Investigation of Fast Ion Confinement in the Gas Dynamic Trap

The confinement of the fast, anisotropic ions is one of the basic objectives of the GDT experimental research program. The approach consists in comparing the measured ion parameters with those predicted by computer simulations based on the theory of Coulomb collisions. A broad set of diagnostics for measurements of fast ion parameters has been developed. In particular, it includes the measurement of the local energy distribution function. In parallel the Monte Carlo transport code FIT, which simulates fast ion histories in the frame of the lassical theory has been developed. The comparison of the measured and computed parameters clearly shows that the energy confinement time of the fast ions is governed by Coulomb collisions only and significant anomalous ion losses were not yet observed in GDT experiments up to the present plasma parameters.