The Io plasma torus is thought to lie in Jupiter's centrifugal equator, a location that depends on Jupiter's rotation and magnetic field. Yet previous observations and predictions of the location of the Io plasma torus are inconsistent. Here we test the hypothesis that the Io plasma torus lies in the centrifugal equator by comparison of observations by Juno radio occultations to predictions derived from Juno‐era magnetic field models. These observations determine the locations of two torus components: The cold torus is centered near 5.3 Jovian radii (R _J ), and the “torus beyond 5.5 R _J ,” dominated by the warm torus, is centered near 5.9 R _J . The observations deviate by 1–2° from the planar centrifugal equator expected for a Voyager epoch dipolar magnetic field. In each observation, the locations of distinct torus regions differ by as much as 1° indicating significant radial structure. The root‐mean‐square error between observation and prediction is smaller for predictions from the JRM09 magnetic field model than for predictions from the VIP4 magnetic field model, confirming the JRM09 model is an improvement over the VIP4 model. Agreement between observations and predictions improves for the warm torus if the magnetic field contributions of a nominal magnetospheric current sheet model are included but worsens for the cold torus. Magnetic field conditions around 5.3 R _J are adequately represented by an internal field model without the current sheet. Conditions around 5.9 R _J require internal and external contributions. These results place constraints on properties of the magnetospheric current sheet during the Juno epoch.

中文翻译：

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离子等离子体圆环在哪里？朱诺无线电掩星法对木星磁场模型预测的观测结果比较

离子等离子体圆环被认为位于木星的离心赤道中，该位置取决于木星的旋转和磁场。然而，先前对Io血浆环面位置的观察和预测是不一致的。在这里，我们通过比较Juno无线电掩盖观测与Juno时代磁场模型得出的预测，来检验Io等离子体圆环位于离心赤道中的假设。这些观察结果确定了两个圆环分量的位置：冷圆环位于5.3 Jovian半径（R _J）的中心，“圆环超过5.5  R _J ”（由温暖圆环主导）的中心位于5.9  R _{J的中心。}。观测结果与Voyager时代双极磁场所期望的平面离心赤道偏离了1-2°。在每个观察结果中，不同的环面区域的位置相差1°，说明明显的径向结构。JRM09磁场模型的预测值与VIP4磁场模型的预测值相比，观测值与预测值之间的均方根误差较小，这证明JRM09模型是对VIP4模型的改进。如果包括标称磁层电流表模型的磁场贡献，则观测值和预测值之间的一致性会改善温暖的圆环，但对于寒冷的圆环会恶化。5.3 R _J附近的磁场条件 没有当前工作表的内部场模型足以表示。大约5.9 R _J的条件 需要内部和外部的贡献。这些结果限制了朱诺时期的磁层电流表的特性。