Backscattering cascade of beam modes off ambient density fluctuations Journal Article uri icon

Overview

abstract

  • The effects of a given nonthermal low-frequency density-fluctuation spectrum on the amplification of Langmuir waves by a ‘‘bump-on-tail’’ beam of electrons are studied. The density-fluctuation spectrum is assumed to contain a uniform distribution of wavelengths ranging from much shorter than the beam mode wavelength to of the same order. This permits multiple large-angle (back) scattering to occur. One-dimensional numerical solutions of the kinetic equations are found which yield criteria for linear saturation of the beam instability by a cascade of backscattering to high wavenumber. The relevant time scales and spectral shapes are also determined in both the stable and unstable regions. Linear damping and Cerenkov emission by a possible nonthermal tail of electrons is taken into account. An application is made to the beam modes observed simultaneously with density fluctuations off the Jovian bow shock. It is shown that the observed level of density fluctuations is sufficient to saturate the unstable Langmuir waves, although nonthermal Landau damping may prevent a cascade to very high wavenumbers.

publication date

  • September 1, 1983

has restriction

  • closed

Date in CU Experts

  • February 4, 2015 7:26 AM

Full Author List

  • Russell DA; Goldman MV

author count

  • 2

Other Profiles

International Standard Serial Number (ISSN)

  • 0031-9171

Additional Document Info

start page

  • 2717

end page

  • 2730

volume

  • 26

issue

  • 9