Components of the wave magnetic field in a helicon discharge have been measured with a singleturn, coaxial magnetic probe, left and righthanded helical antennas, as well as planepolarized antennas, were used. Us2055345a1 high density helicon plasma source for wide. In addition, the plasma density of seven operational helicon plasma source devices, having a common nagoya antenna, is compared with the simulation results of our proposed antenna and the common. Wall charging of a helicon antenna wrapped plasma filled dielectric tube. The ionization efficiency of helicon plasma discharge is explored by chang ing the low axial magnetic field gradients near the helicon antenna. Ion trajectories plotted for 200 ions placed near the maximum ion density. Design and development of a 1kwclass helicon antenna thruster. Pdf wall charging of a helicon antenna wrapped plasma. This antenna will be fed with 1 mw of rf power at 476 mhz, and it is expected to drive current and heat the plasma based on computational predictions and experimental results from a previously installed low power. The influence of the electromagnetic wave pattern symmetry on the plasma density and absorption power in a helicon plasma source with a common antenna nagoya is analysed by using the standard comsol multiphysics 5. So far, there is no theoretical explanation for the formation. Plasma density and magnetic field strength are modified to maximize the collisional power absorption in the helicon plasma. Aanesland et al fluctuation in a helicon plasma with additional immersed antenna 361 fig.
Apr 16, 2018 to construct a large volume helicon plasma source, we set the radii of plasma and antenna to be 0. Helicon plasma with additional immersed antenna in contact with the plasma but in the matching network there is a tune capacitor that plays the role of a dc block, allo wing the. Design of a novel high efficiency antenna for helicon. Helicon wave excitation with rotating antenna fields david g. A rf antenna 31 and 32 of a novel serpentine configuration is used to couple electromagnetic energy into the source chamber to create helicon plasma waves in the source chamber 26. Helicon plasma with additional immersed antenna in contact with the plasma but in the matching network there is a tune capacitor that plays the role of a dc block, allowing the electrode to develop a negative selfbias with current. The feed line is connected between the bottom of the helix and the ground plane. Consider a cylindrical plasma with a radially varying density profile immersed in a co axial static magnetic field b z0. Effects of antenna wavenumber spectrum and metal end plate on. Direct measurements of parallel currents consistent with slow waves in the plasma edge 14 did not resolve the controversy as other experimental groups. A spiral antenna helicon plasma source is characterized experimentally at applied magnetic flux densities below 60 g and applied rf powers below 800 w.
In 41, the effect of the density nonuniformity on the. This fact challenges the notion that the helicon antenna deposits rf power into the plasma via excitation of conventional whistler waves. Development of electrodeless radiofrequency plasma thrusters, e. We will present langmuir probe data showing plasma density and electron temperature over a range of plasma parameters. Hiiper space propulsion simulation using plasma module. Pdf fluctuation in a helicon plasma with additional. Establishing plasma densities and magnetic field strengths under the antenna that suppress nonresonant mode conversion to the slowwave are thought to be responsible for operating in the heliconmode. Helicon plasma with additional immersed antenna request pdf. Helical and helicon antennas are routinely used to generate inductively coupled plasmas, but there are only a few simulations or experimental data with comparisons among them.
Development of highdensity helicon plasma sources and their. A magnetic nozzle is provided by permanent magnets arrays and an argon plasma is produced by a. The proposed applications of helicon sources have included plasma processing, ion laser pumping, toroidal plasmas, and ion sources for electric propulsion. A helicon discharge is an excitation of plasma by helicon waves induced through radio frequency heating. The simulation suggests that nearly all of the ions are lost to the walls before exiting the helicon tube. Basic features of hw plasma in rf discharges, an oscillating electric field is excited by, e. Discharge modes and wave structures using loop antennae in a. Aug 27, 2012 a radiofrequency rf antenna for helicon plasma thruster experiments is developed and tested using a permanent magnets helicon plasma source immersed in a vacuum chamber. A comparative study of radiofrequency antennas for helicon. Electron heating in microwaveassisted helicon plasmas. Measurements of helicon wave propagation and ar ii emission.
