Characteristics of spectra from the Martian bow shock and comparison with Venus, Earth, AMPTE, Jupiter, and Saturn

We present plasma wave spectra from crossings of the Martian bow shock by the Phobos 2 spacecraft and compare them with spectra from bow shocks at other planets and the AMPTE lithium release. We find that the shock spectra of the inner planets are very similar in shape, and their wave energy densities, when normalized to the upstream electron thermal energy density, are comparable. However, the Martian shock spectrum most resembles the spectrum from AMPTE, which may indicate either the presence of pickup particles or processes involving ions with gyroradii that are large compared with the size of the interaction region. The normalized wave amplitudes at Mars are midway between the high normalized amplitudes found at Jupiter and Saturn and the lower, normalized amplitudes at Earth. This is consistent with a trend that has recently been shown to occur out to Neptune's bow shock.