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关于充流体钻孔中的纵波和横波
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作者 傅旦丹 何樵登 陆敬安 《石油地球物理勘探》 EI CSCD 北大核心 1998年第1期71-77,共7页
虽然钻井中的声波传播理论已比较成熟,但在纵、横渡的激发机制方面仍存在着一些不同的观点。本文通过对纵、横波割线积分进行分析,导出了其远场近似解的表达式,并探讨了稳态情况下的共振和非共振纵、横波振幅的衰减问题,获得的主要... 虽然钻井中的声波传播理论已比较成熟,但在纵、横渡的激发机制方面仍存在着一些不同的观点。本文通过对纵、横波割线积分进行分析,导出了其远场近似解的表达式,并探讨了稳态情况下的共振和非共振纵、横波振幅的衰减问题,获得的主要结论如下:(1)共振纵、横波皆有几何扩散现象。其中,共振纵波的振幅按Z-1衰减;而共振横波的振幅则近似按衰减。(2)共振纵波的振幅与岩石、流体密度比P2/P1及纵、横波速度vP和vs有关;而共振横渡的幅度值除与上述几个因素有关外,还与共振频率、井半径α和流体速度vf有关。(3)非共振纵波的几何衰减介于z-1和[zln(z/α)]-1之间;而非共振横渡的几何衰减则介于z-2和之间。(4)在纵、横渡远场近似解中不存在奇点。 展开更多
关键词 纵波 横波 声波测井 测井 充流体 钻孔
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顶部电离层Pc3压缩波的波动特征 被引量:2
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作者 曾正君 张莹 +3 位作者 杜爱民 罗浩 区家明 郭志芳 《地球物理学进展》 CSCD 北大核心 2020年第3期918-924,共7页
基于2014年至2017年SWARM三颗卫星四年的磁场观测数据,我们挑选出Pc3压缩波事件,研究了顶部电离层Pc3压缩波活动强度的磁纬-磁地方时分布、随磁地方时变化的季节特征以及地理经纬度分布,并进一步分析了Pc3压缩波发生频次的分布特征.结... 基于2014年至2017年SWARM三颗卫星四年的磁场观测数据,我们挑选出Pc3压缩波事件,研究了顶部电离层Pc3压缩波活动强度的磁纬-磁地方时分布、随磁地方时变化的季节特征以及地理经纬度分布,并进一步分析了Pc3压缩波发生频次的分布特征.结果表明,中高纬和低纬的Pc3压缩波可能存在不同的激发机制.中高纬地区的扰动强度随高度衰减,且高纬地区几乎所有地方时都可以观测到Pc3压缩波,可能主要是由入射的阿尔芬波与电离层相互作用产生;而低纬地区扰动强度没有明显的高度依赖性且主要发生日侧,可能主要是上游波以快模波的形式直接传播到电离层所致.同时,该研究结果给出了入射阿尔芬波和电离层相互作用耦合产生Pc3压缩波理论模型的观测证据. 展开更多
关键词 Pc3压缩波 顶部电离层 阿尔芬波 场线共振
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Multi-spacecraft observations of ULF waves during the recovery phase of magnetic storm on October 30, 2003 被引量:11
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作者 YongFu Wang SuiYan Fu +4 位作者 QiuGang Zong Biao Yang ZuYin Pu Lun Xie XuZhi Zhou 《Science China(Technological Sciences)》 SCIE EI CAS 2008年第10期1772-1785,共14页
Based on observations obtained by Cluster C1, GOES 10, 12, and Polar, the global ULF wave properties are studied during the recovery phase of a very intense magnetic storm-Halloween storm (October 31, 2003, 21:00–23:... Based on observations obtained by Cluster C1, GOES 10, 12, and Polar, the global ULF wave properties are studied during the recovery phase of a very intense magnetic storm-Halloween storm (October 31, 2003, 21:00–23:00 UT). The results indicate that the ULF waves’ properties observed by different satellites, such as amplitude, period, etc. show large variations. This can be interpreted as that Field Line Resonance (FLR) might take place in the region where Cluster C1 passed. The compressional wave of the cavity mode coupled with FLR’s shear Alfven wave and fed energy to the latter, forming a large-amplitude toroidal mode. From the point of period, Cluster C1 observed the shortest period, GOES 10, 12 observed the middle, while Polar observed the longest. The wave period of toroidal mode observed by Cluster C1 kept almost unchanging when Cluster C1 passed L range from 11.7 to 5.3. Using the Squared Wavelet Coherence analysis method, we estimated that the FLR region in the dayside magnetosphere could expand to at least 4 local time widths. The toroidal mode observed by Polar was a standing wave, while the poloidal mode was a propagating wave, the observation results could be well explained by the waveguide mode theory. Since the solarwind speed V <SUB>x</SUB> was &#8722;800 km/s and the dynamic pressure varied little, we speculated that the source of the ULF wave was the Kelvin-Helmholtz instability at the magnetopause triggered by high speed solarwind. 展开更多
关键词 magnetic STORM ULF wave poloidal MODE TOROIDAL MODE compressional MODE cavity MODE Field line Resonance (FLR)
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Recent progress on ULF wave and its interactions with energetic particles in the inner magnetosphere 被引量:16
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作者 Theodore A. FRITZ 《Science China(Technological Sciences)》 SCIE EI CAS 2008年第10期1620-1625,共6页
The global distribution properties of Ultra Low Frequency wave (ULF) in the inner magnetospgere and its interactions with energetic particles, such as the wave-particle resonance, modulation, and particle acceleration... The global distribution properties of Ultra Low Frequency wave (ULF) in the inner magnetospgere and its interactions with energetic particles, such as the wave-particle resonance, modulation, and particle acceleration, are active topics in space physics research. These problems are fundamentally important issues to understand the energy transport from the solar wind into the magnetosphere. In this paper we briefly reviewed the recent research progress on ULF wave and its interactions with energetic particles in the inner magnetosphere; furthermore, we suggested some open questions for future study. 展开更多
关键词 radiation BELT PARTICLE PARTICLE acceleration ULF wave compressional MODE cavity MODE poloidal MODE TOROIDAL MODE Field line Resonance (FLR) ENERGETIC particles modulation
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