can someone explain this paragraph in easy way.i have presentation and maybe The Dr, will ask me a question about this paragraph

The revolutionary characteristic of a gasdynamic laser is that, unlike early electric discharge lasers with their attendant problems of arc discharges in huge volumes, gasdynamic lasers may be built up to large sizes without significant physical complications. Population inversions are caused by simply thermal processes within the supersonic expansion, and such gasdynamic processes are independent of the supersonic flow's lateral extent