, Eurico R. De Paula, Acacio C. Neto, Angela M. Santos, Inez S. Batista
Melissa: System Description And Spectral Features Of Pre- And Post-Midnight F-Region Echoes, Fabiano S. Rodrigues, Weijia Zhan, Marco A. Milla, B. G. Fejer, Eurico R. De Paula, Acacio C. Neto, Angela M. Santos, Inez S. Batista
All Physics Faculty Publications
Most of the low‐latitude ionospheric radar observations in South America come from the Jicamarca Radio Observatory, located in the western longitude sector (∼75°W). The deployment of the 30 MHz FAPESP‐Clemson‐INPE (FCI) coherent backscatter radar in the magnetic equatorial site of São Luis, Brazil, in 2001 allowed observations to be made in the eastern sector (∼45°W). However, despite being operational for several years (2001–2012), FCI only made observations during daytime and pre‐midnight hours, with a few exceptions. Here, we describe an upgraded system that replaced the FCI radar and present results of full‐night F‐region observations. This radar is referred to …
Embedding The Su(3) Sector Of So(8) Supergravity In D = 11, Gabriel Larios, Praxitelis Ntokos, Oscar J. Varela
Embedding The Su(3) Sector Of So(8) Supergravity In D = 11, Gabriel Larios, Praxitelis Ntokos, Oscar J. Varela
All Physics Faculty Publications
The SU(3)-invariant sector of maximal supergravity in four dimensions with an SO(8) gauging is uplifted to D = 11 supergravity. In order to do this, the SU(3)-neutral sector of the tensor and duality hierarchies of the D = 4 �� = 8 supergravity is first worked out. The consistent D = 11 embedding of the full, dynamical SU(3) sector is then expressed at the level of the D = 11 metric and three-form gauge field in terms of these D = 4 tensors. The redundancies introduced by this approach are eliminated at the level of the D = 11 four-form …
Minimal D = 4 �� = 2 Supergravity From D = 11: An M-Theory Free Lunch, Gabriel Larios, Oscar J. Varela
Minimal D = 4 �� = 2 Supergravity From D = 11: An M-Theory Free Lunch, Gabriel Larios, Oscar J. Varela
All Physics Faculty Publications
We present a new consistent truncation of D = 11 supergravity to D = 4 �� = 2 minimal gauged supergravity, on the seven-dimensional internal Riemannian space corresponding to the most general class of D = 11 solutions with an AdS4 factor and �� = 2 supersymmetry. A truncation ansatz is proposed and its consistency checked at the level of the D = 11 Bianchi identity, bosonic equations of motion, and supersymmetry variations of the gravitino. The general class includes an �� = 2 AdS4 solution dual to the conformal, low energy physics phase corresponding to a mass …
Dynamic Secondary Electron Emission In Rough Composite Materials, Leandro Olano, Maria E. Dávila, John R. Dennison, Petronilo Martín-Iglesias, Isabel Montero
Dynamic Secondary Electron Emission In Rough Composite Materials, Leandro Olano, Maria E. Dávila, John R. Dennison, Petronilo Martín-Iglesias, Isabel Montero
All Physics Faculty Publications
The interaction of ionizing radiation with matter is of critical importance in numerous areas of science and technology like space and vacuum technology and even medicine and biotechnology. Secondary electron emission is a consequence of electron irradiation on materials. We achieve extremely low secondary electron emission yield values smaller than 0.2, even up to incident electron energies ~1 keV, due to an undocumented synergy between neighbouring metal and dielectric domains in composite samples. To investigate this experimental discovery, we propose a simple 3D model where the dielectric and metallic domains are arranged in parallel and interleaved. The proposed surface profile …
Generalized Near Horizon Extreme Binary Black Hole Geometry, Jacob Ciafre, Shahar Hadar, Erin Rickenbach, Maria J. Rodriguez
Generalized Near Horizon Extreme Binary Black Hole Geometry, Jacob Ciafre, Shahar Hadar, Erin Rickenbach, Maria J. Rodriguez
All Physics Faculty Publications
We present a new vacuum solution of Einstein’s equations describing the near horizon region of two neutral, extreme (zero-temperature), corotating, nonidentical Kerr black holes. The metric is stationary, asymptotically near horizon extremal Kerr (NHEK), and contains a localized massless strut along the symmetry axis between the black holes. In the deep infrared, it flows to two separate throats which we call “pierced-NHEK” geometries: each throat is NHEK pierced by a conical singularity. We find that in spite of the presence of the strut for the pierced-NHEK geometries the isometry group SL(2,R)×U(1) is restored. We find the physical parameters and entropy.
