It’s where incoming charged particles and plasma from the rest of the universe collide with the solar wind - on one side the “wind” (charged particles emitted by the sun) heading away from our sun and pushing everything away and on the other incoming particles where our wind isn’t strong enough anymore to overpower them. The firewall is the “boundary”. It’s not literally a wall of fire, it’s not literally wind, it’s not literally pushing away all other particles (some have energies that can overcome the solar wind and some aren’t charged), and it’s not a discrete boundary but more a region of space.
Space is filled with euphemistic language to try to help build mental models of reality that we actually have 0 experience with and can’t really observe but kind of act like things we do know intuitively.
> also where I can study these stuff
Well I got this link by googling “solar firewall” and it’s literally the first link. Improving your self empowerment and willpower to look up trivially accessible information yourself is step #1. There’s also a small up and coming website called Wikipedia that I’ve heard contains information you can go read and contains links to dig deep even further. There’s also plenty of YouTube personalities that devote their channel to “these stuff” that can give you intro-level perspectives as they target a lay audience (eg Neil deGrasse Tyson).
Its past the influence of our sun. At least as measured by the on board tec of the time. Sort of out in the void between the stars but at these distances just barely out.
