Balloon

The balloon boundary is available for use in Magnetostatic, Eddy Current, Transient, Electrostatic, AC Conduction, and DC Conduction solver type designs. Balloon boundaries model the region outside the drawing space as being nearly “infinitely” large – effectively isolating the model from other sources of current or magnetic fields. Visualize the background object as extending to infinity along the edges identified as balloon boundaries.

For magnetic solution types, the magnetic vector potential, A_Z or A_F, goes to zero at infinity. The lines of magnetic flux are neither tangential to nor normal to a balloon boundary.

For electric field solution types, two types of balloon boundaries are available:

Charge	Models the case where the charge at infinity matches the charge in the solution region, forcing the net charge to be zero. Physically, this represents an electrically insulated system. This is the default for Electrostatic solutions.
Voltage	Models the case where the voltage at infinity is zero. Physically, this represents an electrically grounded system. In most cases, the results will be very similar to those produced with the Charge option; however, the charge at infinity may not exactly match the charge in the drawing region.

The E-field is neither tangential to nor normal to a balloon boundary.

Note: The Balloon boundary condition creates a background geometry that can be used in the Fields Calculator. See Fields Calculator's Geometry Command for more details.