Complete screening of an Electric field?

  • #1
Hi,
I have difficulty understanding the term screening.
Screening is reducing of the electric field, as far as I have understood until now.

1. Why does screening occurs? Is it due to collective interaction of plasmons?
2. If we have a slow electric field, will screening occur or will it not occur? Same question for fields that varies a lot.
3. If the electric field is reduced as much as possible, does that means that screening = 0 and that it is complete?

Thank you.
 

Answers and Replies

  • #2
berkeman
Mentor
59,009
9,104
Hi,
I have difficulty understanding the term screening.
Screening is reducing of the electric field, as far as I have understood until now.

1. Why does screening occurs? Is it due to collective interaction of plasmons?
2. If we have a slow electric field, will screening occur or will it not occur? Same question for fields that varies a lot.
3. If the electric field is reduced as much as possible, does that means that screening = 0 and that it is complete?

Thank you.
Welcome to the PF. :smile:

Do you mean Electric field shielding, like with a Faraday Cage? https://en.wikipedia.org/wiki/Faraday_cage
 
  • #3
Thank you :)
No, actually I am looking at electric field screening for solids (metals). I read Wikipedias page about it but I still dont get it.
 
  • #4
Chandra Prayaga
Science Advisor
650
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If you make a hollow inside a metal block and sit inside it, you are shielded from any electric fields outside. For a static electric filed, the screening is complete.
 
  • #5
If you make a hollow inside a metal block and sit inside it, you are shielded from any electric fields outside. For a static electric filed, the screening is complete.
Could you answer my questions as in 1, 2 and 3? I dont understand where the hollow comes from. And when the screening is complete.
 
  • #6
Chandra Prayaga
Science Advisor
650
149
OK. We may be talking of totally different things. Could you please desctibe what you mean by the word "screening?". Perhaps if you could give us the reference to the Wikipedia pages you have read, we could get the context.
 
  • #7
OK. We may be talking of totally different things. Could you please desctibe what you mean by the word "screening?". Perhaps if you could give us the reference to the Wikipedia pages you have read, we could get the context.
I am looking at electric field screening for solids (metals). Thomas-Fermi screening. I dont know if its the same or two different things though...
 
  • #8
Chandra Prayaga
Science Advisor
650
149
Thanks. This is a topic on which I have no views.
 
  • #9
marcusl
Science Advisor
Gold Member
2,754
405
No, plasmons are something else, this deals primarily with, e.g., the free electron gas in a metal. An externally applied electric field causes electrons to move around in such a way as to minimize the energy in the bulk. The configuration of electron density is such that the externally applied field becomes negated on the other side of this layer. An analogous thing happens to a charge that is introduced into the solid. A change of density in a spherical layer forms to counteract it. These are the screening effect that you are referring to.
 
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