BAS UASD Theory and Modelling: HOTRAY
The HOTRAY Program

The HOTRAY code was developed at the British Antarctic Survey by Richard Horne (Reference) and is designed to carry out ray tracing in a hot, collisionless, magnetised plasma. It has been applied to waves in the Earth's ionosphere and magnetosphere, as well as the magnetosphere of Jupiter and laboratory type plasmas.

The code has 4 features which set it apart from other lesser codes ! It includes :

  1. Propagation in a hot or cold plasma.
  2. Electrostatic and electromagnetic waves.
  3. Multiple ion species.
  4. Unstable electron and ion distribution functions.
The code can calculate the path integrated growth or decay of waves as they propagate through the plasma for an unstable particle distribution which may consist of a temperature anisotropy, loss cone, ring or beam distribution. The code is limited to :

  • Linear instabilities.
  • WKB approximation - (e.g., wavelengths small compared to spatial gradients).
  • Non-relativistic effects.
The program has been used sucessfully to investigate :

  • Waves at HF in the ionosphere.
  • Electromagnetic ion cyclotron waves, (Earth's magnetosphere and Jupiter)
  • Whistler mode waves, e.g., whistlers, plasmaspheric hiss and auroral hiss.
  • Z mode waves, in the auroral region and at the plasmapause.
  • Magnetosonic waves in the equatorial region.
  • Electrostatic Bernstein waves at geostationary orbit.
  • Lower Hybrid waves in the auroral region.

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