Physics and chemistry of impact vapor clouds: Applications to the Earth and the origin and evolution of life

撞击蒸气云的物理和化学：在地球和生命的起源和进化中的应用

• 批准号: 16204033
• 负责人: MATSUI Takafumi
• 金额: $ 32.95万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16204033/
• 关键词: glass laser; laser gun; impact degassing; carbonate; impact vapor clouds; high-speed gun; meteoritic impact phenomena; greenhouse-effect gas; ユゴニオ状態方程式; L6阻石; エンスタタイト結晶; L6隕石

In this research project, we conducted two major tasks. The first is development of a high-speed laser gun. In this task, we succeeded in launching metal projectiles up to 〜6 km/s. This velocity is the maximum velocity of a typical two-stage light-gas gun, which is one of the most commonly used conventional launching technologies. Furthermore, we experimentally verifed the theoretical scaling rule indicating that launch velocity is proportional to the square root of the ratio of laser intensity to target column mass. This scaling rule shows that the conversion from laser energy to projectile kinetic energy is high, leading to a expectation that further increase in laser intensity will increase substantial launch velocity with this technology. A laser gun, unlike a two-stage light-gas gun, is free from possible contamination of combustion gas. Taking advantage of this property, we conducted a second task: impact degassing experiments in an open system. In this task, we focused on impact degassing phenomena of carbonates, because degassed CO_2 may have played an important role in the evolution of surface environment of terrestrial planets as a major greenhouse gas. Degassing experiments of carbonates have been conduced extensively mostly in the United States since 1980's. However, experimental results are now subject to questions because they are mostly done in a closed system, in which back reaction between degassed gas and depleted target rocks may take place easily. In our experiments, we used crystalline calcite targets and gold and cupper projectiles. Preliminary results indicate that degassing efficiency saturates at peak pressures higher than 33GPa, strongly suggesting that complete degassing occurs at shock pressure 33GPa or lower. This pressure threshold value is significantly lower than 40-50 GPa obtained by Ahrens and colleagues, suggesting that the impact degassing may occur at much higher efficiency than previously though.

在这个研究项目中，我们进行了两项主要任务。首先是高速激光枪的发展。在这次任务中，我们成功地发射了速度高达~ 6公里/秒的金属弹丸。这个速度是典型的两级轻气炮的最大速度，是最常用的传统发射技术之一。此外，我们还通过实验验证了理论尺度规则，表明发射速度与激光强度与靶柱质量之比的平方根成正比。这一比例规律表明，激光能量到弹体动能的转换是很高的，可以预期激光强度的进一步提高将使该技术的发射速度大幅提高。激光枪不像两级光气枪，它不受燃烧气体的污染。利用这一特性，我们进行了第二个任务：在开放系统中进行冲击脱气实验。由于脱气后的CO_2作为一种主要的温室气体，可能在类地行星表面环境的演化过程中发挥了重要的作用，因此本课题将重点研究碳酸盐的撞击脱气现象。自20世纪80年代以来，碳酸盐脱气实验主要在美国进行。然而，实验结果现在受到质疑，因为它们大多是在一个封闭的系统中进行的，在这个系统中脱气气体和耗尽的目标岩石之间容易发生反反应。在我们的实验中，我们使用了结晶方解石靶和金铜弹。初步结果表明，脱气效率在峰值压力高于33GPa时达到饱和，强烈表明在冲击压力为33GPa或更低时发生完全脱气。这一压力阈值明显低于Ahrens及其同事获得的40-50 GPa，这表明撞击脱气的效率可能比以前高得多。

项目成果

Velocity distributions of high-velocity ejecta from regolith targets

风化层目标高速喷射物的速度分布

• 发表时间: 2005
• 期刊: Icarus 178
• 作者: Yamamoto;S.;T.Kadono;S.Sugita;T.Matsui
• 通讯作者: T.Matsui

HCN formation by the chemical interaction between high-speed impact fragments and a planetary atmospher

高速撞击碎片与行星大气之间的化学相互作用形成 HCN

• 发表时间: 2006
• 期刊: Proceedings of the 39^<th> Lunar and Planetary Symposium
• 作者: Kurosawa;K.;K.Ishibashi;S.Sugita;T Kadono;S.Ohno;T.Matsui
• 通讯作者: T.Matsui

Laboratory experiments of Titan tholin formed in cold plasma at various pressures : Implication for nitrogen-containing polycyclic aromatic compounds in Titan Haze

不同压力下冷等离子体中形成泰坦索林的实验室实验：对泰坦雾霾中含氮多环芳香族化合物的影响

• 发表时间: 2004
• 期刊: Icarus 168
• 作者: Imanaka;H.;B.N.Khare;E.L.O.Bakes;C.P.Mckay;D.P.Cruikshank;S.Sugita;T.Matsui;R.N.Zare
• 通讯作者: R.N.Zare

The effect of thermal decomposition of silicate on carbon chemistry in impact vapor plumes 1 : Effect of impact size

硅酸盐热分解对撞击蒸气羽流中碳化学的影响 1：撞击尺寸的影响

• 发表时间: 2004
• 期刊: Proceedings of 37th ISAS Lunar Planetary Symposium 37(印刷中)
• 作者: Ishibashi;K.;S.Ohno;S.Sugita;T.Kadono;T.Matsui
• 通讯作者: T.Matsui

Breakup of molten silicate by high-velocity gas flow

高速气流破碎熔融硅酸盐

• 发表时间: 2005
• 期刊: Proceedings of 37th ISAS Lunar Planetary Symposium 37
• 作者: T.Kadono;M.Arakawa;A.Kouchi
• 通讯作者: A.Kouchi