Research Assistant long-distance Is it reasonable to ask for a research assistant position (field of economics) over email to a professor who doesn't live in my country/city?
I'm assuming that you want to stay where you are if accepted and carry out the research remotely from the professor and any of his/her research groups. 

Whether reasonable or not, it is possible to ask. But also expect skepticism. If you don't know the person already then it isn't very likely to be accepted, but again, it is possible. But your mail would need to present interesting reasons why the professor would want to accept you. 

A professor who meets regularly in seminar with groups of students would have more trouble with such a plan than one who prefers to meet individually. Computer mediated communication is pretty common now and as the field doesn't require lab work, I see no absolute block. But if the research requires working with human subjects then you have to figure out how and where to do that, complicated also by the rules and regulations, perhaps, of two places, not just one. But a lot of small groups work collaboratively while the members stay in their separate countries, meeting only occasionally. 

But, it is easy to send an email, a bit harder to make it interesting, and possibly harder still to be convincing. But not impossible. 

It is also possible for people working remotely to meet now and again, whether through travel direct to the other place or at a conference or other professional meeting.