When your Sahaswara chakra is open, you become pure awareness. You are pure consciousness. You are constantly expanding in your one-ness with all that is. Like a ray of the sun, you are a part of that huge ball of energy that sends it forth and cannot exist without it, yet you are an individual expression of it.
So yes, this chakra exists. I am very aware of it as a portal for feeling the Divine One-ness. Combined with the Third Eye Chakra, which is the sixth spiritual energy center of the body, many revelations flow to and through us, turning us into bodies of light. The more open and clear we keep this chakra, the clearer becomes our inner peace and profound gratitude for Life.