Dejan Petkow

Effect of Nuclear Side Reactions on Magnetic Fusion Reactors in Space

A generalized burn criterion for thermonuclear fusion reactors in space is extended with respect to side reactions among all reactant and product species contained in a magnetically confined fusion plasma. The obtained criterion is verified against two simpler forms and a D-T mixture with a 1:1 fuel ratio. The power balance based on a newly developed flux scheme model is solved in conjunction with particle balances. Side reactions are observed to broaden the ignition temperature curve and keep or increase the temperature optimum under the given conditions. This is hinting at options to enhance the ingitability of aneutronic reactions. A brief fusion propulsion modelling was performed with D-T plasma volumes of 10 and 30m both with 1:1 and 4:1 mixture ratios. It is found that this fueling entails huge space craft masses and thus small accelerations confirming older conclusions on the limited suitability of D-T plasmas for fusion space propulsion.

Verification of a Ground-State Ionization Model for Electrons and Neutrals within a DSMC Code

The simplified ionization model within a Direct Simulation Monte Carlo approach as part of a numerical scheme for approximately solving of the Boltzmann equation for rarefied, non-continuum plasma flows is presented. The considered electron-neutral ionization process is modeled by the ionization cross section given by Lotz. Accordingly, the model for the recombination as an implementation test is outlined. Preliminary results are presented and discussed in the context of further model improvements.