THEMIS-A: On Board spin fits (FIT) of Electric (EFI) and Magnetic (FGM) field. On-Board Spin-fit electric and magnetic field data

https://doi.org/10.48322/6nb7-ze78

2023-07-30 12:34:56.789

THEMIS-A: On Board spin fits of Electric (EFI) and Magnetic (FGM) fields. This file contains data EFI and FGM that has been despun on-board to 3 second resolution. It stores meta information like the number of points that contributed to each spin and the standard deviation of those points. For the EFI data it also stores variables with the Z component of the EFI data zeroed and the Z component of the EFI estimated using the E.B=0 equality. The need to use an estimated Z axis for the EFI is due to error in measurements from the EFI axial booms. These data are provided in DSL (despun spacecraft L-Z vector), GSM, and GSE coordinates.

NASA contract NAS5-02099 and V. Angelopoulos for use of data from the THEMIS Mission. Specifically: J. W. Bonnell and F. S. Mozer for use of EFI data.

spase://VMO/NumericalData/THEMIS-A/Fits/PT3S

spase://VMO/NumericalData/THEMIS/A/Fits/PT3S

spase://VSPO/NumericalData/THEMIS/A/Fits/PT3S

Online

Open

CDF

None

Online

Open

CSV

PT3S

THEMIS A Fluxgate Magnetometer Spin Fit Deviation

tha_fgs_sigma

Fluxgate magnetometer on-board instrument measurements are at higher resolution. This parameter stores the standard deviation of the fluxgate magentometer spin fit for each spin resolution element of this data quantity in nT.

Calculations of spin-fit for these data are performed on-board.

PT3S

nT

10e-9>T

0.0

25000.0

NaN

THEMIS A Fluxgate Magnetometer Spin Fit Data DSL

tha_fgs_dsl

FGS (spin-fit) magnetic field vector in despun spacecraft coordinates (DSL). To despin, these data are direction corrected using the spin-model and binned down from the cadence of the instrument to the cadence of each spin (3-sec). These coordinates (DSL) use the Z axis of the spin plane (L Vector), not the probe geometric Z axis.

Calculations of spin-fit for these data are performed on-board.

PT3S

nT

10e-9>T

THEMIS A Fluxgate Magnetometer Spin Fit Data GSE

tha_fgs_gse

FGS (spin-fit) magnetic field vector in GSE coordinates. These data are despun. To despin, these data are direction corrected using the spin-model and binned down from the cadence of the instrument to the cadence of each spin (3-sec). Then they are converted to GSE on the ground.

Calculations of spin-fit for these data are performed on-board.

PT3S

nT

10e-9>T

THEMIS A Fluxgate Magnetometer Spin Fit Data GSM

tha_fgs_gsm

FGS (spin-fit) magnetic field vector in GSM coordinates. These data are despun. To despin, these data are direction corrected using the spin-model and binned down from the cadence of the instrument to the cadence of each spin (3-sec). Then they are converted to GSM coordinates on the ground.

Calculations of spin-fit for these data are performed on-board.

PT3S

nT

10e-9>T

THEMIS A Fluxgate Magnetometer Spin-Fit Data Times

tha_fgs_time

Dates/Times for each measurement in seconds since 01-Jan-1970 00:00:00 UTC

Unleaped seconds

PT3S

s

0.0

5.0E9

NaN

THEMIS A Electric Field Instrument Spin Fit Deviation

tha_efs_sigma

Electric Field Instrument on-board measurements are at higher resolution. This parameter stores the standard deviation of the electric field instrument spin fit for each spin resolution element of this data quantity in mV/m.

Calculations of spin-fit for these data are performed on-board. Electric Field Booms for THEMIS A were deployed on January 14 2008 at 1700 UT. Measurements should not be considered valid before the deploy date. Z-axis measurements should be treated very carefully. Because the Z-axis booms are much shorter than the spin plane booms, the measurements in the Z-axis are much more inaccurate.

