期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
Charging Mechanism of Lightning at the Molecular Level
1
作者 See Leang Chin Xueliang Guo +6 位作者 Harmut Schroeder Di Song Andong Xia Fan’ao Kong Huanbin Xu Tiejun Wang Ruxin Li 《Atmospheric and Climate Sciences》 2023年第4期415-430,共16页
Cloud electrification is one of the oldest unresolved puzzles in the atmospheric sciences. Though many mechanisms for charge separation in clouds have been proposed, a quantitative understanding of their respective co... Cloud electrification is one of the oldest unresolved puzzles in the atmospheric sciences. Though many mechanisms for charge separation in clouds have been proposed, a quantitative understanding of their respective contribution in a given meteorological situation is lacking. Here we suggest and analyze a hitherto little discussed process. A qualitative picture at the molecular level of the charge separation mechanism of lightning in a thundercloud is proposed. It is based on two key physical/chemical natural phenomena, namely, internal charge separation of the atmospheric impurities/aerosols inside an atmospheric water cluster/droplet/ice particle and the existence of liquid water layers on rimers (graupels and hailstones) forming a layer of dipoles with H<sup>+</sup> pointing out from the air-water interface. Charge separation is achieved through strong collisions among ice particles and water droplets with the rimers in the turbulence of the thundercloud. This work would have significant contribution to cloud electrification and lightning formation. 展开更多
关键词 Cloud Electrification Charge Separation COLLISION Molecular Level
下载PDF
Lightning in a Forest (Wild) Fire: Mechanism at the Molecular Level
2
作者 See Leang Chin Xueliang Guo +4 位作者 Harmut Schroeder Huanbin Xu Tie-Jun Wang Ruxin Li Weiwei Liu 《Atmospheric and Climate Sciences》 2024年第1期128-135,共8页
The mechanism of lightning that ignites a forest fire and the lightning that occurs above a forest fire are explained at the molecular level. It is based on two phenomena, namely, internal charge separation inside the... The mechanism of lightning that ignites a forest fire and the lightning that occurs above a forest fire are explained at the molecular level. It is based on two phenomena, namely, internal charge separation inside the atmospheric cloud particles and the existence of a layer of positively charged hydrogen atoms sticking out of the surface of the liquid layer of water on the surface of rimers. Strong turbulence-driven collisions of the ice particles and water droplets with the rimers give rise to breakups of the ice particles and water droplets into positively and negatively charged fragments leading to charge separation. Hot weather in a forest contributes to the updraft of hot and humid air, which follows the same physical/chemical processes of normal lightning proposed and explained recently[1]. Lightning would have a high probability of lighting up and burning the dry biological materials in the ground of the forest, leading to a forest (wild) fire. The burning of trees and other plants would release a lot of heat and moisture together with a lot of smoke particles (aerosols) becoming a strong updraft. The condition for creating lightning is again satisfied which would result in further lightning high above the forest wild fire. 展开更多
关键词 Forest Wild Fire LIGHTNING Molecular Level
下载PDF
Rydberg state excitation in molecules manipulated by bicircular two-color laser pulses
3
作者 Wenbin Zhang Yongzhe Ma +5 位作者 Chenxu Lu Fei Chen Shengzhe Pan Peifen Lu Hongcheng Ni Jian Wu 《Advanced Photonics》 SCIE EI CAS CSCD 2023年第1期19-26,共8页
Multiphoton resonant excitation and frustrated tunneling ionization,manifesting the photonic and optical nature of the driving light via direct excitation and electron recapture,respectively,are complementary mechanis... Multiphoton resonant excitation and frustrated tunneling ionization,manifesting the photonic and optical nature of the driving light via direct excitation and electron recapture,respectively,are complementary mechanisms to access Rydberg state excitation(RSE)of atoms and molecules in an intense laser field.However,clear identification and manipulation of their individual contributions in the light-induced RSE process remain experimentally challenging.Here,we bridge this gap by exploring the dissociative and nondissociative RSE of H2 molecules using bicircular two-color laser pulses.Depending on the relative field strength and polarization helicity of the two colors,the RSE probability can be boosted by more than one order of magnitude by exploiting the laser waveform-dependent field effect.The role of the photon effect is readily strengthened with increasing relative strength of the second-harmonic field of the two colors regardless of the polarization helicity.As compared to the nondissociative RSE forming H2,the field effect in producing the dissociative RSE channel of eHt;HT is moderately suppressed,which is primarily accessed via a three-step sequential process separated by molecular bond stretching.Our work paves the way toward a comprehensive understanding of the interplay of the underlying field and photon effects in the strong-field RSE process,as well as facilitating the generation of Rydberg states optimized with tailored characteristics. 展开更多
关键词 strong-field Rydberg state excitation molecular dissociative ionization bicircular two-color fields multiphoton resonant excitation frustrated tunneling ionization
原文传递
A concept for multiterawatt fibre lasers based on coherent pulse stacking in passive cavities 被引量:11
4
作者 Sven Breitkopf Tino Eidam +9 位作者 Arno Klenke Lorenz von Grafenstein Henning Carstens Simon Holzberger Ernst Fill Thomas Schreiber Ferenc Krausz Andreas Tunnermann Ioachim Pupeza Jens Limpert 《Light(Science & Applications)》 SCIE EI CAS 2014年第1期62-68,共7页
Since the advent of femtosecond lasers,performance improvements have constantly impacted on existing applications and enabled novel applications.However,one performance feature bearing the potential of a quantum leap ... Since the advent of femtosecond lasers,performance improvements have constantly impacted on existing applications and enabled novel applications.However,one performance feature bearing the potential of a quantum leap for high-field applications is still not available:the simultaneous emission of extremely high peak and average powers.Emerging applications such as laser particle acceleration require exactly this performance regime and,therefore,challenge laser technology at large.On the one hand,canonical bulk systems can provide pulse peak powers in the multi-terawatt to petawatt range,while on the other hand,advanced solid-state-laser concepts such as the thin disk,slab or fibre are well known for their high efficiency and their ability to emit high average powers in the kilowatt range with excellent beam quality.In this contribution,a compact laser system capable of simultaneously providing high peak and average powers with high wall-plug efficiency is proposed and analysed.The concept is based on the temporal coherent combination(pulse stacking)of a pulse train emitted from a high-repetition-rate femtosecond laser system in a passive enhancement cavity.Thus,the pulse energy is increased at the cost of the repetition rate while almost preserving the average power.The concept relies on a fast switching element for dumping the enhanced pulse out of the cavity.The switch constitutes the key challenge of our proposal.Addressing this challenge could,for the first time,allow the highly efficient dumping of joule-class pulses at megawatt average power levels and lead to unprecedented laser parameters. 展开更多
关键词 cavity dumping cavity enhancement coherent pulse addition high average power and high peak power ultrafast lasers
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部