Zmode-rayTracing

# ARTEMIS-P Anisotropic Ray Tracer for Electromagnetism in Magnetospheres, Ionospheres and Solar wind, including Polarisation A short description of the code is available in the [Proceedings of the 2013 URSI-France meeting](http://ursi-france.telecom-paristech.fr/fileadmin/journees_scient/docs_journees_2013/data/articles/000052.pdf). ## Requirement ### Compilation The default compiler is [GNU Fortran Compiler](https://gcc.gnu.org/wiki/GFortranBinaries). It is also possible to compile with [Intel Fortran Compiler](https://www.intel.com/content/www/us/en/developer/tools/oneapi/fortran-compiler.html#gs.i844d1). ## How to run ### input files There are 2 initialization files : * _init_environ.txt_ : contains initial values of the environement. * _init_raytracing.txt_ : constains all parameters for the initialization of the program. ### Defining Density and Magnetic Field Currently, the density and magnetic field are defined by an analytical function only. In the file _environ.f90_, the routine _magneticf_ calculates the magnetic field and _density_ computes the electron density. ### Outputs the program produces for each ray a file containing various data calculated at each time step and along the trajectory of the ray. ### Future improvements It will be possible to load a complete environment from a simulation for instance. In addition, the format of the results will also be updated. ## Description of input files You need to specify all the lines. You can find two simple examples on Toy1 and Toy2 branches. ### _init_environ.txt_ : * n0 in cm^-3 ; used in computation of Ne (see the routine _density_ in _environ.f90_). * z0 in km ; used in the computation of Ne (see the routine _density_ in _environ.f90_). * B0 in T ; used in computation of B (see the routine _magneticf_ in _environ.f90_). * z0B in km ; used in computation of B (see the routine _magneticf_ in _environ.f90_). ### _init_raytracing.txt_ : * <directory_name> : maximum length = 4. * <integrator_name> : choose between RK4 and RK4F. * frequency in kHz (real). * number of rays (integer). * number of iterations (integer). * coordinate system. Choose between cart or sphr. * length units. Choose between km, m or rs. * initial position of rays (x,y,z). Give the initial position of each ray on a different line. * wave vector k (kx, ky, kz). Give the initial position of each ray on a different line. * propagation mode. "X" for extraordinary mode or "O" for ordinary mode. Give the initial position of each ray on a different line. * maximum value of refractive index (integer). * initial time step (real). * maximum time step (real). * minimum time step (real). ## Description of result files For the moment the results are written in a .dat file as columns. There is one file per ray which are written in the folder specified in init_raytracing.txt. Each line corresponds to a time step except the first one which is the header. Here is the list of saved parameters : * position (x, y, z) in cartesian coordinates * wave vector (kx, ky, kz) in cartesian coordinates * refractive index * time step * group velocity * phase velocity * (k, B) angle in degree * (r, B) angle in degree (cannot be calculated during the first iteration) * covered distance * magnetic field (Bx, By, Bz) in Tesla * plasma frequency in Hz * cyclotron frequency in Hz * upper hybrid frequency * electron density in cm^-3 * polarization ratios of Ey/Ex, Ez/Ex and Ez/Ey * propagation mode (ordinary or extra-ordinary) * limiting polarisation vector ('VP' -> polar variable, 'LP' -> limiting polar) * relative error between two time step * dispersion error