Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 13 of 13 for “"helicon source"”.
-
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 …
-
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 …
-
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 …
-
Ion flux maps and helicon source efficiency in the VASIMR VX-100 experiment using a moving Langmuir probe array
… that measured and mapped ion flux and plasma source efficiency in a flowing plasma with large (∼1.5 T) external magnetic fields in the VASIMR (Variable Specific Impulse Magnetoplasma Rocket) VX-100 experiment. The probe array was swung through an argon plasma revealing a detailed …
-
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. …
-
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 …
-
Secondary Plasma Sources for Ionized Physical Vapor Deposition
The helicon antenna sits remotely outside the vacuum system, so all shadowing and contamination problems which the other two sources exhibit are eliminated. Ionization fractions to the substrate of 51 +/- 10% with a deposition rate of 847 +/- 42 A/min. are found. Without the antenna, the ionization …
-
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 …
-
Investigation of a space propulsion concept using inertial electrostatic confinement
This thesis discusses 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 …
-
Theoretical studies of the VASIMR plasma propulsion concept
… consists of three main components: a low energy helicon plasma source, which creates cold plasma via rf-discharge; an ion cyclotron-resonance heating (ICRH) section, which is used to deposit rf-power into the plasma; and a magnetic nozzle, which forms highly directed superalfvenic outgoing plasma …
-
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 …
-
Physics of RF heating systems on proto-MPEX
… controlled fusion as a commercial energy source is faced with many challenges. One of the main challenges being the development of Plasma Facing Components (PFC) that can survive the extreme environment encountered in a fusion reactor. To expedite the testing and development of PFCs Oak …
-
Langmuir Probe Investigations of Helicon Wave Discharges in Three-Dimensions of a Commercial-Scale Plasma Processing Reactor
Made available in DSpace on 2017-07-06T18:55:40Z (GMT). No. of bitstreams: 3 Norman_Jeffrey_E_MS.pdf: 131280649 bytes, checksum: 8855837adc5e4a5499477d831ae9054d (MD5) Norman_Jeffrey_E_MS_ABS.pdf: 587265 bytes, checksum: 169d41c371af9d5cccc4c7791a7b01b3 (MD5) license.txt: 4813 bytes, checksum: …