Spectral properties of Langmuir and beam-mode waves observed inside terrestrial foreshock by Cluster spacecraf

0472426 - ÚFA 2017 US eng A - Abstract
Píša, David - Souček, Jan - Santolík, Ondřej
Spectral properties of Langmuir and beam-mode waves observed inside terrestrial foreshock by Cluster spacecraf.
AGU Fall Meeting. San Francisco: American Geophysical Union, 2016. SM13A-2187.
[AGU Fall Meeting 2016. 12.12.2016-16.12.2016, San Francisco]
Institutional support: RVO:68378289
Keywords : electrostatics plasma waves * Langmuir waves * beam-mode waves * bow shock * Cluster spacecraf
Subject RIV: BL - Plasma and Gas Discharge Physics
https://agu.confex.com/agu/fm16/meetingapp.cgi/Paper/156912

Electrostatic plasma waves are commonly observed in the upstream regions of planetary shocks. Solar wind electrons accelerated at the shock front are reflected back into the solar wind and form electron beams. The electron distribution becomes unstable and electrostatic waves are generated inside the foreshock region. The processes of generation and evolution of electrostatic waves significantly depend on the solar wind plasma conditions and generally exhibit complex behavior. Langmuir waves can be identified as intense narrowband emission at the local plasma frequency and weaker broadband beam-mode waves below and above the plasma frequency deeper in the downstream region. We present a long-term survey of Langmuir and beam-mode waves in the vicinity of the plasma frequency observed upstream of the terrestrial bow shock by the Cluster spacecraft. Using solar wind data and bow shock positions from OMNI, as well as in-situ measurements of interplanetary magnetic field, we have mapped all available spacecraft positions into foreshock coordinates. For a study of plasma waves, we have used spectra and local plasma frequencies obtained from a passive and active mode of the WHISPER instrument. We show a spatial distribution of wave frequencies and spectral widths as a function of foreshock positions and solar wind conditions.

Permanent Link: http://hdl.handle.net/11104/0269737