29. Thomson Scattering Unit

Figure 29.1: The ThomsonScattering unit with ray tracing directory tree.

The ThomsonScattering unit records a Thomson scattering spectrum of certain sections of the domain at certain simulation times. There are currently two versions of the unit: 1) a more recent version, which takes into account deflection of both laser and detector rays as well as energy deposition by the laser rays and 2) an initial simple version in which no ray tracing is performed (i.e. all laser and detector rays move in straight lines). The first version is computationally more involved, as it is not known beforehand where the Thomson scattering region is located due to ray deflection. To preserve flexibility and for comparison tests, the first version allows for suppression of ray deflection and energy deposition as well as ray power depletion while crossing the domain. This way one can study different ray effects on the Thomson spectra.

Currently, for the first version, ray deflection is done using the cell average algorithm AVG 17.4.4.1 described in the EnergyDeposition unit. Placement of several detectors are possible, with more than one detector receiving rays from the same laser. However, no detector can record spectra coming from different lasers. The possibility of placing several detectors associated with the same laser allows a detailed study of how the Thomson spectra change with orientation of the detector.