The most basic aura is the personal space bubble.  If two personal space bubbles intersect (people are standing uncomfortably close to each other),they repel, and the people move apart.  The size and shape of this bubble can be modified: running or being important will make people give a person more space.  Social interaction in this model is bubbles pushing, merging, and popping each other.

Different moods or ways of interacting can be represented by different colors.  My list so far is hostility(red), command(yellow), persuasion(green), submission(blue), stealth, and kindness(pink).  Please suggest refinements to this list.

Stealthy aura just compresses the person's aura, so he interacts less with people around him.

Each person has multiple auras with different strengths, but only the strongest one or two are visible. 

Examples of interactions:

Bill draws a weapon, which projects a large hostile aura in front of him, repelling most people nearby.  Jane's outermost aura was hostile, so when Bill's aura hits hers, they clash, and Jane's aura pushes back until the two reach equilibrium.  To push Bill's aura back further, Jill can move forward, put more energy into hostility, or focus her hostility in one direction. If Bill's hostile aura is pushed back far enough to expose one of his other auras, his hostility is broken, and he's can't use it for some time.  He will behave according to the aura that was revealed.

The boss shouts, sending a pulse of commanding aura out,  When this aura hits one of his employees, that employee's aura is flipped to submissive.  The boss can now focus his commanding aura into a line, grab his employees with it, and move them around.