Aura is a radiation.,an awareness field.,like a persanol rainbow.,.,
i have seen people glow.,.,very white type of light.,.
,i bet you have a beautifull aura+

any object that has electricity moving about along with thermal energy etc will have an electromagnetic field.
if you put iron filings around a magnet the iron filings will react to hte very strong electromagnetic field there.
at it's most basic level, the aura is a representation of your body's EM field.
it depends on your beliefs though if you want to take it further.
I would say that the em aura is the most basic level of the auric field. if you go up a level you will find the etheric body and then the spirit body.
the way i view it, this is actually stepping up into higher dimensions. these higher dimensions are given names, the one above ours is teh astral plane and above that is heaven. there are other names for them as well.

to summarise and also elaborate. the aura is a energy field that extends out of your body. it reacts to you and your surroundings.
the vibration of it will produce the sensation of colour in auric field photography and also in those who can 'see' the aura.
the vibration of it will be able to suggest things that are going on in your emotions, your physical body and in your spiritual body as well.