My full name on passport is Amir Hisham Ahmed Al-Attraqchi (first three names + surname). In my publication, I only used the first and the surname (i.e. Amir Al-Attraqchi). Is it going to be a problem proving the publications to be mine?
I'm worried about proving this when applying for new universities, promotions or fellowships
Arguably, you did the right thing.
In my experience, too many names tend to confuse people. I have 2+2 and I saw my name being cited in lots of different ways, without any consistency.
One thing that really helps to prove that you are the same person is to set up an ORCID and use it in the publications.
None of the names listed in my publications are identical to the one in my passport or birth certificate. In fact, I have one or two diplomas where this is also the case.
When I applied for an honourary post in a university in China, they questioned this exact discrepancy and required me to show that my diplomas and publications were mine. (I've found out that the idea of a name is different there than in my home country.) I managed to convince them by presenting a statutory declaration (or affidavit, for those outside the Commonwealth) to that effect.
This might work in your case.
Good luck.
Note: Edited to explain what a statutory declaration is. Thanks for the link, @Nij.
It shouldn't be a problem at all. It's very easy to believe that Omar Husham Ahmed Al-Attraqchi and Omar Al-Attraqchi are the same person because it's very common to abbreviate names in that way. I and most of my British co-authors have three names; we only use the first and last of them on our papers.
People's legal name and publication name often differ much more substantially than yours. For example, in many western cultures, women often change their name when they get married. Female academics often continue to publish under their birth name so all their papers appear with the same name. I don't think they have to spend any time convincing people they wrote their papers.
That is very unlikely unless the name you choose to use for publication is very common in the field that you work in. In the US, a person named "John Smith" might need to distinguish himself in a field with a lot of practitioners. Otherwise, I see no problem.
Another consideration is how formal you want to be. If you are a young academic building a reputation, it might be advantage to err on the side of formality rather than the opposite. As you grow into the profession and meet lots of people, etc., you can move to a less formal name if you would then want to. Some academics I know insist on being represented in print very formally so as to build a "brand". In person they are not formal at all.
However, since names like el Masri, indicate places, Timmy el Masri might not be very distinguishing (assuming lots of Egyptians are named Timmy). So think about that. Icelandic (and old Norwegian) surnames names are traditionally also not especially distinguishing: Lavransdottir (daughter of Lavrans).
I share a real name with another academic. Fortunately he is not in the same field. We are unlikely to be confused. An internet search on our common name can confuse people, however.
As everyone has said, publication names don't have to match an official name such as that on your passport. The answer by Fabio Dias mentions ORCID. This is a good way to make sure that all the publications with different variants of a name are by the same person (and distinguish between two or more people with the same name).
This doesn't directly fix your problem of proving that you are the person who 'owns' that particularly ORCID. However, as part of the public information attached to an ORCID, you can include information such as employment, which would make that connection. Or a supervisor is likely to be a coauthor and probably one of your referees, so that also makes the connection.
