I mean in my opinion, you can spend a lot of time trying to make that EXACT sound and not be able to do it and just be frustrated, or you can dissect it to the point where you can do something super similar, just maybe not exact.

Honestly it sounds like a sample that just has a ton of reverb on it, sidechained to a ghost trigger with maybe a white noise layer thrown in there. Could just be a really bright reverb too with no white noise. If you were to get a saw wave, add an amp,  and just various types of distortion, and then just play around with some higher octaves, I'm sure you could sample it, make a kind of one shot with it, then add a ton of reverb to it and get a similar sound. Or just find a cool sample.

Sounds like he just found and or made a cool sample, threw some reverb on it, side chained it, and then called it a day. Hope that helps a little bit! maybe someone else on here will know exactly what that sound was!

What is it you're trying to recreate, the way the tone alternates every half beat so that it sounds more open/higher on the off-beat?

Well, what I've done to try and recreate it is just use white noise with a ton of reverb on it sidechained to a ghost trigger but it's not nearly as loud and echo-y as it is in the example. 

I've heard this same kind of effect with a ton of other trance/ prog trance songs, especially under Anjuna's label but can't really seem to properly recreate it.