1. A. I. Morozov, Fiz. Plazmy 29, 261 (2003) [Plasma Phys. Rep. 29, 235 (2003)].
2. K. N. Kozubskii, V. M. Murashko, Yu. P. Rylov, et al., Fiz. Plazmy 29, 277 (2003) [Plasma Phys. Rep. 29, 251 (2003)].
3. V. Kim, J. Propuls. Power 14, 736 (1998).
4. R. Hofer and R. Gallimore, NASA Final Contractor Report, CT-2003-212893 (2003).