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spedas / bleeding_edge

IDL-based Space Physics Environment Data Analysis Software (bleeding edge)
http://www.spedas.org
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Calibrate out FGM-Z (DSL) offset in THEMIS-E #45

Closed jameswilburlewis closed 1 year ago

jameswilburlewis commented 1 year ago

The FGM instrument on THEMIS_E has developed an offset in the DSL-Z component (about 114 nT, stable for now). The leading theory is that the feedback circuitry has failed for that axis. Running the instrument in open-loop mode may restore correct functioning.

Short term: We need to update the L1->L2 calibration routines/data for THEMIS-E to remove this offset from the FGM waveforms and spin fits, reprocess data back to when the anomaly started, and watch for changes in the offset.

Longer term: This might mean breaking the FGM instrument mode out in the L1 products, in case open-loop operation changes the offset.

jameswilburlewis commented 1 year ago

Changing the instrument mode didn't help. The FGM team has validated the new spin axis offset for THEMIS-E and it is now in the calibration files....nothing else to do here.