I What Prevents Electrons from Expanding Radially in White Dwarfs?

[MarkL]

From Wikipedia : White dwarfs resist gravitational collapse primarily through electron degeneracy pressure

What prevents electrons from expanding radially through the space between the ions (carbon, say)?

 

[mathman]

Gravity?

 

[Ibix]

No, electromagnetism I think. If electrons were to migrate outwards the inner part would acquire a positive charge and the outer part a negative charge, which would rapidly become a very strong restoring force bringing back neutrality.

It is possible that you might find that there is a slight variation in local net charge with depth as various different effects push or pull slightly differently on different particles. I don't know for certain. You won't get a pure nucleon core withan electron atmosphere, though.

 

[MarkL]

bring back...or expand till

 

[Vanadium 50]

Huh?

 

[MarkL]

the answer above was: "restoring force bringing back neutrality"
Does this mean,
bring back (to neutrality) = zero electron expansion or prevents electron expansion
or
expand till (neutrality) = electrons expand till force equals fermi pressure = some electron expansion

 

[Ibix]

the answer above was: "restoring force bringing back neutrality"
Does this mean,
bring back (to neutrality) = zero electron expansion or prevents electron expansion
or
expand till (neutrality) = electrons expand till force equals fermi pressure = some electron expansion

As my last paragraph said:

It is possible that you might find that there is a slight variation in local net charge with depth as various different effects push or pull slightly differently on different particles. I don't know for certain.

I'm not sure what question you are asking that isn't answered by that.

 

[MarkL]

Your last paragraph would never influence an electron with enough pressure to support the mass of a star.
Your first paragraph, however, is spot on and intuitive.
And I'm good...thanks for your response.