1,671 research outputs found
A relativistic two-stream instability in an extremely low-density plasma
A linear analysis based on two-fluid equations in the approximation of a cold
plasma, wherein the plasma temperature is assumed to be zero, demonstrates that
a two-stream instability occurs in all cases. However, if this were true, the
drift motion of electrons in an electric current over a wire would become
unstable, inducing an oscillation in an electric circuit with ions bounded
around specific positions. To avoid this peculiar outcome, we must assume a
warm plasma with a finite temperature when discussing the criterion of
instability. The two-stream instability in warm plasmas has typically been
analyzed using kinetic theory to provide a general formula for the instability
criterion from the distribution function of the plasma. However, the criteria
based on kinetic theory do not have an easily applicable form. Here, we provide
an easily applicable criterion for the instability based on the two-fluid model
at finite temperatures, extensionally in the framework of special relativity.
This criterion is relevant for analyzing two-stream instabilities in
low-density plasmas in the universe and in Earth-based experimental devices.Comment: 18pages, 4 figures, accepted for pubblication on Po
Evaluation and correlation of diffusion coefficient data : the most probable values of the self-diffusion coefficients of gaseous methane
The experimental diffusion coefficient data of gaseous methane available in the literature have been evaluated from the view-point of their reliability, and correlated with temperature and pressure. The most probable values are presented in the table covering the range of temperature from 198.15 to 348.15 K and that of pressure up to 260×10^5 Pa
Influence of Surface Treatment on the Strength of Solid-State Diffusion-Bonded Interface of Tin(Materials, Metallurgy & Weldability, INTERNATIONAL SYMPOSIUM OF JWRI 30TH ANNIVERSARY)
The structure and behavior of the arctic cyclone in summer analyzed by the JRA-25/JCDAS data
AbstractIn this study, three-dimensional structures and the life-time behavior of arctic cyclones are investigated as case studies, using reanalysis data of JRA-25 and JCDAS. In recent years, arctic region has undergone drastic warming in conjunction with the reduced sea ice concentration in summer. The rapid reduction of the sea ice concentration is explained, to some extent, by a pressure dipole of the arctic cyclone and Beaufort high over the Arctic Ocean. This paper presents some case studies for the structure of the arctic cyclone.It is found by the analysis of this study that the arctic cyclone indicates many differences in structure and behavior compared with the mid-latitude cyclone. The arctic cyclones move rather randomly in direction over the Arctic Ocean. The arctic cyclone has a barotropic structure in the vertical from the surface to the stratosphere. The arctic cyclone detected at the sea level pressure is connected with the polar vortex at the 500 hPa level and above. Importantly, the arctic cyclone has a cold core in the troposphere and a warm core around the 200 hPa level. The mechanism of the formation is discussed based on the analyzed structure of the arctic cyclones
Current-Induced Magnetization Switching and CPP-GMR in 30 nm φ Scale Spin Valves Fabricated Using EB-Assisted CVD Hard Masks
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