1,742 research outputs found
Iron charge states observed in the solar wind
Solar wind measurements from the ULECA sensor of the Max-Planck-Institut/University of Maryland experiment on ISEE-3 are reported. The low energy section of approx the ULECA sensor selects particles by their energy per charge (over the range 3.6 keV/Q to 30 keV/Q) and simultaneously measures their total energy with two low-noise solid state detectors. Solar wind Fe charge state measurements from three time periods of high speed solar wind occurring during a post-shock flow and a coronal hole-associated high speed stream are presented. Analysis of the post-shock flow solar wind indicates the charge state distributions for Fe were peaked at approx +16, indicative of an unusually high coronal temperature (3,000,000 K). In contrast, the Fe charge state distribution observed in a coronal hole-associated high speed stream peaks at approx -9, indicating a much lower coronal temperature (1,400,000 K). This constitutes the first reported measurements of iron charge states in a coronal hole-associated high speed stream
Spatial dependence of the local diffusion coefficient measured upstream of the November 12, 1978 interplanetary traveling shock
Characteristics of wuprathermal particles accelerated by quasi-parallel interplanetary traveling shocks have been generally explained in terms of a first order Fermi mechanism. Such models require diffusive scattering of particles upstream of the shock. This scattering is characterized by a local diffusion coefficient, kappa, which is determined by the local power density of waves in the upstream region. The dependence of the diffusion coefficient of suprathermal upstream protons on distance from the November 12, 1978 interplanetary traveling shock using a different approach is studied. Unlike previous studies this method, which is based on measurements of particle streaming and intensity gradients, does not rely on predictions. The local spatial variations of Kappa upstream of the November 12, 1978 shock have been chosen for study because the characteristics of this quasi-parallel shock have been extensively studied, and also because of its favorable geometry (i.e. B field nearly radial)
Observation of pick-up ions in the solar wind: Evidence for the source of the anomalous cosmic ray component?
Singly ionized energetic helium has been observed in the solar wind by using the time of flight spectrometer SULEICA on the AMPTE/IRM satellite between September and December, 1984. The energy density spectrum shows a sharp cut off which is strongly correlated with the four fold solar wind bulk energy. The absolute flux of the He(+)ions of about 10000 ion/sq cm.s is present independent of the IPL magnetic field orientation. The most likely source is the neutral helium of the interstellar wind which is ionized by solar UV radiation. It is suggested that these particles represent the source of the anomalous cosmic ray component
Examining the pseudo-standard web search engine results page
Nearly every web search engine presents its results in an identical format: a ranked list of web page summaries. Each summary comprises a title; some sentence fragments usually containing words used in the query; and URL information about the page. In this study we present data from our pilot experiments with eye tracking equipment to examine how users interact with this standard list of results as presented by the Australian sensis.com.au web search service. In particular, we observe: different behaviours for navigational and informational queries; that users generally scan the list top to bottom; and that eyes rarely wander from the left of the page. We also attempt to correlate the number of bold words (query words) in a summary with the amount of time spent reading the summary. Unfortunately there is no substantial correlation, and so studies relying heavily on this assumption in the literature should be treated with caution
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New directions in self-regulation: the role of metamotivational beliefs
Research on self-regulation has primarily focused on how people exert control over their thoughts, emotions, and behavior. Less attention has been paid to the ways in which people manage their motivational states in the service of achieving valued goals. In the present paper, we explore an emerging line of research that focuses on people’s beliefs about their own motivation (i.e., their metamotivational knowledge), as well as the influence of these beliefs on their selection of regulatory strategies. In particular, we review evidence showing that people are often quite sensitive to the fact that distinct motivational states (e.g., eagerness vs. vigilance) are adaptive for different kinds of tasks. We also discuss how other metamotivational beliefs are inaccurate on average (e.g., beliefs about how rewards affect intrinsic motivation). Finally, we consider the implications of metamotivation research for the field of self-regulation and discuss future directions
The mean ionic charges of N, Ne, MG, SI and S in solar energetic particle events
The mean ionic charges of nitrogen, neon, magnesium, silicon, and sulfur in solar flare particle events were determined for 12 flares during the time interval from September 1978 to September 1979. The observations were carried out with the MPI/UoMd ULEZEQ Sensor on the ISEE-3 satellite comparing the results with mean charge states established in a hot coronal plasma under equilibrium conditions, different temperatures for different elements are discussed. These range from approx. 2 million K to 7 million K in a single flare. From flare to flare the variation in temperature for each element is less than the variation between different ion species
Full particle simulation of a perpendicular collisionless shock: A shock-rest-frame model
The full kinetic dynamics of a perpendicular collisionless shock is studied
by means of a one-dimensional electromagnetic full particle simulation. The
present simulation domain is taken in the shock rest frame in contrast to the
previous full particle simulations of shocks. Preliminary results show that the
downstream state falls into a unique cyclic reformation state for a given set
of upstream parameters through the self-consistent kinetic processes.Comment: 4 pages, 2 figures, published in "Earth, Planets and Space" (EPS),
the paper with full resolution images is
http://theo.phys.sci.hiroshima-u.ac.jp/~ryo/papers/shock_rest.pd
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