College of Sciences and Mathematics: Recent submissions
Now showing items 301-320 of 389
Generation of rising-tone chorus in a two-dimensional mirror field by using the general curvilinear PIC code
(2020-05-29)
Recently, the generation of rising-tone chorus has been implemented with one-dimensional (1-D) particle-in-cell (PIC) simulations in an inhomogeneous background magnetic field, where both the propagation of waves and motion ...
Proton velocity ring-driven instabilities and their dependence on the ring speed: Linear theory
(2020-05-28)
Linear dispersion theory is used to study the Alfven-cyclotron, mirror and ion Bernstein instabilities driven by a tenuous (1%) warm proton ring velocity distribution with a ring speed, v(r), varying between 2v(A) and ...
Ring/Shell Ion Distributions at Geosynchronous Orbit
(2020-05-28)
One year's worth of plasma observations from geosynchronous orbit is examined for ion distributions that may simultaneously be subject to the ion Bernstein (IB) instability (generating fast magnetosonic waves) and the ...
Fast Magnetosonic Waves Observed by Van Allen Probes: Testing Local Wave Excitation Mechanism
(2020-05-28)
Linear Vlasov theory and particle-in-cell (PIC) simulations for electromagnetic fluctuations in a homogeneous, magnetized, and collisionless plasma are used to investigate a fast magnetosonic wave event observed by the Van ...
Ion Acceleration Inside Foreshock Transients
(2020-05-28)
Recent observations upstream of Earth's bow shock have revealed that foreshock transients can not only accelerate solar wind ions by reflection at their upstream boundaries but may also accelerate ions inside them. Evidence ...
Particle-in-Cell Simulations of the Fast Magnetosonic Mode in a Dipole Magnetic Field: 1-D Along the Radial Direction
(2020-05-28)
An electromagnetic particle-in-cell code is used to investigate self-consistent evolution of the fast magnetosonic mode in a one-dimensional configuration along the radial direction in a dipole background magnetic field. ...
Equatorial Evolution of the Fast Magnetosonic Mode in the Source Region: Observation-Simulation Comparison of the Preferential Propagation Direction
(2020-05-28)
Recent analysis of an event observed by the Van Allen Probes in the source region outside the plasmapause has shown that fast magnetosonic waves (also referred to as equatorial noise) propagate preferentially in the azimuthal ...
Magnetosheath Reconnection Before Magnetopause Reconnection Driven by Interplanetary Tangential Discontinuity: A Three-Dimensional Global Hybrid Simulation With Oblique Interplanetary Magnetic Field
(2020-05-28)
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 ...
The Hall Electric Field in Earth's Magnetotail Thin Current Sheet
(2020-05-28)
One of the most important properties of Earth's magnetotail thin current sheet (TCS) is that its current is predominantly contributed by magnetized electrons. The Hall electric field, normal to the TCS and generated by ...
Test-Particle Simulations of Linear and Nonlinear Interactions Between a 2-D Whistler-Mode Wave Packet and Radiation Belt Electrons
(2020-05-27)
Using test-particle simulations, we describe (in 2-D) the interaction of an ensemble of electrons with a discrete whistler-mode wave packet, which propagates with a moderate wave-normal angle with respect to the background ...
Two-Dimensional Particle-in-Cell Simulation of Magnetosonic Wave Excitation in a Dipole Magnetic Field
(2020-05-27)
The excitation of magnetosonic waves in the meridian plane of a rescaled dipole magnetic field is investigated, for the first time, using a general curvilinear particle-in-cell simulation. Our simulation demonstrates that ...
Two-Dimensional gcPIC Simulation of Rising-Tone Chorus Waves in a Dipole Magnetic Field
(2020-05-26)
Rising-tone chorus waves have already been successfully produced in a mirror magnetic field with the use of one- and two-dimensional particle-in-cell (PIC) simulations. However, in reality, the background magnetic field ...
Modeling of a New Electron Acceleration Mechanism Ahead of Streamers
(2020-05-26)
Head‐on collisions between negative and positive streamers have been proposed as a mechanism behind X‐ray emissions by laboratory spark discharges. Recent simulations using plasma fluid and particle in cell models of a ...
Longitudinal Analysis of a Diversity Support Program in Biology: A National Call for Further Assessment
(2020-05-26)
National calls to improve the performance and persistence of students from historically underrepresented backgrounds in science have led to a surge of research on inclusive, evidence-based teaching methods. Less work has ...
With Big Data Comes Big Responsibilities for Science Equity Research
(2020-05-26)
Our ability to collect and access large quantities of data over the last decade has been revolutionary for many social sciences. Suddenly, it is possible to measure human behavior, performance, and activity on an unprecedented ...
Discovery and broad relevance may be insignificant components of course-based 1 undergraduate research experiences (CUREs) for non-biology majors
(2020-05-26)
Course-based undergraduate research experiences (CUREs) are a type of laboratory learning environment associated with a science course in which undergraduates participate in novel research. According to Auchinchloss et ...
Contrasting evolution of virulence and replication rate in an emerging bacterial pathogen
(2020-05-26)
Host resistance through immune clearance is predicted to favor pathogens that are able to transmit faster and are hence more virulent. Increasing pathogen virulence is, in turn, typically assumed to be mediated by increasing ...
Spin splittings from first-order symmetry-adapted perturbation theory without single-exchange approximation
(2020-05-20)
The recently proposed spin-flip symmetry-adapted perturbation theory (SF-SAPT) first-order exchange energy [Patkowski et al., J. Chem. Phys. 148, 164110 (2018)] enables the standard open-shell SAPT approach to treat arbitrary ...
Cluster perturbation theory. IV. Convergence of cluster perturbation series for energies and molecular properties
(2020-05-20)
The theoretical foundation has been developed for establishing whether cluster perturbation (CP) series for the energy, molecular properties, and excitation energies are convergent or divergent and for using a two-state ...
Cluster perturbation theory. I. Theoretical foundation for a coupled cluster target state and ground-state energies
(2020-05-20)
We introduce a new class of perturbation models-the cluster perturbation (CP) models-where the major drawbacks of Moller-Plesset perturbation theory and coupled cluster perturbation theory have been eliminated. In CP theory, ...