Helicon plasma sources do not require electrodes or grids directly immersed in the plasma, and also present an axial magnetic field confining the plasma discharge. These factors are believed to provide them with long operational lifetimes because of the reduced potential for surface etching. The physics of helicon waves, cylindrical magnetized plasmas, sheaths, and plasma-surface interactions are discussed in the context of this claim. Practical implementation aspects are also reviewed, along with relevant experimental results. It is shown that understanding the distribution of ion density within the source, the presence of induced potentials in its surfaces, and the physics of low-energy sputtering reactions is essential to properly model erosion phenomena within helicons, and consequently predict their performance in practical applications.

Helicon plasma sources produce high-density discharges without the need of electrodes in direct contact with the plasma, which is thought to provide them with long operational lifetimes. An explicit steady-state analytical model is described with the capability of depicting the 2D plasma density distribution, the sheath potentials and the estimated sputtering and etch rates along the plasma-facing components of the source. The individual constituting submodels are fitted against available experimental data, and the model is used to predict erosion rates within the VX-CR research helicon plasma source. Erosion within these components is dependent on the value of plasma density along the boundaries, the electron temperature and the particular ion-target material combination. The highest erosion rates are found along the upstream system boundary, followed by the regions near the helicon antenna straps where a capacitive RF sheath is formed. The assumptions and limitations of the model are discussed, and future improvements are proposed.