Mars nightside electron impact process frequency empirical model

With the aim of improving global simulations of the Martian ionosphere, we present an empirical model of 137 electron impact processes---including ionization, dissociation, and excitation---on the nightside of Mars, based on MAVEN in situ data collected between 2014 and December 2019., , , # Mars nightside electron impact process frequency empirical model

[https://doi.org/10.5061/dryad.pc866t1wm](https://doi.org/10.5061/dryad.pc866t1wm)

The frequencies of 137 different electron impact processes in the Martian nightside ionosphere---including ionization, dissociation, and excitation---are modeled separately. Species considered are: CO_2, N_2, Ar, O, and CO. Model parameters are: magnetic field strength, magnetic elevation angle, magnetic topology, solar wind pressure, and altitude. Characterization of the degradation of electron precipitation as the altitude decreases and atmospheric density increases has been calculated using a weighted number density of neutrals as its basis, and used to adjust frequencies. This calculation is explained in more detail in a manuscript currently in prep. Magnetic topology types are described in Xu et al. 2019, though here \"night closed\" and \"night void\" topologies are combined. Topology type codes are: 0-undefined, 1-day closed, 2-cross ..., , **Changes after Mar 6, 2025:** New version of empirical model (202509) includes 5 additional years of SWEA data. SWEA data of all data qualities is included, and a corrective factor intended to statistically correct for anomalous low energy fluxes is randomly applied to a subset of the data. A detailed description of this process is forthcoming. This has been shown to introduce less than 1% additional error into calculated electron impact process rates, which we consider to be negligible, especially given their large inherent variability.

为改进全球火星电离层模拟，我们基于2014年至2019年12月期间收集的MAVEN（火星大气与挥发物演化任务）原位探测数据，构建了火星夜侧137种电子碰撞过程（包括电离、解离与激发）的经验模型。
# 火星夜侧电子碰撞过程频率经验模型

https://doi.org/10.5061/dryad.pc866t1wm

我们分别建模了火星夜侧电离层中137种不同电子碰撞过程的发生频率，涵盖电离、解离与激发三类过程。所考虑的大气成分包括：CO₂、N₂、Ar、O与CO。模型输入参数涵盖磁场强度、磁仰角、磁拓扑结构、太阳风压强与海拔高度。

我们以加权中性粒子数密度为基准，计算了随海拔降低、大气密度升高时电子沉降的衰减特性，并利用该结果修正各碰撞过程的发生频率。该计算的详细说明将刊载于目前正在筹备的研究手稿中。磁拓扑类型的定义详见Xu等人2019年的研究，但本研究中将"夜间闭合"与"夜间空洞"两类拓扑进行了合并。拓扑类型编码规则如下：0-未定义，1-日间闭合，2-跨极...

**2025年3月6日后的更新内容：** 本经验模型的新版本（版本号202509）新增了5年的太阳风电子分析仪（SWEA，Solar Wind Electron Analyzer）探测数据。所有数据质量等级的SWEA数据均被纳入本数据集，同时会随机对部分数据应用校正因子，以从统计学层面修正异常低能通量问题。该处理流程的详细说明即将公开。已有测试表明，该操作仅会使电子碰撞过程频率的计算误差增加不足1%，我们认为该误差可忽略，尤其考虑到该过程本身存在较大的固有变异性。