Hydra/DDEIS Spectrogram Information

• C(E,t)
  Spin-averaged electron and ion counts as a function of energy, E, and universal time, t.
  Corrections that have been made to the raw spacecraft counts:
  
  • Glint removal
  • Dead-time correction
  • Background removal (if possible)
  • Intra-box gain correction
  • Inter-box gain correction
  • For each block of data (measuring time of 13.8 seconds), interpolation to the lowest and highest energies found for the whole day is performed. This is particularly important for those days in which there were multiple spacecraft data collection modes.

• The average energy for both electrons and ions appears as a black line.

• To the right of the spectrogram:
  Orbit plot shows the location of the spacecraft with respect to the earth and it's magnetic field.

• Above the spectrogram:
  • L(R_E), the equatorial distance from the center of the earth to the dipole magnetic field line the spacecraft is traversing.
  • Lat_ML, the latitude of the spacecraft in SM (Solar-Magnetospheric) coordinates.
  • PSI Status Bar, indicates whether or not the PSI experiment is running.
  • Electron Background Status Bar, indicates the value of the background subtracted from the electron counts.

• Below the spectrogram:
  • Ion Background Status Bar, indicates the value of the background subtracted from the ion counts.
  • UT, Universal Time, in hours.
  • ILT, Invariant Latitude, which is defined as the latitude of the foot of the dipole magnetic field line which the spacecraft is traversing.
  • MLT, Magnetic Local Time
  • R, the distance to the spacecraft in units of earth radii.