The Modeling of the Interactions of Pellets With Magnetic Fusion Plasmas for Alpha Particle Diagnostics

A model for the interactions of hydrogen and carbon pellets with thermonuclear fusion plasmas has been developed and solved to determine the charge-state spatial distributions in the ablation cloud surrounding the pellet. The ionization is treated in a self-consistent manner in the energy balance and the collisional radiative (CR) model is used to calculate the ionization levels. External plasma electron effects on ionization are included. The electron heat flux is modeled as a multigroup distribution. The channelling of the flow along the field line is treated phenomenologically by restricting the cross-sectional area of the flow. The predictions of the model are compared with the results from the General Atomics experiments on the TEXT tokamak for C + 2 and C + 3 clouds of definite size. A reasonable agreement for the C + 2 cloud is found