Robuta

https://www.aanda.org/articles/aa/abs/2009/18/aa11496-08/aa11496-08.html The ionization fraction gradient across the Horsehead edge: an archetype for molecular clouds |... ionization fraction https://www.muni.cz/en/research/publications/1620816 Evolution of ionization fraction of sputtered species in standard, multi-pulse and reactive HiPIMS...