Solar Response And Long‐Term Trend Of Midlatitude Mesopause Region Temperature Based On 28 Years (1990–2017) Of Na Lidar Observations, Chiao-Yao She, Uwe Berger, Zhao-Ai Yan, Tao Yuan, F.-J. Lübken, David A. Krueger, Xiong Hu
Solar Response And Long‐Term Trend Of Midlatitude Mesopause Region Temperature Based On 28 Years (1990–2017) Of Na Lidar Observations, Chiao-Yao She, Uwe Berger, Zhao-Ai Yan, Tao Yuan, F.-J. Lübken, David A. Krueger, Xiong Hu
All Physics Faculty Publications
We present midlatitude solar response and linear trend from Colorado State University/Utah State University Na lidar nocturnal temperature observations between 1990 and 2017. Along with the nightly mean temperatures (_Ngt), we also use the corresponding 2‐hr means centered at midnight (_2MN), resulting in vertical trend profiles similar in shapes as those previously published. The 28‐year trend from _Ngt (_2MN) data set starts from a small warming at 85 km, to cooling at 87 (88) km, reaching a maximum of 1.85 ± 0.53 (1.09 ± 0.74) at 92 (93) km and turns positive again at 102 (100) km. The 6‐month winter …
On The Balance Between Plasma And Magnetic Pressure Across Equatorial Plasma Depletions, J. Rodríguez-Zuluaga, C. Stolle, Y. Yamazaki, H. Lühr, J. Park, Ludger Scherliess, J. L. Chau
On The Balance Between Plasma And Magnetic Pressure Across Equatorial Plasma Depletions, J. Rodríguez-Zuluaga, C. Stolle, Y. Yamazaki, H. Lühr, J. Park, Ludger Scherliess, J. L. Chau
All Physics Faculty Publications
In magnetized plasmas such as the ionosphere, electric currents develop in regions of strong density gradients to balance the resulting plasma pressure gradients. These currents, usually known as diamagnetic currents decrease the magnetic pressure where the plasma pressure increases, and vice versa. In the low‐latitude ionosphere, equatorial plasma depletions (EPDs) are well known for their steep plasma density gradients and adverse effect on radio wave propagation. In this paper, we use continuous measurements of the magnetic field and electron density from the European Space Agency's Swarm constellation mission to assess the balance between plasma and magnetic pressure across large‐scale EPDs. …
Equatorial Disturbance Dynamo Vertical Plasma Drifts Over Jicamarca: Bi‐Monthly And Solar Cycle Dependence, Luis A. Navarro Dominguez, B. G. Fejer, Ludger Scherliess
Equatorial Disturbance Dynamo Vertical Plasma Drifts Over Jicamarca: Bi‐Monthly And Solar Cycle Dependence, Luis A. Navarro Dominguez, B. G. Fejer, Ludger Scherliess
All Physics Faculty Publications
We use extensive incoherent scatter radar observations from the Jicamarca Radio Observatory to study the local time and bi‐monthly dependence of the equatorial disturbance dynamo vertical plasma drifts on solar flux and geomagnetic activity. We show that the daytime disturbance drifts have generally small magnitudes with largest values before noon and an apparent annual variation. Near dusk, they are downward throughout the year with largest values during the equinoxes and smallest during June solstice. These downward drifts increase strongly with solar flux, and shift to later local times. They also increase with increasing geomagnetically active conditions with no apparent local …
The Long‐Term Trends Of Nocturnal Mesopause Temperature And Altitude Revealed By Na Lidar Observations Between 1990 And 2018 At Midlatitude, Tao Yuan, Stanley C. Solomon, Chiao -Y. She, D. A. Krueger, Han-Li Liu
The Long‐Term Trends Of Nocturnal Mesopause Temperature And Altitude Revealed By Na Lidar Observations Between 1990 And 2018 At Midlatitude, Tao Yuan, Stanley C. Solomon, Chiao -Y. She, D. A. Krueger, Han-Li Liu
All Physics Faculty Publications
The mesopause, a boundary between mesosphere and thermosphere with the coldest atmospheric temperature, is formed mainly by the combining effects of radiative cooling of CO2, and the vertical adiabatic flow in the upper atmosphere. A continuous multidecade (1990‐2018) nocturnal temperature data base of an advanced Na lidar, obtained at Fort Collins, CO (41°N, 105°W), and at Logan, UT (42°N, 112°W), provides an unprecedented opportunity to study the long‐term variations of this important atmospheric boundary. In this study, we categorize the lidar‐observed mesopause into two categories: the “high mesopause” (HM) above 97 km during nonsummer months, mainly formed through the radiative …
