除了@Michael[优秀的答案][1],记住,磁场(就像电场)下降的距离平方的倒数。举个例子中使用的磁铁LHCb实验在欧洲核子研究中心。这是一个大的偶极磁铁最大场强有点高于1 t(地球磁场是平均约40 - 50 uT强)。这所说的相似类别的磁铁用于弯曲的质子束流继续他们在大型强子对撞机的圈子(磁场强度约为7.7 t)。如下图中可以看到,在5米的距离已经减少到20吨(与标签3),通过约一千倍。这仍然是比地球磁场强一千倍,但连续工作授权人已经允许在200吨。[![描述][2]][2]的[技术设计报告LHCb磁铁][3]。另外你应该记住这个实验(实际上整个LHC)约100米的地下,所以磁铁的磁场基本上是无法觉察的在地面上,甚至对上面。——有,然而,其他对环境的潜在影响:加速器消耗大量的电力((对200 MW的峰值)[4])。 Generating this power has an impact on the environment, as already mentioned. Materials can get activated when being irradiated by the beams. These materials (most notably anything made of iron) are kept under radiological supervision and can only be taken out of the underground area if there is no radioactivity detectable (anymore). One does not want to contaminate the environment with radioactive materials. Some detector components contain substances which are regulated because of their impact on the environment (because they are greenhouse gases). The LHCb RICH1, for example, contains perfluorbutan (C4F10). The amounts are negligible on a global scale, though. The [beam pipe at the interaction regions consists of Berryllium ][5], whose dust is toxic. Special care is needed when working around it (and probably when dismantling it at some point). [1]: //www.hoelymoley.com/a/14025/12645 [2]: https://i.stack.imgur.com/rTPXi.jpg [3]: http://lhcb-magnet.web.cern.ch/lhcb-magnet/TDR/html/lhcb-magnet.html [4]: https://home.cern/about/engineering/powering-cern [5]: http://beryllium.eu/beryllium-beam-pipe-used-in-centrepiece-of-cern-large-hadron-collider/