The solar wind is filled with various magnetic field fluctuations, and one of the most widespread types of such fluctuations is solar wind discontinuities. They are rapid high-amplitude magnetic field rotations sharing properties of nonlinear Alfvén waves and plane plasma slabs. They are believed to play an important role in the interaction of the solar wind with the Earth’s magnetosphere. Most studies of solar wind discontinuities are based on observations in pristine solar wind, often by solar wind monitors at L1. However, before interacting with the Earth’s magnetosphere, solar wind discontinuities cross the bow shock and can change their properties. In this study, we investigate the transformation of discontinuities due to the bow shock crossing. We compiled a set of 100 high-amplitude (\(>3\) nT) discontinuities observed by ARTEMIS in the upstream of the bow shock and by THEMIS in the downstream from the bow shock crossing (in the Earth’s magnetosheath). Comparison of discontinuity properties in the solar wind and magnetosheath demonstrates discontinuity thinning and current density increase in the magnetosheath. Although all considered solar wind discontinuities mostly resemble rotational discontinuities, in the magnetosheath they start having properties of tangential discontinuities. We reveal a clear dawn–dusk asymmetry of discontinuity properties that are likely related to the asymmetry of the ion foreshock. We discuss how solar wind discontinuity transformation at the bow shock crossing can alter their interaction with the Earth’s magnetosphere.

太阳风充满了各种磁场波动，这种波动最普遍的类型之一是太阳风的不连续性。它们是具有非线性阿尔文波和平面等离子体板特性的快速高振幅磁场旋转。它们被认为在太阳风与地球磁层的相互作用中发挥着重要作用。大多数对太阳风不连续性的研究都是基于对原始太阳风的观察，通常是由 L1 的太阳风监测器进行的。然而，在与地球磁层相互作用之前，太阳风的不连续性会穿过弓形激波并改变它们的特性。在这项研究中，我们研究了由于弓形激波交叉引起的不连续性的转变。我们编译了一组 100 个高振幅 ( \(>3\)nT) ARTEMIS 在弓激波上游和 THEMIS 在弓激波穿越下游（在地球磁鞘中）观察到的不连续性。太阳风和磁鞘中的不连续性特性的比较表明磁鞘中的不连续性变薄和电流密度增加。尽管所有考虑的太阳风不连续性大多类似于旋转不连续性，但在磁鞘中它们开始具有切向不连续性的特性。我们揭示了可能与离子前震的不对称性有关的不连续性的明显黎明-黄昏不对称性。我们讨论了弓形激波交叉处的太阳风不连续变换如何改变它们与地球磁层的相互作用。