高频调幅磁场分布和液面波动行为研究

采用高频磁场外加低频调制信号的方法产生高频调幅磁场，用小线圈法测定线圈内部的磁感应强度，结果表明，在线圈中下位置截面处的磁感应强度最大，而且边缘强于中心部分，调制波信号频率为5Hz、幅值在0．5—7．0V范围内随着幅值增加磁感应强度增加，当幅值为7．0V时对应的磁感应强度为0．029T。该磁场作用下熔体弯月面的行为研究表明，磁感应强度增加则电磁场对熔体的约束力增加，减少了熔体和坩埚间的压力，液面产生规律性波动。

High Frequency Amplitude-modulated Magnetic Field and Behavior of Meniscus Fluctuation

A high frequency amplitude-modulated magnetic field is realized by superposing a low frequency signal on the high frequency magnetic field. And the distribution of magnetic induction density, B, was measured by the small coils method. The results show that the higher B is observed in middle-bottom position, where that at the edge is higher than that of the center. The B can be increased with the increasing in amplitude-modulated value in the range of amplitude-modulated value of 0.5~7 V with amplitude-modulated signal frequency of 5 Hz. The B value of 0.029 T can be observed at the amplitude-modulated value of 7 V . The behavior of molten meniscus fluctuation in the magnetic field indicates that with the increase of magnetic induction density, the defined force is increased, which lessened the pressure between the molten and the crucible to result in the regular fluctuation of the meniscus.