THE GGS POLAR MAGNETIC-FIELDS INVESTIGATION

The magnetometer on the POLAR Spacecraft is a high precision instrumen t designed to measure the magnetic fields at both high and low altitud es in the polar magnetosphere in 3 ranges of 700, 5700, and 47000 nT. This instrument will be used to investigate the behavior of field-alig ned current systems and the role they play in the acceleration of part icles, and it will be used to study the dynamic fields in the polar cu sp, magnetosphere, and magnetosheath. It will measure the coupling bet ween the shocked magnetosheath plasma and the near polar cusp magnetos phere where much of the solar wind magnetosphere coupling is thought t o take place. Moreover, it will provide measurements critical to the i nterpretation of data from other instruments. The instrument design ha s been influenced by the needs of the other investigations for immedia tely useable magnetic field data and high rate (100+ vectors s(-1)) da ta distributed on the spacecraft. Data to the ground includes measurem ents at 10 vectors per second over the entire orbit plus snapshots of 100 vectors per second data. The design provides a fully redundant ins trument with enhanced measurement capabilities that can be used when a vailable spacecraft power permits.