MMS 2 Flux Gate Magnetometer (FGM) DC Magnetic Field, Level 2 (L2), Survey Mode, 8 or 16 Sample/s, v4/5 Data

Both sets of sensors are operated for the entire MMS orbit, with slow survey (8 samples per second) outside of the Region of Interest (ROI), and fast survey (16 samples per second) inside the ROI. Within the ROI, burst mode data (128 samples per second) are also acquired. A detailed description of the MMS fluxgate magnetometers, including science objectives, instrument description, calibration, magnetic cleanliness program, and data flow can be found at link.springer.com/article/10.1007%2Fs11214-014-0057-3 (DOI 10.1007/s11214-014-0057-3).

Additional information can also be found at www-spc.igpp.ucla.edu/ssc/mms (UCLA), and iwf.oeaw.ac.at/de/forschung/erdnaher-weltraum/mms/dfg (IWF, Graz). For the purpose of creating a unified FGM Level 2 data product, burst mode data is taken from DFG and survey mode data is taken from AFG. Because AFG and DFG are cross-calibrated on an orbit-averaged basis, small differences in offset may be observed between Level 2 burst and survey mode data.

Consequently, any differences are within the error of the measurement. Based on preliminary analysis of the data, the absolute error within the Region of Interest (ROI) is estimated to be no more than 0.1 nT in the spin-plane, 0.15 nT along the spin-axis and 0.2 nT in total magnitude.