A segmented multi-loop antenna for selective excitation of azimuthal mode number in a helicon plasma source

Tanikawa, T.; Motomura, T.

doi:10.1063/1.4896041

Title: A segmented multi-loop antenna for selective excitation of azimuthal mode number in a helicon plasma source

Full Record
Other Related Research

Abstract

A flat type, segmented multi-loop antenna was developed in the Tokai Helicon Device, built for producing high-density helicon plasma, with a diameter of 20 cm and an axial length of 100 cm. This antenna, composed of azimuthally splitting segments located on four different radial positions, i.e., r = 2.8, 4.8, 6.8, and 8.8 cm, can excite the azimuthal mode number m of 0, ±1, and ±2 by a proper choice of antenna feeder parts just on the rear side of the antenna. Power dependencies of the electron density n{sub e} were investigated with a radio frequency (rf) power less than 3 kW (excitation frequency ranged from 8 to 20 MHz) by the use of various types of antenna segments, and n{sub e} up to ∼5 × 10{sup 12} cm{sup −3} was obtained after the density jump from inductively coupled plasma to helicon discharges. Radial density profiles of m = 0 and ±1 modes with low and high rf powers were measured. For the cases of these modes after the density jump, the excited mode structures derived from the magnetic probe measurements were consistent with those expected from theory on helicon waves excited in the plasma.

Authors:

Tanikawa, T. ^[1]; Motomura, T. ^[2]

Research Institute of Science and Technology, Tokai University, 4-1-1, Kita-kaname, Hiratsuka, Kanagawa 259-1292 (Japan)
National Institute of Advanced Industrial Science and Technology (AIST), 807-1, Shuku-machi, Tosu, Saga 841-0052 Japan (Japan)

Publication Date:: Mon Sep 15 00:00:00 EDT 2014

OSTI Identifier:: 22314276

Resource Type:: Journal Article

Journal Name:: Review of Scientific Instruments

Additional Journal Information:: Journal Volume: 85; Journal Issue: 9; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0034-6748

Country of Publication:: United States

Language:: English

Subject:: 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANTENNAS; ELECTRON DENSITY; EXCITATION; HELICON WAVES; LENGTH; MAGNETIC PROBES; MHZ RANGE; PLASMA DENSITY; RADIOWAVE RADIATION

Citation Formats


                    Shinohara, S., E-mail: sshinoha@cc.tuat.ac.jp, Tanikawa, T., and Motomura, T. A segmented multi-loop antenna for selective excitation of azimuthal mode number in a helicon plasma source.  United States: N. p., 2014. 
        Web.  doi:10.1063/1.4896041.

Copy to clipboard


                    Shinohara, S., E-mail: sshinoha@cc.tuat.ac.jp, Tanikawa, T., & Motomura, T. A segmented multi-loop antenna for selective excitation of azimuthal mode number in a helicon plasma source.  United States.  https://doi.org/10.1063/1.4896041

Copy to clipboard


                    Shinohara, S., E-mail: sshinoha@cc.tuat.ac.jp, Tanikawa, T., and Motomura, T. 2014.  
        "A segmented multi-loop antenna for selective excitation of azimuthal mode number in a helicon plasma source".  United States.  https://doi.org/10.1063/1.4896041.

Copy to clipboard


                    
@article{osti_22314276,

  title        = {A segmented multi-loop antenna for selective excitation of azimuthal mode number in a helicon plasma source},

  author       = {Shinohara, S., E-mail: sshinoha@cc.tuat.ac.jp and Tanikawa, T. and Motomura, T.},

  abstractNote = {A flat type, segmented multi-loop antenna was developed in the Tokai Helicon Device, built for producing high-density helicon plasma, with a diameter of 20 cm and an axial length of 100 cm. This antenna, composed of azimuthally splitting segments located on four different radial positions, i.e., r = 2.8, 4.8, 6.8, and 8.8 cm, can excite the azimuthal mode number m of 0, ±1, and ±2 by a proper choice of antenna feeder parts just on the rear side of the antenna. Power dependencies of the electron density n{sub e} were investigated with a radio frequency (rf) power less than 3 kW (excitation frequency ranged from 8 to 20 MHz) by the use of various types of antenna segments, and n{sub e} up to ∼5 × 10{sup 12} cm{sup −3} was obtained after the density jump from inductively coupled plasma to helicon discharges. Radial density profiles of m = 0 and ±1 modes with low and high rf powers were measured. For the cases of these modes after the density jump, the excited mode structures derived from the magnetic probe measurements were consistent with those expected from theory on helicon waves excited in the plasma.},

  doi          = {10.1063/1.4896041},

  url          = {https://www.osti.gov/biblio/22314276},
  journal      = {Review of Scientific Instruments},

  issn         = {0034-6748},

  number       = 9,

  volume       = 85,

  place        = {United States},

  year         = {Mon Sep 15 00:00:00 EDT 2014},

  month        = {Mon Sep 15 00:00:00 EDT 2014}

}

Copy to clipboard

Journal Article:

https://doi.org/10.1063/1.4896041

Other availability

Find in Google Scholar

Search WorldCat to find libraries that may hold this journal

Save / Share:

