4,484 research outputs found
Making it in academic psychology: Demographic and personality correlates of eminence
Citations to published work, personality, and demographic characteristics were examined in a sample of male and female academic psychologists. A large sex difference was found in citations with men receiving significantly more recognition. Reputational rankings of graduate school and current institution were significantly related to citations, as were components of achievement motivation. Mastery and work needs were positively related to citations while competitiveness was negatively associated with the criterion. A model of attainment in psychology is proposed and possible explanations for the differential recognition of women are explored
A Variational Fock-Space Treatment of Quarkonium
The variational method and the Hamiltonian formalism of QCD are used to
derive relativistic, momentum space integral equations for a quark-antiquark
system with an arbitrary number of gluons present. As a first step, the
resulting infinite chain of coupled equations is solved in the nonrelativistic
limit by an approximate decoupling method. Comparison with experiment allows us
to fix the quark mass and coupling constant, allowing for the calculation of
the spectra of massive systems such as charmonium and bottomonium. Studying the
results with and without the nonAbelian terms, we find that the presence of the
nonAbelian factors yields better agreement with the experimental spectra.Comment: TEX, no figure
Characteristics of ion flow in the quiet inner plasma sheet
Abstract
We use AMPTE/IRM and ISEE 2 data to study the properties of the high beta (βi \u3e 0.5) plasma sheet, the inner plasma sheet (IPS). Bursty bulk flows (BBFs) are excised from the two databases, and the average flow pattern in the non-BBF (quiet) IPS is constructed. At local midnight this ensemble-average flow is predominantly duskward; closer to the flanks it is mostly earthward. The flow pattern agrees qualitatively with calculations based on the Tsyganenko [1987] model (T87), where the earthward flow is due to the ensemble-average cross tail electric field and the duskward flow is the diamagnetic drift due to an inward pressure gradient. The IPS is on the average in pressure equilibrium with the lobes. Because of its large variance the average flow does not represent the instantaneous flow field. Case studies also show that the non-BBF flow is highly irregular and inherently unsteady, a reason why earthward convection can avoid a pressure balance inconsistency with the lobes. The ensemble distribution of velocities is a fundamental observable of the quiet plasma sheet flow field
An event study to provide validation of TING and CMIT geomagnetic middle-latitude electron densities at the F2 peak
[1] The coupled thermosphere-ionosphere magnetosphere (CMIT) model and the Thermosphere Ionosphere Nested Grid (TING) model have been run to simulate the 15 May 1997 interplanetary coronal mass ejection\u27s (ICME) effects on the Earth\u27s ionosphere and thermosphere. Comparisons were made between these model runs, the IRI-2007 model, and geomagnetic middle-latitude ionosonde data (NmF2) from the World Data Center to determine how well the models simulated the event and to understand the causes of model-data disagreement. The following conclusions were drawn from this study: (1) skill scores were more often negative than positive on average; (2) the best and the worst skill scores occurred on the recovery day; (3) the line plots comparing models to data look better than the skill scores might suggest; (4) skill scores are significantly affected by timing issues and large, short-duration variability; (5) skill scores give an indication of the relative ability of one model relative to another, rather than an absolute statement of model accuracy; (6) the models capture negative storm effects better than they capture positive storm effects; (7) the TING model captured many short duration features seen in the data at high middle latitude stations that result from changes in the size of the auroral oval; (8) CMIT overestimates the energy driving changes in NmF2, whereas TING provides approximately the correct energy input as a result of the saturation effects on potential that are included in TING; and (9) both TING and CMIT electron densities decreased too rapidly after sunset
Energetic magnetosheath ions connected to the Earth\u27s bow shock: Possible source of cusp energetic ions
Van Allen Probes show that the inner radiation zone contains no MeV electrons: ECT/MagEIS data
Abstract
We present Van Allen Probe observations of electrons in the inner radiation zone. The measurements were made by the Energetic Particle, Composition, and Thermal Plasma/Magnetic Electron Ion Spectrometer (MagEIS) sensors that were designed to measure electrons with the ability to remove unwanted signals from penetrating protons, providing clean measurements. No electrons \u3e900 keV were observed with equatorial fluxes above background (i.e., \u3e0.1 el/(cm2 s sr keV)) in the inner zone. The observed fluxes are compared to the AE9 model and CRRES observations. Electron fluxes \u3c200 keV exceeded the AE9 model 50% fluxes and were lower than the higher-energy model fluxes. Phase space density radial profiles for 1.3 ≤ L* \u3c 2.5 had mostly positive gradients except near L*~2.1, where the profiles for μ = 20–30 MeV/G were flat or slightly peaked. The major result is that MagEIS data do not show the presence of significant fluxes of MeV electrons in the inner zone while current radiation belt models and previous publications do
Posteruptive phenomena in coronal mass ejections and substorms: Indicators of a universal process?
[1] We examine phenomena associated with eruptions in the two different regimes of the solar corona and the terrestrial magnetosphere. We find striking similarities between the speeds of shrinking magnetic field lines in the corona and dipolarization fronts traversing the magnetosphere. We also examine the similarities between supra-arcade downflows observed during solar flares and bursty bulk flows seen in the magnetotail and find that these phenomena have remarkably similar speeds, velocity profiles, and size scales. Thus we show manifest similarities in the magnetic reconfiguration in response to the ejection of coronal mass ejections in the corona and the ejection of plasmoids in the magnetotail. The subsequent return of loops to a quasi-potential state in the corona and field dipolarization in the magnetotail are physical analogs and trigger similar phenomena such as downflows, which provides key insights into the underlying drivers of the plasma dynamics
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