Debye length for vacuum

1. Jun 12, 2015

eftrsd

What is the correct value for the vacuum Debye screening length?

2. Jun 12, 2015

ZapperZ

Staff Emeritus
Can you cite a reference for the existence of "vacuum Debye screening length"?

This term makes no sense, because, by definition, the screening length is caused by the presence of other charges (such as a plasma), meaning it is NOT a vacuum. One may consider the plasma to be in a vacuum background for calculation purposes, but this is far from being a vacuum.

Zz.

3. Jun 12, 2015

eftrsd

Thanks Zz for replying. I should have said "air vacuum" which is not the absolute vacuum, of course.
My question is in fact related to a specific problem: The electrostatic potential of a dielectric spherical cavity due to point charge located within it. There are two solutions: one is for Debye length= 0 and one for otherwise. If the cavity is embedded in air\vacuum.. which solution should one consider?
eftrsd.