THz limb sounder (TLS) for lower thermospheric wind, oxygen density, and temperature
THz limb sounder (TLS) for lower thermospheric wind, oxygen density, and temperature
复制标题
用于较低热层风、氧气密度和温度的太赫兹临边探测器 (TLS)
DOI：
--
复制
发表时间：
2016
期刊：
影响因子：
--
通讯作者：
B. Drouin
中科院分区：
文献类型：
--
作者：
Dong L. Wu;J. Yee;E. Schlecht;I. Mehdi;J. Siles;B. Drouin
对于理解复杂的电动力学过程和离子-中性相互作用，中性风是低热层和E区电离层(LTEI)中最关键的测量之一。我们正在开发一种高灵敏度、低功耗、非低温2.06 太赫兹肖特基接收器，用于测量100-140 公里的风廓线。这项名为太赫兹肢体探测仪的新技术旨在通过解决2.06 太赫兹原子氧(OI)排放的风致多普勒频移来测量LTEI风。作为基电子态精细结构能级之间的跃迁，OI发射在350 km高度处于局域热力学平衡状态。LTE的这种特性，加上昼夜能力和小的视线坡度，使得Oi肢体探测对于中性风观测来说是一种非常有吸引力的技术。除了风的测量外，TLS还可以反演LTEI区域的[OI]密度和中性温度。TLS利用了太赫兹接收器技术的快速发展，包括次谐波泵浦(SHP)混频器和基于肖特基二极管的功率倍增器。目前的SHP肖特基接收器已经在环境温度(120-150 K)下对太赫兹频率产生了良好的灵敏度，这是通过航天被动冷却实现的。作为一项新兴技术，TLS可以填补LTEI中性风观测中的关键数据空白，使详细研究带电分子和中性分子之间的耦合和发电机过程成为可能。
Neutral winds are one of the most critical measurements in the lower thermosphere and E region ionosphere (LTEI) for understanding complex electrodynamic processes and ion‐neutral interactions. We are developing a high‐sensitivity, low‐power, noncryogenic 2.06 THz Schottky receiver to measure wind profiles at 100–140 km. The new technique, THz limb sounder (TLS), aims to measure LTEI winds by resolving the wind‐induced Doppler shift of 2.06 THz atomic oxygen (OI) emissions. As a transition between fine structure levels in the ground electronic state, the OI emission is in local thermodynamic equilibrium (LTE) at altitudes up to 350 km. This LTE property, together with day‐and‐night capability and small line‐of‐sight gradient, makes the OI limb sounding a very attractive technique for neutral wind observations. In addition to the wind measurement, TLS can also retrieve [OI] density and neutral temperature in the LTEI region. TLS leverages rapid advances in THz receiver technologies including subharmonically pumped (SHP) mixers and Schottky‐diode‐based power multipliers. Current SHP Schottky receivers have produced good sensitivity for THz frequencies at ambient environment temperatures (120–150 K), which are achievable through passively cooling in spaceflight. As an emerging technique, TLS can fill the critical data gaps in the LTEI neutral wind observations to enable detailed studies on the coupling and dynamo processes between charged and neutral molecules.