Temporal, Energy, and Angular resolution of the TIMAS data available as PAPCO plots and in the underlying CDF data file

General

• The TIMAS instrument is a state-of-the-art energetic ion mass spectrograph with very high energy, mass, angle and temporal resolution
• Because of limited telemetry bandwidth data are averaged and compressed on board and transmitted to the ground as data products of varying temporal, energy, mass, and angular resolution
• Only data from low and medium resolution distribution function data products, (LRDF and MRDF) are used in PAPCO plots or included in the CDF files.

  Data Product	Mass Resolution	Energy Resolution	Angle Resolution	Time Resolution
  MRDF (medium resolution distribution function)	1 of 4 ranges of mass steps corresponding to one of the major magnetospheric species (H+, O+, He+ and He++)	The 14 of 28 interleaved energy steps sampled during the spin period. OR optionally, the 14 energy steps summed into 7 energy steps.	104 solid angle segments covering ~98% of the full 4 pi solid angle	1 spin (6 seconds). Note because the two detector Heads sample ~ 180 degrees out of phase, it is possible to obtain 3 second resolution when MRDF's from HEAD A and B are combined.
  LRDF (low resoultion distribution function)	1 of 4 ranges of mass steps corresponding to one of the major magnetospheric species (H+, O+, He+ and He++)	7 energy steps.	32 solid angle segments covering ~98% of the full 4 pi solid angle	on board accumulation for 1, 2, 4, 8, 16, or 32 spin periods (6 to 192 second resolution)

Temporal Resolution of CDF DATA and PAPCO PLOTS

• H+ and O+ fluxes are normally available with 2 spin (12 second) resolution and He+ and He++ fluxes with 2 (12 second) or 4 (24 second) resolution depending on the Timas operating mode

ENERGY/ANGLE RESOLUTION IN CDF DATA FILES

Data are stored in the CDF file for
• 28 energy steps covering the range 0.015 - 33 keV/e
  • Some operating modes and/or data products average the 28 energy channels to 7 on board. During data processing fluxes from the broad energy chanels are uniformly distributed into the original 4 energy chanels. NOTE This means that, at time, the energy resolution available in the CDF file is higher than is justified by the data transmitted to ground.
  • The CDF file contains several variables that flag the ground processing steps. The Energy_status variable and others are described in the CDF skeleton table.
• 12 uniformly spaced angular bins covering the pitch angle range 0 - 180 degrees.
  
  • The MRDF data product (described in the table above) has angular resolution that justifies presenting data with 15 degree resolution; the LRDF data product does not.
    This means that, at times, the angular resolution is
  • The CDF file contains several variables that flag the source data products included in the CDF file. The PA_status variable and others are described in the CDF skeleton table.

RESOLUTION OPTIONS ON PAPCO PLOTS

The plots can, at times, have higher energy resolution than is justified. See the discussion in the section above on the Energy/angle resolution in CDF data files.
• High Resolution PAPCO OPTION
  Selects data obtained with the full energy (i.e. 28 step) and angular resolution (i.e. MRDF data products) available. As described above.
  The selection for high resolution is based on the PA_status and Energy_status values in the input data file.
  
  • Pitch-Angle Plot -
    • PA_status = 0
    • Energy_status = 0
  • Energy Spectrum Plot -
    • PA_status = 0 OR unweighted plot option selected
    • Energy_status = 0
• Medium Resolution PAPCO OPTION
  Passes all data in the CDF input file, including data acquired with lower energy resolution than justified by the 28 energy steps shown in the plot.
  The angular resolutionData for the full, field aligned, perdicular, and field opposed angular ranges is not compromised by processing by selecting the Medium resolution option.
  The selection for medium resolution is based on the PA_staus and Energy_status variables in the input data file
  
  • Pitch-Angle Plot -
    • PA_status < 5
    • Energy_status < 99
  • Energy Spectrum Plot -
    • Pa_status < 5 OR unweighted plot option chosen
    • Energy_status < 99