The TianQin space gravitational waves (GW) observatory will contain three geocentric and circularly orbiting spacecraft with an orbital radius of 10⁵ km, to detect the GW in the milli‐hertz frequency band. Each spacecraft pair will establish a 1.7 × 10⁵ km‐long laser interferometer immersed in the solar wind and the magnetospheric plasmas to measure the phase deviations induced by the GW. GW detection requires a high‐precision measurement of the laser phase. The cumulative effects of the long distance and the periodic oscillations of the plasma density may induce an additional phase noise. This study aims to model the plasma induced phase deviation of the interspacecraft laser signals, using a realistic orbit simulator and the Space Weather Modeling Framework model. Preliminary results show that the plasma density oscillation can induce the phase deviations close to 2 × 10⁻⁶ rad/Hz^1/2 or 0.3 pm/Hz^1/2 in the milli‐hertz frequency band and it is within the error budget assigned to the displacement noise of the interferometry. The amplitude spectrum density of phases along three arms become more separated when the orbital plane is parallel to the Sun‐Earth line or during a magnetic storm. Finally, the dependence of the phase deviations on the orbital radius is examined.

中文翻译：

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天琴引力波天文台的空间等离子体密度振荡对航天器激光测距的影响

天琴太空引力波（GW）天文台将包含三个地心圆轨道飞行器，其轨道半径为10 ⁵  km，以检测毫赫兹频段的GW。每对航天器将建立一个1.7×10 ⁵ 公里长的激光干涉仪浸没在太阳风和磁层等离子体中，以测量由GW引起的相位偏差。GW探测需要对激光相位进行高精度测量。长距离的累积效应和等离子体密度的周期性振荡可能会引起额外的相位噪声。这项研究的目的是使用真实的轨道模拟器和太空天气建模框架模型对航天器激光信号的等离子体感应相位偏移进行建模。初步结果表明，等离子体密度振荡可以引起接近2×10 ^-6  rad / Hz ^1/2或0.3 pm / Hz ^1/2的相位偏差。在毫赫兹频段内，并且在分配给干涉测量位移噪声的误差预算之内。当轨道平面平行于太阳-地球线或在磁暴期间，沿三个臂的相位的振幅谱密度变得更加分离。最后，检查了相位偏差对轨道半径的依赖性。