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Choyal Y. Minami K. Granatstein V.L. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2004,32(6):2157-2168
The linear dispersion relation of a backward-wave oscillator (BWO), derived earlier by the authors, is modified to include effects of RF surface current at the beam-vacuum interface. This modified dispersion relation results in an unstable interaction between the slow cyclotron mode (SCM) and the structure mode in addition to the conventional Cherenkov instability caused by the slow space charge mode. Numerical analysis is then carried out using parameters of a BWO experiment at University of Maryland. Fine structure of the SCM instability is elucidated. The analysis indicates that BWO radiation would not be suppressed near cyclotron absorption in an infinitely long system. 相似文献
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A solvent extraction separation of uranium, in the presence of thorium, cerium and lanthanides with a new calix[4]resorcinarene bearing eight hydroxamic acid groups (C4RAHA) is described. Quantitative extraction of uranium is possible in ethyl acetate solution of C4RAHA at pH 8.0. The lambda(max) and molar absorptivity (varepsilon) for uranium is 356nm and 8352Lmol(-1)cm(-1). The Binding ratio of uranium with C4RAHA as evaluated by Job's method is 4:1. The system obeys Beer's law over the range 0.075-6.0mugml(-1) of uranium with Sandell sensitivity 0.0284mugcm(-2). A preconcentration factor of 142 was achieved by directly aspirating the extract for GF-AAS measurements. The two-phase stability constant evaluated at 25 degrees C for uranium is 15.91. The complexation is characterized by favorable enthalpy and entropy changes. A liquid membrane transport study of uranium was carried out from source to the receiving phase under controlled conditions and a mechanism of transport is proposed. Uranium has been determined in standard and environmental samples. 相似文献
3.
An analytical and numerical study of backward wave oscillator (BWO) in linear regime is presented to get an insight into the
excitation of electromagnetic waves as a result of the interaction of the relativistic electron beam with a slow wave structure.
The effect of background plasma on the BWO instability is also presented. 相似文献
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Analytical and numerical study of the stability of sheet electron beam in periodically cusped magnetic field (PCM) is made.
The beam has been considered as having diffused density profile. The conditions for beam focusing are discussed. 相似文献
5.
Yaduvendra Choyal Lalit Gupta Prasad Deshpande Krishna Prasad Maheshwari Kailash Chander Mittal Suresh Chand Bapna 《Pramana》2008,71(6):1301-1310
In this paper, a high power relativistic backward wave oscillator (BWO) experiment is reported. A 230 keV, 2 kA, 150 ns relativistic
electron beam is generated using a Marx generator. The beam is then injected into a hollow rippled wall metallic cylindrical
tube that forms a slow wave structure. The beam is guided using an axial pulsed magnetic field having a peak value 1 T and
duration 1 ms. The field is generated by the discharge of a capacitor bank into a solenoidal coil. A synchronization circuit
ensures the generation of the electron beam at the instant when the axial magnetic field attains its peak value. The beam
interacts with the SWS modes and generates microwaves due to Cherenkov interaction. Estimated power of 2 MW in TM01 mode is observed.
相似文献
6.
Sawhney R. Maheshwari K.P. Choyal Y. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1993,21(6):609-613
A linear theory of the excitation of electromagnetic waves in a plasma-filled backward-wave oscillator driven by an intense relativistic electron beam is presented. It is found that the spatial growth rate of backward-wave instability exhibits a resonant increase for a particular value of fill-plasma density. Results are compared to the results of an experiment by K. Minami et al. (1988) on a high-power backward-wave oscillator 相似文献
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