Magnetometer (MAG)

The magnetometer (MAG) experiment (Figure below ) will provide in-situ measurements of the heliospheric magnetic field with high precision. In addition to studies of the near-Sun heliospheric plasma and fields, MAG will address how the magnetic field links into space and evolves over the solar cycle; how waves and turbulence are generated and dissipated, and how heliospheric structures develop in the inner solar system. The magnetometer instrument comprises two digital fluxgate sensors operated in the dual-magnetometer mode (both in shadow and mounted on the instrument boom behind the spacecraft body) and an electronics box located inside the spacecraft structure. In-board to out-board sensor separation on the boom will be ~2 m. The fluxgate sensor design is highly suited to the Solar Orbiter mission, since it exhibits excellent stability, both with respect to time and changing temperature. A photograph of one of the sensors (cover removed) is shown below. This sensor design has solid space heritage, having flown successfully on Cassini and Double Star. The dual-magnetometer technique allows background fields induced by the spacecraft to be subtracted from the true heliospheric magnetic field.

In addition to the fluxgate sensors with their own dedicated front-end electronics, the main functional elements of the instrument are an instrument controller unit (ICU) to control the instrument and manage communications with the spacecraft, and a power converter unit (PCU) for provision of secondary voltages to the sensor electronics, ICU and sensor heaters. The instrument block diagram is shown left. The MAG instrument is largely autonomous in operation, requiring only a minimum of commanding for selecting from a set of science operations modes and corresponding telemetry bit-rates. Preliminary thermal modelling shows that each sensor will require 0.6 W to maintain the sensors within the operating temperature range. The power of the required heaters will be confirmed once a boom design is selected and more detailed studies of the thermal environment have been completed.

Also available MAG specifications.