标题： 研究木星极光电子束中的磁场波动 显示英文标题

标题： Investigating Magnetic Field Fluctuations in Jovian Auroral Electron Beams

摘要： 朱诺号航天器为探索木星极光生成机制提供了独特的机会。 对朱诺号数据的过去分析极大地推进了我们对其极光加速过程的理解，然而，很少有研究在联合系统分析中使用朱诺号上的多个仪器。 本研究利用了前20次近日点飞行期间朱诺号紫外光谱仪（UVS）、木星能量粒子探测仪（JEDI）和朱诺磁强计（MAG）的测量数据。 在与扩散极光相关的磁场线上，我们一致发现时间尺度为几秒到1分钟的小尺度磁场波动，振幅高达100 nT。 在直接与主要辐射相连的磁场线上，电子分布是场对齐的，能量范围主要为宽频带，并伴有时间尺度为数十分钟的数100 nT的大尺度磁场扰动（除一次情况外）。 这些大尺度扰动通常与准静态场对齐电流有关。 由于磁强计的数字化限制，在距离小于4个木星半径的主辐射区附近，小尺度磁场无法被分辨。 然而，在朱诺号在超过4RJ处穿越主极光磁场线的所有情况下，数字化限制显著降低，我们检测到2 nT到10 nT的小尺度磁场波动，这与湍流谱一致。 相关的能量通量投射到木星上可以超过1000 mW/m²。 电子分布的总体宽频带性质以及主辐射区持续存在小尺度磁场波动表明，波粒相互作用可能主导性地贡献于木星极光过程的能量。 显示英文摘要

摘要： The Juno spacecraft provides a unique opportunity to explore the mechanisms generating Jupiter's aurorae. Past analyses of Juno data immensely advanced our understanding of its auroral acceleration processes, however, few studies utilized multiple instruments on Juno in a joint systematic analysis. This study uses measurements from the Juno Ultraviolet Spectrograph (UVS), the Jupiter Energetic particle Detector Instrument (JEDI), and the Juno Magnetometer (MAG) from the first 20 perijoves. On magnetic field lines associated with the diffuse aurora, we consistently find small-scale magnetic field fluctuations with amplitudes of up to 100 nT on time scales of seconds to 1 minute. On magnetic field lines directly linked to the main emission, the electron distribution is field-aligned, mostly broad-band in energy, and accompanied by large-scale magnetic field perturbations of several 100 nT on time scales of tens of min (except one case). These large-scale perturbations are generally associated with quasistatic field-aligned electric currents. Small-scale magnetic fields are not resolved over the main emission zone closer than radial distances 4 Jovian radii due to the digitization limit of the magnetometer. However, in all cases where Juno crosses the main auroral field lines beyond 4RJ, the digitization limit is significantly reduced and we detect small-scale magnetic field fluctuations of 2 nT to 10 nT consistent with a turbulent spectrum. Associated energy fluxes projected to Jupiter can exceed 1000 mW/m2. The general broad-band nature of the electron distributions and the consistent presence of small-scale magnetic field fluctuations over the main emission support that wave-particle interaction can dominantely contribute to power Jupiter's auroral processes.