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I have a hover tanks zipping around in my setting. None of these vehicles utilize physical optical view ports. All information is gathered from sensors. As such there are a multitude of cameras, radars, lidars etc.

My hover tanks need to use chaff to defend themselves against enemy radar and radar guided weaponry. In modern day aerial combat, chaff is used to defend against radar guided missiles. However modern radars use doppler shift to distinguish between the speed of a chaff cloud, and the speed of a jet. Thus, reorientating the seeker onto their target. Consequently, chaff seems to work better on naval vessels as part of a layered defense.

Though my hover tanks are fast, they aren't jet like fast. However, they do have a few advantages. They have the ability to suspend certain types of (sci fi) particles in the air around them up to a certain speed. They already use these exotic particles as a glorified particle shield. By the same extension, I have a cloud of particles that can be disseminated into the air around the tank that are capable of interfering with enemy radar waves. These particles can also be suspended/held up around the hover tank up to certain speeds, reducing the effectiveness of things like doppler shift.

This particle like cloud acts like chaff in that it scatters radar waves and causes erroneous returns or simply reflects radar waves off completely. While not perfect enough to stop a radar from seeing an enemy tank or a human from interpreting that there may be something out there, the resolution is low enough that it can cause warhead seekers and targeting computers to have a tougher time.

Why does my suspended exotic particle cloud reflect/scatter or jam radar waves?

As I understand, chaff works because they're cut in a fashion that works against radar waves and their lower frequency/ longer wavelengths. The actual metalic nature and its shape helps damage a radar's return capability. Chaff is essentially in the physical/larger domain of jamming techniques.

This particle cloud system will be working on a far smaller scale than chaff in terms of size. Essentially operating on the electromagnetic spectrum. At present I am unsure if things in the particle or electromagnetic scale are capable of reflecting or redirecting wavelengths in a way chaff does. Ideally an answer, answers the question in that scale/realm.

Lastly, any answer doesn't have to be rooted in hard science. Plausible/sci-fi will be just as effective considering the answer will focus on what the particle cloud is doing. Suspending the particles is already a stretch from reality.

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  • $\begingroup$ There is no way in this universe to reflect or absorb all radar frequencies; you always design your countermeasures to work against what the enemy is likely to use, not against everything that he may use if he knew beforehand what countermeasures you have available. For example, chaff works for the specific wavelengths against which is it supposed to work. $\endgroup$
    – AlexP
    Nov 8, 2022 at 14:26
  • $\begingroup$ I'm unclear about what the question is. You seem to be asking us why it does something but without telling us exactly what it does or the circumstances under which it's operating. Can you clarify. $\endgroup$
    – Escaped dental patient.
    Nov 8, 2022 at 17:25
  • $\begingroup$ Is there a question here? How chaff reflects radar is well understood. Why can't you use that explanation? Please remember that, per the help center, brainstorming is strongly discouraged. $\endgroup$
    – JBH
    Nov 8, 2022 at 19:20
  • $\begingroup$ @AlexP Correct. In this case the particle cloud is working on wavelengths that the enemy may use, since this is for military applications at a ground level. Functionally it works like chaff in that its configured pre-packaged against certain wavelengths. Just to expand, depending on the type of radar emitter and frequency, different tubes with particles detonate like a confetti cannon and are then suspended around the tank. But a single tube, a single particle cloud will be optimized for a certain shallow range. Just like normal chaff is. $\endgroup$
    – FIRES_ICE
    Nov 8, 2022 at 21:51
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    $\begingroup$ @AngryMuppet Essentially, I have a particle cloud that is mimicking the effects of chaff against radar waves. There's an explanation for why chaff works. I want to achieve the same result but using a particle cloud. The explanation for why a particle cloud is scattering radar waves like chaff is the question I'm posing. Right now the particle cloud can be made up of anything technically. Different particles will obviously work in different ways when it comes to reflecting radar $\endgroup$
    – FIRES_ICE
    Nov 8, 2022 at 21:59

4 Answers 4

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Do you know why gold (and also copper) has its peculiar yellow color instead of the more common grayish hue typical of most metals?

It's because of plasmon resonance: the surface electrons, excited by light, have a peculiar resonance that favors the reflection of frequencies in the yellow range of the spectrum.

And do you know why certain birds exhibit metallic colors on their feathers? Because of resonance in their microstructure.

In your case something similar can happen: the cloud of particles resonates with the radar wavelengths in a way that prevent them from bouncing back to the receiver.

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You don't necessarily need magical soft-scifi particles... plasma stealth plausibly exists in the real world using regular flavors of matter.

When electromagnetic waves, such as radar signals, propagate into a conductive plasma, ions and electrons are displaced as a result of the time varying electric and magnetic fields. The wave field gives energy to the particles. The particles generally return some fraction of the energy they have gained to the wave, but some energy may be permanently absorbed as heat by processes like scattering or resonant acceleration, or transferred into other wave types by mode conversion or nonlinear effects. A plasma can, at least in principle, absorb all the energy in an incoming wave, and this is the key to plasma stealth

The nice thing is that plasma stealth can be used against visible light too... the same basic technique can be used against LIDAR as well as RADAR, though something that worked against one may not work against the other

Generating and confining a (probably nonthermal) plasma cloud around your tanks is left as an exercise for the reader. It would definitely not be easy, but it doesn't require handwavium.

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    $\begingroup$ Ugh, surrounding your tank with a sheet of blindingly luminous flame seems a rather counter-intuitive way to hide it... I mean, the tank is literally a powerful light source! Who needs radar? $\endgroup$
    – AlexP
    Nov 8, 2022 at 18:48
  • $\begingroup$ @AlexP surprise has a quality all of its own. Who is going to be prepared to admit to their superiors that they just lost a company of armored vehicles to what was apparently some kind of open-air disco. $\endgroup$
    – Starfish Prime
    Nov 8, 2022 at 19:10
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Your particles are drones. They actively jam radar.

The particles around your tank are suspended by themselves. The tanks is cloaked in a flock of microdrones. These microdrones both reflect radar but more importantly jam radar. Multiple assembled drones form a virtual antenna and broadcast radar waves of the types detected incoming. These are broadcast in all directions, confounding those trying to use radar to pinpoint the tank location and direct fire. Drones also have infrared lasers over a broad wavelength, confounding overhead passive sensors trying to locate the tank via heat signature.

Sensors on the tank augment those of the drones. Drones can charge themselves using an induction pad on the tank and at any given time a few are taking a break and charging up there.

Some of the drones have sensor capacity and leave the flock to serve the tank as eyes in the sky, increasing "visual" range.

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Perhaps your particles absorb or reflect radar. If they are round and reflective, the reflected image would seem to break apart.

Alternatively, perhaps the radar locks onto particle clouds, directing any missiles to where the hover tank was just at, so the tank must constantly be moving in order to dodge incoming missiles.

https://en.wikipedia.org/wiki/Chaff_(countermeasure)

According to Wiki, it does look like chaff is still a current part of warfare used specifically to distract and misdirect missiles. I think you are on the right track.

The targets send a broadcast to bounce off the chaff to make it look more active, referred to as JAFF or CHILL. This is probably ideal for your purposes.

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