How is "being in a flow" explained cognitively? When wathcing the European Championship athletics, I hear many people talking about being in a "flow". Flow is defined as follows:


  Flow is an optimal psychological state that occurs when there is a balance between perceived challenges and skills in an activity (Csikszentmihalyi, 1990). It is a state of concentration so focused that it amounts to absolute absorption in an activity. 1


This sound nice, but to me it is still a quite abstract definition and it is not really clear to me how being in a flow works. Is there a more low level (cognitive) explanation of being in a flow? 

I thought that this paper could shine some light on the subject, but I am unable to access it.
There is a six-step breakdown of 'the flow' or 'zone' from it's creator Mihály Csíkszentmihályi


  
  Intense and focused concentration on the present moment
  Merging of action and awareness
  A loss of reflective self-consciousness
  A sense of personal control or agency over the situation or activity
  A distortion of temporal experience
  Experience of the activity as intrinsically rewarding, also referred to as autotelic experience
  


Which can be found from his website

There's also a photo available that denotes when flow would be considered achieved. (Upper Right)



For even easier understanding, an example of the six steps in order from my personal life, 


When implementing or working on a new project in Excel/VBA (Work I'm very comfortable with) I usually start with music to block out distractions and assist in focusing.
As my process moves on I'm no longer able to hear the music, though it's still on. My brain is queuing next lines of code to test and my fingers are an output.
I'm less focused on mistakes, mishaps, meetings, or just general things on my plate. My only issue is my task-at-hand
I am the author and implementation. The code is mine. It's finished when I am.
In deep focus, a day that started at 9am and feels like may be 10am is actually closer to 1pm... and I should eat.
Every proper step IS rewarding, I'm challenging myself with a problem and completing work.