PT3S

mV/m

10e-3>V/m

0.0

1000.0

NaN

THEMIS A Electric Field Instrument Spin Fit Data DSL

tha_efs_dsl

EFS (spin-fit) electric field vector in despun spacecraft coordinates (DSL) To despin, these data are direction corrected using the spin-model and binned down from the cadence of the instrument to the cadence of each spin (3-sec). These coordinates use the Z axis of the spin plane(L Vector), not the probe geometric Z axis.

Calculations of spin-fit for these data are performed on-board. Electric Field Booms for THEMIS A were deployed on January 14 2008 at 1700 UT. Measurments should not be considered valid before the deploy date. Z-axis measurements should be treated very carefully. Because the Z-axis booms are much shorter than the spin plane booms, the measurements in the Z-axis are much more inaccurate.

PT3S

mV/m

10e-3>V/m

THEMIS A Electric Field Instrument Z=0 Spin-Fit Data DSL

tha_efs_0_dsl

EFS (spin-fit) electric field vector with Z=0 in despun spacecraft coordinates. (DSL) To despin, these data are direction corrected using the spin-model and binned down from the cadence of the instrument to the cadence of each spin (3-sec). Since the Z component of the electric field has large error, it has been set to zero in this data quantity. These coordinates use the Z axis of the spin plane(L Vector), not the probe geometric Z axis.

Calculations of spin-fit for these data are performed on-board. Electric Field Booms for THEMIS A were deployed on January 14 2008 at 1700 UT. Measurments should not be considered valid before the deploy date. The Z axis is zeroed for this quantity because the Z-axis booms are much shorter than the spin plane booms and thus the measurements in the Z axis are much more inaccurate.

PT3S

mV/m

10e-3>V/m

THEMIS A Electric Field Instrument E dot B = 0 Spin-Fit Data DSL

tha_efs_dot0_dsl

EFS (spin-fit) electric field vector with E dot B = 0 in despun spacecraft coordinates. (DSL) To despin, these data are direction corrected using the spin-model and binned down from the cadence of the instrument to the cadence of each spin (3-sec). Since the Z component of the electric field has large error, the value of Ez that makes the dot product of E and B closest to zero is used in this data product, rather than the measured Z value. These coordinates use the Z axis of the spin plane (L Vector), not the probe geometric Z axis.

Calculations of spin-fit for these data are performed on-board. Electric Field Booms for THEMIS A were deployed on January 14 2008 at 1700 UT. Measurments should not be considered valid before the deploy date. The Z axis is estimated for this quantity because the Z-axis booms are much shorter than the spin plane booms and thus the measurements in the Z axis are much more inaccurate.

PT3S

mV/m

10e-3>V/m

THEMIS A Electric Field Instrument Spin Fit Data GSE

tha_efs_gse

EFS (spin-fit) electric field vector in GSE coordinates. Data are first despun on-board, then converted to GSE coordinates on the ground. To despin, these data are direction corrected using the spin-model and binned down from the cadence of the instrument to the cadence of each spin (3-sec).

Calculations of spin-fit for these data are performed on-board. Electric Field Booms for THEMIS A were deployed on January 14 2008 at 1700 UT. Measurments should not be considered valid before the deploy date. Z-axis measurements should be treated very carefully. Because the Z-axis booms are much shorter than the spin plane booms, the measurements in the Z-axis are much more inaccurate.

PT3S

mV/m

10e-3>V/m

THEMIS A Electric Field Instrument Z=0 Spin-Fit Data GSE

tha_efs_0_gse

EFS (spin-fit) electric field vector with Z=0 in GSE coordinates. Data are first despun on-board, then converted to GSE coordinates on the ground. To despin, these data are direction corrected using the spin-model and binned down from the cadence of the instrument to the cadence of each spin (3-sec). Since the Z component of the electric field has large error, it has been set to zero in this data quantity.

