Questions about The force awakens lightsaber VFX

Hello everyone

I'm a newbie but I have been following this form and Star Wars visual effects for years. My question is after seeing the force awakens trailer Kylo Ren's lightsaber effect appears to have that gyroscopic affect as seen in ANH. My question is are they using the same rotating reflective blade technique that they used in the original? Or they simply doing it the way they did in the prequel trilogy with digital rotoscoping?

 

Expect it to be completely digital. More reliable, easier to shoot, more design flexibility.

 

That and it looks nothing like the saber blades in ANH. Not even remotely... at least to me.

 

It appears to have a mist or exhaust fumes around the blades.

 

And I don't think this new lightsaber is the norm, I think it's only Kylo Ren's that will look like this. Possibly because it's because it's experimental.

 

It sounds like it crackles, which suggests that it is an unstable blade. While I know JJ is a fan of practical effects (which is why we love him, right?) I wouldn't expect something like the lightsaber blades (which, let's be honest, BARELY worked in ANH) to be using those nearly ancient techniques.

 

Will they be using the texallium prop blades as used in Revenge of the Sith or wood like in A New Hope?