THE RELATIONSHIP BETWEEN THE MAGNETIC-FIELD IN THE MARTIAN MAGNETOTAIL AND UPSTREAM SOLAR-WIND PARAMETERS

Magnetic field data measured by the MAGMA instrument in the Martian ma gnetotail lobes are compared with the ram pressure of the upstream sol ar wind observed by the TAUS instrument in the circular orbits of the Phobos 2 spacecraft. High correlation was found between the magnetic f ield intensity in the Martian magnetotail lobes and the solar wind ram pressure. From this relationship the average flaring angle of the Mar tian magnetotail was determined as similar to 13 degrees, and the aver age magnetosonic Mach number was estimated as similar to 5. The observ ed relationship between the Martian magnetotail magnetic field intensi ty and the solar wind magnetic field reflects the correlation of the s olar wind magnetic field to the ram pressure providing a value of simi lar to 7 for the average Alfvenic Mach number. The flaring angle obtai ned for the Martian magnetotail was found to be an intermediate value between the flaring angle of the magnetotail of the Earth and that of Venus at comparable distances.