138:(ICP) is the presence of a magnetic field directed along the axis of the antenna. The presence of this magnetic field creates a helicon mode of operation with higher ionization efficiency and greater electron density than a typical ICP. The Australian National University, in Canberra, Australia, is currently researching applications for this technology. A commercially developed magnetoplasmadynamic engine called
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The practical significance of the surface mode, and its ultra-high current density, was not recognized in the original papers, but came to prominence a few years later when
Boswell discovered the superior plasma generating ability of helicons – achieving plasma charge densities 10 times higher than
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Longmier, B. W., Squire, J. P., Cassady, L. D., Ballenger, M. G. Carter, M. D., Olsen, C., Ilin, A. V., Glover, T. W., McCaskill, G. E., Chang Diaz, F. R., Bering III, E. A., and Del Valle, J. (September 2011) “VASIMR® VX-200 Performance
Measurements and Helicon Throttle Tables Using Argon and
99:
loss in such surface regions tends to a non-zero limit. The surface mode is especially prevalent in cylindrical samples parallel to the magnetic field, a configuration for which an exact solution has been found for the equations, and which figures importantly in subsequent experiments.
364:
Marini, C., Agnello, R., Duval, B. P., Furno, I., Howling, A. A., Jacquier, R., Karpushov, A. N., Plyushchev, P., Verhaegh, K., Guittienne, Ph., Fantz, U., WĂĽnderlich, D., BĂ©chu, S., and
Simonin, A. (January 2017) "Spectroscopic characterization of
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Klozenberg, J. P., McNamara, B., and
Thonemann, P. C. (March 1965) "The dispersion and attenuation of helicon waves in a uniform cylindrical plasma". Journal of Fluid Mechanics 21 (3): 545–563. DOI:10.1017/S0022112065000320.
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Goodman, J. M. (15 July 1968) "Helicon waves, surface-mode loss, and the accurate determination of the Hall coefficients of
Aluminum, Indium, Sodium, and Potassium". Physical Review 171 (1): 641–658. DOI:
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in a metal: the electric or magnetic fields are quickly reflected upon trying to enter the metal. (Hence the shine of metals.) However, skin depth depends on an inverse proportionality to the square root of
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Boswell, R. W. (October 1984) "Very efficient plasma generation by whistler waves near the lower hybrid frequency". Plasma
Physics and Controlled Fusion 26 (10): 1147–1162. DOI:10.1088/0741-3335/26/10/001.
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Charles, C., Boswell, R. W., and
Lieberman, M. A. (December 2006) "Xenon ion beam characterization in a helicon double layer thruster." Applied Physics Letters 89:261503 (3 pgs) DOI: 10.1063/1.2426881.
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term) is that at places where the sample surface runs parallel to the magnetic field, one of the modes contains electric currents that “go to infinity" in the limit of perfect conductivity; so that the
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Bowers, R., Legéndy, C. R., and Rose, F. E. (November 1961) "Oscillatory galvanomagnetic effect in metallic Sodium". Physical Review
Letters 7 (9): 339–341. DOI: 10.1103/PhysRevLett.7.339.
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Aigrain, P. (1961) Proceedings of the
International Conference on Semiconductor Physics (Publishing House of the Czechoslovak Academy of Science, Prague, 1961) p. 224.
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Goodman, J. M. and Legéndy, C. R. (May 1964) "Joule loss in a 'perfect' conductor in a magnetic field". Cornell
University Materials Science Center Report No. 201.
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120:
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Chen, F. F. (December 1996) "Helicon plasma sources" in: High Density Plasma Sources: Design, Physics and Performance, Oleg A. Popov (ed) (Elsevier-Noyes) print
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Poulsen, R. G. (1977) "Plasma etching in integrated circuit manufacture – A review" Journal of Vacuum Science and Technology 14 (1): 266 DOI: 10.1116/1.569137
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Boswell, R. W. and Chen F. F. (December 1997) "Helicons – the early years". IEEE Transactions on Plasma Science 25 (6): 1229–1244. DOI: 10.1109/27.650898.
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Since then, helicons found use in a variety of scientific and industrial applications – wherever highly efficient plasma generation was required, as in
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helicon plasmas generated by a resonant antenna for neutral beam applications in fusion." Nuclear Fusion 57:036024 (9pp) DOI:10.1088/1741-4326/aa53eb
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Boswell, R. W. (July 1970) "A study of waves in gaseous plasmas". Ph.D. Thesis, School of Physical Sciences, Flinders University of South Australia. (
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Legéndy, C. R. (September 1964) "Macroscopic theory of helicons". The Physical Review 135 (6A): A1713–A1724. DOI:10.1103/PhysRev.135.A1713.
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Krypton.” 32nd International Electric Propulsion Conference, held in Wiesbaden, Germany, September 11–15, 2011 (Wiesbaden: IEPC-2011-156).
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55:(rather than parallel as it would be without the magnetic field); so that the propagating component of the waves is corkscrew-shaped (
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One property of the helicon waves (readily demonstrated by a rudimentary calculation, using only the Hall effect terms and a
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selectivity and variable Si etch profiles". Applied Physics Letters 47 (10): 1095–1097 DOI: 10.1063/1.96340.
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both make use of helicons in their plasma heating phase). Helicons are also utilized in the procedure of
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70:, given conditions of low temperature and high magnetic fields. Most electromagnetic waves in a normal
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Boswell, R. W. and Henry D. (15 November 1985) "Pulsed high rate plasma etching with variable Si/SiO
183:". Philosophical Transactions of the Royal Society A. 246 (908): 113. DOI: 10.1098/rsta.1953.0011.
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also uses helicon discharge for generation of plasma in its engine. Potentially,
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A helicon discharge is an excitation of plasma by helicon waves induced through
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http://people.physics.anu.edu.au/~rwb112/hr/index.htm#Boswell_Thesis_directory
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are not able to do this, since the high conductivity of metals (due to their
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had been achieved with earlier methods, without a magnetic field.
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plasma-based rockets are suitable for interplanetary travel.
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Helicons have the special ability to propagate through pure
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Low-frequency EM wave created in plasmas by a magnetic field
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39:. The first helicons observed were atmospheric
199:(Ph.D thesis). Australian National University.
161:Variable Specific Impulse Magnetoplasma Rocket
121:Variable Specific Impulse Magnetoplasma Rocket
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181:An investigation of whistling atmospherics
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196:Helicon Waves in High Density Plasmas
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47:in the waves is dominated by the
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156:Helicon double-layer thruster
144:helicon double-layer thruster
117:helicon double-layer thruster
193:Darryn A. Schneider (1998).
225:American Journal of Physics
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136:inductively coupled plasma
31:that can exist in bounded
431:Electromagnetic radiation
221:"Helicon Waves in Solids"
290:10.1103/PhysRev.171.641.
132:radio frequency heating
219:B.W. Maxfield (1969).
35:in the presence of a
29:electromagnetic wave
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27:is a low-frequency
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167:References
80:skin depth
72:conductor
41:whistlers
425:Category
347:, ebook
150:See also
119:and the
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61:Aigrain
57:helical
33:plasmas
25:helicon
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140:VASIMR
68:metals
369:and D
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