Page History

...

Overview

The FPI L2 data products reflect the full range of ~few eV to ~32 keV plasma populations in proximity to the spectrometers.  This includes the ambient plasma environment within that energy range and – on occasion – spurious plasma populations induced in the vicinity of the spacecraft.  For example, when the MMS EDI instrument is emitting 500 eV electrons, one or more FPI spectrometers often registers the signal in DES energy bin 16. 

It is up to the data user to review the data and carefully consider what the measured signals indicate about the natural plasma environment versus what is indicated about any spacecraft induced plasma environment.  M

The FPI team works diligently to remove as many induced effects as is possible from the FPI moment values (des-moms and dis-moms files) within our data processing pipeline.  In some cases, there remains work to be done, which is often best carried out on an event-by-event basis. We provide the FPI full plasma distributions (des-dist and dis-dist files) without correction so that custom analysis work can be done.performed appropriate to the specific hypothesis under study.

Following is a checklist of known data features and recommendations for mitigation:

Quality Flags <-- heed the warnings!

Many of the features discussed below are automatically flagged during the L2 data processing procedures.

FPI tags its data with a variety of quality flags to indicate intervals that need special warrant consideration -- and perhaps correction -- when using the data for event analysis.  It is important to check these and address any noted features.  Many of the features below are automatically flagged in the L2 data.  The FPI quality flag definitions are identical for quicklook and L2 data products.   

See child page on L2 quality flags for detailed information and for contributions of plotting routines to quickly plot them.

...