A.T. Field

Sachiel's A.T. Field can be seen when Evangelion Unit-01 comes in contact with it

Evangelion Unit-01 raising an A.T. Field, causing a slight blur (click for animation)

An A.T. Field (short for "Absolute Terror Field") is an invincible barrier which Angels can generate. Conventional weapons such as those used by the combined military forces of the United Nations are effectively useless in penetrating an A.T. Field. Essentially, the only thing that can penetrate an A.T. Field is another A.T. Field, such as those created by the Evangelions. The Evangelions can create AT Fields equal to those of the Angels because the Evas are created from the cloned genetic material of Angels.

Besides the Evas, the only "conventional" weapon which has even marginal effect on the Angels is the N² Mine. The most powerful bombs ever created, N² mines are the pinnacle of the United Nation's arsenal. Still, they have only been moderately effective at stunning several of the weaker Angels temporarily, but against some Angels with strong A.T. Fields, even multiple N² mines have failed to do any damage whatsoever. There was one other instance where an A.T. Field was breached without the use of the Evas, the fight against Ramiel. Although the usage of "conventional" in terms of a positron rifle is debatable, a positron rifle using the electricity of the entire power grid of Japan managed to pierce Ramiel's A.T. Field and destroy the Angel.

Later in the series, the Angel Kaworu Nagisa reveals that every living thing possesses an A.T. Field: Angels and Evangelions just have A.T. Fields so strong that they are easily detectable and can stop even physical attacks. "A.T. Fields" which regular humans generate are what literally holds individual beings' egos together, separating individuals. Ultimately this is the cause of loneliness and pain in the world, keeping individual people apart.

In the climax of The End of Evangelion, the Rei/Adam/Lilith hyper-being generates, along with the Mass Production Evangelions and Evangelion Unit-01, a massive "Anti A.T. Field" which neutralizes all A.T. Fields across the world, causing all of humanity to revert into the primordial soup of LCL, merging into a single super-organism in the climax of the Human Instrumentality Project.

Typically, A.T. Fields are invisible. A.T. Fields can interact with objects to cause them to move and is hypothesized that it is the source of some of the Angel's ability to levitate (most notably, Kaworu). When they are raised or when they interact with an object, a slight blur can be seen. In Episode 03, when Evangelion Unit-01 raises an A.T. Field, a slight blur can be seen momentarily. When the Spear of Longinus is pulled from the moon in Episode 26', the same blur can be seen momentarily. During the fight between Evangelion Unit-01 and Unit-02 (controlled by Kaworu) in Terminal Dogma, a momentary blur can be seen followed by the Nerv staff detecting an A.T. Field. Although they are invisible, A.T. Fields can be seen when they come in contact violently with something physical or with energy weapons, forming concentric octagonal yellow lines. This can be seen in Episode 02 when Evangelion Unit-01 collides with Sachiel's A.T. Field, in Episode 22, Arael's A.T. Field can be seen when it deflects a blast from a positron rifle. The blur caused by its physical manifestation and the visible yellow lines can also be seen in many other places throughout the series.

Notes

• The phrase "Absolute Terror Field" is never actually mentioned within the series itself. It only appears in the opening credits.
• Since the very earliest days of Evangelion analysis, there has been a rumor that A.T. Field is a genuine psychological term that describes the barrier that seperates autism patients from the world around them. However, extensive searching of online Psychology researches and forums has failed to find any use of the term other than in reference to NGE. Therefore, we have concluded that this rumor is false.
• Although when an A.T. Field is visible, it's usually concentric octagons. However, there are 2 instances where this is not the case. First, in Episode 06 when Nerv staff reviews an energy blast that deflects off of Ramiel's A.T. Field, it is seen as hexagons on the display, eventhough they were octagons earlier, this is a visual continuity error. The second instance is in Episode 13 when lasers were deflected by Iruel's A.T. Fields which were purple hexagons and were not concentric.