Export Metadata

Save to My Library

Similar records in OSTI.GOV collections:

Modeling of profile effects for inductive helicon plasma sources

Journal Article Mouzouris, Y; Scharer, J - IEEE Transactions on Plasma Science

A computer code for modeling existing and new helicon sources for materials processing has been developed. The Nagoya type-III, helical, and Stix coil antennas have been modeled to study and examine plasma density and temperature profile effects on power absorption of a small fraction (n{sub fe}/n{sub e} {approx} 5%) of fast electrons (T{sub e-fast} {approx} 40 eV) which provide ionization of the neutral gas in the experiment, and bulk (T{sub e-slow} {approx} 3 eV) electron distributions in an argon gas. The ANTENA computer code, originally written by B. McVey to study ion cyclotron waves, was modified and used to studymore »« less
https://doi.org/10.1109/27.491753
Current generation by helicons and LH waves in modern tokamaks and reactors FNSF-AT, ITER and DEMO. Scenarios, modeling and antennae

Journal Article Vdovin, V. - AIP Conference Proceedings

The Innovative concept and 3D full wave code modeling Off-axis current drive by RF waves in large scale tokamaks, reactors FNSF-AT, ITER and DEMO for steady state operation with high efficiency was proposed [1] to overcome problems well known for LH method [2]. The scheme uses the helicons radiation (fast magnetosonic waves at high (20–40) IC frequency harmonics) at frequencies of 500–1000 MHz, propagating in the outer regions of the plasmas with a rotational transform. It is expected that the current generated by Helicons will help to have regimes with negative magnetic shear and internal transport barrier to ensure stabilitymore »« less
https://doi.org/10.1063/1.4864523
Ion acceleration in a helicon source due to the self-bias effect

Journal Article Wiebold, Matt; Sung, Yung-Ta; Scharer, John - Physics of Plasmas

Time-averaged plasma potential differences up to 165 V over several hundred Debye lengths are observed in low pressure (p{sub n} < 1 mTorr) expanding argon plasmas in the Madison Helicon eXperiment (MadHeX). The potential gradient leads to ion acceleration greater than that predicted by ambipolar expansion, exceeding E{sub i} Almost-Equal-To 7 kT{sub e} in some cases. RF power up to 500 W at 13.56 MHz is supplied to a half-turn, double-helix antenna in the presence of a nozzle magnetic field, adjustable up to 1 kG. A retarding potential analyzer (RPA) measures the ion energy distribution function (IEDF) and a sweptmore »« less
https://doi.org/10.1063/1.4714605
Towards an optimal antenna for helicon waves excitation

Journal Article Guittienne, Ph; Chevalier, E; Hollenstein, Ch - Journal of Applied Physics

Helicon sources are known to produce high-density plasmas and have found many applications. Different types of antenna have been used for helicon excitation but none of them generate a radio-frequency (rf) field that matches the helicon wave field determined by the dispersion equation. We show that this match can be obtained to a very good approximation by using a birdcage type antenna. Our plasma experiments show that a helicon regime with electron densities up to 5x10{sup 12} cm{sup -3} is obtained for very low rf power injection (typically 200 W), and at an unusual operating pressure up to 25 Pa.
https://doi.org/10.1063/1.2081107
Discharge regimes and density jumps in a helicon plasma source

Conference Shinohara, S; Yonekura, K

A high density plasma source using a helicon wave is becoming very attractive in plasma processing and confinement devices. In the previous work, the characteristics of this wave and plasma performance with diameters of 5 and 45 cm have been studied, and the helicon wave was only observed after the density jump. Recently, density jumps from the low to high electron densities with a level of 10{sup 13} cm{sup {minus}3} were investigated by changing the antenna wavenumber spectrum, and the obtained results were compared with the inductively coupled plasma (ICP). However, the mechanisms of density jumps and plasma production aremore »« less

Similar Records