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Magnetotail-Inner Magnetosphere Transport Associated With Fast Flows Based on Combined Global-Hybrid and CIMI Simulation
Get PDFUsing the combined Auburn global hybrid simulation code in 3-D (ANGIE3D) and the Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model, we investigate the self-consistent connection of fast flow injections from the tail plasma sheet and the inner magnetosphere under a southward IMF. In the dynamic run, the hybrid results provide the CIMI model with 3-D magnetic field and the electric potential at the high latitude ionosphere boundary as well as the full ion phase space distribution function at the CIMI outer boundary at the equator. The simulation shows that magnetotail reconnection, which has a dawn-dusk size of similar to 1-5 R-E, recurs with a period of several minutes, resulting in recurring localized fast flow injections. Strong ion temperature anisotropy and non-Maxwellian distributions are present in the fast flows, and the braking of fast flows due to the dipole-like field results in further perpendicular heating in the injection sources. Multiple fast flow injections lead to multiple peaks in the particle fluxes in the inner magnetosphere as well as layers of upward and downward field-aligned currents at the ionosphere, and low energy particles penetrate deeper radially than the high energy particles. The combined ANGIE3D-CIMI model can be used to calculate the global kinetic physics that contains both Region-1 and Region-2 field-aligned currents.PublishedYe
Why does ethical leadership matter? Exploration and future direction for sales research
Get PDFThe purpose of this study is to gain a better understanding of the relationship between ethical leadership and an employee’s work-related attitudes about, and behaviors for, their company. Using social learning theory, the authors examine how a manager’s ethical leadership influences the relationship between an employee’s job satisfaction and organizational commitment. This research uses structural equation modeling (SEM) to investigate the direct and moderated relationships among these variables using data from 250-employees working in United States-based companies. Results suggest that an employee’s perceptions of ethical leadership moderate the relationship between their job satisfaction and organizational commitment. Implications for managers and directions for future research are provided.Ye
George Eliot's Enchanted Real
No full textArticle from the George Eliot Review, digitized and hosted by the George Eliot Review Online.Publishe
Modulation of Magnetosonic Waves by Background Plasma Density in a Dipole Magnetic Field: 2-D PIC Simulation
Get PDFRecent satellite observations, combined with instability analyses, have shown that the background plasma density variation can modulate the magnetosonic (MS) waves by controlling the wave excitation. However, the detailed modulation process needs to be identified since the MS waves propagate nearly perpendicular to the background magnetic field. In this study, we investigate the MS wave modulation by background plasma density using a 2-D general curvilinear particle-in-cell simulation in the meridian plane of a dipole magnetic field. The simulation model consists of three plasma components: the background cold electrons and protons and ring distribution protons. We find that MS waves can be locally generated by ring distribution protons in the low plasma density region, while no MS wave is generated in the high density region. These MS waves are confined near the local source region since they are damped by the background cold plasma. The background protons gain more energy than background electrons, implying the plasmaspheric protons may dominate the modulation of MS waves. Moreover, we have also investigated the generation and propagation of MS waves in the plasmapause density structure. Our simulation results demonstrate that the background plasma density variation can modulate the MS waves and may play an important role in the spatial distribution of MS waves.PublishedYe
Comparison of CIMI Simulations and TWINS Observations on June 28 and 29, 2013
Get PDFA moderate geomagnetic storm (Sym/H similar to-100 nT) during June 28 and 29, 2013 was studied using Comprehensive Inner Magnetosphere-Ionosphere (CIMI) simulations and results were compared with Two wide-angle Imaging Neutral-atom Spectrometers (TWINS) observations of the spatial and temporal evolution of ring current (RC) ions including ion pressure, anisotropy, intensity, and median energy. At the onset of the storm (11:00 UT on June 28), TWINS ion pressure peaks were located radially outward and dusk ward compared to CIMI. During the main phase and the recovery phase (06:00 UT on June 28 to 16:00 UT on June 29), southward IMF Bz and rapid AE index fluctuations were observed indicating substorm ion injections and TWINS observed multiple ion pressure peaks at least one of which were found to be close to the locations of CIMI ion pressure peaks. TWINS also observed regions of parallel pressure anisotropy near pre-midnight sectors. The RC ion energies in TWINS were found to be very low (<10 keV) indicating convective transport of O+ ions. When the storm had nearly recovered post 17:00 UT on June 29, TWINS and CIMI observed single pressure peaks but TWINS ion pressure peaks were radially outward compared to CIMI. Also, the spatial profiles of TWINS ion energies showed gradual removal of low-energy ions. Over all, TWINS and CIMI results were found to agree on the general features of the RC. However, effects of shielding electric fields, particle injections, and presence of O+ ions were more prominent in TWINS data.PublishedYe
The Portraits of a Lady: Images of George Eliot by Sir Frederic W. Burton
No full textArticle from the George Eliot Review, digitized and hosted by the George Eliot Review Online.Publishe
Sympathy, Morality, and Metaphor: ‘Janet’s Repentance’ and ‘Recollections of Ilfracombe’
No full textArticle from the George Eliot Review, digitized and hosted by the George Eliot Review Online.Publishe
Global Hybrid Simulations of Interaction Between Interplanetary Rotational Discontinuity and Bow Shock/Magnetosphere: Can Ion-Scale Magnetic Reconnection be Driven by Rotational Discontinuity Downstream of Quasi-Parallel Shock?
Get PDFIon-scale magnetic reconnection has been observed downstream of the terrestrial quasi-parallel (Q-parallel to) shock. Whether it is driven by interplanetary discontinuities or turbulent Q-parallel to shock, however, is unclear. Using three-dimensional global hybrid simulation, we investigate the generation of magnetic reconnection downstream of the Q-parallel to shock, while an interplanetary rotational discontinuity (RD) is launched to the bow shock. Cases with various solar wind Alfven Mach numbers, M-A = 3.0 to 8, and propagation directions of the RD are presented. The propagation direction n is assumed to be in the GSE xz plane and pointing earthward, with n = (-sin(theta(12)/2),0,-cos(theta(12)/2)), where theta(12) is the angle between the upstream (B-1) and downstream (B-2) magnetic fields across the transmitted RD. It is found that magnetic reconnection occurs inside the RD downstream of the Q-parallel to shock, forming flux ropes extending along the dawn-dusk direction about tens of ion inertial lengths. Large-amplitude low-frequency waves originated from the Q-parallel to shock lead to the bending and squeezing of the field lines around the RD, which play an important role in triggering reconnection inside the RD. As the RD impacts the dayside magnetopause, magnetopause reconnection takes place between the field lines behind the RD and geomagnetic field lines. Nevertheless, no reconnection is found downstream of the Q-parallel to shock itself or outside the RD in the magnetosheath. The existent and structure of reconnection in the magnetosheath are found to strongly depend on the parameters M-A and n. Our simulation shows that ion-scale magnetic reconnection is driven by an external driver in the form of the compression of an RD around the bow shock and in the magnetosheath, rather than caused by the turbulent Q-parallel to shock alone.PublishedYe