Radar Reflection: Charged vs Non-Charged Objects

[faiello]

A question I’ve been trying to figure out for the last 5 years with a friend of mine:

Would the radar reflection from an object be different if the object is charged or not charged?

 

[berkeman]

Welcome to the PF.

Summary:: Does charge affect the reflectivity of radar?

A question I’ve been trying to figure out for the last 5 years with a friend of mine:

Would the radar reflection from an object be different if the object is charged or not charged?

Not for any reason that I can think of. Do you have a reason to believe it would?

 

[DaveE]

For classical electromagnetism, you will want to learn about superposition early on in your studies.

Unless you have specific concerns about the materials involved, then no.

However, I can imagine that if there is an enormously large amount of charge (more than you're likely to ever see) then yes. If, somehow, you could strip a conductor of all of it's conduction band electrons, then it may act like an insulator. If you could add lots of electrons (like a static charge) to an insulator, then they would interact with the radar EM wave. In the real world, this doesn't happen.

 

[sophiecentaur]

then it may act like an insulator.

Not just that - it would be charged to millions of GigaVolts so not easy to measure its resistivity.

 

[Andy Resnick]

Summary:: Does charge affect the reflectivity of radar?

A question I’ve been trying to figure out for the last 5 years with a friend of mine:

Would the radar reflection from an object be different if the object is charged or not charged?

Presumably you mean that the object has excess free charges (or not). Radar reflects off of the ionosphere (a plasma), which is one example of your question:

https://en.wikipedia.org/wiki/Over-the-horizon_radar

 

[sophiecentaur]

Presumably you mean that the object has excess free charges (or not). Radar reflects off of the ionosphere (a plasma), which is one example of your question:

https://en.wikipedia.org/wiki/Over-the-horizon_radar

However, a plasma is more or less neutrally charged so it's probably more like a conductor than an insulator - there being so many (almost equal numbers of) free electrons and ions around.

I think the question must be mainly about how you can affect the conductivity with an external field.

Perhaps (as usual) we should ask the OP about the context of this question which has almost certainly come out of some practical situation, involving radar. Perhaps involving lightning? Whatever, it would not be straight forward or ideal conditions.

 

[hutchphd]

My guess is that prospect of a radar "cloaking device" may be involved.
I would mention that light is in the same spectrum as radar (quite a bit shorter wavelength ($10^4$ at least) and I don't know of any visual phenomena directly caused by charging the illuminated object to high potential.

 

[sophiecentaur]

When someone asks an open ended question it can take many posts before the real meat of the question gets revealed.
I often wonder if people imagine we have second sight on PF.

 

[Ibix]

I often wonder if people imagine we have second sight on PF.

Mixing us up with PsychicsForums.