Comparison of noise levels of two magnetometer types and their suitability for different space environments

The plasma environment around Earth has markedly different characteristics of the magnetic field across distinct spatial regions. In the solar wind, beyond Earth's magnetic influence, the magnetic field is relatively low and less fluctuating. In contrast, the magnetosheath – the region between the bow shock and the magnetopause – is characterized by significantly more turbulent magnetic fields. Within the magnetosphere, the magnetic field can go up to tens of thousands of nanotesla (nT). Traditionally, fluxgate magnetometers (FGM) have been the standard instrument for space-based magnetic field measurements. However, in recent years, alternative technologies such as anisotropic magnetoresistive (AMR) sensors and optically pumped magnetometers have been proposed and, in some cases, deployed. This study compares the noise performances of two magnetometers, an FGM and an AMR, by evaluating their amplitude spectral density measurements across various near-Earth regions of space. The potential of each sensor type for investigating specific phenomena is also evaluated.