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磁场的方向与作用
吴绍东 （广西横县邮政局六景支局，六景，530313；26 岁，男） 摘 要 提出“同向磁场互相排斥，逆向磁场互相吸引”原理并介绍其的运用，认为“同名磁极互相排斥，异名磁极互相吸引”的提法是不妥当的，提出了对“磁极”的修改建议。 关键词 磁场；磁极；磁力 分类号 O 482.51 磁场是磁源相互作用的媒介，磁源的相互作用效果与磁场的方向关系直接相关，本文所提出的“同向磁场互相排斥，逆向磁场互相吸引”原理是一个既可用于判断，也可用于分析磁场之间的相互作用现象的较为根本的电磁学原理，有了“同向磁场互相排斥，逆向磁场互相吸引”原理，则“楞次定律”、“左手定则”、“右手定则”、“右手螺旋法则”、“同名磁极互相排斥，异名磁极互相吸引”等一系列的判断方法可以不运用。 我们知道，理论是从有限的实践中总结出来的看法，“同名磁极互相排斥，异名磁极互相吸引”是一个简单而早已形成的共识，科学界对其一直缺乏深人的论证，本文认为其的提法是不妥当的，并提出对“磁极”的修改建议等。 1 同向磁场互相排斥，逆向磁场互相吸引 我们可以根据磁源的磁场的相互“接触”处的方向来判断，分析磁源之间的相互作用现象，即：“相触磁场同向则相斥，逆向则相吸。 如图1，两块异名磁极互相靠近的磁铁，会由于它们的磁场的相互“接触”处相互逆向而互相吸引，即“逆向磁场互相吸引”。且相互逆向的磁场会由于互相吸引的原因而“拼接”起来(符合实验事实及磁力线不相交观点，如图2),而“拼接”后的磁场又会由于磁场的同向相斥的原因而鼓起(如图2)。在此，我们可以认识到“同向磁场互相排斥，逆向磁场互相吸引”原理不仅可以用于判断磁铁之间的相互作用效果，其还是我们用于描述磁场的变化、形成、形态的理论工具。 图3所示的运动正电荷会由于其所产生的磁场与其所进入的磁场左侧相互逆向、右侧相互同向而向左偏转。即是此电荷在磁场相互“吸”、“斥”的共同作用下作向左偏转运动。在此，“同向磁场互相排斥，逆向磁场互相吸引”原理不仅可以用于判断运动电荷的受力方向，还体现出了所受的力是一个磁场相互“吸”、“斥”的合力。 如图4，磁铁对环形线圈作靠向运动，试判断此环形线圈的感应电流方向。根据“作用与反作用原理”（楞次定律是“作用与反作用原理"在磁场中的一种表达方式，在运用“同向磁场互相排斥，逆向磁场互相吸引”原理判断、分析电磁感应现象时，可以直接利用更具普遍性的“作用与反作用原理”，可以不采用楞次定律的协助来理解电磁现象）可知，此环形线圈周围会感应出阻碍磁铁的磁场运动的感应磁场，结合“同向磁场互相排斥”原理分析可知，此环形线圈周围所感应出的感应磁场的方向的上部为逆时针方向，下部为顺时针方向，再经安培定则（右手伸直的拇指所指方向为电流方向，弯曲的另外四指所指方向为磁场方向）判断即可知道此环形线圈的感应电流方向。 2 同名磁极未必相斥， 异名磁极未必相吸 课本上的“同名磁极互相排斥，异名磁极互相吸引”、“同向电流互相吸引，反向电流互相排斥”这两个结论是互相矛盾的。如图5.如果按“同名磁极互相排斥，异名磁极互相吸引"来分析，则是:电磁铁上的A点与B、C两点是互相吸引的关系，B点与C点之间是互相排斥的关系。如果按“同向电流互相吸引，反向电流互相排斥"来分析，则是：电磁铁上的A点与B,C两点是互相排斥的关系，B点与C点之间是互相吸引的关系。同理，对于如图5一样放置的天然磁铁，如果按“同向电流互相吸引，反向电流互相排斥”（“电流方向”按“分子流假说”判断）或者“同向磁场互相排斥，逆向磁场互相吸引”来分析，我们都会认为：磁铁的上侧各处与下侧各处之间是互相排斥的关系，而上侧各处之间是互相吸引的关系，下侧各处之间也是互相吸引的关系(可按“分子流假说”分析，磁铁的侧面以外部分是整体中和的），这也是对“磁铁两极不可分割”的理解。图1所示的两块磁铁之所以表现出“异名磁极互相吸引”的样子，那是由于它们“同侧相吸”的原因，而它们的对角侧则是互相排斥的关系。 图6所示的两块磁铁，如果按“同名磁极互相排斥”来分析，它们应该是互相排斥的关系，但事实上它们是互相吸引的。此现象可按“逆向磁场互相吸引”来分析：由于两块磁铁的磁场的相互“接触”处相互逆向，所以两块磁铁会在磁场的互相吸引、“拼接”、收缩的作用下吸合起来。 在图7所示的情况下，两块磁铁会表现出互相排斥的现象，但假若我们以“同名磁端互相排斥”来理解此现象，那亦是不太妥当的。因为“磁端”上的A、B两处仍然是互相吸引的关系，它们之所以表现出互相排斥的样子，那是由于它们的上侧及下侧磁场与中部的“拼接”磁场之间互相排斥力相对较大的原因。 如图8,当小磁片Q沿虚线l向放置于平整桌面上的圆柱形磁铁K靠近时，K会向何方向滚动？如果按“同名磁极互相排斥，异名磁极互相吸引”来分析，则是:Q的N极对K的N极有一个方向指向左上方的排斥力，K应会向左滚动。如果按“同向磁场互相排斥，逆向磁场互相吸引”来分析，则是：Q的上侧磁场对K的右侧磁场有一个方向指向右上方(或正上方、近正上方)的排斥力，对K的左侧磁场有一个方向指向右下方的吸引力，K应会向右滚动。实验表明:当Q大约(具体与两磁铁有关)在虚线i与j之间的范围内靠近K时，K皆会向右滚动，“同名磁极互相排斥,异名磁极互相吸引”的提法是与实验事实相矛盾的；当Q大约（具体与两磁铁有关）在虚线i的左侧或虚线j的右侧的范围内靠近K时,K会受到向左滚动的力，“同名磁极互相排斥,异名磁极互相吸引”的提法此时巧合于实验事实，而“同向磁场互相排斥，逆向磁场互相吸引”原理皆能很好地解释实验事实，若将磁力较强的磁铁K，Q拿于手上做实验，可以明显地感受到上述磁力现象的力的“吸”“斥”关系。 如图9，如果按“同名磁极互相排斥,异名磁极互相吸引"来分析，则是：磁铁的N极与磁针的N极互相排斥，与磁针的S极互相吸引，所以磁针会顺时针偏转90。如果按“同向磁场互相排斥，逆向磁场互相吸引”来分析，则是:磁铁的左侧磁场与磁针的下侧磁场会由于相互逆向的原因而互相吸引、“拼接”，而磁场的“拼接”使得磁铁的右侧磁场与磁针的上侧磁场有了相互“接触”处，最后，磁针在其的上侧磁场与磁铁的右侧磁场的互相吸引、“拼接”、收缩等的主要作用下，顺时针偏转90°。在此，我们可以认识到“同名磁极互相排斥，异名磁极互相吸引”在一些情况下所作出的判断虽然是大致符合实验结果的，但其的分析过程仍然是不妥当的。 如果我们把通电环形线圈拉直，那其的两个磁极便不存在了，磁极显然是由磁场的“特殊流向”所围成的一种物理现象，就如空气的“特殊流向”形成了龙卷风，并不是龙卷风产生了空气，其与“电荷产生电场”的逻辑是不相同的，因自由电荷的存在而推想自由磁荷(磁单极)的存在的思想是值得探讨的。笔者认为磁极的提法容易使人理解为“磁极是一种物质”，为了更便于人们对电磁现象的准确理解，或许把磁铁的两个磁极合称为“磁陷流”或者其它名称更为合理，“磁陷流”的方向可以以“·”、“×”标注于磁铁两端，磁力线(现课本称“磁感应线")不是真正存在的线，它是对磁场的一种形象表达方式 ，磁力线可考虑改称为“磁场状态表达线(磁态线)”。
（责任编辑 唐汉民）
广西大学学报(自然科学版) 第24卷增刊 1999年6月 收稿日期:1999-03-20 〖百度翻译〗↓
Direction and function of magnetic field
Wu Shaodong (Liujing branch of Guangxi Hengxian post office, Liujing, 530313; 26 years old, male) abstract This paper puts forward the principle of "the same direction magnetic field repels each other, the opposite magnetic field attracts each other" and introduces its application. It holds that the formulation of "the same name magnetic pole repels each other, the different name magnetic pole attracts each other" is not appropriate, and puts forward the modification suggestions for "the magnetic pole". Key word magnetic field;magnetic pole;magnetic force Classification number O 482.51 Magnetic field is the medium of interaction of magnetic source, and the interaction effect of magnetic source is directly related to the direction of