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海口马鞍岭火山综合观测台与琼中基准地磁台相距约86km,前者将GM4磁通门磁力仪安装在特制的弱磁性大理石箱体中,开展地磁场D,H,Z三分量相对观测;后者将Flearplus和Over—hauser磁通门磁力仪安装在无磁性地磁房中,开展F总场绝对观测和D,H,Z三分量相对观测。通过两个台站D,H,Z三分量变化场的相关对比分析,相关系数皆达到0．98以上。这说明,在火山区开展地磁相对观测是可行的,而采用弱磁性大理石箱体安放磁通门磁力仪进行地磁相对观测具有很高的推广价值。 相似文献
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北天山地震带的航磁异常与深部构造 总被引：2，自引：1，他引：2
通过分析天山和邻近地区的航磁资料，划分出了４个较大的具有不同基底性质和深部构造特征的磁异常区。天山地区的地震大多数都发生在基底隆起或坳陷的附近，在深部磁场图像中，它们则位于天山高磁性块体与周围弱磁性区域之间，那里不仅是正负磁异常的转换带，而且是明显的大地构造边界。介质的磁性与其它地球物理资料一样，也是反映地震活动区域深部构造的一个重要标志。 相似文献
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海安地震台在地磁观测项目迁建过程中,对地磁观测墩体材料,尝试采用钢化玻璃替代弱磁性石材,取得良好效果,相关工作对今后地磁台站建设改造有一定借鉴作用。 相似文献
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地磁测量仪器发展综述 总被引：1，自引：1，他引：0
主要介绍了国内外地磁测量仪器的发展历史以及地磁测量仪器在陆地、海洋、航空和卫星地磁测量领域中的应用,最后对该类仪器的发展趋势进行了展望. 相似文献
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通过地磁测量来预报地震，是从19世纪才逐步发展起来的。地壳的构造运动表现为许多形式，板块的沉降、断层的错动、火山爆发、滑坡、地震、泥石流等都是典型的构造运动。这些现象的发生与地壳的温度、应力有着非常大的关系。前苏联卡拉尼柯夫和卡皮查作了几个成功的岩石磁性压缩实验，获得了岩石磁性与温度和压力的关系，发展了压缩效应理论。 相似文献
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陈钦才 《地震地磁观测与研究》1990,11(1):48-55
参照国际地磁协会（IAGA）历次的建议，在琼中台址附近10km直径范围内进行了以1：25000为底图的三分量地磁测量和相应的地质调查。磁测结果表明，台址附近属于较弱的磁异常区，而地面其它的人为磁性源对台站资料的影响尚无明显反映。从而为研究琼中台磁场的区域代表性提供了根据，也为琼中台磁性环境污染的长期监测奠定了基础。 相似文献
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一、引言地磁短周期变化的转换函数与地震关系的研究是近年来震磁关系研究中开拓的新的研究领域,并已取得了许多重要的成果。地磁脉动的观测资料除了用于更深入地研究地磁场变化的物理特征外,同时可为研究地磁短周期变化提供更短周期的资料。观测地磁脉动资料需要灵敏度较高的地磁测量仪器,从而要求仪器工作在磁噪声较小的环境中。按最近中美协商的合作搞磁脉动观测台址环境的要求,其背景场的干扰噪声要小于 相似文献
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大连九龙地磁台的材料磁性检测 总被引：1，自引：0，他引：1
本文介绍了大连九龙地磁台建设工作中,对建筑材料进行选定,磁性检测,以及施工过程中用G856质子旋进式磁力仪进行磁性跟踪监测。实践证明,这样做能很好地满足地磁台站建设规范的技术要求。 相似文献
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宁蒗-盐源地震前的西昌地磁短临异常特征 总被引：2，自引：0，他引：2
1 西昌地磁台基本情况简介 西昌地磁台位于西昌市西郊的泸山园艺场内,距市中区5 km.占地面积约200 m2属国家二类基本地磁台.台址位于川滇棱形块体的安宁河断裂东面,紧靠则木河断裂西侧,属第四纪冲积、坡积带.土壤层大部为坚硬板土和昔格达砾岩,无明显磁性.室内外磁场总强度水平梯度一般小于5 nT/m.仪器观测室和记录室均采用无磁性或弱磁性灰沙砖、木结构材料建筑.室内全年最低温度11.5 ℃,最高28.1 ℃.日温差一般小于0.3 ℃,最大周日变化均为0.5 ℃.相对温度小于80%.现有投测于1986年的绝对观测CJ6地磁经纬仪两台(水平度盘最小刻度1′),投测于1958年的CZM-2质子旋进式分量仪一台(最小读数1 nT);投测于1985年的CB3地磁记录仪两台(标度值相对误差＜1.5%). 相似文献
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为了提高空间磁场探测精度,磁测卫星一般将磁强计安装在长伸杆的顶端,同时通过整星磁洁净控制,来减小磁强计安装位置的磁场干扰量.针对低轨磁测卫星的特点,提出零磁场环境下卫星极弱干扰磁场的高精度测量方法,模拟在轨地磁场环境下卫星感应磁场的标定方法,以及磁力矩器剩磁不确定量的处理方法.通过以上方法对卫星本体产生的干扰磁场实施严格的标定和数据修正,可有效减小其影响,极大提升空间磁场探测精度.该方法已应用于电磁监测卫星,将整星的磁场干扰不确定量降低一个量级,达到优于0.3 nT的水平. 相似文献
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D. Heyner D. Schmitt J. Wicht K.-H. Glassmeier H. Korth U. Motschmann 《地球物理与天体物理流体动力学》2013,107(4):419-429
