Self‐modulation of an intense relativistic electron beam

High levels of coherent current and energy oscillations appeared on an intense relativistic electron beam traversing a smooth drift tube in which two or more coaxial cavities were inserted. The frequency of oscillation depended strongly on the geometry of the drift region but only weakly on beam current and voltage. The frequency spectrum of modulation was monochromatic. By changing geometry, frequencies of up to 3 GHz were observed. Relativistic electron beams with voltages varying from 0.25 to 1 MeV and currents from 1 to 8 kA were modulated with efficiencies approaching 100%. The structure of the electron bunches was tailored by changes in the geometry. Both theory and particle simulation show that the presence of the cavities along the drift tube altered the simple streaming motion of the beam in a smooth drift tube resulting in a highly nonlinear beam behavior. The complex beam dynamics was governed by formation of virtual cathodes, reflexing electrons, and autoacceleration. Shaped electron bunches h...

[1]  D. Ryutov,et al.  Powerful relativistic electron beams in a plasma and in a vacuum (theory) , 1974 .

[2]  Peter T. Kirstein,et al.  Space-Charge Flow , 1968 .

[3]  D. Hammer,et al.  Catastrophic disruption of the flow of a magnetically confined intense relativistic electron beam , 1972 .

[4]  J. Poukey,et al.  Limiting current for hollow rotating beams , 1974 .

[5]  M. L. Sloan,et al.  Autoresonant Accelerator Concept , 1973 .

[6]  M. Reiser Laminar‐flow equilibria and limiting currents in magnetically focused relativistic beams , 1977 .

[7]  R. C. Davidson Theory of nonneutral plasmas , 1974 .

[8]  M. Friedman AUTOACCELERATION OF AN INTENSE RELATIVISTIC ELECTRON BEAM , 1973 .

[9]  R. Collin Foundations for microwave engineering , 1966 .

[10]  R. Miller,et al.  An Introduction to the Physics of Intense Charged Particle Beams , 1982 .

[11]  Y. Carmel,et al.  Intense Coherent Cherenkov Radiation Due to the Interaction of a Relativistic Electron Beam with a Slow-Wave Structure , 1974 .

[12]  A. Drobot,et al.  Propagation of intense relativistic electron beams through drift tubes with perturbed walls , 1983 .

[13]  M. Friedman,et al.  Production and Focusing of a High Power Relativistic Annular Electron Beam , 1970 .

[14]  L. N. Kazanskii,et al.  Selfacceleration in intense electron beams , 1971 .

[15]  M. Friedman,et al.  Microsecond Duration Intense Relativistic Electron Beams , 1972 .

[16]  R. Briggs Space-charge waves on a relativistic, unneutralized electron beam and collective ion acceleration , 1976 .

[17]  V. Serlin,et al.  Interaction of a modulated intense relativistic electron beam with a cavity , 1984 .

[18]  M. Friedman Automodulation of an intense relativistic electron beam , 1974 .

[19]  M. Friedman The C.P.A. (A Collective Particle Accelerator) , 1979, IEEE Transactions on Nuclear Science.

[20]  M. Read,et al.  Limiting currents in unneutralized relativistic electron beams , 1973 .

[21]  A. Mondelli,et al.  The interaction between a modulated intense relativistic electron beam and a background plasma , 1975 .

[22]  T. Lockner,et al.  Collective acceleration of electrons using an autoacceleration process , 1980 .

[23]  R. D. Evans,et al.  Atomic Nucleus , 2020, Definitions.

[24]  M. Friedman Emission of intense microwave radiation from an automodulated relativistic electron beam , 1975 .

[25]  V. Serlin,et al.  Conversion of the energy of intense relativistic electron beams into high‐power electrical pulses , 1983 .