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The transport of cosmic rays in the interplanetary medium is considered in terms of the kinetic equation describing the energetic
particle scattering by magnetic irregularities and their focusing by the regular interplanetary magnetic field. The analytical
expression for solar cosmic ray distribution function in the approximation of radial regular magnetic field is obtained and
the evolution of energetic particle angular distribution is analyzed. The obtained results can be used for the analysis of
ground-level enhancements of cosmic ray intensity. 相似文献
2.
B. A. Shakhov M. Jurcisin E. Jurcisinova M. Stehlik 《Kinematics and Physics of Celestial Bodies》2012,28(5):225-231
The phenomenon of magnetic field generation in an astrophysical plasma in the frame of developed magnetohydrodynamic (MHD) turbulence is considered. The functional quantum field renormalization group approach is applied to helical anisotropic MHD developed turbulence which is stabilized by the self-generated homogeneous magnetic field. The purpose of the study is to calculate the value as well as direction of the magnetic field in the stochastic dynamo model. The generated magnetic field is determined by ignoring divergent rotor part of Green function of the magnetic field. It is shown that the magnetic field direction is connected with unique existing vector n describing the anisotropic turbulence forcing. 相似文献
3.
The quantum field model is used to study the correlation functions of velocity and magnetic fluctuations in helical developed
MHD turbulence of solar wind which is generated by random forces with mixed noise correlators. The exponential increase of
the magnetic fluctuations is stabilized by spontaneous symmetry breaking mechanism, which leads to the creation of homogeneous
magnetic field 〈E〉, and consequently, gives rise to the α-effect. The maximum value of the α-effect is determined in the Kolmogorov universal
regime and its contribution to the proton acceleration is estimated. The contribution of the α-effect to ∼100 MeV proton acceleration
is discussed and compared with the 2nd Fermi acceleration mechanism.
This article was submitted by the authors in English. 相似文献
4.
Statistical acceleration of cosmic rays in a turbulent medium is considered. Charged particles are assumed to acquire energy in a bounded region of space and leave the acceleration region due to spatial diffusion caused by the scattering of cosmic rays in turbulent magnetic fields. Analytical solutions of the cosmic ray transport equation are obtained and equilibrium space-energy distributions of high-energy particles are studied in the acceleration region and beyond. 相似文献
5.
The non-diffusive transport of an anisotropic pulse of cosmic ray charged particles in an inhomogeneous medium with a regular magnetic field is considered. Both the angle particle distribution in a source and the angle dependence of a detector response as well as the time dependent particle injection from the source into the medium are comprised. The temporal dependences of the particle number and of the detected particle intensity are demonstrated at various distances from the source. It is shown that the temporal profiles are strongly dependent on the anisotropy value and they have dissimilar behaviour for different asymptotic direction of detector. 相似文献
6.
The propagation of energetic particles in the interplanetary space is considered on the basis of kinetic equation describing
the scattering of charged particles by magnetic irregularities and the particle focusing by regular magnetic field. Our analysis
confirms that angular distribution of solar cosmic rays contains a valuable information about properties of the particle scattering
in the interplanetary magnetic field. Steady state solutions of the kinetic equation are applied to the analysis of solar
proton events. 相似文献
7.
A theory of the transport of an anisotropic pulse of charged particles injected into the interplanetary magnetic field is applied to an anisotropic ground level event on 24 May 1990. For this event the kinetic regime is considered when the mean free path is comparable with the distance from particle source. Both the source angular particle distribution and the angular dependence of a detector response are included. The theoretically predicted temporal profiles are compared with the particle intensity records measured by several neutron monitors with different asymptotic directions. 相似文献
8.
The exact analytic expression for the density of energetic charged particles, which were injected by an instantaneous point
source at a particular pitch angle into the interplanetary medium, has been derived. We start from the Boltzmann kinetic equation
with the collision integral describing the isotropic particle scattering by "massive" magnetic clouds. The solution has been
obtained without any expansion parameters in the 3-dimensional vector form, then it was projected into the cylindrical coordinate
system. The space-time particle distribution is disscussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
9.
Juvenile and adult winter flounder,Pseudopleuronectes americanus Walbaum (Pleuronectidae), from the Navesink River and Sandy Hook Bay, New Jersey, U.S., were examined for ontogenetic, seasonal, and spatial variation in dietary content. Fish (n=1291 non-empty) were placed by cluster analysis of dietary content into three size groups: 15–49, 50–299, and ≥300 mm total length. Clear ontogenetic patterns were revealed, in particular the disappearance of calanoid copepods from the diet as fish grew >50 mm and an increase in number of taxa in the diet with growth. Fish in size group 1 fed upon spionid polychaetes, the calanoid copepodEurytemora affinis, and ampeliscid amphipods. Fish in size group 2 added various species of polychaetes, amphipods, and siphons of the bivalveMya aremaria to their diets. Size group 2 was present during all months of the survey, but only minor seasonal differences in their diet were apparent. One obvious change was the increase in consumption of the shrimpCrangon septemspinosa in summer and fall. Size group 3 fish, collected mainly in fall, ate large volumes ofM. arenaria and glycerid polychaetes. Cluster analysis showed a largescale spatial pattern in diet among fish of size group 1, related to the presence ofE. affinis in winter flounder diets in the river and a marsh cove in the bay. Small-scale spatial differences in diets of fish in size group 2 were possibly related to prey distribution. 相似文献
10.
Habitat use,temporal abundance variability,and diet of blue crabs from a New Jersey estuarine system
In a long-term, spatially comprehensive beam trawl survey of the Navesink River-Sandy Hook Bay estuary, the blue crabCallinectes sapidus was one of the most abundant species. Seasonal changes in abundance were evident, with low abundances in summer followed
by peak abundances in the fall, after juveniles recruited to the estuary. We saw no long-term trends in abundance during the
5 yr study. Location in the navesink River or Sandy Hook Bay explained most of the variance in abundance within any one survey.
In diet analyses, we found evidence of cannibalism in all seasons, but in the size range of crabs caught in this study (10–180
mm), we did not find a relationship between cannibalism and juvenile crab abundance. Within surveys, crabs divided into 20
mm size categories showed no sizerelated differences in location within the estuary or among 7 habitat types examined (algae
bed, amphipod bed, beach, channel, marsh edge, mid-depth, and sandbar). Channels and sandbars tended to exhibit lower crab
abundance than other habitats. Shallow habitats with and without cover were equally preferred by juvenile blue crabs, implying
that the presence of structure was not critical. Spatial models of crab abundance (<- 80 mm carapace width) to environmental
data were fit from several seasons of intensive sampling in the Navesink River-Sandy Hook Bay estuary between summer 1996
and spring 1998. These models indicated that fine-grained sediments, tmmperature, depth, and salinity were good indicators
of crab abundance in spring, summer, and fall. Using these spatial models and environmental data collected in subsequent seasons
(summer 1998−fall 1999), we were able to predict blue crab abundance in the river as evidenced by significant correlations
between predicted and observed abundances. For the size range of crabs examined here, physical conditions may be as important
as structural habitat types or cannibalism in determining habitat use in northerly estuaries. 相似文献
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