Radar reflection

  • Thread starter faiello
  • Start date
  • #1
faiello
1
0
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?
 

Answers and Replies

  • #2
berkeman
Mentor
64,151
15,365
Welcome to the PF. :smile:

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?
 
  • #3
DaveE
Science Advisor
Gold Member
2,832
2,482
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.
 
  • #4
sophiecentaur
Science Advisor
Gold Member
27,834
6,335
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.
 
  • #5
Andy Resnick
Science Advisor
Education Advisor
Insights Author
7,755
2,679
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
 
  • Like
Likes DaveE and sophiecentaur
  • #6
sophiecentaur
Science Advisor
Gold Member
27,834
6,335
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.
 
  • #7
hutchphd
Science Advisor
Homework Helper
2022 Award
5,355
4,516
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.
 
  • #8
sophiecentaur
Science Advisor
Gold Member
27,834
6,335
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.
 
  • #9
Ibix
Science Advisor
Insights Author
2022 Award
10,098
10,669
I often wonder if people imagine we have second sight on PF.
Mixing us up with PsychicsForums. :oldgrumpy:
 

Suggested for: Radar reflection

  • Last Post
Replies
15
Views
784
  • Last Post
Replies
2
Views
295
  • Last Post
Replies
10
Views
479
  • Last Post
Replies
25
Views
3K
Replies
1
Views
400
Replies
5
Views
799
Replies
3
Views
645
  • Last Post
Replies
6
Views
583
  • Last Post
Replies
3
Views
597
Replies
1
Views
498
Top