Terrestrial Low Frequency bursts: escape paths of radio waves through the bow shock
Abstract
From the analysis of more than hundred Low Frequency (LF) burst spectra observed by the Wind spacecraft near the Lagrange point L1, we propose an interpretation of the frequency-time characteristics of these spectra, and we use these characteristics to sound the bow shock structure at large tailward distances from Earth. Except for a few LF bursts, neither the solar wind overdensities nor the shock density barrier can explain the observed low-frequency cutoff f_c of the LF bursts. Scattering on plasma density inhomogeneities has to be introduced to account for f_c, for the onset time of the LF burst, which increases when the frequency decreases towards f_c, and for the shape of the LF burst spectra below twice the solar wind plama frequency. This implies that the bow shock still exists beyond 1000 R_E from the Earth.
- Publication:
-
EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA.....3380L