Helicon volume production of H$^−$ and D$^−$ using a resonant birdcage antenna on RAID
Résumé
Negative ion production by volumetric processes is investigated in the RAID linear device using experiments and modeling. Measurements by optical emission spectroscopy, cavity ring-down spectroscopy, and Langmuir probe assisted laser photodetachment are combined and reveal that H$^−$ and D$^−$ ions are distributed in a halo around the plasma column with densities of 2 × 10$^{16}$ m$^{-3}$ for only a few kilowatts of RF power in a Cs-free plasma. A hydrogen transport fluid code shows that RAID plasmas have a hot electron core favorable to ro-vibrational excitation and dissociation of H$_2$ molecules. Dissociative attachment to ro-vibrationally excited H$_2$ molecules is the only significant source of H$^−$ anywhere in the RAID volume
Domaines
Plasmas
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Licence : CC BY - Paternité
Licence : CC BY - Paternité