Data Descriptions
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L2 GMOM Data Quality Flag Descriptions
There is a data_quality flag variable associated with each GMOM L2 data type. (Data types include: 'ptiff' = Particle GMOM Ion ESA Full mode, SST Full mode, 'pteff' = Particle GMOM Electron ESA Full mode, SST Full mode, 'ptirf' = Particle GMOM Ion ESA Reduced mode, SST Full mode, 'pterf' = Particle GMOM Electron ESA Reduced mode, SST Full mode, 'ptibb' = Particle GMOM Ion ESA Burst mode, SST Burst mode, 'ptebb' = Particle GMOM Electron ESA Burst mode, SST Burst mode. Full mode denotes low time resolution, high angular resolution data. Reduced mode denotes high time resolution, low (or no) angular resolution data, and Burst mode denotes high time resolution, high angular resolution data.
For each data type:
Flag Value 0 = Okay data.
Flag Value 1 = No ESA spacecraft potential available. The moments have been calculated using a value of zero for the spacecraft potential. Photoelectrons which would normally be excluded from density calculations are included in the calculations, resulting in inaccurate values for electron moments. Ion moments are less affected. All data prior to EFI boom deployment (THA (P5) 14 Jan 2008, 1700 UT.THB (P1) 17 Nov 2007, 0600 UT, THC (P2) 16 May 2007, 2100 UT, THD (P3) 7 Jun 2007, 1700 UT, THE (P4) 7 Jun 2007, 1900 UT) are flagged.
Flag Value 2 = Counter saturation detected in raw ESA data. Raw data are accumulated as bytes; this flag denotes time intervals for which the counters are saturated at a value of 255. Typically this can happen for Reduced mode data in high density regions.
Flag Value 4 = Probe is in the solar wind, but not in solar wind mode. In ESA solar wind mode, the angular bin size is reduced in the direction of the solar wind to provide accurate integration over the angular bins. If the probe is in the solar wind, but not in solar wind mode, the accuracy of moments is reduced. The solar wind is characterized by high flow velocity and low temperature; for this flag a probe is considered to be in the solar wind if V_ion > 250 km/s And T_ion < 50 eV *(V_ion/300 km/s). The values of V_ion and T_ion are obtained from the on-board moment ('peim') data. Since the on-board moments are only valid after 2 August, 2007 for probe A and 10 August 2007 for the other probes, this flag is not set prior to those times.
Flag Value 8 (for Reduced mode data only) = In slow survey mode, ESA reduced data only has one angular bin. Velocity cannot be measured here. If there exists a flow the velocity calculation will be inaccurate. This flag is set for the reduced data if the flow velocity, as measured by the full mode data, is greater than the thermal velocity obtained from the temperature.
Flag Value 16 = Earth shadow; the Sun is blocked by the Earth, resulting in problems with spin period calculations.
Flag Value 32 = Lunar shadow.
Flag Value 64 = Maneuver flag
Flag Value 128 = ESA Density mis-match, either n_ion > 2*n_electron or n_electron > 2*n_ion
Flag Value 256 = Counter saturation detected in SST data. This is set if the count rate for the given data type is greater than 10000 counts/second.
Flag Value 512 = SST Attenuator error, stuck attenuator or incorrect attenuator indicator.
Flag Value 1024 = Spin period too low (less than 2.5 seconds) or too high (greater than 5 seconds). The nominal spin period is 3 seconds.
Flag Value 2048 = Earth shadow
Flag Value 4096 = Lunar shadow