How do fluxgate magnetometers work

What is a Fluxgate? The fluxgate magnetometer is a magnetic field sensor for vector magnetic field. It has traditionally been used for navigation and compass work as well as metal detection and prospecting. Fluxgate magnetometer designs fall into broadly two styles, those employing rod cores and those using ring cores.

Whilst there are many alternative designs mostly based on rod cores none have reached the state of development and performance attributed to two styles. For this reason this page is intended to apply only to the twin rod and ring core fluxgate variants. In a magnetically neutral background, the input and output currents match. However, when the core is exposed to a background field, it is more easily saturated in alignment with that field and less easily saturated in opposition to it.

Hence the alternating magnetic field, and the induced output current, are out of step with the input current. The tuned sensor waveform is shown in red in Figure 2d. With external magnetic field When there is an external field, the half core generating a field in the opposite direction of the external field for first transition in Figure 2c, shown in green comes out of saturation sooner and the half core in same sense as the external field comes out of saturation later.

Measuring the field The size and phase of the induced spikes tells us about the magnitude and direction of the external field. Print Email. Development of future high-performance next-generation sensors requires the ability to produce new high-quality cores. A team at the University of Iowa, working with national and international collaborators, has demonstrated a manufacturing process that produces cores that match the noise performance of most cores in use today and has revealed potential optimizations that could enable lower noise sensors, miniature sensors for nanosatellites, and efficient high-volume production of sensors for constellation missions.

Rather, the new fluxgate cores are manufactured from scratch and integrated into a modern spaceflight magnetometer design. The ferromagnetic cores are produced starting from base metal powders that are melted into custom alloys in-house, cold-rolled into thin foils, formed into the geometry of a fluxgate core, and subjected multi-step heat treatments to optimize their magnetic properties.

The team then integrates the resulting cores into a complete fluxgate sensor ready for a spaceflight application. MAGIC is a five-year effort to design, build, test, and fly a next-generation spaceflight fluxgate demonstrating the new core technology. In the last 18 months, MAGIC has established a new spaceflight instrument team and is undertaking two major technical projects.

First, we are completing a detailed investigation into the factors that control magnetic noise in permalloy fluxgate sensors with the goal of achieving unprecedentedly low magnetic noise measurements and developing miniature sensors that match the noise performance of the larger cores in use today.

Secondly, we are developing a complete flight-ready magnetometer design based on this new core technology. Future missions of 10s to s of small, low-cost spacecraft each carrying a miniature magnetometer will enable us to characterize the global morphology of the magnetosphere.