Emberjs: Save persistent data from remote API to local storage

I am still a little confused about the way Ember fetches data from remote API and save them in the browser.

So I have created a REST Adapter to get sets of records with an Ajax call, a serializer, and the corresponding model. Suppose they are posts, and I have successfully made a posts index page where the user can click on any post to get into the post detail page.

The Ajax call happens on the index page, and using the Ember inspector, it is clear that all the records are stored in the local store.

But when I click the "back link" which is available on every post detail page, it does redirect to '/posts/' but it seems to make the ajax call again. So all the posts are fetched from the API once again making the page much less responsive.

Here's my questions:

1. How does that part of Ember work and how do I make Ember simply get the records from the local store without making Ajax call again and again? (unless the user refresh the browser)
2. If I make a GET request to 'post/1' , no data will be available since in this route no Ajax call should be made. But how do I let the data show? Should I set up another REST adapter for individual post or is it possible to get the record from the local store if an Ajax call has been made?

Hope that makes sense and thanks in advance!