magnetic field. The principle of "mutual repulsion of the same direction magnetic field and mutual attraction of the reverse magnetic field" proposed in this paper is a more fundamental electromagnetic principle that can be used to judge and analyze the interaction phenomenon between magnetic fields According to the principle of field mutual attraction, a series of judgment methods such as Lenz's law, left-hand rule, right-hand rule, right-hand spiral rule, mutual exclusion of magnetic poles of the same name and mutual attraction of magnetic poles of different names can not be used. We know that the theory is a view summed up from the limited practice, "the same name poles repel each other and the different name poles attract each other" is a simple and long-standing consensus, the scientific community has been lack of deep argument for it, this paper thinks that its formulation is not appropriate, and puts forward suggestions for the modification of "magnetic pole". 1 The same direction magnetic field repels each other and the opposite magnetic field attracts each other We can judge according to the direction of the mutual "contact" of the magnetic field of the magnetic source, and analyze the interaction phenomenon between the magnetic sources, that is: "the same direction of the phase contact magnetic field repels each other, and the opposite direction attracts each other. As shown in Figure 1, two magnets with different magnetic poles close to each other will attract each other due to the mutual "contact" of their magnetic fields, i.e. "opposite magnetic fields attract each other". And the opposite magnetic fields will be "spliced" due to mutual attraction (in line with the experimental facts and the view that the magnetic lines are not intersected, as shown in Figure 2), and the "spliced" magnetic fields will be blown up due to the same direction of the magnetic fields (as shown in Figure 2). Here, we can realize that the principle of "mutual repulsion of the same direction magnetic field and mutual attraction of the reverse magnetic field" can not only be used to judge the interaction effect between magnets, but also be a theoretical tool for us to describe the change, formation and shape of magnetic field. The moving positive charge shown in Fig. 3 will deflect to the left due to the mutual reversal of the generated magnetic field and the left side of the entered magnetic field, and the mutual co direction of the right side. That is to say, the charge deflects to the left under the mutual action of the magnetic fields. Here, the principle of "mutual repulsion of the same direction magnetic field and mutual attraction of the reverse magnetic field" can not only be used to judge the force direction of the moving charge, but also reflect that the force received is a resultant force of mutual "attraction" and "repulsion" of the magnetic field. As shown in Fig. 4, the magnet moves towards the ring coil, and tries to judge the induced current direction of the ring coil. According to the "principle of action and reaction" (Lenz's law is an expression of "principle of action and reaction" in magnetic field, when using the principle of "mutual repulsion of the same direction magnetic field and mutual attraction of the reverse magnetic field" to judge and analyze electromagnetic induction phenomenon, the more universal "principle of action and reaction" can be directly used, and the assistance of Lenz's law can not be used to understand electromagnetic Phenomenon) it can be seen that the induced magnetic field around the ring coil will obstruct the magnetic field movement of the magnet. According to the analysis of the principle of "mutual repulsion of the same direction magnetic field", the upper part of the induced magnetic field around the ring coil is counter clockwise, the lower part is clockwise, and then through the ampere rule (the direction of the right extended thumb is the current direction, and the curved one In addition, the direction indicated by the other four fingers is the direction of the magnetic field). 