I've been thinking about a similar yet not the same idea as the OP of this elderly thread. I don't know how to properly interact with that thread as a obviously do not have an answer nor am I allowed to comment, so I am posting a new question.
Said OP wants to excite the strings of an electric guitar with an electromagnet, using it kind of as a new sort of reverb.
I understand that a string (or anything) made of metal would be pulled twice in a full sine cycle since the interaction between a magnet and a piece of metal is always "pull", never "push", so both positive and negative maximum current in an electromagnet will cause it to pull, leaving the fundamental frequency rather untouched on average (but exciting the first harmonic, but that's a different question).
What I do not understand is, why, that being said, the EBow oviously works quite well and excites the fundamental frequency, apparently without any octave dividing as suggested in the aforementioned thread. I guess it is because, as in a speaker driver, there are permanent magnets involved, but then it seems as the answers of said thread are not correct, at least the one suggesting using the driver coil of a speaker. Also, I'm interested in a more detailed explanation, since me as a non physicist, I'm getting headaches trying to figure it out in my head.
