In magnetoacoustic tomography with magnetic induction and magnetically mediated thermoacoustic imaging, tissues are exposed to an alternating field, generating magnetoacoustic and thermoacoustic effects in the tissues. This study aimed to investigate the relationship between magnetoacoustic and thermoacoustic effects in a low-conductivity object put in a Gauss-pulsed alternating magnetic field. First, the derivations of the magnetic flux density and electric field strength induced by a Gauss-pulsed current flowing through the coil based on the theory of electromagnetic field were examined. Second, the analytical solution of the magnetic field was studied by simulation. To validate the accuracy of the analytical solution, the analytical solution and the numerical simulation of the magnetic flux density were compared. It shows that the analytical solution coincides with the numerical simulation well. Then, based on the theoretical analysis of the acoustic source generation, numerical studies were conducted to simulate pressures excited by magnetoacoustic and thermoacoustic effects in low-conductivity objects similar to tissues in the Gauss-pulsed magnetic field. The thermoacoustic effect played a leading role in low-conductivity objects placed in the Gauss-pulsed magnetic field, and the magnetoacoustic effect could be ignored. This study provided the theoretical basis for further research on magnetoacoustic tomography with magnetic induction and magnetically mediated thermoacoustic imaging for pathological tissues.

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脉冲磁场激发的声源研究

在具有磁感应和磁介导热声成像的磁声层析成像中，组织暴露于交变场中，在组织中产生磁声和热声效应。本研究旨在研究置于高斯脉冲交变磁场中的低电导率物体的磁声和热声效应之间的关系。首先，基于电磁场理论研究了流经线圈的高斯脉冲电流感应的磁通密度和电场强度的推导。其次，通过仿真研究了磁场的解析解。为了验证解析解的准确性，将解析解与磁通密度的数值模拟进行了比较。表明解析解与数值模拟吻合较好。然后，在对声源产生的理论分析的基础上，进行了数值研究，以模拟高斯脉冲磁场中类似于组织的低电导率物体的磁声和热声效应激发的压力。热声效应在放置在高斯脉冲磁场中的低电导率物体中起主导作用，磁声效应可以忽略不计。该研究为进一步研究磁感应磁声层析成像和磁介导的病理组织热声成像提供了理论依据。进行了数值研究以模拟高斯脉冲磁场中类似于组织的低电导率物体中的磁声和热声效应激发的压力。热声效应在放置在高斯脉冲磁场中的低电导率物体中起主导作用，磁声效应可以忽略不计。该研究为进一步研究磁感应磁声层析成像和磁介导的病理组织热声成像提供了理论依据。进行数值研究以模拟在高斯脉冲磁场中类似于组织的低电导率物体中由磁声和热声效应激发的压力。热声效应在放置在高斯脉冲磁场中的低电导率物体中起主导作用，磁声效应可以忽略不计。该研究为进一步研究磁感应磁声层析成像和磁介导的病理组织热声成像提供了理论依据。并且磁声效应可以忽略不计。该研究为进一步研究磁感应磁声层析成像和磁介导的病理组织热声成像提供了理论依据。并且磁声效应可以忽略不计。该研究为进一步研究磁感应磁声层析成像和磁介导的病理组织热声成像提供了理论依据。