Speaker
Arun Pandey
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P1.1021.pdf
Negative Hydrogen Ion Production in HELEN-1 (HELicon Experiment
for Negative ion source)
A. Pandey1, Debrup Mukherjee, M. Bandyopadhyay1, 2, A. Chakraborty2
1
Institute for Plasma Research, HBNI, Gujarat, India
2
ITER-India, Institute for Plasma Research, Gujarat, India
Helicon wave heated plasmas sources are very efficient in terms of ionization per unit power
consumed. Owing to the production of high plasma density in helicon plasma sources, these
sources could be used for an efficient negative ion source in terms of RF power budgeting is
concerned. In the HELEN1 device at IPR, helicon plasma using hydrogen gas is produced by
applying RF Power of 13.56 MHz at 900-1000W using a Nagoya-III antenna for exciting m
= ±1 azimuthal mode in the plasma. The characteristic density jump from inductively
coupled mode to Helicon mode is observed at Prf ~ 800W. This density jump depends on
the neutral pressure as well as the axial magnetic field. Two diagnostic methods are used to
measure negative hydrogen ion density. Cavity Ring Down Spectroscopy (CRDS) technique
and laser photo-detachment (LPD) technique using a 1064 nm Nd:YAG laser and an RF
compensated Langmuir probe. Typical plasma density in the present experimental
configuration is ~ 1012cm-3 and typical negative ion density is ~ 109cm-3 measured by Cavity
Ring Down Spectroscopy (CRDS) technique. The negative ion density is correlated with the
particle balance model.
1. Arun Pandey et al., Performance evaluation of a permanent ring magnet based helicon plasma source for
negative ion source research, Rev. Sci. Instrum. 88, 103509 (2017).
