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Cooling an Optically Trapped Ultracold Fermi Gas by Periodical Driving
Published on: March 30, 2017
来自金星的离子通过等离子唤醒损失
S Barabash1, A Fedorov, J J Sauvaud
1Swedish Institute of Space Physics, S-98128 Kiruna, Sweden. stas@irf.se
Nature
|November 30, 2007
概括
由于大气逃逸,金星已经失去了大量的水. 金星快车的数据显示,氧气和离子正在逃逸,这表明地球历史上水的大量流失.
科学领域:
- 行星科学 行星科学
- 大气科学 大气科学
- 天体生物学 天体生物学
背景情况:
- 金星和地球可能始于类似的水库存.
- 金星的 deuterium-to-hydrogen比率远高于地球,这表明大气的进化是显著的.
- 目前的热逃逸率很低,但非热逃逸机制是活跃的.
研究的目的:
- 为了确定从金星大气层中逃逸的主要离子.
- 量化关键大气物种的逃逸率和逃逸比率.
- 了解推动金星大气损失的机制.
主要方法:
- 利用Venus Express的测量来分析逃逸的离子.
- 识别了包括O+,He+和H+在内的逃离离子.
- 通过等离子板和诱导磁层边界层确定逃生路径.
主要成果:
- 确定了O +,He +和H +作为主要的逃离离子.
- 测量的逃逸率比率:Q ((H+) / Q ((O+) = 1.9 和 Q ((He+) / Q ((O+) = 0.07.
- 观察到H+和O+逃逸率与中性逃逸率相结合,接近水的静态度比.
结论:
- 金星在其历史上经历了大量的水损失.
- 离子逃生机制在金星大气演变中起着至关重要的作用.
- 目前的逃逸率表明正在进行的水损失与水的静态度相一致.
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