It’s a green lantern’s ring getting powered up. Whenever a new GL is made/assigned (or it runs out of juice), it needs to be powered. The big lantern powers the little ring and when you 1st use it (and need a recharge), you need to power it.
Green Lanterns are normal people that are ‘chosen’, so instead of the job you were doing, you’re now a GL. A new beginning. And a hell of a job promotion.
At least that is what I was going for, obviously it didn’t get across
From the wiki page:
Originally Green Lantern power rings typically held a limited charge. In earlier appearances, they required recharging every twenty-four hours, but more recently they possess a fixed amount of regular charge: that is, the charge is good for twenty-four hours of ‘typical’ use, but extended or extensive use will drain the charge more quickly. Green Lantern rings typically reserve a small portion of their power for a passive force field that protects its wielder from mortal harm. In dire emergencies, that energy reserve can be tapped at the expense of said protection. Power rings are usually recharged by a Green Lantern’s personal battery, which looks like an old fashioned lantern made of dark green metal. The user typically points the ring towards the lantern, and usually gives the Green Lantern oath (below) while recharging the ring. These batteries are directly linked to the Central Power Battery on Oa and do not themselves need recharging.