Methodology:

- using Cluster and Van Allen Probes orbit position data (short term data,
  whenever possible), calculate the positions of all six spacecraft for all
  periods when the Cluster spacecraft are within 10 Re (geocentric) of the
  Earth.
- using a model magnetic field (IGRF-10 + T89c external field), trace down to
  the magnetic footpoint (same hemisphere) of each spacecraft.
- express the footpoints in the SM coordinate system (magnetic
  latitude--mLat--and magnetic local time--MTL), and calculate the separation of
  each Cluster/Van Allen pair as an arc length on the Earth's surface. Any such
  separation under 10 degrees is flagged as an initial conjunction candidate.
- filter to remove candiates where the Cluster spacecraft is beyond 9 Re
  and where the the difference in MLT is over ~10 degrees.
- in cases where the Cluster/Van Allen pair are in opposite hemispheres, but
  where one of them is within ~5 degrees of the magnetic equator, redo the
  magnetic trace so that footpoints in the same hemisphere (that of the
  spacecraft further from the equator) are obtained, and then proceed with the
  above analysis as normal.
- compare all flagged opportunities to the existing Cluster/WBD data-taking
  schedule, and then manually asses and select all viable conjunctions.

- note that for the first few conjunctions in September 2013, a simpler analysis
  was used, one which did not consider cross-hemisphere cases.


Directory contents:

- files of the form conj-ops-list*.txt will contain position info and analyses
  for all flagged conjunction possibilities (for the time period indicated in
  the file name).

- files of the form suggested-conjunction-ops* will contain the WBD suggestions
  for conjunctions.

- files of the form va-scheduled-bursts* will contain the burst mode periods
  that the Van Allen Probes are proposing to schedule.