The GGS/POLAR magnetic fields investigation

The magnetometer on the POLAR Spacecraft is a high-precision instrument designed to measure the magnetic fields at both high and low altitudes in the polar magnetosphere in three ranges of 700, 5700, and 47,000 nT. This instrument will be used to investigate the behavior of field-aligned current systems and the role they play in the acceleration of particles, and it will be used to study the dynamic fields in the polar cusp, magnetosphere, and magnetosheath. It will measure the coupling between the shocked magnetosheath plasma and the near polar cusp magnetosphere where much of the solar wind magnetosphere coupling is thought to take place. Moreover, it will provide measurements critical to the interpretation of data from other instruments. The instrument design has been influenced by the needs of the other investigations for immediately useable magnetic field data and high rate (100+ vectors/s) data distributed on the spacecraft. Data to the ground includes measurements at 10 vectors per second over the entire orbit plus snapshots of 100 vectors per second data. The design provides a fully redundant instrument with enhanced measurement capabilities that can be used when available spacecraft power permits. (Author)