マイクロ波放電型イオンスラスターμ20 作動特性の磁場強度?周波数依存性

摘要

This paper presents the development status of a 20-cm diam. microwave discharge ion thruster which generates 30 mN ofthrust with an electric power of 1kW. By optimizing the discharge chamber length, magnetic field and propellant flowinjection, ion currents of up to 600 mA at a microwave power of 147 W had been obtained at a frequency of 4.25 GHzwith conventional SmCo magnets. A higher frequency of 5.9 GHz and stronger NdFeB magnets have been tested forperformance enhancement and turned out to be very promising. A beam current of 700mA at a microwave power of 165W was demonstrated that corresponds to a thrust of 35.6 mN at a beam voltage of 1100 V. Increase of the voltage to 1500V like Hayabusa's μ10 thrusters would gain the maximum thrust to 41.6 mN.