The seven layer model has a traceable history and a recent one. A layered subtle anatomy entered English language occultism through Theosophy in the late nineteenth and early twentieth centuries, in works such as Leadbeater's Man Visible and Invisible of 1902. The particular seven layer sequence in circulation today, with these names in this order, is later still: it was set out by Barbara Brennan in Hands of Light in 1987, and most contemporary aura charts descend from that book rather than from the Theosophical material behind it.
Mental Body. The Theosophical sources also carry a mental body, and here the modern layer is roughly continuous with the older one. The differences are of description rather than of existence, which makes this layer a useful control against the ones that were genuinely rearranged.
On testing, the record is short and it is worth stating plainly. No instrument has detected a layered field of this kind. Kirlian photography, often produced as evidence, images corona discharge from a high voltage field and responds to moisture and pressure rather than to anything vital. Kilner's 1911 dicyanin screen work was not replicated. The most direct test was published in JAMA in 1998, in which practitioners who said they could feel a human energy field were asked to say which of their hands one was near and were correct about as often as chance would predict. The atlas records this layer as a documented feature of a real modern tradition, and attributes the claim to that tradition rather than making it.
Sources Rainbow Body: A History of the Western Chakra System from Blavatsky to BrennanKurt Leland with A Close Look at Therapeutic TouchLinda Rosa, Emily Rosa, Larry Sarner and Stephen Barrett, The Skeptic's Dictionary: A Collection of Strange Beliefs, Amusing Deceptions, and Dangerous DelusionsRobert Todd Carroll