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Showing 1 to 20 of 43 for “"helicon"”.
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Resonant ion heating in a helicon plasma
… controlling the ion temperature anisotropy in a helicon plasma source. The system uses two rectangular coils placed on either side of the cylindrical pyrex vacuum chamber to create a time dependent magnetic field transverse to the steady state axial field. A 1 kW, 25--125 kHz RF generator powers …
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Propulsion mechanisms in a helicon plasma thruster
… of a compact electric thruster utilizing a helicon plasma source is investigated with the goal of identifying potential thrust mechanisms. Performance characteristics such as thrust, specific impulse, ion cost and thrust efficiency are discussed and related to plasma parameters. The design …
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Plasma Dynamics in a High-Power Helicon Source
… up to 100 kW. Previous studies have shown that Helicon Coupled Plasmas (HCPs) can generate higher plasma densities at lower powers, and hence, could be used to improve the efficiency of these systems. However, limited studies have been performed that compare ICPs and HCPs at powers greater than …
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Plasma Dynamics in a High-Power Helicon Source
… up to 100 kW. Previous studies have shown that Helicon Coupled Plasmas (HCPs) can generate higher plasma densities at lower powers, and hence, could be used to improve the efficiency of these systems. However, limited studies have been performed that compare ICPs and HCPs at powers greater than …
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Development and Test of a Permanent Magnet Helicon Thruster
… and Retarding Potential Analyzer diagnostics for helicon thruster research. A helicon thruster using permanent magnets was also designed and tested. The helicon has several advantages, but the main disadvantage is the use of electromagnets to generate the required magnetic field, requiring a high …
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Analysis of power balance in a helicon plasma source
This thesis analyses the Helicon Injected Inertial Plasma Electrostatic Rocket (HIIPER), a space propulsion concept consisting of a helicon source for plasma generation and an ion extraction method using a nested pair of inertial electrostatic confinement (IEC) grids that are asymmetrically …
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Analysis of a Water Vapor Helicon Thruster Using Emission Spectroscopy
A helicon thruster was developed to research the use of emission spectroscopy diagnostics. Helicon thrusters differ from conventional electric propulsion systems in that the conductive components that power the thruster do not contact the plasma propellant. Because of this design, propellants that …
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Development and Characterization of Conventional and Inverted Helicon Plasma Sources
Made available in DSpace on 2017-07-06T18:55:19Z (GMT). No. of bitstreams: 3 Masters_Benjamin_C_MS.pdf: 18600523 bytes, checksum: 3032067e89a45e39cfe4a8170385b677 (MD5) Masters_Benjamin_C_MS_ABS.pdf: 52155 bytes, checksum: 4de6d980b5c087fa233baf754ce1dc2b (MD5) license.txt: 4813 bytes, checksum: …
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Power balance in a helicon plasma source for space propulsion
… power balance of an electric thruster based on a helicon plasma source is presented. The power balance is shown to be comprised of several variables, including the RF power supplied to the system, dissipative losses in transmission hardware, losses in the neutral confinement tube, uncoupled RF …
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Three Dimensional Imaging of Helicon Wave Fields via Magnetic Induction Probes
… provide fundamental insight into laboratory helicon plasma. The methods and results derived here will supplement and aid the design of future helicon plasma sources.
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Physics of the helicon antenna on the prototype materials exposure experiment
"Proto-MPEX has been operating in a high-density “helicon-mode” of operation. The helicon mode of operation is classified by an increase in target on-axis electron density (6e19 m^-3) and a decrease in electron temperature (2 – 3 eV) during a helicon pulse. This transition is observed when …
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Empirical aspects of a Mini-Helicon Plasma Thruster Experiment (mHTX@MIT)
A helicon plasma source experiment has been developed and then constructed in the MIT Space Propulsion Laboratory (SPL) vacuum chamber. This experiment allows study of the intrinsic advantages of efficient helicon plasma production for use in space electric propulsion. Historical helicon experiment …
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Slow wave ion heating and parametric instabilities in the HELIX helicon source
… responsible for intrinsic ion heating in helicon sources. Two possible mechanisms have been identified: ion Landau damping of the slow wave and parametrically driven instabilities. Consistent with ion Landau damping of the slow wave, the perpendicular ion temperatures 35 cm downstream of …
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Dynamics of Turbulence and Flows in a Helicon Plasma Under Electrode Biasing
… sheared flow were carried out using the linear Helicon-Cathode (HelCat) device. Without any outside influence, such as biasing or momentum input, fluctuations were observed. The dynamics of these fluctuations was found to vary with magnetic field, varying in both frequency and mode number. At …
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Optimization of a helicon plasma source for maximum density with minimal ion heating
… and perpendicular ion temperatures in an argon helicon plasma are presented for five different antennas: A Nagoya type III antenna, a double-saddle antenna, a 19 cm long m = +1 helical antenna, a 30 cm long m = +1 helical antenna and a 19 cm m = +1 helical antenna with wide straps. …
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An analysis of energy balance in a helicon plasma source for space propulsion
This thesis covers work done on the mHTX@MIT helicon source as it relates to the analysis of power losses. A helicon plasma is a rather complex system with many potential loss mechanisms. Among the most dominant are optical radiation emission, wall losses due to poor magnetic confinement, and poor …
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Analysis of energy balance in a helicon coupled to an inertial electrostatic confinement device
The characteristics of the helicon plasma injection into the IEC were explored. The first such analysis was a COMSOL simulation to determine the voltage as a function of position in the helicon dielectric tube when the IEC cathode is biased to several kilovolts. This COMSOL simulation contained no …
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