Pmc Turbo: Studying Gravity Wave And Instability Dynamics In The Summer Mesosphere Using Polar Mesospheric Cloud Imaging And Profiling From A Stratospheric Balloon, David C. Fritts, Amber D. Miller, C. Bjorn Kjellstrand, Christopher Geach, Bifford P. Williams, Bernd Kaifler, Natalie Kaifler, Glenn Jones, Markus Rapp, Michele Limon, Jason Reimuller, Ling Wang, Shaul Hanany, Sonja Gisinger, Yucheng Zhao, Gunter Stober, Cora E. Randall
Pmc Turbo: Studying Gravity Wave And Instability Dynamics In The Summer Mesosphere Using Polar Mesospheric Cloud Imaging And Profiling From A Stratospheric Balloon, David C. Fritts, Amber D. Miller, C. Bjorn Kjellstrand, Christopher Geach, Bifford P. Williams, Bernd Kaifler, Natalie Kaifler, Glenn Jones, Markus Rapp, Michele Limon, Jason Reimuller, Ling Wang, Shaul Hanany, Sonja Gisinger, Yucheng Zhao, Gunter Stober, Cora E. Randall
All Physics Faculty Publications
The Polar Mesospheric Cloud Turbulence (PMC Turbo) experiment was designed to observe and quantify the dynamics of small‐scale gravity waves (GWs) and instabilities leading to turbulence in the upper mesosphere during polar summer using instruments aboard a stratospheric balloon. The PMC Turbo scientific payload comprised seven high‐resolution cameras and a Rayleigh lidar. Overlapping wide and narrow camera field of views from the balloon altitude of ~38 km enabled resolution of features extending from ~20 m to ~100 km at the PMC layer altitude of ~82 km. The Rayleigh lidar provided profiles of temperature below the PMC altitudes and of the …
First Ground‐Based Conjugate Observations Of Stable Auroral Red (Sar) Arcs, C. Martinis, J. Baumgardner, M. Mendillo, Michael J. Taylor, T. Moffat-Griffin, J. Wroten, C. Sullivan, R. Macinnis, B. Alford, Y. Nishimura
First Ground‐Based Conjugate Observations Of Stable Auroral Red (Sar) Arcs, C. Martinis, J. Baumgardner, M. Mendillo, Michael J. Taylor, T. Moffat-Griffin, J. Wroten, C. Sullivan, R. Macinnis, B. Alford, Y. Nishimura
All Physics Faculty Publications
During the geomagnetic storm of 1 June 2013, all‐sky imagers located at geomagnetically conjugate locations at Millstone Hill, USA (42.6°N, 71.4°W, 50.9° mag lat) and at Rothera, Antarctica (67.5°S, 68.1°W, ‐53.2° mag lat), allowed us to measure a stable auroral red (SAR) arc simultaneously in both hemispheres for the first time. The arc measured in one hemisphere was observed very close to its conjugate location in the opposite hemisphere. While spatial characteristics, such as equatorward motion and latitudinal extent, were similar at both sites, morphological properties, for example, arc brightness and shape of the poleward edges, differed. The overall brightness …
The International Community Coordinated Modeling Center Space Weather Modeling Capabilities Assessment: Overview Of Ionosphere/Thermosphere Activities, Ludger Scherliess, I. Tsagouri, E. Yizengaw, S. Bruinsma, J. S. Shim, A. Coster, J. M. Retterer
The International Community Coordinated Modeling Center Space Weather Modeling Capabilities Assessment: Overview Of Ionosphere/Thermosphere Activities, Ludger Scherliess, I. Tsagouri, E. Yizengaw, S. Bruinsma, J. S. Shim, A. Coster, J. M. Retterer
All Physics Faculty Publications
The Earth's ionosphere/thermosphere (I/T) system exhibits complicated weather variability that can have adverse effects on human operations and systems, and consequently, there is a need for both accurate and reliable specifications and forecasts for this region. As part of the international effort to evaluate and assess the predictive capabilities of space weather models, four working groups for the I/T system have been created with the goal to devise a concerted model validation effort for the I/T environment. This paper presents an overview of the team efforts and reports on the progress made. As a first step, the working teams have …