Open AccessCharacteristics of Langmuir electric field waveforms and power spectra exhibiting nonlinear behavior in Earth's foreshock
Author(s) -
Sigsbee K.,
Kletzing C. A.,
Pickett J. S.,
Gurnett D. A.,
Schwartz S. J.,
Lefebvre B.,
Lucek E.,
Fazakerley A. N.,
Kucharek H.
Publication year - 2010
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2009ja014948
Subject(s) - physics , amplitude , spectral line , harmonics , atomic physics , computational physics , electric field , optics , quantum mechanics , voltage , astronomy
Langmuir wave characteristics in the Earth's foreshock were examined to identify possible nonlinear wave behavior for two case studies with data from the Cluster Wideband Data Plasma Wave Receiver. The occurrence rates of four types of power spectra near the foreshock edge were determined: (1) spectra with power at the local plasma frequency f pe only, (2) spectra with power at f pe and 2 f pe , (3) spectra with double peaks near f pe , and (4) spectra with double peaks near f pe and peaks at low frequencies indicative of ion acoustic waves. For electric field waveform amplitudes between 0.1 and 22.0 mV/m, most power spectra fell into the f pe only and double‐peaked categories. The maximum Langmuir wave amplitudes and bump‐on‐tail reduced electron distribution functions from Cluster PEACE data were more consistent with saturation of wave growth by electrostatic decay than modulational instabilities. However, few spectra had the double peaks near f pe and ion acoustic waves indicative of electrostatic decay, suggesting other processes may also be at work. For amplitudes greater than 22.0 mV/m, most power spectra fell into the f pe and 2 f pe category, but many of the harmonics were too weak to be clearly distinguished from harmonics caused by instrumental effects.