Speaker
Min-Keun Bae
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P2.3015.pdf
Understanding of effect of negative ions on the sheath formation
by emissive probe and laser induced fluorescence methods
M.-K. Bae1, I.J Kang1, H.T Oh1, I.S. Park1, S.J Jeong1, S.H Lee1, K.-S. Chung1
1
Department of Electrical Engineering, Hanyang University, Seoul, South of Korea
To understand the effect of negative ions on the sheath formation, emissive probe (EP) and
laser induced fluorescence (LIF) method were used. EP has been used to directly measure the
plasma potential profile and the sheath/presheath boundary is identified from the steep slop
change of the emission current. LIF determines ion flow velocities and ion temperatures from
the broadening of fluorescence lines [1,2]. Basic plasma parameters such as plasma density and
electron temperature are also measured by a single electric probe. Negative ion plasma is
generated by the discharge of Ar+O2 gas in a cubical chamber (24 x 24 x 24 cm3) with DC
filament source with the following conditions: ne ~ 108 cm-3, Te ~ 2 eV, Ti ~ 0.1 eV. O2 gas ratio
have been changed 0 ~ 10 % to investigate the effect of negative ion to sheath formation.
Change of sheath width, plasma potential, ion velocity due to ratio of negative ion
concentration will be presented.
References:
[1] In. Je. Kang et al, JINST. 10 (2015) C12019.
[2] G. D. Severn et al, Phys. Rev. Lett. 90 (2003) 145001-1.
