标题： 火星紫外日辉发射的南半球探测：MAVEN/IUVS多年人卫观测的启示 显示英文标题

标题： Investigation of Martian UV Dayglow Emissions in the Southern Hemisphere during Solar Quiet-time Conditions: Insights from Multi-year MAVEN/IUVS Observations

摘要： 火星南半球拥有强烈的壳磁场所集区域（CMF），这些磁场生成局部磁异常，可能会影响火星热层-电离层系统中的大气动力学和能量沉积。 尽管它们对南半球（>200公里）大气的影响已有充分记录，但它们在调节200公里以下大气等离子体和中性粒子行为方面的作用尚不清楚。 通过研究日辉辐射的变化可以理解这些高度的大气情况。 我们利用MAVEN在火星年33到37期间的遥感测量数据，研究了CMF和非CMF区域的几个日辉辐射发射。 特别是，在太阳平静期条件下，研究了CO卡梅伦带、CO2+紫外双线以及波长为297.2纳米、130.4纳米和135.6纳米的氧原子发射在200公里以下的情况。 结果显示，所有发射在昼侧和近终射区的峰值高度和强度都有明显的季节变化。 分子和原子发射的峰值高度变化分别约为20公里和30公里。 在昼侧，发射在CMF和非CMF区域之间的变化很小，表明在这些高度上CMF的影响较小，暗示等离子体去磁化和光化学过程起着关键作用。 此外，由于依赖能量的电子屏蔽和热层膨胀等补偿机制，日辉发射的微小变化可能被掩盖。 本工作首次针对不同季节和太阳天顶角下的CMF和非CMF区域的日辉发射进行了重点研究。 显示英文摘要

摘要： The southern hemisphere of Mars possesses concentrated region of strong crustal magnetic fields (CMF), which generate localized magnetic anomalies that can influence atmospheric dynamics and energy deposition in the Martian thermospheric-ionospheric system. Although their effects on the atmosphere (>200 km) in the southern hemisphere are well documented, however their role in modulating the behavior of atmospheric plasma and neutrals below 200 km are poorly understood. The atmosphere at these altitudes can be comprehended by studying the variation of dayglow emissions. We have investigated few dayglow emissions over the CMF and non-CMF regions using the MAVEN remote-sensing measurements from Martian Years 33-37. Particularly, the CO Cameron bands, CO2+ ultraviolet doublet, and atomic oxygen emissions at 297.2 nm, 130.4 nm, and 135.6 nm have been studied below 200 km during solar quiet-time conditions. The results show strong seasonal variations in all the emissions peak altitudes and intensities in the dayside and near-terminator regions. The variation in the peak altitude of molecular and atomic emissions are nearly 20 km and 30 km, respectively. On the dayside, the emissions show minimal variation across CMF and non-CMF regions, indicating a minimal effect of the CMF at these altitudes, suggesting a key role of plasma demagnetization and photochemical processes. In addition, an insignificant variation in the dayglow emissions is likely masked by compensating mechanisms such as energy-dependent electron shielding and thermospheric expansion. This work presents the first focused investigation on the dayglow emissions over CMF and non-CMF regions across different seasons and solar zenith angles.