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FGM

ResourceID
spase://CNES/Instrument/CDPP-AMDA/THEMIS/E/FGM

Description

THEMIS Flux Gate Magnetometer (FGM) measures the background magnetic field and any low frequency (to 64 Hz) fluctuations superimposed upon it. The FGM can detect variations in the magnetic field within the accuracy of 0.01 nT. The THEMIS FGM uses an updated technology developed in Germany that digitizes the sensor signals directly and replaces the analog hardware by software. Using the digital fluxgate technology results in lower mass of the instruments and improved robustness.

Development Institution: Technical University of Braunschweig, (TU-BS), Germany
FGM Lead: K. H. Glassmeier (TUBS)

The data are transimitted as several different types that vary in time resolution and availability. The fluxgate magnetometer engineering (FGE) quantity is available only during enginneering triggers(typically during perigee). FGE is provided at 1/8 second resolution, but is generally not processed to scientific quality standards. The fluxgate magnetometer low resolution data (FGL) is available during THEMIS fast survey mode. FGL is provided at 1/4 second time resolution. The FGL data is spin-phase corrected and calibrated on the ground for use in scientific data analysis. The fluxgate magnetometer high resolution data is available during THEMIS particle burst mode. It is provided at 1/128 second resolution. The FGH data is spin-phase corrected and calibrated on the ground for use in scientific data analysis. The fluxgate magnetometer spin fit data (FGS) is available at all times. It is provided at 3 second resolution; the nominal period of one THEMIS spacecraft resolution. FGS data is spin-phase corrected on-board. The equatorial correction is done using an A+Bsin(theta)+Ccos(theta) correction. Theta is the spinphase and a 0 spinphase is defined to be at the sunpulse. The Coefficients A,B, & C that were used in spin-phase correction can be found in the THEMIS level 1 FIT data CDF. The axial component of the FGS data is generated by taking the average of the z measurements over each spin. Additional calibrations and cleanup of FGS data may also be performed on the ground. All data types are provided in Despun Spacecraft L-Vector Corrected (DSL), Geocentric Solar Eclipitic(GSE), and Geocentric Solar Magnetospheric(GSM) coordinates. Information about the requested spacecraft mode can be found associated with the THEMIS housekeeping data CDF. The housekeeping cdf stores engineering quantities.

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Details

Version:2.4.1

Instrument

ResourceID
spase://CNES/Instrument/CDPP-AMDA/THEMIS/E/FGM
ResourceHeader
ResourceName
FGM
AlternateName
Tri-axial Fluxgate Magnetometer
ReleaseDate
2017-01-20 21:10:04Z
Description

THEMIS Flux Gate Magnetometer (FGM) measures the background magnetic field and any low frequency (to 64 Hz) fluctuations superimposed upon it. The FGM can detect variations in the magnetic field within the accuracy of 0.01 nT. The THEMIS FGM uses an updated technology developed in Germany that digitizes the sensor signals directly and replaces the analog hardware by software. Using the digital fluxgate technology results in lower mass of the instruments and improved robustness.

Development Institution: Technical University of Braunschweig, (TU-BS), Germany
FGM Lead: K. H. Glassmeier (TUBS)

The data are transimitted as several different types that vary in time resolution and availability. The fluxgate magnetometer engineering (FGE) quantity is available only during enginneering triggers(typically during perigee). FGE is provided at 1/8 second resolution, but is generally not processed to scientific quality standards. The fluxgate magnetometer low resolution data (FGL) is available during THEMIS fast survey mode. FGL is provided at 1/4 second time resolution. The FGL data is spin-phase corrected and calibrated on the ground for use in scientific data analysis. The fluxgate magnetometer high resolution data is available during THEMIS particle burst mode. It is provided at 1/128 second resolution. The FGH data is spin-phase corrected and calibrated on the ground for use in scientific data analysis. The fluxgate magnetometer spin fit data (FGS) is available at all times. It is provided at 3 second resolution; the nominal period of one THEMIS spacecraft resolution. FGS data is spin-phase corrected on-board. The equatorial correction is done using an A+Bsin(theta)+Ccos(theta) correction. Theta is the spinphase and a 0 spinphase is defined to be at the sunpulse. The Coefficients A,B, & C that were used in spin-phase correction can be found in the THEMIS level 1 FIT data CDF. The axial component of the FGS data is generated by taking the average of the z measurements over each spin. Additional calibrations and cleanup of FGS data may also be performed on the ground. All data types are provided in Despun Spacecraft L-Vector Corrected (DSL), Geocentric Solar Eclipitic(GSE), and Geocentric Solar Magnetospheric(GSM) coordinates. Information about the requested spacecraft mode can be found associated with the THEMIS housekeeping data CDF. The housekeeping cdf stores engineering quantities.

Acknowledgement
NASA contract NAS5-02099 and V. Angelopoulos for use of data from the THEMIS Mission, K. H. Glassmeier, U. Auster and W. Baumjohann for the use of FGM data provided under the lead of the Technical University of Braunschweig and with financial support through the German Ministry for Economy and Technology and the German Center for Aviation and Space (DLR) under contract 50 OC 0302
Contacts
RolePersonStartDateStopDateNote
1.PrincipalInvestigatorspase://SMWG/Person/Vassilis.Angelopoulos
2.CoInvestigatorspase://SMWG/Person/Rumi.Nakamura
3.CoInvestigatorspase://SMWG/Person/Wolfgang.Baumjohann
4.CoInvestigatorspase://SMWG/Person/Karl-Heinz.Glassmeier
5.TechnicalContactspase://SMWG/Person/Uli.Auster
InformationURL
Name
THEMIS-B Fluxgate Magnetometer
URL
Description

Instrument description from NSSDC database

PriorIDs
spase://SMWG/Instrument/THEMIS-B/FGM
InstrumentType
Magnetometer
InvestigationName
Tri-axial Fluxgate Magnetometer
ObservatoryID