| Autor: |
Zhao, Ruocan, Liu, Zhenwei, Xue, Xianghui, Zhou, Hang, Wang, Zhaofeng, Liu, Yingyu, Li, Jiangtao, Sun, Dongsong, Lan, Jiaxin, Chen, Tingdi, Zhao, Dongfeng, Dou, Xiankang |
| Předmět: |
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| Zdroj: |
Space Weather: The International Journal of Research & Applications; Aug2024, Vol. 22 Issue 8, p1-10, 10p |
| Abstrakt: |
In this work, we present a metastable helium lidar system for the measurements of metastable helium He(23S) density in the thermosphere and lower exosphere. This lidar system consists of a high power 1,083 nm pulsed laser, a 1 m aperture laser beam expander, six 1 m aperture receiving telescopes and a superconducting nanowire single‐photon detector (SNSPD). This system realizes metastable helium density detection up to 1,000 km. Daily rapid variation of metastable helium density within several hours was measured with a height resolution of 50 km for the first time. It demonstrates the capability of ground‐based lidar for continuous height‐resolved detection of the atmospheric metastable helium in the height range of 200–1,000 km. This is a promising tool to help study the coupling of neutral and ionized atmosphere in this height range and further providing observation basis for space weather prediction. Plain Language Summary: Many different kinds of lidar have been well developed for tens of years and can detect the atmosphere up to 180 km by different principles (such as aerosol scattering, Rayleigh scattering, resonance fluorescence scattering and so on). However, in the higher height range of 200–1,000 km, there are almost no suitable methods to monitoring the atmosphere continuously from the ground, except for one choice: metastable helium lidar. In this work, we built a powerful 1,083 nm pulsed laser and emit it vertically in to the atmosphere, the metastable helium atoms resonance with the laser and emits fluorescence photons. The scattered photons from the very high atmosphere are collected and focused by the large aperture telescope on the ground and detected by the photoelectric detector. Building such a lidar has many difficulties that have never been encountered by other conventional lidars, such as the large signal attenuation by long distance. This powerful lidar is built successfully in 2023 and make observations for several months. The first high quality initial data of the observed metastable helium density profile in 200–1,000 km is shown in this paper. This observation will continuously provide useful observation for the study of space physics and space weather forecasting. Key Points: A metastable helium lidar system for the measurements of metastable helium He(23S) density in 200–1,000 km has been developedDaily rapid variation of metastable helium density within several hours was measured with a height resolution of 50 km for the first timeThis is a promising tool to help providing observation basis for space weather prediction [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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