2 The magnetic poles of the same name may not repel each other, and the magnetic poles of different names may not attract each other The two conclusions in the textbook are contradictory: "the same pole repels each other, the different pole attracts each other", "the same direction current attracts each other, and the reverse current repels each other". As shown in Figure 5, if the analysis is based on "the poles of the same name repel each other, and the poles of different names attract each other", then the relationship between point a, point B and point C on the electromagnet is mutual attraction, and the relationship between point B and point C is mutual exclusion. If the analysis is based on "the same direction current attracts each other and the reverse current repels each other", then it is: point a on the electromagnet is mutually exclusive with point B and point C, and point B and point C are mutually attractive. Similarly, for a natural magnet placed as shown in Figure 5, if we analyze it according to "mutual attraction of the same direction current and mutual repulsion of the reverse current" (judged according to "molecular current hypothesis" for "current direction") or "mutual repulsion of the same direction magnetic field and mutual attraction of the reverse magnetic field", we will think that the mutual repulsion relationship exists between the upper side and the lower side of the magnet, while the upper side and the lower side respectively There is a mutual attraction relationship between them, and there is also a mutual attraction relationship between them on the lower side (according to the analysis of "molecular flow hypothesis", the outside part of the side of the magnet is totally neutral), which is also the understanding of "the two poles of the magnet are inseparable". The reason why the two magnets shown in Fig. 1 show "attraction of different magnetic poles" is that they "attract each other on the same side", while their diagonal sides are mutually exclusive. If the two magnets shown in Figure 6 are analyzed according to the principle of "the poles of the same name repel each other", they should repel each other, but in fact they are attracted to each other. This phenomenon can be analyzed according to "mutual attraction of reverse magnetic field": because the magnetic field of two magnets is "in contact" with each other, the two magnets will be attracted together under the mutual attraction, splicing and contraction of the magnetic field. In the case shown in Figure 7, the two magnets will show mutual repulsion, but if we understand this phenomenon by "mutual repulsion of magnetic ends of the same name", it is not appropriate. Because a and B on the "magnetic end" are still attractive to each other, the reason why they are repulsive to each other is that the repulsive force between their upper and lower magnetic fields and the "splicing" magnetic field in the middle is relatively large. As shown in Figure 8, when the small magnetic disc q is close to the cylindrical magnet K placed on the flat table along the dotted line L, in what direction will k roll? If the analysis is based on "the poles of the same name repel each other, and the poles of different names attract each other", then the N-pole of Q has a repulsive force that points to the top left of the N-pole of K, and K should roll to the left. If the analysis is based on "the same direction magnetic field repels each other, and the reverse magnetic field attracts each other", it is: the upper magnetic field of Q has a repulsive force to the right magnetic