Propulsion mechanisms in a helicon plasma thruster

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.Includes bibliographical references (p. 107-110).Electric thrusters offer an attractive option for various in-space propulsion tasks due to their high thrust efficiencies. The performance characteristics 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 and fabrication of a prototype compact helicon thruster is presented, including design of a radio-frequency power delivery system, electromagnets and a propellant flow system. The design of plasma diagnostics and associated measurement techniques are discussed including a retarding potential analyzer, mach probes and langmuir probes. These diagnostics are used to measure plasma properties such as electron temperature, plasma density, and ion flow velocities. Thruster performance characteristics are then derived from these measurement results. Significant ion acceleration is demonstrated in both Argon and Nitrogen plasmas and potential mechanisms for this are discussed.by Nareg Sinenian.S.M

Processing Integrated Circuit Layouts Using Python: A Case Study On Rapid Prototyping

This paper narrates our experience developing, in a relatively short time, an application to rasterize layers of integrated circuit (IC) layout definitions specified in the Calma Graphic Data System (GDS) II file format. We developed software to parse GDS-II IC layouts to generate a bitmap of regions of the chip that are filled with material such as metal, poly-silicon, etc. Such bitmaps are useful for analyzing the geometry of IC design and implementation. We developed the software in the Python programming language, reputed for use in rapid application development environments. Our experience developing and validating the application provides useful insights into the general methodology of iterative development, and the suitability of Python in non-traditional, rapid prototyping environments. Our experience shows that the choice of a versatile programming language can greatly improve productivity in a rapid application development environment where there is incomplete information at the outset