ooh... so THAT'S what explosionSphere1 is for!
No. It's the 3D expanding white sphere you see when a rocket hits something.
And you can't model it, you have to script the parameters in, kind of like a brick. You need to create a bounding box for the emitter or some such to treat the emitterNode like an emitterObject (like a brick for instance).
Class reference,
http://iam.colum.edu/students/RBatten/torqueDoxygen/classParticleEmitter.html#388c5c771e34e590e3b2c33069b8362fIt is hugely complicated and I don't advise trying to do something like shape a mushroom cloud explosion using this system. Unless you want to overwrite the particle emitter functions for something or add your own new parameters don't even bother. To my knowledge no one has ever played with these special functions for Blockland either so I can't confirm whether we can even access them.
You'll have a much easier time simply scripting the projectile to create a new z-axis projectile that fires upwards "onCollision" or "explosion" or something, which could create the stem and huge mushroom cloud with explodeOnDeath.