ELECTRICALLY-ACTIVATED CLOUD CHEMISTRY IN THE ATMOSPHERES OF BROWN DWARFS AND EXOPLANETS

棕矮星和系外行星大气中的电激活云化学

• 批准号: ST/X000885/2
• 负责人: Craig Stark
• 金额: $ 30.43万
• 依托单位: University of Glasgow
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FX000885%2F2
• 关键词: ELECTRICALLY; ACTIVATED; CLOUD; CHEMISTRY; ATMOSPHERES

The dynamic atmospheres in large, planetary and stellar objects are complex systems, but have a particular fundamental aspect that transcends the fluid description: they are electrical in nature, at least in part. Just as lightning on Earth is produced by the sudden release of electrical charge accumulated on ice crystals in thunder clouds, active atmospheres containing aerosols and dust particles can develop pockets of intense but transient electrical activity. Such events have a great significance for atmospheric evolution: the release of free charge into a neutral atmosphere can markedly affect the gaseous chemistry, since this makes possible non-equilibrium chemical pathways that are unavailable via conventional equilibrium processes. Moreover, the charging of grains and aerosols has an onward impact on the radiation that can be observed remotely. Grain-grain interactions can produce populations of non-thermal free electrons, from processes such as the release of grain charge via localised strong surface electric fields, and from modifying the energy distribution of free electrons moving in the presence of inertial, charged particles. Anomalous radio signatures have been detected from Brown Dwarf atmospheres, which are an ideal vehicle for exploring the concepts described here. We propose to explore, theoretically, numerically and with due consideration of observational data, the impact of free and deposited charge on the cloudy atmospheres of Brown Dwarfs, including the generation of such free charge (ionization processes, including lightning) and the characteristic radiation signature of beams, charged aerosols and unique chemistry. In so doing we believe that we can contribute fresh insight into the character and evolution of these fascinating objects.

大型行星和恒星物体中的动态气氛是复杂的系统，但具有特定的基本方面，超越了流体描述：它们本质上是电气的，至少部分是部分电气。正如地球上的闪电是通过在雷云中积聚在冰晶上的电荷的突然释放而产生的一样，含有气溶胶和灰尘颗粒的活跃气氛可以产生强烈但短暂的电活动的口袋。此类事件对大气进化具有重要意义：将自由电荷释放到中性大气中可以显着影响气态化学反应，因为这使得通过常规平衡过程无法获得的非平衡化学途径可能。此外，谷物和气溶胶的充电对辐射具有不断的影响，可以远程观察到。谷物粒的相互作用可以从诸如通过局部强的表面电场释放晶粒电荷的过程以及在存在惯性，带电的颗粒的存在下移动的自由电子的能量分布，从而产生非热无热电子的种群。从棕色矮人的气氛中检测到了异常的无线电标志，这是探索此处描述的概念的理想工具。我们建议在理论上，数字上探索，并在适当考虑观察数据，自由和沉积电荷对棕色矮人的云层大气的影响，包括产生这种自由电荷（电离过程，包括闪电）以及光束的特征辐射，带电辐射，带电的气溶胶和独特的化学。通过这样做，我们相信我们可以对这些迷人物体的性格和演变做出新的见解。