sewing-life alchemist
whats an AATF
That's supposed to be AT Field, the AT being an acronym for "Absolute Terror" so "Absolute Terror Field". At the beginning of Neon Genesis Evangelion it's depicted as a physical barrier that Angels and the Evangelions themselves can erect around themselves, making them impervious to all conventional weapons save for the N2 bombs and mines (conventional explosives as powerful as a nuclear bomb sans the radiation and nuclear fallout thereof which is replaced by a strong electromagnetic pulse). Even then some Angels were capable of producing AT Fields that were completely resistant to the N2 weapons.
However, Neon Genesis Evangelion is also noted for being a philosophical series and psychological for that matter pertaining to one's self and
how one's self deals with their environment, how they view the world and most of all other people.
That said, later in the series, it is said that all beings possess an AT Field. It is the "wall" that we put around ourselves to protect us from the environment and how we see the world our own eyes (external reality) and other egos (other people's "self") and thus it supports the concept of an existence separate from others/another's existence. This is in turn the cause of loneliness and pain and can be related to what is called in Evangelion, "The Hedgehog's Delimma". It is when you feel loneliness and suffer from your choosing to isolate yourself from the world and the people who live in it, yet you do this because you know that peopl ALSO have the potential to hurt you. Like when you fall in love with someone and they break your heart.