9,016 research outputs found
Photoionization measurement study
An analysis was conducted of a gas window photoionization device for studying cosmic X-rays in the region 20 eV to 1 keV. The detecting element is an argon proportional counter whose window is a two-dimensional supersonic gas jet. Spectroscopic features of the incoming radiation can be determined by the choice of gas forming the jet (as well by the fluid dynamic parameters of the flow). The choice of gas can be made from pure substances and/or compounds with Z between 1 and 10. The counter walls can be prepared for selective analysis of the extreme ultraviolet radiation
Statistical Mechanics of Charged Particles in the Pressure of Magnetic Irregularities
Statistical mechanics of charged particles in presence of magnetic irregularitie
The one-dimensional Lennard-Jones system: collective fluctuations and breakdown of hydrodynamics
The dynamical correlations of a model consisting of particles constrained on
the line and interacting with a nearest--neighbour Lennard--Jones potential are
computed by molecular--dynamics simulations. A drastic qualitative change of
the spectral shape, from a phonon--like to a diffusive form, is observed upon
reducing the particle density even ad moderate temperatures. The latter
scenario is due to the spontaneus fragmentation of the crystal--like structure
into an ensemble of "clusters" colliding among themselves. In both cases, the
spectral linewidths do not follow the usual q^2 behaviour for small wavenumbers
q, thus signalling a breakdown of linearized hydrodynamics. This anomaly is
traced back by the presence of correlations due to the reduced dimensionality.Comment: To be published in European Physical Journal
Study of cosmic rays in the solar environment Final report, 12 Jan. 1968 - 11 Jan. 1971
Convection-diffusion equation for closed formulation of cosmic ray transport theory in solar environmen
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