In most cases, directional helical antennas are mounted over a ground plane, while omnidirectional designs may not be. Cold plasma finite element wave model for helicon waves. Towards an optimal antenna for helicon waves excitation helyssen. Pdf optimization of radiofrequency helicon plasma sources for the development of space plasma thrusters whose thrust efficiency and specific im pulse.
Introduction among the available plasma sources capacitive and inductive, helicon sources have been found much more ef. This thesis investigates helicon wave propagation in a 1. A compact helicon plasma source was prepared to produce high density plasma 10 cm3 that enables the electromagnetic acceleration. Fluctuation in a helicon plasma with additional immersed antenna ane aanesland, christine charles, rod boswell, and ashild fredriksen abstractfluctuations in the. An approach for helicon plasma source improvement consists in helicon wave excitation optimiza tion by means of specific antenna designs. Helicon waves in high density plasmas plasma physics at kulgun. The resulting plasma has been characterized over a wide range of magnetic field strengths and input power levels. M ethods of exciting and confining plasmas are discussed, and the current state of the art in. Rf antenna the helicon antenna is the interface to the plasma to deliver the rf power. It was found that the window to obtain a high density plasma, with a density of more than 10 cm. Helicon discharges have been suggested for semiconductor processing by perry et ac. To construct a large volume helicon plasma source, we set the radii of plasma and antenna to be 0.
Helicon wave excitation with helical antennas max light and francis f. A plasma processing device 25 including a vacuum chamber 27 for processing a substrate 29 and a source chamber 26 for generating a plasma is disclosed where the source chamber 26 has a noncylindrical geometry. Us2055345a1 high density helicon plasma source for. This study summarizes the basic theory behind the operation of plasma antennas based on a survey of patents and technical publications. Helicontype radiofrequency plasma thrusters and magnetic. The presence of this magnetic field creates a helicon mode of operation with. A highpower helicon antenna has been designed and is being installed at diiid with initial conditioning to start in late 2019. The plasma acceleration methods are divided into three categories. Helicon antenna radiation patterns in a highdensity. In addition to the helicon plasma sources, the ion source also includes a diffusion chamber. Helicon sources operate over a wide range of densities from 101010cm3 and magnetic. Helicon waves in high density plasmas plasma physics at.
Radiofrequency antenna for suppression of parasitic. The gas plasma antenna conducts electron current like a metal and hence can be made into an antenna but with distinct advantages. Propulsion mechanisms in a helicon plasma thruster by nareg sinenian submitted to the department of nuclear science and engineering. Discharge modes separated by density jumps in a helicon plasma source were controlled successfully by changing the antenna wavenumber spectrum with a twoloop antenna, in addition to varying the.
Helicon wave excitation with rotating antenna fields. A comparative study of radiofrequency antennas for helicon plasma sources view the table of contents for this issue, or go to the journal homepage for more 2015 plasma sources sci. A helical antenna is an antenna consisting of one or more conducting wires monofilar, bifilar, or quadrifilar with 1, 2, or 4 wires respectively wound in the form of a helix. Pdf a new configuration for an antenna, which increases the absorption power and plasma density, is proposed for helicon plasma sources.
Helicon power system the helicon antenna is part of an rlc circuit that is driven by a sic mosfetbased full. This work measures the thrust of a helicon plasma source using a nulltype inverted pendulum thrust stand over a range of rf. Appleton developed a theory for electromagnetic waves in magnetized. Plasma performance excited by m0 helicon wave was investigated by the use of an antenna with one, two and four loops, changing the antenna wavenumber spectrum. Us6087778a scalable helicon wave plasma processing.
