Description of the data format of GENE output

There are two different output files. The nrg and the kin file. The first contains the timetrace information, such as density, temperatures and the transport fluxes, all spatially averaged. As the information amount is low, a lot of timesteps can be written.

The second file, the kin file (there are as many of these files as there are species, for the electrons called kine and the ions kini file) contains at only some timesteps (typically all 500-2000) ten 3D fields of plasma quantities. These files become rather big.


The entries in this file for each timestep are written in ASCII sequentially. One entry looks like

2.4862E+01 4.4911E+00 2.1926E+01 1.2346E+02 1.8177E+00 1.1874E-02 1.2012E+01 -3.4358E-02
3.5781E+01 1.7368E+02 2.3356E+01 1.2562E+01 1.8177E+00 1.1874E-02 2.7023E+00 2.4421E-02

The first line contains the time, at which the data has been written out. Then there follow as many lines as species considered in the run. In the sample case there are two lines, the first for the electrons, the second for the ions.

The columns does have the meaning
n^2 u_par^2 T_par^2 T_perp^2 Gamma_es Gamma_em Q_es Q_em
All quantities are spatially averaged over the full simulation volume.


In contrast to the nrg file, the kin files are binary files. All entries consist of 8-byte floating point numbers. All timesteps are written sequentially and each entry consists of the time and ten 3D fields. The fields itself are written perpendicular plane ordered. The dimensions of one perpendicular plane are Nx+2Nxb times Ny+2*Nyb where Nx and Ny are the number of the inner points and Nxb and Nyb the number of halo boundary points on each side. In parallel direction there are Nz+2Nzb planes. For the two-dimensional planes the x-index is running fastest.
The fields are
  1. electrostatic potential phi
  2. electromagnetic potential A_par
  3. density or density of passing particles
  4. parallel temperature or parallel temperature of the passing particles, T_par
  5. perpendicular temperature, T_perp
  6. parallel flux of parallel heat, q_par,par
  7. parallel flux of perpendicular heat, q_par,perp
  8. parallel fluid velocity, u_par
  9. density of the trapped particles
  10. parallel temperature of the trapped particles

Sample output files

The result of one run is shown here. It is calculated for a typical case of trapped-electron mode driven turbulence. You can find the nrg_827 and the kine_827 files. The runparameters can be found in the par_827 file, which will be read by the IDL files of the following section.

IDL script for reading the kin file

There are three small IDL subroutines which reads in one timestep out of the kin file. In the new version of the code (GENE 10), there is an additional file written to the output, which contains all of the information which is in the par file and some more information. The main reason for this new file is that it is now better readable and extendible. The new file is called parnew and contains all information in the form of key=value pairs. It can be read with the new IDL script.
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Tilman Dannert