Accession Number:

ADA046802

Title:

Comparative Study of the Axial and Azimuthal Bunching Mechanisms in Electromagnetic Cyclotron Instabilities.

Descriptive Note:

Interim rept.,

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s):

Report Date:

1977-09-01

Pagination or Media Count:

28.0

Abstract:

A comparative study is presented of the axial and azimuthal bunching mechanisms of the electromagnetic electron cyclotron instability. Axial bunching can be described with a nonrelativistic treatment, but azimuthal bunching is relativistic in origin. As is well known, the axial bunching mechanism drives the Weibel-type instability while the azimuthal bunching mechanism drives the electron cyclotron maser instability. For an electron ensemble of cold helical trajectories, a unified physical interpretation is presented for both instabilities. It is shown that the two bunching mechanisms are actually simultaneously present in either instability and compete with one another. As a result, the dominant mechanism determines the type of instability. A criterion for distinguishing the two types of instabilities is derived. It is shown that the energy of the electrons plays an insignificant role in the criterion and, hence, should not be a factor in the justification of a nonrelativistic treatment. Regimes of validity of nonrelativistic models are defined, however. Applications to gyroton experiments are discussed.

Subject Categories:

  • Lasers and Masers
  • Particle Accelerators
  • Quantum Theory and Relativity

Distribution Statement:

APPROVED FOR PUBLIC RELEASE