Data quality
and flags
Magnetic field (MIF-M/PRAM)
- |B|: Magnetic field total value (average of magnitudes).
- Bxe, Bye, Bze: magnetic field cartesian GSE vector
(average).
- Bxm, Bym, Bzm: magnetic field cartesian GSM vector
(average).
- SFb: Magnetometer status flag.
- M1: Magnetic spectral amplitude, 1-4 Hz
- M2: Magnetic spectral amplitude, 600-850 Hz
- SFm: Status flag
Data: Magnetic
field vectors and total value are computed as 2 min. averages.
Wave amplitudes are the averaged output of passband filters, processing
signal from fluxgate and search-coil magnetometers.
Flag:
Measurements are marked by SFb flag "10", "11", "12", showing the magnetometer
(MIF-M/FM-3I/FGM) used. Records with no real measurements are filled by fill values and
marked by flag "2". One standard SFm flag "10" is used for wave data. Records
with no real measurements are filled by fill values and
marked by flag "2".
Note: If attitude data is not available
Y and Z vector components cannot be determined and fill values are
used instead.
Units: nT and
nT/sqrt(Hz).
Thermal electrons (ELECTRON)
- Ne: Electron density.
- Ee: Electron mean energy.
- Ne1: Electron density without lowest energies.
- Ee1: Electron mean energy without lowest energies.
- SFe: ELECTRON status flag.
Data:
Moments Ne, Ee are calculated over the full energy range of
measurements. Second set (Ne1, Ee1) is computed over the energy
range with excluded lowest energy steps (lower than 20-50 eV) to
reduce influence of photoelectrons.
Density and energy are computed as 2 min. averages of
the respective moments of each energy spectrum measured by one (usually middle)
ELECTRON plate in fast modes and by all 8 plates in slow modes. ELECTRON mode
and primary energy range are coded in the status flag.
Flag: Status flag for valid data is a two-digit decimal
number. Its most significant digit (1/2/3) shows current primary energy range of
measuremens (12-26000/35-26000/169-26000 eV). Its less significant
digit shows number of the instrument plate used in the moment calculation (1-8,
numbered from the sunward direction in fast modes; 0 - all plates are used in
slow mode). Records with no real measurements are filled by fill values and
marked by flag "2".
Units: #/cc (density) and
eV (energy).
Thermal ions (CORALL)
- Ni: Ion density.
- Ti: Ion temperature.
- Vixe, Viye, Vize: GSE ion bulk velocity.
- Vixm, Viym, Viym: GSM ion bulk velocity.
- |Vi|: Ion bulk velocity magnitude.
- SFi: Status flag.
Data: Ion
moments are computed once per spacecraft spin. Time corresponds to the start of
spin.
The energy range of measurements is 25-25000 eV.
Fields
of view of CORALL plates don't cover sunward and antisunward directions, and
flows from these directions are measured with less reliability. Solar wind ion
flow is completely out of CORALL FOV. Parameters are computed on the ground once
per spin (about 2
min) with the use of the least squares fit by 3D shifted Maxwellian
distribution. Time corresponds to the beginning of the measurement cycle.
Flag: CORALL KP are marked by Status flag
"10" when attitude data is not available and by "11" when attitude data is
available. Records with no real measurements are filled by fill values and
marked by flag "2".
Note: If attitude data is not available
Y and Z vector components cannot be determined and fill values are
used instead.
Units: #/cc (density),
km/s (velocity), eV (temperature).
Ion Composition (PROMICS)
- D6H, D8H, D10H: H+ counts (three directions).
- D6O, D8O, D10O: O+ counts (three directions).
- SFp: PROMICS status flag.
Data:
Counts of H+ and O+ ions are accumulated during one spin period by detectors D6
(antisunward looking), D8 (spin plane), D10 (sunward looking) of TRICS2
subsystem (1.0-30 keV). Time corresponds to the start of spin.
Flag: PROMICS mode is coded in the status flag "11-75".
