Maser

Anisotropic Ray Tracer for Electromagnetics in Magnetosphere, Ionosphere and Solar wind including Polarization

Thursday 15 February 2018, by Baptiste Cecconi

ARTEMIS-P: A general Ray Tracing code in anisotropic plasma for radioastronomical applications.

Ray tracing techniques are important tools in the study of radio waves propagation. Based on the calculation of the trajectory of electromagnetic energy through a given medium (ionosphere, solar wind, tokamak...), these techniques provide approximate solutions of Maxwell’s equations in this medium. Since the 50’s, many different ray tracing techniques were developed, from geometrical ones, as Poeverlein method, to numerical ones, as Haselgrove method. This latter is probably the most useful technique for a general study of the propagation of radio waves in the terrestrial ionosphere. The general form of the Haselgrove equations allows us to extend their application not only in the terrestrial ionosphere but also in any anisotropic plasma, which is a common medium in the solar system, from the Sun to planetary magnetospheres.

Planetary magnetospheres result from the interaction between the solar wind and the planetary magnetic field. Planetary radio emissions are produced by the precipitation of plasma electrons along the magnetic field lines, close to the magnetic poles. After their emission, the radio waves propagate through this inhomogeneous and anisotropic medium.

In order to compute the refractive effects sustained by such radio waves through planetary magnetospheres, we have been developing ARTEMIS-P (Anisotropic Ray Tracer for Electromagnetics in Magnetosphere, Ionosphere and Solar wind including Polarization), a general three-dimensional ray tracing code based on the Haselgrove equations, which also include computation of the polarization state along the ray path. The ARTEMIS-P code has already been used to study the propagation ‘over the horizon’ of Saturn Electrostatic Discharges and the propagation of Terrestrial Kilometric Radiation through the auroral cavities.

Reference:

  • Gautier, A.-L., PhD dissertation 2013. PDF