Experimental and numerical validation of ion extractor grids

plasma;electric propulsion;Inertial Electrostatic Confinement (IEC);Helicon Injected Inertial Plasma Electrostatic Rocket (HIIPER);extractor grids

Bercovici, Benjamin ; Miley ; George H.

关键词: plasma;    electric propulsion;    Inertial Electrostatic Confinement (IEC);    Helicon Injected Inertial Plasma Electrostatic Rocket (HIIPER);    extractor grids;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/72822/Benjamin_Bercovici.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

The experimental plasma thruster named the Helicon Injected Inertial Plasma Electrostatic Rocket (HIIPER)at the University of Illinois at Urbana-Champaign (UIUC) is currently being investigated. HIIPER featuresan Inertial Electrostatic Con nement (IEC) grid that is made asymmetrical by cutting out several wires toenlarge one of the openings in the spherical grid. When fed with a non-fusing gas such as argon, HIIPERoperates in a mode where a very sharp plasma beam forms and exits the system through the IEC's asymmetry,thus allowing the existence of a net non-zero momentum. Such an operating mode is called "Jet-Mode".However, it was demonstrated that the exiting plasma beam is mostly dominated by electrons, as opposed toions. Since electrons carry a very small momentum due to their light mass, an asymmetrical IEC producingan electron-dominated beam is not a viable propulsion device. In order to provide a greater thrust when theIEC is operating in the Jet-Mode, heavier particles such as neutralized ions must exit through the beam.This thesis focuses on the validation of so-called extractor grids, which are electrostatic components thatcan alter the potential pro le inside the system, and therefore enable the escape of heavier particles towardsthe preferred exit direction that would otherwise be trapped inside the system. The validation processmentioned before was two-fold:rst, a 2D, axisymmetric, electrostatic Particle-In-Cell code was developedin order to benchmark the di erent extractor grid designs and select those which performed the best ation extraction. In particular, it was demonstrated that some speci c parameters have a favorable e ecton particle extraction. Second, an experimental campaign consisting in the testing of the extractor gridsdesigns, as well as improving the experimental set-up, was carried out. Conclusions were then drawn on thecapacity of HIIPER to act as a space thruster, once augmented with extractor grids. Based on the result ofthis work, suggestions for future research are made.