field of K, which points to the upper right (or the upper right, near the upper right); the left magnetic field of K has a direction which points to the lower right, and K should roll to the right. Experiments show that when q is about (specifically related to two magnets) to K in the range between dotted line I and j, K will roll to the right, "the same name poles repel each other, and the different name poles attract each other" is contradictory to the experimental facts; when q is about (specifically related to two magnets) to K in the left of dotted line I or the right of dotted line j, K will be forced to roll to the left, "the poles of the same name repel each other, The expression of "attraction of different magnetic poles" coincides with the experimental facts at this time, and the principle of "mutual repulsion of the same direction magnetic field and mutual attraction of the reverse magnetic field" can explain the experimental facts very well. If the magnet K and Q with strong magnetic force are put on the hand for experiments, the "attraction" and "repulsion" relationship of the force of the above-mentioned magnetic phenomena can be obviously felt. As shown in Figure 9, if the analysis is based on "the poles of the same name repel each other, and the poles of the different names attract each other", then it is: the N poles of the magnet repel each other with the N poles of the magnetic needle, and the S poles of the magnetic needle attract each other, so the magnetic needle will deflect 90 clockwise. If the analysis is based on "the same direction magnetic field repels each other, and the reverse magnetic field attracts each other", it is: the left magnetic field of the magnet and the lower magnetic field of the magnetic needle will attract each other and "splice" each other due to the reverse reason, and the "splice" of the magnetic field makes the right magnetic field of the magnet and the upper magnetic field of the magnetic needle have "contact" with each other. Finally, the upper magnetic field of the magnetic needle and the right magnetic field of the magnet Under the main action of mutual attraction, splicing and contraction of the side magnetic field, the clockwise deflection is 90 °. In this paper, we can realize that the judgment of "the same name poles repel each other, and the different name poles attract each other" in some cases is generally consistent with the experimental results, but the analysis process is still inappropriate. If we straighten the electrified ring coil, its two magnetic poles will not exist. The magnetic pole is obviously a physical phenomenon surrounded by the "special flow direction" of the magnetic field. For example, the "special flow direction" of the air forms a tornado, not a tornado produces air, which is different from the logic of "electric field generated by charge". Because of the existence of free charge, we can deduce free magnetic field The idea of the existence of charge (monopole) is worth exploring. The author thinks that the formulation of magnetic pole is easy to be understood as "the magnetic pole is a kind of substance". In order to make it easier for people to understand the electromagnetic phenomenon accurately, it may be more reasonable to call the two magnetic poles of a magnet "magnetic notch" or other names. The direction of "magnetic notch" can be marked on both ends of the magnet with "·" and "×". The magnetic field line (now called "magnetic induction line" in textbooks) does not really exist In, it is an image expression of magnetic field. The magnetic field line can be considered to be renamed "magnetic state expression line (magnetic state line)".
(Responsible editor Tang Hanmin)
Journal of Guangxi University(Natural Science Edition) Volume 24 supplement June 1999 Date of receipt:1999-03-20 ↑〖百度翻译〗 |