D. A. I. Munindradasa* and G. A. J. Amaratunga

Department of Electrical Engineering and Electronics
University of Liverpool, Brownlow Hill, Liverpool L69 3BX, United Kingdom
muni@liv.ac.uk

Nitrogen plasma is commonly generated by passing a current in a gas column, specially for nitrogen laser applications[1,2]. The optical cavity poisoning due to electrode evaporation and the excessive heat dissipation on to vacuum tube wall by diffused plasma can lead to an unstable system. An electrode-less, confined plasma system can improve the performance of such a system. Helicon wave excitation allows the selective energy transfer in to plasma species via Landau damping. Landau damping has been used for Ar ion laser [3] and for silicon plasma excitation [4]. A. Ganguli et al. have reported Ar plasma generated in a microwave discharge by Landau damping [5].

In this work we report a novel method to generate nitrogen plasma and helicon wave generated plasma is compared with the conventional inductively coupled RF plasma. In the experiments reported, RF power at 13.56MHz is launched in to nitrogen gas via double loop helicon antenna and an axial magnetic field up to 0.12T is applied. The plasma tube is comprised of three separate zones of magnetic field. The density of nitrogen plasma in the chamber was 2-6 X 1010 cm-3. The optical emission characteristics of the N plasma under helicon wave excitation are also reported.

[1] A.V. Martinez and V. Aboites, IEEE J. of Quantum Electronics, 29 (8), 1993.
[2] V.P. Tzolov, K.A. Grozdanov and P.A. Atanasov, J. Appl. Phys., 75 (2), 1994.
[3] P. Zhu and R.W. Boswell, Phy. Rev. Lett., 63 (26), 1989.
[4] A. Durandet, C.A. Davis and R.W. Boswell, Appl. Phy. Lett., 70 (14), 1997.
[5] A. Ganguli, R.K. Jarwal, R.D. Tarey and M.K. Akhtar., IEEE Trans. on Plas. Sci., 25 (5), 1997.