The diffusion chamber has an extraction aperture oriented along the same axis as the dielectric cylinder of the helicon plasma source. Diiid will be the first tokamak to use such an antenna at mw power levels to couple rf power to the plasma to drive current and heat the plasma as predicted by specialized physics codes. Also explore the seminar topics paper on plasma antennas with abstract or synopsis, documentation on advantages and disadvantages, base paper presentation slides for ieee final year electronics and telecommunication engineering or ece students for the year 2015 2016. Plasma antennas refer to a wide variety of antenna concepts that incorporate some use of an ionized medium. Plasma antenna plasma antennas are radio frequency antennas that employ plasma as the guiding medium for electromagnetic radiations. Comparison of helical and helicon antennas as sources of. Effect of inhomogeneous magnetic field on plasma generation in a. Higher power increased power can be achieved in the plasma antenna than in the. Design of a novel high efficiency antenna for helicon plasma.
Pdf antenna design and optimization for helicon plasma thruster. A radiofrequency rf antenna for helicon plasma thruster experiments is developed and tested using a permanent magnets helicon plasma source immersed in a vacuum chamber. Effects of antenna wavenumber spectrum and metal end plate. Plasma acceleration in a compact helicon source using rf antennae. Establishing plasma densities and magnetic field strengths under the antenna that suppress nonresonant mode conversion to the slowwave are thought to be responsible for operating in the helicon mode. Helicon waves of plasma are propagated from the source chamber into the vacuum chamber by a magnetic field having substantially parallel magnetic field lines extending from. The difference between a helicon plasma source and an inductively coupled plasma icp is the presence of a magnetic field directed along the axis of the antenna. Pdf design of a novel high efficiency antenna for helicon plasma. Helicon double layer thruster concept for high power nep. Thus, selection of the appropriate number of turns, or the type of helical or helicon antenna to use is empirical. Rf discharges can be sustained by an electric field of capacitive, inductive or wave origin.
It is shown that, for a given rf power, a magnetostatic field applied to an inductively coupled plasma increases the electron concentration fourfold. Helicon waves in gaseous plasma were first observed by lehane and thonemann 1 and later studied extensively by boswell 2, who pointed out that high density plasmas could be produced by helicon wave excitation with radiofrequency generators in the kilowatt re. Us6087778a scalable helicon wave plasma processing device. A highpower helicon antenna for the diiid tokamak and its. An ion source, capable of generating high density wide ribbon ion beam, utilizing one or more helicon plasma sources is disclosed. Sep 30, 2016 helical and helicon antennas are routinely used to generate inductively coupled plasmas, but there are only a few simulations or experimental data with comparisons among them. An rf inductive plasma is known to support both capacitive and inductive mode. Simulations were done for two common types of rf antennas, namely, half. Electromagnetic simulation of helicon plasma antennas for. The strong radial density gradient of the plasma a creates regions of alternating propagation and evanescence b for the microwaves in green and red respectively in both argon c and helium d, shown varying with rf power helicon chamber helical rf antenna and helium plasma bright filaments at microwave injection. When electric current circulates on the antenna and waves are emitted, they can be. Introduction for future steadystate tokamak reactor, numerous previous. Kirichenko scientific center institute for nuclear research national academy of sciences, kiev 03680, ukraine abstract coupling of various helicon antennas to lowpressure dense plasma column was modeled theoretically and measured. Antenna radiation patterns in the vicinity of a helicon antenna are investigated in hydrogen.
For example, while the internal helicon antenna supports. Coupling of rf antennas to large volume helicon plasma. Resonance frequency in helicon antenna produced plasma. The concept simply has a radiofrequency plasma productionheating source and a magnetic nozzle, while it seems to include many aspects of physics and engineering issues. A new configuration for an antenna, which increases the absorption power and plasma density, is proposed for helicon plasma sources. The protompex helicon antenna is a quarter turn right handed helical twist antenna powered by rf at. Charging of a plasma filled dielectric glass wall wrapped in a helicon antenna to be submitted.
Pdf helicon plasma with additional immersed antenna. Request pdf helicon plasma with additional immersed antenna a primary rf power hpower at. May 22, 2019 development of electrodeless radiofrequency plasma thrusters, e. The length is assumed to be infinite, although the axial range of. The following technological concepts are important to plasma antennas. Before the use of the spiral antenna,1921 few attempts were made using various shapes of antennas such as loop, helical, saddle coil types2,5 to produce a.
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