Calculations of spin-fit for these data are performed on-board. Electric Field Booms for THEMIS A were deployed on January 14 2008 at 1700 UT. Measurments should not be considered valid before the deploy date. The Z axis is zeroed for this quantity because the Z-axis booms are much shorter than the spin plane booms and thus the measurements in the Z axis are much more inaccurate. The Z-axis is zeroed prior to conversion to GSE coordinates, so the zeroed axis will probably not be colinear with the Z axis of the GSE coordinate system.

PT3S

mV/m

10e-3>V/m

THEMIS A Electric Field Instrument E dot B = 0 Spin-Fit Data GSE

tha_efs_dot0_gse

EFS (spin-fit) electric field vector with E dot B = 0 in GSE coordinates. Data are first despun on-board, then converted to GSE coordinates on the ground. To despin, these data are direction corrected using the spin-model and binned down from the cadence of the instrument to the cadence of each spin (3-sec). Since the Z component of the electric field has large error, the value of Ez that makes the dot product of E and B closest to zero is used in this data product, rather than the measured Z value.

Calculations of spin-fit for these data are performed on-board. Electric Field Booms for THEMIS A were deployed on January 14 2008 at 1700 UT. Measurments should not be considered valid before the deploy date. The Z axis is estimated for this quantity because the Z-axis booms are much shorter than the spin plane booms and thus the measurements in the Z axis are much more inaccurate. The Z-axis is estimated prior to conversion to GSE coordinates, so the estimated axis will probably not be colinear with the Z axis of the GSE coordinate system.

PT3S

mV/m

10e-3>V/m

THEMIS A Electric Field Instrument Spin Fit Data GSM

tha_efs_gsm

EFS (spin-fit) electric field vector in GSM coordinates. Data are first despun on-board, then converted to GSM coordinates on the ground. To despin, these data are direction corrected using the spin-model and binned down from the cadence of the instrument to the cadence of each spin (3-sec).

Calculations of spin-fit for these data are performed on-board. Electric Field Booms for THEMIS A were deployed on January 14 2008 at 1700 UT. Measurments should not be considered valid before the deploy date. Z-axis measurements should be treated very carefully. Because the Z-axis booms are much shorter than the spin plane booms, the measurements in the Z-axis are much more inaccurate.

PT3S

mV/m

10e-3>V/m

THEMIS A Electric Field Instrument Z=0 Spin-Fit Data GSM

tha_efs_0_gsm

EFS (spin-fit) electric field vector with Z=0 in GSM coordinates. Data are first despun on-board, then converted to GSM coordinates on the ground. To despin, these data are direction corrected using the spin-model and binned down from the cadence of the instrument to the cadence of each spin (3-sec). Since the Z component of the electric field has large error, it has been set to zero in this data quantity.

Calculations of spin-fit for these data are performed on-board. Electric Field Booms for THEMIS A were deployed on January 14 2008 at 1700 UT. Measurments should not be considered valid before the deploy date. The Z axis is zeroed for this quantity because the Z-axis booms are much shorter than the spin plane booms and thus the measurements in the Z axis are much more inaccurate. The Z-axis is zeroed prior to conversion to GSM coordinates, so the zeroed axis will probably not be colinear with the Z axis of the GSM coordinate system.

PT3S

mV/m

10e-3>V/m

THEMIS A Electric Field Instrument E dot B = 0 Spin-Fit Data GSM

tha_efs_dot0_gsm

EFS (spin-fit) electric field vector with E dot B = 0 in GSM coordinates. Data are first despun on-board, then converted to GSM coordinates on the ground. To despin, these data are direction corrected using the spin-model and binned down from the cadence of the instrument to the cadence of each spin (3-sec). Since the Z component of the electric field has large error, the value of Ez that makes the dot product of E and B closest to zero is used in this data product, rather than the measured Z value.

Calculations of spin-fit for these data are performed on-board. Electric Field Booms for THEMIS A were deployed on January 14 2008 at 1700 UT. Measurments should not be considered valid before the deploy date. The Z axis is estimated for this quantity because the Z-axis booms are much shorter than the spin plane booms and thus the measurements in the Z axis are much more inaccurate. The Z-axis is estimated prior to conversion to GSM coordinates, so the estimated axis will probably not be colinear with the Z axis of the GSM coordinate system.

