WAVE OBSERVATIONS AT THE FORESHOCK BOUNDARY IN THE NEAR-MARS SPACE

Wave and plasma measurements carried out by the Phobos-2 spacecraft in the Martian environment indicate that a part of solar wind electrons and ions are reflected and accelerated at the Martian bow shock. These particles streaming back into the solar wind lead to the formation of the foreshock region upstream the planetary bow shock. It is shown th at the general structure of the foreshock at Mars is similar to that o f the foreshock region upstream the Earth's bow shock. However, the el ectric emissions observed at frequencies around 100 Hz at the leading edge of electron foreshock at Mars have been never reported for observ ations in the similar region at Earth. The burst of these waves occurs before the spacecraft enters the electron foreshock identified with t he onset of electron plasma waves and calculations of the magnetic con nection to the planetary bow shock.