It sounds like you want to play the effect on the player, but just higher up than the player's feet. Is that correct?
You could try spawning an invisible dummy object and playing the effect on that object instead of playing it on the player. You might have to create an invisible form in the CK for this purpose.
Disclaimer: I didn't test this and It's been a while since I wrote any papyrus code.
;generate an object based on your invisible form
ObjectReference tempObject = PlayerRef.PlaceAtMe(yourInvisibleForm)
;move the object to the player, 30 units below the player's head (might have to play with the exact number here)
tempObject.MoveTo(PlayerRef, 0.0, 0.0, PlayerRef.GetHeight() - 30.0)
;play your effect on the invisible object
yourVisualEffect.Play(tempObject)