Theory of microwave generation by an intense relativistic electron beam in a rippled magnetic field

1974 ◽  
Vol 17 (2) ◽  
pp. 463 ◽  
Author(s):  
Wallace M. Manheimer
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Relativistic Electron ◽  
Relativistic Electron Beam ◽  
Microwave Generation

Fast-wave interaction with a relativistic electron beam

1974 ◽  
Vol 11 (2) ◽  
pp. 299-309 ◽  
Author(s):  
P. Sarangle
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Electron Beam ◽  
Relativistic Electron ◽  
Microwave Radiation ◽  
Relativistic Electron Beam ◽  
Parametric Instability ◽  
Travelling Wave ◽  
Fast Wave ◽  
Coupled Modes

The excitation of a relativistic electron beam, by means of a fast waveguide structure, is examined. Here the beam is injected into a modified waveguide, and interacts with the modes of the guide in such a way as to transform some of its energy into microwave radiation. This microwave generation device, called the Ubitron, is based upon a fast-wave excitation of a magnetically modulated relativistic electron beam. The beam is modulated by injecting it into a small spatially periodic magnetic field region within the guide. Analysis of this interaction shows that the slow space charge beam mode couples actively to the fast transverse electric guide mode. The result is parametric instability of the coupled modes. Synchronism between the doppler-shifted transverse travelling wave and the undulating electron beam results in a transfer of energy from the beam to the transverse field. The parametrically growing field can be a source of microwave radiation. The period magnetic field, together with the beam density, provide the coupling media between the unstable waves. The growth rate of the instability is shown to depend, in a nonlinear manner, on the product of the beam plasma frequency and the strength of the applied rippled magnetic field. The growth rate is obtained as a function of the system parameters.

scholarly journals HIGH-CURRENT RELATIVISTIC ELECTRON BEAM FOCUSING IN PLASMA

2021 ◽  
pp. 30-34
Author(s):  
О.V. Manuilenko ◽  
A.V. Pashchenko ◽  
V.G. Svichensky ◽  
B.V. Zajtsev
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
External Magnetic Field ◽  
Relativistic Electron ◽  
Relativistic Electron Beam ◽  
Beam Current ◽  
High Current ◽  
Plasma Parameters ◽  
Beam Focusing ◽  
Envelope Equation

The analysis of the envelope equation for high-current relativistic electron beam propagation in plasma in an external uniform magnetic field is presented. The envelope equation is obtained in a Hamiltonian form with an effective potential, which depends from electron beam and plasma parameters, and external magnetic field. Hamiltonian aproach allows fully analyze the behavior of the beam envelope as a function of the beam current, beam energy, plasma density and conductivity, as well as on the external magnetic field and the initial beam angular momentum.

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