Most significant digit (1-7) shows availability of data from TRICS1, TRICS2,
TRICS3 subsystems:
1 - TRICS1 on, TRICS2 off, TRICS3 off,
2 - TRICS1
off, TRICS2 on, TRICS3 off,
3 - TRICS1 on, TRICS2 on, TRICS3 off,
4 -
TRICS1 off, TRICS2 off, TRICS3 on,
5 - TRICS1 on, TRICS2 off, TRICS3 on,
6 - TRICS1 off, TRICS2 on, TRICS3 on,
7 - TRICS1 on, TRICS2 on, TRICS3
on
Less significant digit shows instrument mode: 1/2/3/4/5 -
S/M/F/D/FED. Records with no real measurements are filled by fill values and
marked by flag "2".
Note: In the slowest "S" mode counts,
summed over 4 spins are divided by 4 and repeated 4 times.
Units: Raw counts.
Energetic particle fluxes (DOK-2)
- Fe1: Electron flux 21-26 keV (1st electron
sensor);
- Fe2: Electron flux 76-95 keV (1st electron
sensor);
- Fp1: Proton flux 22-28 keV (1st proton
sensor);
- Fp2: Proton flux 21-27 keV (2st proton
sensor);
- SFe1, SFe2, SFp1, SFp2: Status flags for each parameter.
Data: First electron and proton sensors are offset at
an angle 180 deg with respect to the spacecraft X axis (look
antisunward). Second electron and proton sensors can scan angle range 45-180
deg or can be fixed at angles 45, 90, 135, 180 deg with
respect to the sunward direction. Data are averaged in the 2 min. intervals.
Flag: A separate Status Flag is assigned to each parameter.
SFs are set to "11-15" and "21-25" for valid data. Most significant digit (1 -
low or 2 - high) indicates level of the energy threshold. Up to now (1997) all
data are taken at low energy threshold. Higher energy threshold can be used in
the future in case of degradation of a sensor. Less significant digit indicates
sensor orientation with respect to sunward direction ( 1, 2, 3, 4, 5 correspond
respectively to 45, 90, 135, 180 deg. and scan). Records with no real
measurements are filled by fill values and
marked by flag "2".
Note: Scanning mechanism of the second
sensor is not operational since 1 November 1995 and this sensor is permanently
offset at an angle 62 deg irrespective from the status flag value.
Note: Files have version number "1". From January 1st till
March 1996 second electron flux parameter was taken from the energy range 21-26
keV from the 2nd electron sensor and such files have version "2".
Units: 1/cm/cm/s/ster/keV.
Energetic particle fluxes (SKA-2)
- Fe3: Electron flux 150-500 keV.
- Fp3: Proton flux 1-3 MeV.
- SFep3: Status flag.
Data:
Electron and proton sensors of EV-3 subsystem are offset at an angle 135
deg with respect to the spacecraft X axis (sunward direction) and
have FOV about 40 deg. Data are averaged in the 2 min. intervals.
Flag: One standard ("10") flag is used for the SKA-2 data.
Records with no real measurements are filled by fill values and
marked by flag "2".
Units: 1/cm/cm/s/ster/keV.
Plasma wave amplitudes (MIF-M/PRAM)
- M1: Magnetic spectral amplitude, 1-4 Hz
- M2: Magnetic spectral amplitude, 20-30 Hz
- M3: Wave spectral amplitude, 20-30 Hz
- M4: Wave spectral amplitude, 120-150 Hz
- M5: Wave spectral amplitude, 350-450 Hz
- M6: Wave spectral amplitude, 600-850 Hz
- M7: Wave spectral amplitude, 1900-2100 Hz
- SFm: Status flag
- Bx, DBx: Mean and variance of magnetic field GSE Bx in
2-min interval.
- Ba, DBa: Mean and variance of magnetic field total value
in 2-min interval.
Data: M1 and M2 wave amplitudes
are the averaged output of passband filters, processing signal of the fluxgate
magnetometer (magnetic field spectral amplitude). M3-M7 wave amplitudes are the
averaged output of passband filters, processing signal of the search-coil
magnetometer (magnetic field spectral amplitude, status flag 10) or of the
Langmuir split probe (plasma current density spectral amplitude, status flag
11).
Flag: Status flag "10" is used for records with
magnetic field amplitudes in parameters M3-M7. Status flag "11" is used for
records with plasma current density amplitudes in parameters M3-M7. Records with
no real measurements are filled by fill values and
marked by flag "2".
