Design of an ICRF plasma thruster antenna by TOPICA

A typical RF plasma thruster is comprised of an RF plasma source, an open-ended magnetic confinement device, an RF acceleration unit and a magnetic nozzle. The usual choice for the acceleration is to employ the Ion-Cyclotron resonance frequency (ICRF), a well established technology in fusion experiments for transferring large RF powers to magnetized plasmas. To help design RF thruster ICRF antennas, TOPICA (Torino Polytechnic Ion Cyclotron Antenna) code [1] has been recently extended to handle cylindrically symmetric plasmas. The latter entailed developing a wholly new module of TOPICA charged with the task of solving Maxwell's equations in cylindrical magnetized warm plasmas and yielding the Green's function$\underline{\underline {\tilde {Y}}} (m,k_z )$, i.e. the relationship at the air-plasma interface between the transverse magnetic and electric fields in the spectral (wavenumber) domain. The approach to the problem of determining the antenna input impedance relies on an integral-equation formulation for the self-consistent evaluation of the current distribution on the conductors. This work reports on TOPICA evolution and presents the design of an RF thruster ICRF antenna. \begin{enumerate} \item V. Lancellotti et al., Nucl. Fusion, \textbf{46} (2006) S476-S499 \end{enumerate}