Various possibilities are currently under discussion to explain the observed weakness of the intrinsic magnetic field of planet Mercury. One of the possible dynamo scenarios is a dynamo with feedback from the magnetosphere. Due to its weak magnetic field, Mercury exhibits a small magnetosphere whose subsolar magnetopause distance is only about 1.7 Hermean radii. We consider the magnetic field due to magnetopause currents in the dynamo region. Since the external field of magnetospheric origin is antiparallel to the dipole component of the dynamo field, a negative feedback results. For an αΩ-dynamo, two stationary solutions of such a feedback dynamo emerge: one with a weak and the other with a strong magnetic field. The question, however, is how these solutions can be realized. To address this problem, we discuss various scenarios for a simple dynamo model and the conditions under which a steady weak magnetic field can be reached. We find that the feedback mechanism quenches the overall field to a low value of about 100–150 nT if the dynamo is not driven too strongly. 相似文献
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Magnetic mapping for the detection and characterization of UXO: Use of multi-sensor fluxgate 3-axis magnetometers and methods of interpretation 总被引：1，自引：0，他引：1
Marc Munschy Daniel Boulanger Patrice Ulrich Mustapha Bouiflane 《Journal of Applied Geophysics》2007,61(3-4):168-183
Fluxgate vector magnetometers can be powerful instruments in magnetic mapping and in the detection of unexploded ordnance (UXO). Being lightweight and having low power requirements, they allow the development of multi-sensor use. The main problems in using fluxgate magnetometers arise from calibration errors and drift but these can be overcome using a quick and simple method of calibration in the field. This method also has the advantage of compensating permanent and induced magnetic fields generated by magnetized objects carried with the sensors. Measurement accuracy is similar to that obtained with scalar magnetometers. Multi-magnetometer profiling allows direct inversion of raw magnetic data along profiles in order to locate and characterize dipoles typically generated by UXO. The method used is a non-linear inverse procedure that estimates the three coordinates and magnetization vector of the dipole. Application of the technique to both a synthetic case and a field example illustrates the advantages of the method compared with the use of the analytic signal. 相似文献
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We determine the nonlinear drift velocities of the mean magnetic field and nonlinear turbulent magnetic diffusion in a turbulent convection. We show that the nonlinear drift velocities are caused by three kinds of the inhomogeneities; i.e., inhomogeneous turbulence, the nonuniform fluid density and the nonuniform turbulent heat flux. The inhomogeneous turbulence results in the well-known turbulent diamagnetic and paramagnetic velocities. The nonlinear drift velocities of the mean magnetic field cause the small-scale magnetic buoyancy and magnetic pumping effects in the turbulent convection. These phenomena are different from the large-scale magnetic buoyancy and magnetic pumping effects which are due to the effect of the mean magnetic field on the large-scale density stratified fluid flow. The small-scale magnetic buoyancy and magnetic pumping can be stronger than these large-scale