Question about cgs vs SI units in the context of the Debye Length

[ehchandlerjr]

TL;DR

Would have thought cgs and SI would give the same debye length when converted to the same units, but they don't. What is the physical meaning difference, and how do I know which equation to use.

Hello - I am trying to understand the physical meaning the undergirds the Debye length as it pertains to different unit systems. I understand that fundamentally its the distance at which the distribution of ions doesn't differ by more than the effect of k_B*T from the rest of the solution, plasma, whatever. But what I don't understand is why cgs and SI can give such radically different values. If they just came out as different values with different units, whatever. But I can convert both to meters, and get completely different numbers. I'm writing a review article, and this isn't really my field, but all the papers I came across had different expressions, and I dug a little deeper, and found this confusion, and I don't know how to resolve it. I'd just be somewhat vague, but I don't even know how to kindof defend the choice of one or the other equation, other than saying, "everywhere else I used SI," which isn't a very good answer.

HELP!

 

[DrClaude]

Equations will be different when using CGS compared to SI, so one cannot simply change the units of the values used. Could this be source of your problem?

https://en.wikipedia.org/wiki/Gaussian_units

 

[Lord Jestocost]

TL;DR Summary: Would have thought cgs and SI would give the same debye length when converted to the same units, but they don't. What is the physical meaning difference, and how do I know which equation to use.

Hello - I am trying to understand the physical meaning the undergirds the Debye length as it pertains to different unit systems. I understand that fundamentally its the distance at which the distribution of ions doesn't differ by more than the effect of k_B*T from the rest of the solution, plasma, whatever. But what I don't understand is why cgs and SI can give such radically different values. If they just came out as different values with different units, whatever. But I can convert both to meters, and get completely different numbers. I'm writing a review article, and this isn't really my field, but all the papers I came across had different expressions, and I dug a little deeper, and found this confusion, and I don't know how to resolve it. I'd just be somewhat vague, but I don't even know how to kindof defend the choice of one or the other equation, other than saying, "everywhere else I used SI," which isn't a very good answer.

HELP!

Maybe, the following might be of help (from the University of Maryland):

Converting between SI and Gaussian units​

 

[pines-demon]

SI and cgs units can have different values even for observables with no units. For example the magnetical susceptibility $\chi$ is given in SI by $\mathbf M = \chi \mathbf M$ but in the usual cgs (Gaussian) units it is given by $\mathbf M = 4\pi \chi \mathbf H$. So in SI, superconductors have $\chi=-1$ and in cgs $\chi=-\frac{1}{4\pi}$.

THAT SAID: I think that the Debye length should be the same in cgs and SI. What values are you using can you provide an example?