A high current compact ECR ion source
- Paper number
IAC-06-C4.P.4.14
- Author
Dr. Kazutaka Nishiyama, Japan Aerospace Exploration Agency (JAXA), Japan
- Coauthor
Mr. Ryoichi Kikuchi, Tokyo Institute of Technology, Japan
- Coauthor
Dr. Hitoshi Kuninaka, Japan Aerospace Exploration Agency (JAXA)/ISAS, Japan
- Coauthor
Prof. Haruki Takegahara, Tokyo Institute of Technology, Japan
- Year
2006
- Abstract
A new electron cyclotron resonance (ECR) ion source "µ6" has been developed in the laboratory. It is a scaled down model of our µ-series microwave discharge ion thrusters. The ECR condition at 4.2 GHz is obtained in a multicusp arrangement using a set of two SmCo magnet rings on a base plate of a cylindrical ionization chamber with a plasma volume 6 cm in diameter and 2 cm in height. The microwave is launched with a quarter-wavelength straight electric antenna and a N-type connector. The ionizer length and chamber diameter were experimentally optimized. The xenon ion current to a negatively biased metal grid has been measured to estimate ion beam current that can be extracted with ion optics. With the same power density and discharge pressure as larger thrusters µ10 and µ20, ion current density of the µ6 is almost the same as larger thrusters. Although ion production cost and propellant utilization efficiency are worse than larger thrusters, the µ6 under this operation range will be suitable for micro-thrusting applications. Sudden increase of the ion current was observed when the pressure or the microwave power was four times larger. A current density of 7 mA/cm2 has been reached with an incident microwave power of 100 W and a chamber pressure of 0.098 Pa. This implies that the µ6 will generate a 10 mN thrust at an ion production cost of 400 eV/ion and propellant utilization efficiency of 50%. The thrust density will be as large as that of electron-bombardment or radio-frequency ion thrusters. The µ6 has been operated with different gases like O2 and N2 and generated about a half ion current as Xe. The small dimensions of this ion source and its performance at high-current regime allow to use it not only in applications such as electric propulsion and material processing on the ground, but also as an primary ion source for secondary ion mass spectroscopy(SIMS) of scientific space missions.
- Abstract document
- Manuscript document
IAC-06-C4.P.4.14.pdf (🔒 authorized access only).
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