Bi-Directional Excitation of Radio Frequency Waves Using a Helical Antenna in Non-Uniform Plasmas towards a Compact Magnetoplasma Thruster

Satoshi  Nakamoto; Hiromasa  Takeno; Yoshifumi  Hayashi; Yasuyoshi  Yasaka

doi:10.4236/ojapps.2014.413051

Yasuyoshi Yasaka^*, Yoshifumi Hayashi, Hiromasa Takeno, Satoshi Nakamoto

Abstract: Magnetoplasma thruster is one of the attractive plasma engines for space propulsion in future manned deep space exploration. Usually two helical antennas are equipped to produce and heat plasmas with separate radio frequency sources. It is presented in this paper that a helical antenna, which is used to launch one wave mode in one direction so far, exhibits bi-directional nature, where the waves with different mode numbers are launched and couple with electrons and ions selectively in opposite directions. A two-dimensional numerical calculation is performed to predict wave propagation and power absorption in a non-uniform hydrogen plasma immersed in a non-uniform external static magnetic field, based on the hot plasma theory. It is confirmed that appropriate choice of the excitation condition of the antenna can select axial propagation direction of specific wave modes and consequently select a species that absorbs power from generated waves. A small-scale experiment is performed to confirm the prediction of the calculation. By measuring a change in electron and ion temperatures due to the wave launch from the helical antenna, it is found that both the production and heating at different axial positions are accomplished simultaneously by one antenna showing that another type of the radio frequency driven magnetoplasma thruster would be achieved.

Keywords: Plasma Thruster, Magnetoplasma, Radio Frequency, Helical Antenna, Plasma Waves

Cite this paper: Yasaka, Y. , Hayashi, Y. , Takeno, H. and Nakamoto, S. (2014) Bi-Directional Excitation of Radio Frequency Waves Using a Helical Antenna in Non-Uniform Plasmas towards a Compact Magnetoplasma Thruster. Open Journal of Applied Sciences, 4, 523-532. doi: 10.4236/ojapps.2014.413051.

References

[1] Yasaka, Y., Hayashi, Y., Takeno, H., Nakamoto, S. and Kinoshita, Y. (2013) Bi-Directional Excitation of ICRF Waves in Non-Uniform Plasmas towards a Compact RF-Driven Magnetoplasma Thruster. Proceedings of the 31st International Conference on Phenomena in Ionized Gas, Granada, 14-19 July 2013, 2-058.
http://www.icpig2013.net/papers/294_3.pdf

[2] Chang-Diaz, F. and Squire, J. (2004) The VASIMR Engine: Project Status and Recent Accomplishments. AIAA Aerospace Sciences Meeting and Exhibit, AIAA, Reston, 2004, Article ID: 0149.

[3] Bering, E., Chang-Diaz, F., Squire, J., Glover, T., Carter, M., McCaskill, G., Longmier, B., Brukardt, M., Chancery, W. and Jacobson, V. (2010) Observations of Single-Pass Ion Cyclotron Heating in a Trans-Sonic Flowing Plasma. Physics of Plasmas, 17, Article ID: A043509.
http://dx.doi.org/10.1063/1.3389205

[4] Miljak, D. and Chen, F.F. (1998) Helicon Wave Excitation with Rotating Antenna Fields. Plasma Sources Science and Technology, 7, 61-74.
http://dx.doi.org/10.1088/0963-0252/7/1/009

[5] Lee, C. (2008) Experimental Studies of a Helicon Plasma. Ph.D. Thesis, University of Texas, Austin, UMI 3320977.

[6] Yasaka, Y., Majeski, R., Browning, J. and Hershkowitz, N. (1988) ICRF Heating with Mode Control Provided by a Rotating Field Antenna. Nuclear Fusion, 28, 1765. http://dx.doi.org/10.1088/0029-5515/28/10/005

[7] Arefiev, A.V. and Breizman, B.N. (2004) Theoretical Components of the VASIMR Plasma Propulsion Concept. Physics of Plasmas, 11, 2942.
http://dx.doi.org/10.1063/1.1666328

[8] Yasaka, Y., Tobita, N. and Tsuji, A. (2013) Control of Plasma Profile in Microwave Discharges via Inverse-Problem Approach. AIP Advances, 3, Article ID: 122102.

[9] Yasaka, Y., Fukuyama, A., Hatta, A. and Itatani, R. (1992) Two-Dimensional Modeling of Electron Cyclotron Resonance Plasma Production.
Journal of Applied Physics, 72, 2652-2658. http://dx.doi.org/10.1063/1.351566

[10] Hojo, H., Tatematsu, Y. and Saito, T. (2007) Full-Wave Maxwell Simulations for Electron Cyclotron Resonance Heating. Fusion Science and Technology, 51, 164-167.

[11] Yasaka, Y. and Itatani, R. (1980) Direct Comparison between Circularly and Linearly Polarized RF Fields in ICRF Heating. Nuclear Fusion, 20, 1391-1396.
http://dx.doi.org/10.1088/0029-5515/20/11/006

[12] Yasaka, Y., Nishino, S., Yamamoto, M., Nakamoto, S., Takeno, H. and Yonemori, H. (2012) Novel Control of Magnetoplasma Thruster by Using a Rotating Radio Frequency System. Journal of Propulsion and Power, 28, 364-370.
http://dx.doi.org/10.2514/1.B34271

[13] Ohuchi, M., Endoh, T. and Kubota, T. (1996) Measurement of Ion Energy Distribution Functions Behind an Ion Sheath. Annual Report, Research Institute for Technology, No. 15, Tokyo Denki University, Tokyo, 77-82. (In Japanese)
http://souken.dendai.ac.jp/db_pdf/1994/7.Q94-M32.pdf