Data Descriptions

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L2 ESA Data Quality Flag Descriptions

There is a data_quality flag variable associated with each ESA L2 data type. (Data types include: 'peif' = Particle ESA Ion Full mode, 'peef'= Particle ESA Electron Full mode, 'peir' = Particle ESA Ion Reduced mode, 'peer' = Particle ESA Electron Reduced mode, 'peib' = Particle ESA Ion Burst mode, 'peer' = Particle ESA Electron Full 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 information on the ESA instrument, please read instrument_esa.shtml and esa_non_ideal.shtml. Note that not all of the conditions discussed in the above link are flagged. An example data quality variable name is 'tha_peif_data_quality', for THEMIS A. For each data type, a flag value of 0 indicates that the data currently has no issues. A non-zero value for the flag means that there may be problems. Non-zero values are totals of the values described below. For example, a flag value of 3 means that the spacecraft potential is missing (flag = 1) and there is counter saturation (flag = 2).

For each data type:

Flag Value 0 = Okay data.

Flag Value 1 = No 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 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 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, the 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


Link to the ESA Data Variable Descriptions     Link to ESA Instrument Information
Link to the ESA Data Processing History    
Link to electron ESA Configuration History     Link to ion ESA Configuration History