Physics Asked on December 8, 2020
What are the maximum safe acute and chronic magnetic field intensites for a human being?
I imagine with sufficiently intense fields the Lorentz force is going to cause issues with nerve impulses, but at what field intensity do these issues occur? What specifically does the field interfere with? Can chronic exposure to lower intensity fields also cause issues? Which parts of the nervous system are most impacted by these fields?
Can fields of lower intensity cause other problems that make this nerve issue irrelevant?
The WHO has some guidelines, but this seems more related to MRI tech safety and doesn’t really go into the biophysics of the situation. Additionally, they talk about issues which appear while moving through the fields, which seems to imply they’re talking about low frequency field variation because an MRI field isn’t spatially uniform.
I don't know anything about long term health effects. The guidelines mentions that noticeable effects begin around 2 Tesla. This is in line with what I have heard. On the other hand, this mentions public exposure limits of 40 milliTesla. Here is a paper from the NIH that discusses health effects of neodynium magnets, but doesn't mention field strength.
Keep in mind that 2 Tesla is an extremely strong field. You are not likely to find it except right next to a large superconducting magnet. Or possibly between the poles of an exceptional research grade non-superconducting electromagnet.
Keep in mind that even if a strong magnetic field has no direct effect on a normal person, it could be harmful to a person with, say, a pacemaker.
Also, a field that strong can turn a stray piece of metal into a dangerous projectile.
Motion in a magnetic field matters because it exerts a force on moving electric charges. $vec F = q vec v times vec B$. This means for example, a copper wire feels no force, unless an electric current is moving inside it. In people, nerve impules are small brief currents. This may be why people feel effects in large fields. Walking means charges are moving faster.
Answered by mmesser314 on December 8, 2020
Get help from others!
Recent Questions
Recent Answers
© 2024 TransWikia.com. All rights reserved. Sites we Love: PCI Database, UKBizDB, Menu Kuliner, Sharing RPP