This is the timing controller which specifies when the ignitor is "on", where what "on" means is Ignitor dependent.

Always Activator

Indicates that the Ignitor is always on. The Always activator node that corresponds to this option has no additional properties.

Pulse Activator

Allows the ignitor to be turned on for a user-specified duration during the simulation. The Pulse activator node corresponds to this option.

These are the volume shapes (selected from the Volume Shape manager under Tools) which represent the area or volume for the ignitor to "ignite", where "ignite" is dependent on the type of ignitor. Mesh cells which are contained within these volume shapes have their properties changed as specified by the ignitor when it is on.