Abstract

The validity of the lambda-meter method for determining the quiet Sun velocity field using the Si I 1082.7 nm line is investigated. To this end, the intensity profiles of this line were calculated for the solar disk center by means of NLTE simulations in a three-dimensional model atmosphere describing the small-scale magnetic activity in the quiet solar photosphere. The velocity field recovered using the lambda-meter method from theoretical NLTE profiles of the Si I 1082.7 nm line was compared with the velocity field from the model atmosphere. The influence of atmospheric and instrumental effects on the results is considered. These effects are atmospheric turbulence and light diffraction by telescope aperture, such as VTT, GREGOR, and EST/DKIST. It is shown that, in the case of observations of the Si I 1082.7 nm line on large-diameter telescopes like GREGOR and EST/DKIST with a spatial resolution substantially better than 0.27″, the lambda-meter method provides reliable values of the velocity field for the lower and upper solar photosphere. For the middle photosphere, the correlation between the inferred and the real velocities is worse, particularly when using the smaller diameter telescopes like VTT. Under a poor spatial resolution exceeding 2″, information about the velocity field can be obtained only for the uppermost photospheric layers. For this case, the lambda-meter velocities turn out to be noticeably smaller than the real values.

中文翻译：

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使用Lambda-Meter方法对Si太阳的速度场诊断：Si I 1082.7 nm线

摘要

研究了使用Si I 1082.7 nm线确定拉姆计的方法的有效性。为此，在描述安静太阳光层中小规模磁活动的三维模型环境中，通过NLTE模拟，计算了该线的强度分布图，用于太阳盘中心。将使用Lambda计法从Si I 1082.7 nm线的理论NLTE轮廓中恢复的速度场与来自模型大气的速度场进行了比较。考虑了大气和仪器效应对结果的影响。这些影响是大气湍流和望远镜孔径（例如VTT，GREGOR和EST / DKIST）引起的光衍射。结果表明，在观察到Si I 1082的情况下。在大直径望远镜（如GREGOR和EST / DKIST）上具有7 nm的线，其空间分辨率明显优于0.27英寸，该λ计方法为上下太阳光球提供了可靠的速度场值。对于中间的光球，推定速度与实际速度之间的相关性更差，尤其是在使用较小直径的望远镜（如VTT）时。在超过2英寸的不良空间分辨率下，仅对于最上层的光球层才能获得有关速度场的信息。对于这种情况，λ速度明显小于实际值。对于中间的光球，推定速度与实际速度之间的相关性更差，尤其是在使用较小直径的望远镜（如VTT）时。在超过2英寸的不良空间分辨率下，仅对于最上层的光球层才能获得有关速度场的信息。对于这种情况，λ速度明显小于实际值。对于中间的光球，推定速度与实际速度之间的相关性更差，尤其是在使用较小直径的望远镜（如VTT）时。在超过2英寸的不良空间分辨率下，仅对于最上层的光球层才能获得有关速度场的信息。对于这种情况，λ速度明显小于实际值。