Units: nT/sqrt(Hz) or
A/cm/cm/sqrt(Hz) .
Radio intensity flux (AKR)
- S1: Radiointensity flux, 100 kHz
- S2: Radiointensity flux, 252 kHz
- S3: Radiointensity flux, 500 kHz
Data: AKR emissions are supposed to be seen in these
frequency ranges. Parameters are calculated from the output of passband filters
(bandwidth 10 kHz) which process signal from the big loop antenna (1.5 sq.m),
positioned in the spacecraft spin plane (YZ GSE). Data are averaged in 2 min. intervals.
Flag: No Status Flag.
Units:
W/m/m/Hz.
Antisunward ion flux (VDP)
- FF: Ion flux.
Data: Antisunward
charged flux is measured by the sunward-looking Faraday cup of the VDP
experiment. The retarding potential on the grid of this Faraday cup is -170
V. Only positive values of the measured charged flux (ion flux in the
solar wind and magnetosheath) are included in this dataset. The Faraday cup is
offset along the spacecraft spin axis (looks to the Sun) and has field of view
about 120 deg. In the solar wind and flank magnetosheath all ion flux
is within the field of view of the instrument. In the front-side magnetosheath,
where the ion velocity vector is strongly deflected from the Sun-Earth line, up
to 30% of the flux can be out of field of view. Data are averaged in the 2 min. intervals.
Flag: No Status Flag.
Units:
#/cm/cm/s.
INTERBALL-TAIL orbital data
- Xe, Ye, Ze: INTERBALL-TAIL position vector, cartesian GSE
- Xm, Ym, Zm: INTERBALL-TAIL position vector, cartesian GSM
- Vx, Vy, Vz: INTERBALL-TAIL velocity vector, cartesian GSE
- SFo: Spacecraft orbit status flag
- Dx, Dy, Dz: INTERBALL-1 subsatellite separation vector,
cartesian GSE
- SFs: Spacecraft separation status flag
Data: INTERBALL-1 orbital data are given once per 2
min.
Flag: Valid data are marked by flags "0". Missing data
are marked by flags "2".
Units: Re [6370 km]
(position), km/s (velocity), km (separation).
Polar Cap activity index
- PCN: Northern Polar Cup Index (Thule)
- PCS: Southern Polar Cup Index (Vostok)
- SFN: Thule Status Flag
- SFS: Vostok Status Flag
Data:
The resolution of the northern cap PC-index is 5 min and of the southern one is
15 min. One time scale with the 5 min step is used for both indices and each (15
min) value of southern index is repeated three times.
Flag: Separate Status Flags are
given for the PC-index data from each station. Their values are "0" for valid
and "2" for missing data.
Units: mV/m.
Timing and averaging algorithms
UT time scale with the 2 min step is
used for all KP except PROMICS and CORALL ones (see below).
Parameters are averaged in the 2 min. intervals centered on the round odd
minutes. Ion KP (PROMICS and CORALL data) are given once per
spacecraft spin period (approximately 117-118 s). Here the time corresponds to
the beginning of measurement cycle (spin).
In the ASCII file time record "yddd hh mm ss" can be decoded
as follows:
y - last digit of year (e.g., "5" for "1995")
ddd - day of year ("Jan 1" - day "1")
hh mm ss - UT time of measurement.
Data quality and status flags
An effort is taken to remove telemetry and
time errors from data. Magnetometer offsets are extracted. Effects caused by the
spacecraft-plasma interaction (influence of floating potential, interferences in
the wave data, etc) are not corrected.
Parameters are supplied with Status Flags (SF). All SFs are one byte unsigned
integers. Usually one SF is assigned to KP from one instrument.
Only data from DOK-2 instrument have separate SFs for each parameter because
DOK-2 sensors can operate independently.
Status flags:
SF - data quality
0, 10 and - Valid data
higher
2 - value is missing
In case of missing data (SF = 2) filling value -1.0E31 is substituted.
Modes of operation, limiting data validity or changing significantly physical
sense of the KP are marked by SFs higher than "10".
Post-gap flag variables are added in the CDF files according to CDF ISTP
guidelines. See CDF ISTP guidelines description for more information.