Large-amplitude electrostatic waves associated with magnetic ramp substructure at Earth's bow shock
Article first published online: 3 AUG 2006
Copyright 2006 by the American Geophysical Union.
Geophysical Research Letters
Volume 33, Issue 15, August 2006
How to Cite
2006), Large-amplitude electrostatic waves associated with magnetic ramp substructure at Earth's bow shock, Geophys. Res. Lett., 33, L15104, doi:10.1029/2005GL025564., , , , , , and (
- Issue published online: 3 AUG 2006
- Article first published online: 3 AUG 2006
- Manuscript Accepted: 15 JUN 2006
- Manuscript Revised: 25 APR 2006
- Manuscript Received: 20 DEC 2005
 We present Polar observations of high frequency (100 Hz ≲ f ≲ 4000 Hz) electrostatic (ES) waves at Earth's bow shock under extreme solar wind conditions. Although solitary waves are observed, the most prevalent structures in the magnetic ramp are coherent, large-amplitude (up to 80 mV/m) ES wave packets, which last 10–30 cycles, and propagate at varied obliquities relative to the magnetic field. The ES wave power is well correlated with maxima in the magnetic ramp substructure, suggesting that these maxima are important source regions. Detailed interferometric based analysis of waveforms show that they have wavelengths of a few hundred meters (e.g., ∼20λD ∼ 0.5ρe) and phase speeds at the acoustic speed, suggesting that they are ion acoustic waves (IAW)s. The IAWs, having potentials ≲1 V with no net change, are not likely to affect bulk plasma energization, though they may scatter the plasma and thus affect plasma thermalization.