7th Asia-Pacific Conference on Plasma Physics, 12-17 Nov, 2023 at Port Messe Nagoya

The effect of magnetic field configurations in ion beam generation using aCompact ECR plasma source
Priti Singh, Anshu Verma, Debaprasad Sahu, Ramesh Narayanan, Ashish Ganguli, R D Tarey
Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi
e-mail (speaker): rams@dese.iitd.ac.in
The mechanism of electron cyclotron resonance (ECR)
power coupling is well known in literature to be one of themost energy efficient processes for plasma applications.
The Plasma Lab at IIT Delhi has indigenously developed
a patented Compact ECR Plasma Source (CEPS) which
has demonstrated the CEPS to be a generic source suitablefor various applications [1, 2]. One of the major emphasisin the recent past has been the studies on high energetic
ion beams that were observed when the CEPS has been
attached to a larger expansion chamber.
The experiments presented in this paper were
undertaken in a cylindrical vacuum chamber with an
indigenously developed ECR plasma source mounted
onto one end of the cylindrical chamber [diameter = 50cm, length = 75 cm], the Medium Volume Plasma System(MVPS) [Fig 1(a)]. The source section uses two different
magnetic field configurations (MF1 and MF2), which are

field configuration (MF1) of CEPS [Fig 1(b)] as well as
the alternate or second magnetic field configuration(MF2) of NEPS [Fig 1(c)] generate suitable ECR fields
within the plasma source section (PSS) but which are still
distinctly different from each other.
A series of experiments were performed for different
operating parameters in both magnetic field
configurations using hydrogen and argon plasmas [3]. The
primary diagnostics used in this work are a set of radial
and axial Langmuir Probes (LPs) along with a Retarding
Field Energy Analyzer (RFEA); all diagnostics being
fabricated in-house [Fig 2]. It was observed that thecomplex magnetic field configuration of MF1 was able togenerate more energetic ion beams as compared to that of
the MF2 configuration.

(b)
Figure 2: Schematic of MVPS showing mounting of the PSS for theCEPS / NEPS and the location of ports for various diagnostics.

The energetic ion beams are currently being studied
from the perspective of plasma applications [2], such asplasma processing and plasma-based thrusters [4, 5].
Details of these investigations would be presented in thiswork.
(c)

Figure 1: (a) Schematic of the essential components of the ECR plasma
source with permanent NdFeB ring magnets; Axial magnetic field profileof (b) MF1 (CEPS) and (c) MF2 (NEPS)

demarcated as Compact ECR Plasma Source (CEPS) andNon-compact ECR Plasma Source (NEPS), with theformer having a more complex magnetic field
configuration (MF1) than the latter (MF2). The magnetic

References[1] A. Ganguli, R. D. Tarey, N. Arora and R.
Narayanan, Plasma Sources Sci. Technol., 25 (2), 025026(8 pp), (2016); doi: 10.1088/0963-0252/25/2/025026[2] A. Ganguli, R. D. Tarey, R. Narayanan, A. Verma, DSahu and N. Arora, Asian Journal of Physics, 30 (1), 119(18 pp), (2021)[3] A. Verma, P Singh, R. Narayanan, D. Sahu, S. Kar, A.
Ganguli and R. D. Tarey, Plasma Research Express, 1 (3),035012 (10 pp), (2019); doi: 10.1088/2516-1067/ab3f90.
[4] A. Ganguli, R. D. Tarey, R. Narayanan, A. Verma,Plasma Sources Sci. Technol., 28 (3), 035014 (8 pp),(2019); doi: 10.1088/1361-6595/ab0969.
[5] A. Verma, A. Ganguli, D. Sahu, R. Narayanan and R.
D. Tarey, Plasma Sources Sci. Technol., 29 (8), 085007(17 pp), (2020); doi: 10.1088/1361-6595/ab97a5.