Key Parameter description

version December 8, 1997

  1. Magnetic field vector (MIF-M/PRAM)
  2. Thermal electrons moments (ELECTRON)
  3. Thermal ions moments (CORALL)
  4. Ion Composition (PROMICS)
  5. Energetic particle flux (DOK-2)
  6. Energetic particle flux (SKA-2)
  7. Plasma wave Amplitudes (MIF-M/PRAM)
  8. Radio intensity flux (AKR)
  9. Antisunward ion flux (VDP)
  10. Orbital data
  11. Polar Cap activity index
  12. Timing and averaging
  13. Data quality and flags
  14. Output formats and distribution

Magnetic field (MIF-M/PRAM)

  1. |B|: Magnetic field total value (average of magnitudes).
  2. Bxe, Bye, Bze: magnetic field cartesian GSE vector (average).
  3. Bxm, Bym, Bzm: magnetic field cartesian GSM vector (average).
  4. SFb: Magnetometer status flag.
  5. M1: Magnetic spectral amplitude, 1-4 Hz
  6. M2: Magnetic spectral amplitude, 600-850 Hz
  7. 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).
Format: File descriptor is "itm". Format of ASCII file records is:
"yddd hh mm ss Bxe Bye Bze Bym Bzm Ba SFb M1 M2 SFm"

Thermal electrons (ELECTRON)

  1. Ne: Electron density.
  2. Ee: Electron mean energy.
  3. Ne1: Electron density without lowest energies.
  4. Ee1: Electron mean energy without lowest energies.
  5. 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).
Format: File descriptor is "itt". Format of ASCII file records is:
"yddd hh mm ss Ne Ee Ne1 Ee1 SFe"

Thermal ions (CORALL)

  1. Ni: Ion density.
  2. Ti: Ion temperature.
  3. Vixe, Viye, Vize: GSE ion bulk velocity.
  4. Vixm, Viym, Viym: GSM ion bulk velocity.
  5. |Vi|: Ion bulk velocity magnitude.
  6. 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).
Format: File descriptor is "itc". Format of ASCII file records is:
"yddd hh mm ss Ni Ti Vixe Viye Vize Viym Vizm |Vi| SFi"

Ion Composition (PROMICS)

  1. D6H, D8H, D10H: H+ counts (three directions).
  2. D6O, D8O, D10O: O+ counts (three directions).
  3. 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.
Format: File descriptor is "itp". Format of ASCII file records is:
"yddd hh mm ss D6H D8H D10H D6O D8O D10O SFp"

Energetic particle fluxes (DOK-2)

  1. Fe1: Electron flux 21-26 keV (1st electron sensor);
  2. Fe2: Electron flux 76-95 keV (1st electron sensor);
  3. Fp1: Proton flux 22-28 keV (1st proton sensor);
  4. Fp2: Proton flux 21-27 keV (2st proton sensor);
  5. 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.
Format: File descriptor is "ite" (together with SKA-2 energetic fluxes). Format of ASCII file records is:
"yddd hh mm ss Fe1 Fe2 Fp1 Fp2 SFe1 SFe2 SFp1 SFp2 Fe3 Fp3 SFep3"

Energetic particle fluxes (SKA-2)

  1. Fe3: Electron flux 150-500 keV.
  2. Fp3: Proton flux 1-3 MeV.
  3. 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.
Format: File descriptor is "ite" (together with DOK-2 energetic fluxes). Format of ASCII file records is:
"yddd hh mm ss Fe1 Fe2 Fp1 Fp2 SFe1 SFe2 SFp1 SFp2 Fe3 Fp3 SFep3"

Plasma wave amplitudes (MIF-M/PRAM)

