Lifetime Prediction And Channel Wall Erosion Accelerate Test Of Hall Thruster

Due to its high efficiency, high specific impulse, and reliability, Hall thruster has been widely applied in orbit missions and space explorations. It intrigues the world wide interests in the electric propulsion field since it had been successfully developed in 1970. However, with the development of the astronautic techniques, the service life of the Hall thruster is required to be increased as well.The basic feature of Hall thruster is that it has a coaxial acceleration channel. In this channel, the electrons are confined in an endless azimuthally drift, and the thrust is produced by the momentum imparted to the positive ions by electric body forces. The channel wall will be sputtered by the striking of the divergent energetic ions during the plasma discharge process. In all erosion processes, the channel wall sputtering erosion is the most important problem that limits the service life of Hall thruster. It is consider that when the channel wall is eroded completely and magnetic pole is exposed to the plasma, this is the time of Hall thruster's lifetime termination.At present the research on the lifetime prediction of Hall thruster is mainly focused on experimental measurement and eroded surface simulation. Because full lifetime experiment will waste lots of time and money, many scientific research institutions are positive developing simulation method to predict Hall thruster's lifetime. These methods included HPHall who is a kind of software used broadly in USA, and semi-experiential methods which are widespread application in Russia. Hall thruster's research in China is just at beginning, hence, this article established a semi-experiential eroded model of channel wall based the phsiycs process in the channel wall. The model includes two sub models, first, model of ion which bombarding the channel wall; second, erosion model of wall. The simulated method that this article applied is Huygens wavelet, which can predict the corner erosion process precisely. Based on the above model and simulated method, this article predicts the channel wall's erosion process of SPT-100, and show contrast with experimental data. Then modify the program and make it possible to predict the lifetime of Hall thruster.Through the research of factors which can impact the eroion rate, incidence angle have a large effect of Hall thruster's lifetime. If the incidence angle of ion are in a certain range, then the lifetime will be obvious enhance. Base on thid theory, this article proposed the magnetic lens to restrain the divergence of ion, and proved this method by simulation and experiment.The most direct and reliable method to determinate the lifetime of Hall thruster is lifetime test. In order to solve the time-consuming long, this article proposed a new accelerate test. By the experimental data of the channel wall which is easy to sputter to extrapolate the eroded surface evolution of channel wall used in Hall thruster. The proof of this method is shown in the article. At last, this article research the accelerate test that proposed by Kim.