Landships II

An alternating magnetic field would induce electrical currents in any conductive material entering it - possibly heating it to incandescence if of sufficient amplitude. A fixed polarity magnetic field will resist the passage of a conductor through induced current (principle used to dampen the oscillations in some beam balances). A strong enough field could possibly both halt a projectile and vapourise it.

You may recall earlier discussion of Giulio Ulivi's "Radiobalistica" - that may have some factual foundation in using high-powered high frequency radio (radar waves we call them now, then all lumped together under "infra red") to induce the same sort of effects you see if placing an incandescent light globe or a CD or whatever metallic items in a microwave oven (not a recommended experiment - find demonstrations on YouTube instead - or some of the stuff at http://amasci.com/weird/microwave/voltage1.html).

All sorts of people (such as Nicola Tesla) were experimenting most enthusiastically with all kinds of radio and magnetic effects, often at most prodigious power levels, from before 1900.

Ionisation? Probably not though I'm sure ionisation was, indeed, experimented on well before 1907. Cathode rays (electron beams) go back to 1875 or before.

You already know or have seen that a conductor moving in an electrical field (or vice-versa) will have electrical current generated within it. That's how generators, alternators, magnetic pickups, turntable magnetic cartridges and many more devices all work. That current creates its own magnetic field which reacts with the field of the inducing magnet (basically it opposes the inducing field). It actually works best if the conductor is non-magnetic. Don't take my word for it - just use a search engine and look up magnetic damping which is the simplest application and closest to producing effects such as those you are talking about.

If the induced current (eddy current - another search term) is high enough, it will generate considerable heat by way of the electrical resistance of the material through which it flows. I have little doubt a magnetic field strong enough to stop a rifle bullet (and maybe even turn it into incandescent vapour) could be generated. I have little doubt experiments were conducted with this in mind, long ago. I have little doubt they were completely impractical because the power requirements would be huge, the "protected" area tiny and, once upon a time, people allocating or subscribing funding for such research had little or no independent idea of the physics involved and/or the scaling factors associated with turning a small-scale demonstration into a practical device.

As also mentioned, a microwave pulse of sufficient power and focus could doubtless achieve a similar result but I am less confident that is achievable, even today. But the Gunn diode from the target acquisition radar of a cold-war era jet fighter, combined with a suitable wave guide, could certainly make a mess of a small rodent, especially if he was wearing a studded collar.

Alas, the popular technology and science journals have always been full of such ideas that capture the imagination and, in their time, are much discussed and enthused over. Very few of them become real-world applications, many of them, perhaps most of them, remain possibilities for future times and circumstances. Also, in 1905/07, the Kaiserlich Deutsches Reich was pushing all sorts of frontiers to assert its scientific and technological pre-eminence and there was much speculative research. In its 47 years, 1871 to 1918, I understand it amassed more Nobel Prizes than all of the other Great Powers combined.