  1. M1: Magnetic spectral amplitude, 1-4 Hz
  2. M2: Magnetic spectral amplitude, 20-30 Hz
  3. M3: Wave spectral amplitude, 20-30 Hz
  4. M4: Wave spectral amplitude, 120-150 Hz
  5. M5: Wave spectral amplitude, 350-450 Hz
  6. M6: Wave spectral amplitude, 600-850 Hz
  7. M7: Wave spectral amplitude, 1900-2100 Hz
  8. SFm: Status flag
  9. Bx, DBx: Mean and variance of magnetic field GSE Bx in 2-min interval.
  10. 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) .
Format: File descriptor is "itw". Format of ASCII file records is:
"yddd hh mm ss M1 M2 M3 M4 M5 M6 M7 SFm Bx DBx Ba DBa"

Radio intensity flux (AKR)

  1. S1: Radiointensity flux, 100 kHz
  2. S2: Radiointensity flux, 252 kHz
  3. 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. Format: File descriptor is "ita". Format of ASCII file records is:
"yddd hh mm ss S1 S2 S3"

Antisunward ion flux (VDP)

  1. 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.
Format: File descriptor is "itf". Format of ASCII file records is:
"yddd hh mm ss FF"

INTERBALL-TAIL orbital data

  1. Xe, Ye, Ze: INTERBALL-TAIL position vector, cartesian GSE
  2. Xm, Ym, Zm: INTERBALL-TAIL position vector, cartesian GSM
  3. Vx, Vy, Vz: INTERBALL-TAIL velocity vector, cartesian GSE
  4. SFo: Spacecraft orbit status flag
  5. Dx, Dy, Dz: INTERBALL-1 subsatellite separation vector, cartesian GSE
  6. 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).
Format: File descriptor is "ito". Format of ASCII file records is:
"yddd hh mm ss Xe Ye Ze Ym Zm Vx Vy Vz SFo Dx Dy Dz SFs"

Polar Cap activity index

  1. PCN: Northern Polar Cup Index (Thule)
  2. PCS: Southern Polar Cup Index (Vostok)
  3. SFN: Thule Status Flag
  4. 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.
Full description of PC index by V.A. Sergeev.
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: Read description.
Format: File descriptor is "igi". Format of ASCII file records is:
"yddd hh mm ss PCN PCS SFN SFS"

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.

Data formats and distribution

Files with INTERBALL-TAIL KP can be accessed in the following ways: Data can be used only according to Rules of the road.

INTERBALL KP are divided in several subsets, each stored in CDF (v.2.4), columnar ASCII and GIF (plots) formats. One file contains one day of data of one subset. Each is KP subset coded by a three-letter descriptor, which is included in the filenames and in the name of the directory, containing all files with this descriptor. In order to reduce size of the directory listings, data in each directory with KP subset are divided in subdirectories named after the year of data (1995, 1996, ...).

Archive structure: 

 directory       data subset                                  descriptor
----------------------------------------------------------------------------
 routines        IDL routines to plot KP files
 doc/ground      PCI data                                               "igi"
 orb/tail        Tail probe orbital data                                "ito"
 dat/tail/ite    Tail probe energetic particle fluxes (DOK-2, SKA2)     "ite"
 dat/tail/itm    Tail probe magnetic field and fluctuations (MIF-M/PRAM) "itm"
 dat/tail/itt    Tail probe electron moments (ELECTRON)                 "itt"
 dat/tail/itp    Tail probe ion composition (PROMICS)                   "itp"
 dat/tail/ita    Tail probe Radiointensity flux (AKR-X)                 "ita"
 dat/tail/itc    Tail probe ion moments (CORALL)                        "itc"
 dat/tail/itf    Tail probe ion flux (VDP)                              "itf"
 dat/tail/itw    Tail probe Plasma wave amplitudes (MIF-M/PRAM)         "itw"

Filenames contain descriptor, date of measurements, and version number: 

     "pppydddv.fff"

ppp  - Descriptor
yddd - last digit of a year and day in a year (January 1st - day no 1).
v    - version number.
fff  - cdf, dat, gif - data formats.
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