EGAS41 - Swansea University

41 st EGAS CP 7 Gdańsk 2009
Ne I excitation rate coefficients for C-R models applied to
electric propulsion
Ch. Berenguer 1 , K. Katsonis 1 , R.E.H. Clark 2
1 GAPHYOR, Laboratoire de Physique des Gaz et des Plasmas, UMR 8578, Université
Paris-sud, 91405 Orsay cedex, France
2 Nuclear Data Section, IAEA, Wagramerstr. 5, A-1400 Vienna, Austria
∗ Corresponding author: konstantinos.katsonis@u-psud.fr,
Because of the possible use of Ne as a fuel gas in electric propulsion devices, we are
developing a Collisional-Radiative (C-R) model valid for low temperature Ne plasma,
encompassing the neutral Ne atom and its first ion, with Ne III as a continuum [1].
This “zero dimension” model is meant for non-intrusive emission spectroscopy diagnostics
giving the local electronic temperature T e and density n e inside a plasma thruster; it
can also be used as a basis for development of a detailed full dimensional model [2].
Validation of the C-R model is underway, mainly by use of a Ne-filled hollow cathode lamp
experimental facility in which the positions and intensities of the principal Ne I and Ne II
spectral lines have been measured. The theoretical spectra obtained by the C-R model rely
on transition probability (A ij ) and electron impact collision excitation (σ e ) data. In the
present contribution we focus on evaluation of the σ e and of the corresponding excitation
rates for the lower levels of Ne I. In addition to the available experimental and theoretical
results [3], we have used the following theoretical methods [4] for the σ e evaluations: i)
The Born approximation (high energy region) in which the structure parameters are of
paramount importance. ii) Distorted Wave (DW) approximation and First Order Many
Body Theory (FOMBT) at electron impact energies approaching the threshold, using
the online interface to the Los Alamos National Laboratory atomic physics codes [5].
iii) Quasi-classical evaluations based on the Hamiltonian formulation of the few body
problem, following numerical CTMC studies.
Acknowledgment
The research leading to these results has received funding from the European Community’s
Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 218862.
References
[1] Ch. Berenguer, K. Katsonis, S. Cohen, P. Tsekeris, M. Cornille, A Collisionnal-
Radiative Model for Low Temperature Ne Plasmas, 31 st IEPC, Ann Arbor, MI USA
[2] K. Katsonis, S. Pellerin, K. Dzierzega, JHTMP 7, 559 (2003)
[3] M.H. Phillips, L.W. Anderson, Chun C. Lin, Phys. Rev. A 12 (1985); M. Allan et al.,
J. Phys. B 42 044009 (2009) and references therein
[4] Ch. Berenguer, Optical Diagnostics of High Energy Density Plasmas, PhD Thesis,
Orsay, February 2009
[5] http://aphysics2.lanl.gov/tempweb/
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