effects when the mean magnetic field is smaller than the equipartition field. We discuss the small-scale magnetic buoyancy and magnetic pumping effects in the context of the solar and stellar turbulent convection. We demonstrate also that the nonlinear turbulent magnetic diffusion in the turbulent convection is anisotropic even for a weak mean magnetic field. In particular, it is enhanced in the radial direction. The magnetic fluctuations due to the small-scale dynamo increase the turbulent magnetic diffusion of the toroidal component of the mean magnetic field, while they do not affect the turbulent magnetic diffusion of the poloidal field. 相似文献
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综合分析EISCAT雷达与卫星当地测量数据,并利用磁层磁场模式对磁力线进行追踪,研究了发生在极光椭圆朝极盖边界附近电离层中,一例反常的背离太阳流动的强等离子体对流事件,及相关的太阳风-磁层-电离层耦合过程.结果表明,磁暴期间IMFBz指向南时观测到这一反常高速对流,及其相应的等离子体性态特征,很可能是向阳侧磁层顶磁重联过程在电离层中的印记. 相似文献
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深水环境下进行大地电磁数据采集,信号幅值微弱,高频分量被严重衰减;仪器承载的环境压力巨大,且伴随底流推曳、淤泥吸附等不利因素;海上作业情况复杂多变,带给设备投放与回收诸多困难.针对这些特殊问题,从理论上分析了大地电磁场在海水及其以下层状介质中的传播规律,计算了电场与磁场随不同水深的衰变比值,研讨了与仪器上浮速度相关的物理因素;从技术上阐述海底大地电磁仪的工作原理,包括信号传感器、数据采集器、声控释放单元以及机械组装部件等等.整套仪器信号分辨率达到nV级,频带宽度为10~0.3×10-3 Hz,最大工作水深4000 m.该仪器搭载“海洋六号”科学考察船,在我国南海中沙群岛海域进行了国内首次深水环境下的大地电磁数据采集试验.结果显示,所研发的仪器性能指标吻合先前的理论推算值,达到设计要求.我国的海底大地电磁探测技术已完全享有自主的知识产权. 相似文献
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HELMUT LINSSER 《Geophysical Prospecting》1970,18(1):119-133
The principle of optical pumping allows the design of magnetometers with high sensitivity. When mapping the field of the total magnetic force, it is no longer possible to make full use of the accuracy of the instruments because the accuracy of the reduction of the diurnal variation is limited. By simultaneously recording with two instruments in different altitudes, the vertical gradient can be measured which doe's not depend on the time variation of the magnetic field. Therefore, the gradiometer seems to be a more adequate tool for oil exploration than the magnetometer. It is investigated in this article whether the results of this gradiometer or the measurements of the total magnetic field by the high sensitive magnetometer are more useful in oil exploration. The article comes to the conclusion that for most problems of oil exploration the total magnetic field is a more valuable unit than the vertical gradient measured directly by the gradiometer. The total magnetic field allows a better investigation of the tectonics than the vertical gradient. The apparent advantages of the gradiometer claimed by its supporters are mainly based on inconsistent mathematical concepts. 相似文献
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本文基于二维三分量可压缩磁流体动力学模拟，数值研究由于磁力线足点在光球层的剪切运动引起日冕电流片中的磁场重联过程。结果表明，磁力线足点的剪切运动作为引起强迫磁场重联的一种触发机制，将加速磁场重联的发展和磁岛的合并过程。结合不稳定性导致等离子体急剧加速，在β∞＝０．１的情况下其加速度达到０．３４νＡ∞／τＡ，等离子体的最大下落速度可达１．９０νＡ∞，大于纯电阻撕裂模情况。还讨论了β∞值对这种磁场重联过程的影响。β∞值越小，磁场重联和磁岛合并过程发展得越快。 相似文献
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分析了影响磁通门磁变仪定向状态函数和经典磁变仪定向状态函数改变的因素，对磁通门磁变仪定向状态函数和经典磁变仪定向状态函数及其稳定性进行了比较，得出了有益的结论。 相似文献