海水运动感应磁场的数值计算方法
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摘要
海水是一种高导电率的流体,处于不停的运动之中。海水运动因切割地磁场而产生感应电流,从而产生感应磁场。本文从毕奥-萨伐尔定律出发,推导出了二维海水运动磁场方程,并利用形函数将其转换成二维离散速度场感应磁场积分表达式,采用高斯数值积分方法计算二维离散速度场感应磁场响应。算例表明,本文计算方法具有较高计算精度。文章还分析了海水运动频率、振幅和水深对感应磁场的影响。
Seawater is a highly conductive fluid which moves continuously.The movement of seawater cutting the magnetic field generates inductive current,thereby induce the magnetic fields.This article obtained 2D wave's magnetic field equations by solving the equations that couple the wave motion equations with the Biot-Savart law.The shape function is introduced to convert magnetic field equations into discrete integral equations which are calculated using Gaussian numerical integration method.The example shows that this method is high-precision.Subsequently,this article discussed how the frequency,amplitude of seawater movement and varying water depth influence the induced magnetic field respectively.
Seawater is a highly conductive fluid which moves continuously.The movement of seawater cutting the magnetic field generates inductive current,thereby induce the magnetic fields.This article obtained 2D wave's magnetic field equations by solving the equations that couple the wave motion equations with the Biot-Savart law.The shape function is introduced to convert magnetic field equations into discrete integral equations which are calculated using Gaussian numerical integration method.The example shows that this method is high-precision.Subsequently,this article discussed how the frequency,amplitude of seawater movement and varying water depth influence the induced magnetic field respectively.
引文
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[2] Lilley F E M,Hitchman A P,Milligan P R,et al.Sea-surface observations of the magnetic signals of ocean swells[J].Geophysical Journal International,2004,159(2):565-572.
[3] C Manoj,A Kuvshinov,S Neetu,et al.Can undersea voltage measurements detect tsunamis?[J].Earth Planets and Space,2010,62:353-358.
[4] H Toh,K Satake,Y Hamano,et al.Tsunami signals from the2006and 2007Kuril earthquakes detected at a seafloor geomagnetic observatory[J].Journal of Geophysical Research:Solid Earth,2011,116:1-10.
[5]张自力,魏文博,刘保华,等.海浪感应电磁场的理论计算[J].海洋学报,2008,30:42-46.Zhang Zi-li,Wei Wen-bo,Liu Bao-hua,et al.Theoretical calculation of electromagnetic field generated by ocean waves[J].Acta Oceanologica Sinica,2008,30:42-46.
[6] M S Longuet-higgins.The electrical field induced by ocean currents and waves,with applications to the method of towed electrodes[J].Deep Sea Research,1954,13(1):1-37.
[7] J T Weaver.Magnetic variations associated with ocean waves and swell[J].Journal of Geophysical Research,1965,70:1921-1929.
[8] K M Bhatt.Motion Induced Noice in Marine Electromagnetic Data[D].[s.l.]:Institut für Geophysik Und Extraterrestrische Physik,2011.
[9] Podney W.Electromagnetic fields generated by ocean waves[J].Journal of Geophysical Research,1975,80:2977-2990.
[10] Sanford T B.Motionally induced electric and magnetic fields in the sea[J].Journal of Geophysical Research,1971,76:3476-3492.
[11] Kuvshinov A V.Electromagnetic induction in the oceans and the anomalous behaviour of coastal C-responses for periods up to 20days[J].Geophysical Research Letters,2005,29:359-365.
[12]徐世浙.地球物理中的有限单元法[M].北京:科学出版社,1994.Xu Shi-zhe.Finite Element Mettod in Geophysice[M].Beijing:Science Press,1994.
[13]叶安乐,李凤歧.物理海洋学[M].青岛:青岛海洋大学出版社,1992.Ye An-le,Li Feng-qi.Physical Oceanography[M].Qingdao:Qingdao Ocean University Press,1992.
[2] Lilley F E M,Hitchman A P,Milligan P R,et al.Sea-surface observations of the magnetic signals of ocean swells[J].Geophysical Journal International,2004,159(2):565-572.
[3] C Manoj,A Kuvshinov,S Neetu,et al.Can undersea voltage measurements detect tsunamis?[J].Earth Planets and Space,2010,62:353-358.
[4] H Toh,K Satake,Y Hamano,et al.Tsunami signals from the2006and 2007Kuril earthquakes detected at a seafloor geomagnetic observatory[J].Journal of Geophysical Research:Solid Earth,2011,116:1-10.
[5]张自力,魏文博,刘保华,等.海浪感应电磁场的理论计算[J].海洋学报,2008,30:42-46.Zhang Zi-li,Wei Wen-bo,Liu Bao-hua,et al.Theoretical calculation of electromagnetic field generated by ocean waves[J].Acta Oceanologica Sinica,2008,30:42-46.
[6] M S Longuet-higgins.The electrical field induced by ocean currents and waves,with applications to the method of towed electrodes[J].Deep Sea Research,1954,13(1):1-37.
[7] J T Weaver.Magnetic variations associated with ocean waves and swell[J].Journal of Geophysical Research,1965,70:1921-1929.
[8] K M Bhatt.Motion Induced Noice in Marine Electromagnetic Data[D].[s.l.]:Institut für Geophysik Und Extraterrestrische Physik,2011.
[9] Podney W.Electromagnetic fields generated by ocean waves[J].Journal of Geophysical Research,1975,80:2977-2990.
[10] Sanford T B.Motionally induced electric and magnetic fields in the sea[J].Journal of Geophysical Research,1971,76:3476-3492.
[11] Kuvshinov A V.Electromagnetic induction in the oceans and the anomalous behaviour of coastal C-responses for periods up to 20days[J].Geophysical Research Letters,2005,29:359-365.
[12]徐世浙.地球物理中的有限单元法[M].北京:科学出版社,1994.Xu Shi-zhe.Finite Element Mettod in Geophysice[M].Beijing:Science Press,1994.
[13]叶安乐,李凤歧.物理海洋学[M].青岛:青岛海洋大学出版社,1992.Ye An-le,Li Feng-qi.Physical Oceanography[M].Qingdao:Qingdao Ocean University Press,1992.