That can just be a visual representation for Riolu sensing Satoshi's spirit through aura, not him literally sending off energy waves.
Look, obviously you guys who are invested into the whole aura idea will want to interpret this as your ideal scenario and that's fine, just rationally speaking it doesn't seem like they're going anywhere with it so don't get your hopes too high, it might just be a nod.
Well, since it haven't been clarified yet, but it could go either way aka., it could hint with Ash having Aura or not having it.
This would all become clear if Riolu later on is only able to sense something from Ash, or if he is also able to sense the "spirit" of other trainers or not. If he is able to sense the "spirit" from other trainers as well, then that mean Ash probably doesn't have Aura, if Ash is the only one from whom Riolu could sense it, then its something different and definitely not just "Spirit".
Remember, it has been already mentioned before (during DP and the Lucario Movie), that while Ash's Aura is similar to the one that the Riolu/Lucario species uses, but Ash can't use that Aura normally (like Aaron and Riley could) and can only sense it.
So, whether Ash has it or not, it doesn't really matter in this current series, since Ash isn't going to become an "Aura Guardian". Its just that people are checking if there is any continuity or not from earlier Sagas.