Langmuir turbulence in the auroral ionosphere: 2. Nonlinear theory and simulations

Journal Article · Fri Apr 01 04:00:00 EST 1994 · Journal of Geophysical Research

DOI:https://doi.org/10.1029/93JA03183· OSTI ID:121277

Newman, D L; Goldman, M V ^[1]; Ergun, R E ^[2]

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1. Univ. of Colorado, Boulder, CO (United States)
2. Univ. of California, Berkeley, CA (United States)

A theoretical interpretation of sounding rocket measurements of intense Langmuir wave fields ({le} 500 mV/m) driven by a stream of 20 eV-4 keV electrons in the lower auroral zone is developed. This interpretation is based on the ability of the 10 {mu}s sampling rate of the wave detector to temporally resolve the structure of the Langmuir wave field envelope. A modified form of the Zakharov equations is used to numerically study beam-driven Langmuir turbulence in the presence of a moderate magnetic field ({Omega}{sub e} {approx} {omega}{sub pe}). Strong Landau damping on observed nonthermal scattered electrons, which is treated in a companion paper, plays an important role by inhibiting backscatter cascade and the development of strong turbulence. A parameterized model of the linear electron stream-driven wave instability is introduced, which incorporates limited quasilinear plateau formation. A reasonable set of parameters is found that yields semiquantitative agreement between observed properties of the Langmuir fields and the results of Zakharov equation simulations, including the amplitude and characteristic frequency of the electric field envelope modulations. 32 refs., 6 figs., 1 tab.

• OSTI ID: 121277
• Journal Information: Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: A4 Vol. 99; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
AURORAL ZONES
DAMPING
IONOSPHERE
NONLINEAR PROBLEMS
PLASMA WAVES
SIMULATION
TURBULENCE