PT3S

mV/m

10e-3>V/m

THEMIS A Electric Field Instrument Spin-Fit Data Times

tha_efs_time

Dates/Times for each measurement in seconds since 01-Jan-1970 00:00:00 UTC

Unleaped seconds

PT3S

s

0.0

5.0E9

NaN

THEMIS A Fluxgate Magnetometer Spin Fit Model DSL

tha_fit_bfit

This parameter contains the calibrated fluxgate magnetometer spin model data in despun spacecraft coordinates (DSL). The spin model uses a sine-wave spin model to calculate the spin and despin. These coefficients(A,B,C), the standard deviation(Sigma), and the average value(Avg.) are provided. The equations used for the model are F = Sum(i=1 to N)[E(t_i) - (A + Bsin(omegat_i)+Ccos(omegat_i))]^2 , delta F/delta A = Sum(i=1 to N)-2[E(t_i) - (A + Bsin(omegat_i) + Ccos(omegat_i))] , delta F/delta B = Sum(i=1 to N)-2[E(t_i) - (A + Bsin(omegat_i) + Ccos(omegat_i))]-sin(omegat_i) , delta F/delta C = Sum(i=1 to N)-2[E(t_i) - (A + Bsin(omegat_i) + Ccos(omegat_i))]cos(omegat_i) , Gamma = sqrt(F/(N-1)) The system of equations is solved and outliers are removed until no more outliers can be removed.

Calculations of spin-fit is performed on-board. The B,C, and Average components of this parameter are very close to the X,Y and Z components(respectively) of the fgs quantity. In this parameter scaling factors are applied, but the data do not have finer calibrations applied. These data are also in despun sensor coordinates, rather than despun spacecraft coordinates. Practically, this means the Z axis is the opposite of the normal DSL coordinate system.

PT3S

nT

10e-9>T

THEMIS A Fluxgate Magnetometer Spin-Fit Model Times

tha_fit_bfit_time

Dates/Times for each measurement in seconds since 01-Jan-1970 00:00:00 UTC

Unleaped seconds

PT3S

s

0.0

5.0E9

NaN

THEMIS A Electric Field Instrument Spin Fit Model DSL

tha_fit_efit

This parameter contains the calibrated electric field instrument spin model data in despun spacecraft coordinates (DSL). The spin model uses a sine-wave spin model to calculate the spin and despin. These coefficients(A,B,C), the standard deviation(Sigma), and the average value(Avg.) are provided. The equations used for the model are F = Sum(i=1 to N)[E(t_i) - (A + Bsin(omegat_i)+Ccos(omegat_i))]^2 , delta F/delta A = Sum(i=1 to N)-2[E(t_i) - (A + Bsin(omegat_i) + Ccos(omegat_i))] , delta F/delta B = Sum(i=1 to N)-2[E(t_i) - (A + Bsin(omegat_i) + Ccos(omegat_i))]-sin(omegat_i) , delta F/delta C = Sum(i=1 to N)-2[E(t_i) - (A + Bsin(omegat_i) + Ccos(omegat_i))]cos(omegat_i) , Gamma = sqrt(F/(N-1)) The system of equations is solved and outliers are removed until no more outliers can be removed.

Calculations of spin-fit is performed on-board. The B,C, and Average components of this parameter are very close to the X,Y and Z components(respectively) of the efs quantity. In this parameter scaling factors are applied, but the data do not have finer calibrations applied.

PT3S

mV/m

10e-3>V/m

THEMIS A Electric Field Instrument Spin-Fit Model Times

tha_fit_bfit_time

Dates/Times for each measurement in seconds since 01-Jan-1970 00:00:00 UTC

Unleaped seconds

PT3S

s

0.0

5.0E9

NaN