The influence of a background plasma on the diocotron instability of a relativistic hollow electron beam. Final report

Technical Report · Tue Sep 01 00:00:00 EDT 1981

OSTI ID:6794351

Bilow, H J; Uhm, H S

The influence of a background plasma on the diocotron instability of a relativistic hollow electron beam is investigated within the framework of a cold fluid model. The background plasma is taken to have a uniform density except at the mean radius of the electron beam where the density is assumed to be discontinuous. Of the charged species comprising the plasma, only the electrons influence the dynamics of the beam-plasma system; the effect of the ions is negligible because of their small plasma frequency. A dispersion relation for the eigenfrequencies of the system is derived and employed to examine instabilities. It is found that the fundamental mode, which is unconditionally stable for a hollow electron beam in a vacuum, is now unstable for certain parameter regimes. The appearance or growth of instabilities with increases in the plasma density discontinuity is observed, while increases in the relativistic factor are seen to exert a stabilizing influence. It is also found that thin beams are generally more unstable than thick ones.

• Research Organization: Naval Surface Weapons Center, Silver Spring, MD (USA)
• OSTI ID: 6794351
• Report Number(s): AD-A-113530/0
• Country of Publication: United States
• Language: English

Related Subjects

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