Speaker
Dr
Min Park
(Korea Atomic Energy Research Institute)
Description
Hydrogen plasmas are widely used in various applications. Particularly, in the fields of nuclear fusion and accelerators, a sufficient amount of hydrogen negative ions are extracted from the plasma and accelerated to form high current negative ion beams. In order to develop plasma sources producing high density negative ions, negative ion density measurement as well as plasma characterization is the first crucial step. Measurement of negative hydrogen ion densities using laser photo-detachment was carried out in an RF inductively coupled hydrogen plasma. Nd:YAG laser at 1064 nm was used to detach electrons from hydrogen negative ions and the detached electrons were collected by a positively biased electrostatic probe. The electrostatic probe, equipped with RF-filters compensating the plasma RF fluctuations, was also used to obtain electron energy distribution functions (EEDFs). Based on electron densities and temperatures calculated from measured EEDFs, negative ion densities were calculated using a set of particle balance equations considering all processes related to negative ion generation and loss. Both negative ion density behaviors obtained by laser photo-detachment and the calculation show quite good agreement.
Primary author
Dr
Min Park
(Korea Atomic Energy Research Institute)
Co-authors
Dr
Bongki Jung
(Korea Atomic Energy Research Institute)
Dr
Doo-Hee Chang
(Korea Atomic Energy Research Institute)
Dr
Seung Ho Jeong
(Korea Atomic Energy Research Institute)
Dr
Tae-Seong Kim
(Korea Atomic Energy Research Institute)
