在LISA,ASTRODI和ASTROD之类用于探讨引力波天文、天文动力学和相对论测试的深空激光探测计划中,暴露在空间粒子环境中的无拖曳测试质量将会受各种带电粒子的影响而带电,引起库伦力和洛伦兹力干扰,从而影响实验数据的精度.在先前的工作中,已用GEANT4工具包模拟了银河宇宙射线中质子和氦核以及太阳高能粒子事件对测试质量的充电过程.文章里,参数化了行星际电子和主要种类的重核,并模拟了由测试质量块在行星际电子和C,H,O等重核环境中的充电速率.行星际电子源主要是木星和银河,而重核主要来自于银河宇宙射线.经过模拟计算,ASTRODI测试质量由行星际电子引起的充电速率大约是行星际质子在太阳活动最小值时的9%,在太阳活动最大值时的28%.行星际重核相对于行星际质子在太阳活动最小值和最大值时的贡献分别约是0.83%和1.64%.
In deep space laser ranging missions for gravitational-wave astronomy, astro- dynamics and test of relativity, like LISA, ASTROD I and ASTROD, charging of drag-free test mass due to exposure of the spacecraft to various energetic particles in the space environ- ment can affect the quality of the science data due to spurious Coulomb and Lorentz forces. In earlier work, the GEANT4 toolkit has been used to simulate the charging of test mass due to protons and He nuclei of primary cosmic rays, and due to four solar energetic particle events. Here the energy spectra of interplanetary electrons and major nuclear species have been parametrized, and the charging rates due to electrons and heavy nuclei C, N and O have been simulated. Interplanetary electrons are mainly Jovian in origin with a Galactic component. Interplanetary heavy nuclei are Galactic cosmic rays in origin. Charging rate of the ASTROD I test mass from interplanetary electrons contribute about -9% that of the interplanetary protons at solar activity minimum, and over -28% at maximum. Interplane- tary heavy nuclei are responsible for -0.83% and -1.64% of charging rates of interplanetary protons at solar activity minimum and at maximum respectively.