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There exists strong interaction between the plasma and channel wall in the Hall thruster, which greatly affects the discharge performance of the thruster. In this paper, a two-dimensional physical model is established based on the actual size of an Aton P70 Hall thruster discharge channel. The particle-in-cell simulation method is applied to study the influences of segmented low emissive graphite electrode biased with anode voltage on the discharge characteristics of the Hall thruster channel. The influences of segmented electrode placed at the ionization region on electric potential, ion number density, electron temperature, ionization rate, discharge current and specific impulse are discussed. The results show that, when segmented electrode is placed at the ionization region, the axial length of the acceleration region is shortened, the equipotential lines tend to be vertical with wall at the acceleration region, thus radial velocity of ions is reduced along with the wall corrosion. The axial position of the maximal electron temperature moves towards the exit with the expansion of ionization region. Furthermore, the electron-wall collision frequency and ionization rate also increase, the discharge current decreases and the specific impulse of the Hall thruster is slightly enhanced.

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Due to the low price, high efficiency and flexible manipulations, the metasurface has attracted more attentions. This paper proposes a new 1-bit configurable reflection array antenna with 11*11 unit cells. The unit cell in the metasurface, which is integrated with one PIN diode, shaped as ‘ancient coin’ can generate reflection phases between 165°-195° (180°±15°). The new phase array antenna can realize flexible manipulations to EM (electromagnetic) waves.