public void setRotateSpeed(float rotateSpeed) {
        this.rotateSpeed = rotateSpeed;
    }
Set the rotation speed in radians/sec for particles
spawned after the invocation of this method.

@param rotateSpeed the rotation speed in radians/sec for particles
spawned after the invocation of this method.
jme3-core/src/main/java/com/jme3/effect/ParticleEmitter.java