Harry and wandless magic

[earendil_fr]

No: HPFGUIDX 96678

I suppose this has been discussed before, but after searching 
thousands of posts in the archives I didn't find anything, apart 
from the interesting thread labeled "Underage magic enforcement" 
(starting post #94458), but nothing about this exact passage. So I 
decided to post this anyway.

As I started re-reading OotP yesterday, something that I hadn't paid 
attention to the first time struck me in the first chapter. It's in 
the scene where Vernon Dursley catches (quite literally) Harry 
listening to the news outside.

(OotP, UK ed., p10)
'Get - off - me!' Harry gasped. For a few seconds they struggled, 
Harry pulling at his uncle's sausage-like fingers with his left 
hand, his right maintaining a firm grip on his raised wand; then, as 
the pain in the top of Harry's head gave a particulary nasty throb, 
Uncle Vernon yelped and released Harry as though he had received an 
electric shock. Some invisible force seemed to have surged through 
his nephew, making him impossible to hold.


To me, it sounds suspiciously like wandless magic (even if Harry was 
holding his wand at the moment, he didn't seem to use it). I know 
it's not the first time Harry performs some (during his childhood, 
against his Aunt Marge), but this one looks quite odd to me.

First, the phrasing. While it's a defensive reflex because Vernon is 
strangling him, it looks as if the nasty throb is what eventually 
provokes the unconscious use of wandless magic. A throb *in the top 
of Harry's head*. Could it be connected to his scar/protection 
somehow? (even if up till now I had always thought the throb was 
solely due to the strangling)

Now about Underage Magic. Why didn't Harry recieve any warning 
letter from the Ministry after this use of wandless magic, since 
they *can* and *do* trace it? (Dobby in CoS, Harry in PoA) Unless 
it's not really wandless magic and instead it's somehow due to his 
scar/protection as I suggested above? Or was the Ministry way too 
busy with other and more important concerns?

BTW, have we ever actually heard of any other wizard performing 
wandless magic? And by wizard I mean no house elves or fantastic 
beasts (who can't own a wand anyway). The only thing I can recall is 
that wizards/witches children frequently show the magic in them 
early in their lives by the uncounscious use of wandless magic. 
(e.g. Neville bouncing on the ground when his great-uncle pushed him 
from the window)

But what about grown wizards? Can they actually use wandless magic, 
an unconscious expression of magic, now that their knowledge/use of 
magic is so much more... well, mastered and conscious? Take Harry 
for example. As a child he used wandless magic (without knowing it 
of course) on several occasions (growing his hair back, etc). But 
after he learned he was a wizard and got a wand, it seems his use of 
wandless magic is getting scarce (twice in 5 years, but I could be 
forgetting something)


Now about wandless magic in general. I'd be curious to know how much
of wandless magic a wizard can perform. And especially how powerful 
it can be, being so... uncontrolable and unpredictable. But I'm 
quite sure I'm forgetting some mentions of wandless magic.


Earendil, confused.