Talk:Electric susceptibility

Isn't this just the low velocity approximation?[edit]

Isn't it less pleasant in relativstic materials? I've encountered mention that D = \epsilon_0 E + P is a nonrelativistic limit. Isn't the full expression something like D = \epsilon_0 E + P + (1/c) [(v/c) x M] where x is the cross product? I seem to recall if you try and eliminate M and P from the expressions for D and H you end up with an infinte series in increasing powers of gamma squared, where gamma is as it usually is in special relativity i.e. gamma = 1/ sqrt{1-v^2/c^2)

Counterpart for H is H = B/mu_0 - M + c [(v/c) x P]

what is it?[edit]

I would say that susceptibility measures how polarizable a dielectric medium is. How susceptible it is to being polarized by an electric field. The greater the susceptibility/polarizability, the more useful it is for making large-value capacitors. Or, you could say, when a material is used to make a capacitor, the greater the susceptibility, the greater the capacitance. Something like that.

Pfalstad 19:52, 2 January 2006 (UTC)[reply]

Thanks, Paul. I'll work something out along those lines,--Light current 20:42, 2 January 2006 (UTC)[reply]

change log[edit]

Mostly just reworded a few things. eg removed the phrase "makes the integral disappear" as the language was a bit causual. The integral hasn't disapeared, we have changed the basis!

Also changed the phrasing of dispersion properties. Do people think a reference to group velocity is required? Also I think there might be too much of a seperation between susceptibility and relative permiability, it might be confusing. They walk hand in hand. Although you dont want people thinking they are the same object, they do differ by unity! Timwilson85 18:00, 21 September 2007 (UTC)[reply]

Restoration or redirect ?[edit]

Almost a year ago, I replaced this article by a redirect to permittivity, mergeing contents there. Now, User:Headbomb restored the former text, arguing

important enough to warrant it's own article.
encourages expansion, like Magnetic susceptibility

Please let us discuss this change.

Pro redirect. Of course the dielectric susceptibility is important. However, importance is not a criterion for or against a redirect. Valid reasons for redirects are listed in Wikipedia:Redirect. Among them:

Related words.
Sub-topics or other topics which are described or listed within a wider article.

Now I would argue that permittivity and susceptibility are two names for almost the same thing, as they are connected by an absolutely trivial formula that defines one in terms of the other. In my understanding, it's just a burden of the past that physicists and electrical engineers have to learn both words. Explaining them in two different articles adds to the burden; it is more likely to cause confusion than to help anybody. Duplicating material in two articles makes maintenance more difficult and discourages editors who hopefully one day will streamline the current text.

I fully agree that electric susceptibility should be explained in similar depth as magnetic susceptibility. However, this does not depend on the lemma; it can as well be done in the permittivity article. From a theoretical physics point de vue, it would be nice to have permittivity redirect to susceptibility. But outside theoretical physics, "permittivity" happens to be more frequently used than "susceptibility". Therefore, I would strongly advocate reverting Headbombs recent revert. -- Marie Poise (talk) 16:33, 6 November 2010 (UTC)[reply]

Obviously I am against that. We have articles on both permeability and magnetic susceptibility, and their connection is as trivial as that of permittivity and electric susceptibility. Obviously the two quantities are intimately related, but they are not quite the same. There's no reason why we can't bring this article to something more comparable to magnetic susceptibility, especially if we expand on non-linear materials. Headbomb {talk / contribs / physics / books} 17:17, 6 November 2010 (UTC)[reply]

Indeed, the connection between permeability and magnetic susceptibility is so trivial that it makes no more sense to maintain those two articles than their electric analogues. Obviously I am for merging them as well. -- Marie Poise (talk) 23:08, 6 November 2010 (UTC)[reply]

I made a merger proposal for the magnetic case. I suggest we continue this discussion on Talk:permeability (electromagnetism). -- Marie Poise (talk) 23:25, 6 November 2010 (UTC)[reply]

Local Field[edit]

What is the local field "that produced the polarization"? How does it differ (in its meaning) from E? 84.227.254.143 (talk) 04:33, 1 April 2014 (UTC)[reply]

Eh?[edit]

The greater the electric susceptibility, the greater the ability of a material to polarize in response to the field, and thereby reduce the total electric field inside the material (and store energy).
I'm sure that anyone who fully understands this concept will be able to parse this sentence. I'm not sure that anyone else can. Twang (talk) 13:53, 26 October 2014 (UTC)[reply]